LOCKHEED MARTIN CORP
S-8, 1995-03-15
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<PAGE>
 
    As filed with the Securities and Exchange Commission on March 15, 1995.
                                                     Registration No. 33-
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549

                              --------------------

                                    FORM S-8

                             REGISTRATION STATEMENT
                                     Under
                           THE SECURITIES ACT OF 1933

                              --------------------

                          LOCKHEED MARTIN CORPORATION
             (Exact name of registrant as specified in its charter)


          Maryland                                       52-1893632
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
incorporation or organization)


                              6801 Rockledge Drive
                            Bethesda, Maryland 20817
                    (Address of principal executive offices)

                              --------------------

                      Martin Marietta Energy Systems, Inc.
                   401(k) Savings Plan for Salaried Employees
                      Martin Marietta Energy Systems, Inc.
                    401(k) Savings Plan for Hourly Employees
                      Martin Marietta Energy Systems, Inc.
                 Savings Plan for Salaried and Hourly Employees
                            (Full title of the plan)

                              --------------------

                           Stephen M. Piper, Esquire
                           Assistant General Counsel
                          Lockheed Martin Corporation
                              6801 Rockledge Drive
                            Bethesda, Maryland 20817
                                 (301) 897-6000
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)

                              --------------------

                        CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------------------------------
                                             Proposed           Proposed
                                              maximum           maximum
Title of securities       Amount to be    offering price       aggregate            Amount of
to be registered          registered(*)    per share(**)   offering price(**)  registration fee(**)
- ---------------------------------------------------------------------------------------------------
<S>                       <C>              <C>              <C>                 <C> 
Common Stock, par
value $1.00 per share...       475,772     $26.52           $12,617,473.44      $4,350.88 
</TABLE>
- --------------------------------------------------------------------------------
(*)  In addition, pursuant to Rule 416(c) under the Securities Act of 1933, this
     Registration Statement also covers an indeterminate amount of plan
     interests to be offered or sold pursuant to the plans to which this
     Registration Statement relates.

(**) At the time of the filing of this Registration Statement on Form S-8, there
     is no market for the Registrant's securities to be offered.  Accordingly,
     the fee has been computed, pursuant to Rule 457(h)(1) and guidance provided
     by the Office of Chief Counsel, based on the book value of the securities
     to be offered as of December 31, 1994.

- --------------------------------------------------------------------------------
<PAGE>
 
                                    PART II

              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


Item 3.   Incorporation of Documents by Reference.
          --------------------------------------- 

     The following documents filed by the Registrant, Martin Marietta
Corporation, Lockheed Corporation or the Plans with the Securities and Exchange
Commission (the "Commission") are incorporated by reference and made a part
hereof:

          (a) The Registrant's Joint Proxy Statement/Prospectus filed pursuant
to Registration Statement No. 33-57645 on Form S-4 filed with the Commission on
February 9, 1995;

          (b) The description of the Registrant's Common Stock contained in the
Registrant's Registration Statement on Form 8-B filed with the Commission
pursuant to Section 12 of the Securities Exchange Act of 1934 (the "Exchange
Act") (as amended on Form 8-B/A filed on March 9, 1995), and any amendment or
report filed for the purpose of updating such description;

          (c) Martin Marietta Corporation's Current Report on Form 8-K filed
with the Commission on February 13, 1995;

          (d) Martin Marietta Corporation's Current Report on Form 8-K filed
with the Commission on February 17, 1995;

          (e) Lockheed Corporation's Current Report on Form 8-K filed with the
Commission on February 21, 1995;

          (f) The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Salaried Employees Annual Report on Form 11-K for the year ended December 31,
1993 filed with the Commission on June 29, 1994;

          (g) The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Hourly Employees Annual Report on Form 11-K for the year ended December 31, 1993
filed with the Commission on June 29, 1994;

          (h) The Martin Marietta Energy Systems, Inc.  Savings Plan for
Salaried and Hourly Employees Annual Report on Form 11-K for the year ended
December 31, 1993 filed with the Commission on June 29, 1994; and

          (i) The Registrant's Current Report on Form 8-K filed with the
Commission on March 15, 1995.


     All documents subsequently filed by the Registrant, Martin Marietta 
Corporation, Lockheed Corporation or the Plans pursuant to Sections 13(a),
13(c), 14 or 15(d) of the Exchange Act prior to
<PAGE>
 
filing of a post-effective amendment which indicates that all securities offered
have been sold or which deregisters all securities then remaining unsold, shall
be deemed to be incorporated by reference into this Registration Statement and
to be a part hereof from the date of the filing of such documents.


Item 4.   Description of Securities.
          ------------------------- 

     Not Applicable


Item 5.   Interests of Named Experts and Counsel.
          -------------------------------------- 

     The Opinion of Counsel as to the legality of the securities being issued
(constituting Exhibit 5) has been rendered by counsel who is a full-time
employee of the Registrant. Counsel rendering such opinion is not eligible to
participate in the Plans.

Item 6.   Indemnification of Directors and Officers.
          ----------------------------------------- 

     The Maryland General Corporation Law authorizes Maryland corporations to
limit the liability of directors and officers to the corporation or its
stockholders for money damages, except (a) to the extent that it is proved that
the person actually received an improper benefit or profit in money, property or
services, for the amount of the benefit or profit in money, property or services
actually received, (b) to the extent that a judgment or other final adjudication
adverse to the person is entered in a proceeding based on a finding that the
person's action or failure to act was the result of active and deliberate
dishonesty and was material to the cause of action adjudicated in the proceeding
or (c) in respect of certain other actions not applicable to the Registrant.
Under the Maryland General Corporation Law, unless limited by charter,
indemnification is mandatory if a director or an officer has been successful on
the merits or otherwise in the defense of any proceeding by reason of his or her
service as a director unless such indemnification is not otherwise permitted as
described in the following sentence. Indemnification is permissive unless it is
established that (a) the act or omission of the director was material to the
matter giving rise to the proceeding and was committed in bad faith or was the
result of active and deliberate dishonesty, (b) the director actually received
an improper personal benefit in money, property or services or (c) in the case
of any criminal proceeding, the director had reasonable cause to believe his or
her act or omission was unlawful. In addition to the foregoing, a court of
appropriate jurisdiction may under certain circumstances order indemnification
if it determines that the director or officer is fairly and reasonably entitled
to indemnification in view of all the relevant circumstances, whether or not the
director or officer has met the standards of conduct set forth in the preceding
sentence or has been adjudged liable on the basis that a personal benefit was
improperly received in a

                                      -2-
<PAGE>
 
proceeding charging improper personal benefit to the director or officer.  If
the proceeding was an action by or in the right of the corporation or involved a
determination that the director or officer received an improper personal
benefit, however, no indemnification may be made if the individual is adjudged
liable to the corporation, except to the extent of expenses approved by a court
of competent jurisdiction.

     Article XI of the charter of the Registrant limits the liability of
directors and officers to the fullest extent permitted by the Maryland General
Corporation Law. Article XI of the charter of the Registrant also authorizes the
Registrant to adopt by-laws or resolutions to provide for the indemnification of
directors and officers. Article VI of the By-laws of the Registrant provides for
the indemnification of the Registrant's directors and officers to the fullest
extent permitted by the Maryland General Corporation Law. In addition, the
Registrant's directors and officers are covered by certain insurance policies
maintained by the Registrant.


Item 7.   Exemption from Registration Claimed.
          ----------------------------------- 

     Not Applicable


Item 8.   Exhibits.
          -------- 

   4-A.   Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for Salaried
          Employees.

   4-B.   Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for Hourly
          Employees.

   4-C.   Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and
          Hourly Employees.

   4-D.   First Amendment to the Martin Marietta Energy Systems, Inc. 401(k) 
          Savings Plan for Salaried Employees.

   4-E.   Second Amendment to the Martin Marietta Energy Systems, Inc. 401(k) 
          Savings Plan for Salaried Employees.

   4-F.   Third Amendment to the Martin Marietta Energy Systems, Inc. 401(k)
          Savings Plan for Salaried Employees. 
 
   4-G.   Fourth Amendment to the Martin Marietta Energy Systems, Inc. 401(k)
          Savings Plan for Salaried Employees.   

   4-H.   Fifth Amendment to the Martin Marietta Energy Systems, Inc. 401(k)
          Savings Plan for Salaried Employees.   

   4-I.   First Amendment to the Martin Marietta Energy Systems, Inc. 401(k)
          Savings Plan for Hourly Employees.   

   4-J.   Second Amendment to the Martin Marietta Energy Systems, Inc. 401(k)
          Savings Plan for Hourly Employees.

   4-K.   Third Amendment to the Martin Marietta Energy Systems, Inc. 401(k)
          Savings Plan for Hourly Employees.

   4-L.   Fourth Amendment of the Martin Marietta Energy Systems, Inc. 401(k)
          Savings Plan for Hourly Employees.

   4-M.   Fifth Amendment to the Martin Marietta Energy Systems, Inc. 401(k)
          Plan for Hourly Employees.
          
   4-N.   First Amendment to the Martin Marietta Energy Systems, Inc. Savings
          Plan for Salaried and Hourly Employees.

   4-O.   Second Amendment to the Martin Marietta Savings Plan for Salaried and
          Hourly Employees.

   4-P.   Third Amendment to the Martin Marietta Energy Systems, Inc. Savings
          Plan for Salaried and Hourly Employees.

   4-Q.   Fourth Amendment of the Savings Plan for Salaried and Hourly Employees
          of Martin Marietta Energy Systems, Inc.

   4-R.   Fifth Amendment to the Martin Marietta Energy Systems, Inc. Savings
          Plan for Salaried and Hourly Employees.

     5.   Opinion of Stephen M. Piper, Esquire

  23-A.   Consent of Ernst & Young LLP (Washington, D.C.).

  23-B.   Consent of Ernst & Young LLP (Los Angeles, CA).

  23-C.   Consent of KPMG Peat Marwick LLP.

  23-D.   Consent of Arthur Andersen LLP.

  23-E.   Consent of Stephen M. Piper, Esquire (contained in Exhibit 5 hereof).

    25.   Powers of Attorney (included as an exhibit to a Registration Statement
          on Form S-8 relating to Lockheed Martin Corporation Directors Deferred
          Stock Plan filed by the Registrant with the Commission on March 15,
          1995 and incorporated herein by reference).

                                      -3-
<PAGE>
 
     The Registrant hereby undertakes that the Registrant will submit or has
submitted the Plans and any amendment thereto to the Internal Revenue Service
("IRS") in a timely manner and has made or will make all changes required by the
IRS in order to qualify the Plans.


Item 9.   Undertakings.
          ------------ 

     (a) The undersigned Registrant hereby undertakes:

         (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

           (i) To include any prospectus required by section 10(a)(3) of the
Securities Act of 1933;

          (ii) To reflect in the prospectus any facts or events arising after
the effective date of the registration statement (or the most recent post-
effective amendment thereof) which, individually or in the aggregate, represent
a fundamental change in the information set forth in the registration statement;

         (iii) To include any material information with respect to the plan of
distribution not previously disclosed in the registration statement or any
material change to such information in the registration statement;

     Provided, however, that subparagraphs (1)(i) and (1)(ii) do not apply if
the information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed by the Registrant pursuant to
section 13 or section 15(d) of the Securities Exchange Act of 1934 that are
incorporated by reference in the registration statement.

         (2) That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

     (b) The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Registrant's annual report pursuant to section 13(a) or section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the

                                      -4-
<PAGE>
 
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore, unenforceable.  In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.

                                      -5-
<PAGE>
 
                                  SIGNATURES


     Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the County of Montgomery, State of Maryland.

                          LOCKHEED MARTIN CORPORATION

Date:  March 15, 1995                     By:  /s/ Frank H. Menaker, Jr.
                                               -------------------------
                                                   Frank H. Menaker, Jr.
                                                   Vice President and
                                                   General Counsel


     Pursuant to the requirements of the Securities Act of 1933, the trustees
(or other persons who administer the Plans) have duly caused this registration
statement to be signed on their behalfs by the undersigned, thereunto duly
authorized, in the County of Anderson, State of Tennessee.

Date:  March 15, 1995                     MARTIN MARIETTA ENERGY SYSTEMS, INC.
                                          401(k) SAVINGS PLAN FOR
                                          SALARIED EMPLOYEES

                                          By:  /s/ Norman E. Sparks
                                                   ----------------
                                                   Norman E. Sparks
                                                   Director--Employee Benefits
                                                   Martin Marietta Energy
                                                   Systems, Inc.

Date:  March 15, 1995                     MARTIN MARIETTA ENERGY SYSTEMS, INC.
                                          401(k) SAVINGS PLAN FOR
                                          HOURLY EMPLOYEES

                                          By:  /s/ Norman E. Sparks
                                                   ----------------
                                                   Norman E. Sparks
                                                   Director--Employee Benefits
                                                   Martin Marietta Energy
                                                   Systems, Inc.
<PAGE>
 
Date:  March 15, 1995                     MARTIN MARIETTA ENERGY SYSTEMS, INC.
                                          SAVINGS PLAN FOR SALARIED AND
                                          HOURLY EMPLOYEES

                                          By:  /s/ Norman E. Sparks
                                                   ----------------
                                                   Norman E. Sparks
                                                   Director--Employee Benefits
                                                   Martin Marietta Energy
                                                   Systems, Inc.


     Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed below by the following persons in the
capacities and on the date indicated.

<TABLE>
<CAPTION>
     Signature                   Title                     Date
     ---------                   -----                     ----
<C>                              <S>                       <C>  
/s/  Daniel M. Tellep            Chairman of the           March 15, 1995
     ----------------            Board and Chief
     Daniel M. Tellep*           Executive Officer
                                 and Director
 
/s/  Marcus C. Bennett           Senior Vice               March 15, 1995
     -----------------           President, Chief
     Marcus C. Bennett*          Financial Officer
                                 and Director
 
/s/  Robert E. Rulon             Controller and Chief      March 15, 1995
     ---------------             Accounting Officer
     Robert E. Rulon*                 
 
/s/  Norman R. Augustine         Director                  March 15, 1995
     -------------------
     Norman R. Augustine*
 
/s/  Lynne V. Cheney             Director                  March 15, 1995
     ---------------
     Lynne V. Cheney*
 
/s/  Edwin I. Colodny            Director                  March 15, 1995
     ----------------
     Edwin I. Colodny*
 
/s/  Lodwrick M. Cook            Director                  March 15, 1995
     ----------------
     Lodwrick M. Cook*
 
/s/  James L. Everett, III       Director                  March 15, 1995
     ---------------------
     James L. Everett, III*
 
/s/  Houston I. Flournoy         Director                  March 15, 1995
     -------------------
     Houston I. Flournoy*
</TABLE>
<PAGE>
 
<TABLE>
<CAPTION>
     Signature                   Title                     Date
     ---------                   -----                     ----
<C>                              <S>                       <C>  
/s/  James F. Gibbons            Director                  March 15, 1995
     ----------------
     James F. Gibbons*
 
/s/  Edward E. Hood, Jr.         Director                  March 15, 1995
     -------------------
     Edward E. Hood, Jr.*
 
/s/  Caleb B. Hurtt              Director                  March 15, 1995
     --------------
     Caleb B. Hurtt*
 
/s/  Gwendolyn S. King           Director                  March 15, 1995
     -----------------
     Gwendolyn S. King*
 
/s/  Lawrence O. Kitchen         Director                  March 15, 1995
     -------------------
     Lawrence O. Kitchen*
 
/s/  Gordon S. Macklin           Director                  March 15, 1995
     -----------------
     Gordon S. Macklin*
 
/s/  Vincent N. Marafino         Director                  March 15, 1995
     -------------------
     Vincent N. Marafino*
 
/s/  Eugene F. Murphy            Director                  March 15, 1995
     ----------------
     Eugene F. Murphy*
 
/s/  Allen E. Murray             Director                  March 15, 1995
     ---------------
     Allen E. Murray*
 
/s/  Frank Savage                Director                  March 15, 1995
     ------------
     Frank Savage*
 
/s/  Carlisle A.H. Trost         Director                  March 15, 1995
     -------------------
     Carlisle A.H. Trost*
 
/s/  James R. Ukropina           Director                  March 15, 1995
     -----------------
     James R. Ukropina*
</TABLE> 
 
                 *By:  /s/ Stephen M. Piper                March 15, 1995
                           ----------------
                          (Stephen M. Piper, Attorney-in-fact**)

- --------------------

     **By authority of Powers of Attorney filed with this Registration
       Statement on Form S-8
<PAGE>
 
                                 EXHIBIT INDEX
<TABLE> 
<CAPTION> 
     Exhibit                                                       Page
     Number                   Description                           No.
     ------                   -----------                          ----
        <S>      <C>                                               <C> 
        4-A.     Martin Marietta Energy Systems, Inc. 401(k) 
                 Savings Plan for Salaried Employees.

        4-B.     Martin Marietta Energy Systems, Inc. 401(k) 
                 Savings Plan for Hourly Employees.

        4-C.     Martin Marietta Energy Systems, Inc. Savings 
                 Plan for Salaried and Hourly Employees.

        4-D.     First Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Salaried 
                 Employees.

        4-E.     Second Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Salaried 
                 Employees.

        4-F.     Third Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Salaried 
                 Employees. 
 
        4-G.     Fourth Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Salaried 
                 Employees.   

        4-H.     Fifth Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Salaried 
                 Employees.   

        4-I.     First Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Hourly 
                 Employees.   

        4-J.     Second Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Hourly 
                 Employees.

        4-K.     Third Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Hourly 
                 Employees.

        4-L.     Fourth Amendment of the Martin Marietta Energy 
                 Systems, Inc. 401(k) Savings Plan for Hourly 
                 Employees.

        4-M.     Fifth Amendment to the Martin Marietta Energy 
                 Systems, Inc. 401(k) Plan for Hourly Employees.
        
        4-N.     First Amendment to the Martin Marietta Energy 
                 Systems, Inc. Savings Plan for Salaried and Hourly 
                 Employees.

        4-O.     Second Amendment to the Martin Marietta Savings 
                 Plan for Salaried and Hourly Employees.

        4-P.     Third Amendment to the Martin Marietta Energy 
                 Systems, Inc. Savings Plan for Salaried and Hourly 
                 Employees.

        4-Q.     Fourth Amendment of the Savings Plan for Salaried 
                 and Hourly Employees of Martin Marietta Energy 
                 Systems, Inc.

        4-R.     Fifth Amendment to the Martin Marietta Energy 
                 Systems, Inc. Savings Plan for Salaried and 
                 Hourly Employees.

          5.     Opinion of Stephen M. Piper, Esquire

       23-A.     Consent of Ernst & Young LLP (Washington, D.C.).

       23-B.     Consent of Ernst & Young LLP (Los Angeles, CA).

       23-C.     Consent of KPMG Peat Marwick LLP.

       23-D.     Consent of Arthur Andersen LLP.

       23-E.     Consent of Stephen M. Piper, Esquire 
                 (contained in Exhibit 5 hereof).

         25.     Powers of Attorney (included as an exhibit to 
                 a Registration Statement on Form S-8 relating 
                 to Lockheed Martin Corporation Directors Deferred 
                 Stock Plan filed by the Registrant with the
                 Commission on March 15, 1995 and incorporated 
                 herein by reference).
</TABLE> 

<PAGE>

                                                                     EXHIBIT 4-A
 
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.

                   401(k) SAVINGS PLAN FOR SALARIED EMPLOYEES

                            Effective April 1, 1984



                   (Amended and Restated as of April 1, 1990)
<PAGE>
 
                               TABLE OF CONTENTS
                               -----------------

                                                                            Page
                                                                            ----
ARTICLE I
DEFINITIONS.................................................................   1
1.   Definitions                                                               1
     1.1     "Additional Contribution.......................................   1
     1.2     "Affiliate.....................................................   1
     1.3     "Before Tax Contribution.......................................   1
     1.4     "Beneficiary...................................................   1
     1.5     "Code..........................................................   1
     1.6     "Committee.....................................................   1
     1.7     "Company.......................................................   2
     1.8     "Company Contribution..........................................   2
     1.9     "Company Service Credit........................................   2
     1.10    "Compensation..................................................   2
     1.11    "Credited Service..............................................   2
     1.12    "Disability....................................................   2
     1.13    "Earnings......................................................   2
     1.14    "Eligible Employee.............................................   3
     1.15    "Employee......................................................   3
     1.16    "ERISA.........................................................   3
     1.17    "Highly Compensated Employee...................................   4
     1.18    "Normal Retirement Date........................................   4
     1.19    "Participant...................................................   4
     1.20    "Personal Investment Account...................................   4
     1.21    "Plan..........................................................   4
     1.22    "Plan Year.....................................................   5
     1.23    "Savings Plan..................................................   5
     1.24    "Tax Deferred Account..........................................   5
     1.25    "Termination of Employment.....................................   5
     1.26    "Trust Agreement...............................................   5
     1.27    "Trust Fund....................................................   5
     1.28    "Trustee.......................................................   5
     1.29    "Valuation Date................................................   5

ARTICLE II
PARTICIPATION, CONTRIBUTIONS AND
 VESTING....................................................................   6
     2.1     Participation..................................................   6
     2.2     Exclusions.....................................................   6
     2.3     Before Tax Contributions.......................................   8
     2.4     Adjustment of Before Tax Contributions.........................   8
     2.5     Company Contributions..........................................  10
<PAGE>
 
     2.6     Additional Contributions.......................................  11
     2.7     Transfers from the Savings Plan................................  12
     2.8     Change from Eligible Employee to Ineligible Employee and
              from Ineligible Employee to Eligible Employee.................  13
     2.9     Revocation of Compensation Reduction...........................  14
     2.10    Limitations on Contributions...................................  14
     2.11    Vesting........................................................  15

     2.12    Limitations on Before Tax Contributions and Additional
              Contributions.................................................  15
     2.13    401(m) Limitations.............................................  15

ARTICLE III
INVESTMENT AND VALUATION OF TAX DEFERRED ACCOUNTS...........................  17
     3.1     General........................................................  17
     3.2     Investment Options.............................................  17
     3.3     Union Carbide Corporation Stock Fund...........................  18
     3.4     Investment Manager.............................................  19
     3.5     Change of Investments..........................................  19
     3.6     Special Rules for Company Officers.............................  20
     3.7     Dividends......................................................  20
     3.8     Rights, Warrants and Scrip.....................................  21
     3.9     Instructions By a Participant For His/Her Tax Deferred
              Account.......................................................  21
     3.10    Purchases and Sales............................................  21
     3.11    Costs and Expenses.............................................  22
     3.12    Custody of Securities..........................................  22
     3.13    Voting Rights..................................................  23
     3.14    Valuation of Tax Deferred Accounts.............................  23
     3.15    Statements Furnished Participants..............................  25

ARTICLE IV
DISTRIBUTIONS, WITHDRAWALS AND LOANS........................................  26
     4.1     Distribution on Termination of Employment......................  26
     4.2     Rehire Prior to Distribution...................................  34
     4.3     Commencement of Benefits.......................................  34
     4.4     Withdrawal by Participant During Employment....................  34
     4.5     Loans..........................................................  37

ARTICLE V

LIMITATION ON MAXIMUM CONTRIBUTIONS BENEFITS UNDER ALL PLANS................  40
     5.1     General........................................................  40
     5.2     Affiliate......................................................  40
     5.3     Limitation Year................................................  40
     5.4     Annual Additions...............................................  40
     5.5     Defined Benefit and Defined Contribution Plans.................  41
     5.6     Aggregation of Defined Contribution Plans......................  41
     5.7     Defined Contribution Plan Limitation...........................  41

                                      ii
<PAGE>
 
     5.8     Defined Contribution Plan Fraction Determination...............  42
     5.9     Defined Benefit Plan Fraction Determination....................  43
     5.10    Combined Limitation............................................  43
     5.11    Alternative Method.............................................  43
     5.12    Participation in Multiple Plans................................  44
     5.13    Notice of Reduction............................................  45

ARTICLE VI
TOP-HEAVY RULES.............................................................  46
     6.1     Top-Heavy Plan.................................................  46
     6.2     Minimum Top-Heavy Benefits.....................................  48
     6.3     Reduction in Combined Limitation...............................  48
     6.4     Key Employee...................................................  48
     6.5     Automatic Removal..............................................  49

ARTICLE VII
TRUST.......................................................................  50
     7.1     Trustee........................................................  50
     7.2     Trust Expenses.................................................  50
     7.3     Plan-to-Plan Transfers.........................................  50

ARTICLE VIII
ADMINISTRATION..............................................................  52
     8.1     Administrative Committee.......................................  52
     8.2     Limitation of Liability; Indemnity.............................  52
     8.3     Compensation and Expenses......................................  53
     8.4     Voting, Chairman, Subcommittees................................  53
     8.5     Payment of Benefits............................................  54
     8.6     Powers and Authority; Action Conclusive........................  55
     8.7     Counsel and Agents.............................................  56
     8.8     Reliance on Information........................................  56
     8.9     Fiduciaries....................................................  57
     8.10    Plan Administrator.............................................  58
     8.11    Notices and Elections..........................................  58
     8.12    Taxes Payable by Trustee.......................................  59
     8.13    Credited Service...............................................  59
     8.14    Company Service Credit.........................................  61
     8.15    Transfer of a Subsidiary, Division, Branch or Business Unit....  63

ARTICLE IX
AMENDMENT, TERMINATION, ADOPTION AND MERGER.................................  64
     9.1     Modification or Amendment of Plan..............................  64
     9.2     Termination of Plan or Discontinuance of Contributions.........  64
     9.3     Expenses of Termination........................................  65
     9.4     Amendments Required for Qualification..........................  65
     9.5     Merger.........................................................  65
     9.6     Portsmouth, Ohio...............................................  66

                                      iii
<PAGE>
 
 ARTICLE X
 MISCELLANEOUS............................................................... 67
     10.1    Claims Procedure...............................................  67
     10.2    Plan Not an Employment Contract................................  67
     10.3    Consent to Terms of Plan and Trust Agreement...................  68
     10.4    Transfer of Interest Not Permitted.............................  68
     10.5    Obligations of Company Limited.................................  73
     10.6    Separation of Invalid Provisions...............................  73
     10.7    Payment to a Minor or Incompetent..............................  73
     10.8    Doubt as to Right to Payment...................................  74
     10.9    Forfeiture Upon Inability to Locate Distributee................  74
     10.10   Contributions Conditioned on Initial Qualification and
              Deductibility.................................................  75
     10.11   No Diversion of Trust Fund.....................................  75
     10.12   Usage..........................................................  76
     10.13   Governing Law..................................................  76
     10.14   Captions.......................................................  76

                                      iv
<PAGE>
 
                    THE MARTIN MARIETTA ENERGY SYSTEMS, INC.
                   401(k) SAVINGS PLAN FOR SALARIED EMPLOYEES

                                  INTRODUCTION
                                  ------------


     The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for Salaried
Employees is the successor plan to the 401(k) Opportunity Plan for Salaried
Nuclear Division Employees of Union Carbide Corporation.  The transfer of the
Plan occurred pursuant to the assumption by Martin Marietta Energy Systems, Inc.
from Union Carbide Corporation of the contract to operate the Department of
Energy facilities in Oak Ridge, Tennessee and Paducah, Kentucky.  The Plan was
adopted in its current form effective April l, 1984.  Any provision regarding a
date prior to April l, 1984 refers either to employment with Union Carbide
Corporation or to participation in the predecessor plan as in effect at that
time.  The Plan as in effect on April 1, 1984 shall apply to employees covered
by collective bargaining agreements, until such date as the Plan shall have been
accepted for such employees by collective bargaining.

          This Plan is established by Martin Marietta Energy Systems, Inc., a
Delaware Corporation and a subsidiary of Martin Marietta Corporation, for the
exclusive benefit of its eligible employees and their beneficiaries.
Participation in this Plan by employees is entirely voluntary.
<PAGE>
 
                                   ARTICLE I
                                  DEFINITIONS
                                  -----------

     1.   Definitions. As used in this Plan, the following terms shall have
          -----------                            
the designated meaning:

     1.1  "Additional Contribution" shall mean a contribution to a
           -----------------------                                
Participant's Tax Deferred Account made pursuant to Section 2.6 of this Plan.

     1.2  "Affiliate" shall mean, except as otherwise provided in Article
           ---------                                                     
V, each of (a) any corporation (other than the Company) of which at least 80% of
the total combined voting power of all classes of stock entitled to vote is
owned at the time of reference, either directly or indirectly, by the Company,
(b) any other trade or business (other than the Company), whether or not
incorporated, which, at the time of reference, is controlled by or under common
control with the Company, within the meaning of section 414(c) of the Code or
(c) any member (other than the Company), at the time of reference, of an
affiliated service group within the meaning of section 414(m) of the Code, which
includes the Company.

     1.3  "Before Tax Contribution" shall mean a contribution to a
           -----------------------                                
Participant's Tax Deferred Account made pursuant to Section 2.3 of this Plan.

     1.4  "Beneficiary" shall mean the person, persons or estate entitled
           -----------                                                   
under Section 4.1.5 to receive any amount under this Plan in the event of a
Participant's death.

     1.5  "Code" shall mean the Internal Revenue Code of 1986, as from time
           ----                                 
to time amended.

     1.6  "Committee" shall mean the Administrative Committee provided for
           ---------                               
in Article VIII of this Plan.
<PAGE>
 
     1.7   "Company" shall mean Martin Marietta Energy Systems, Inc., a Delaware
            -------                                                    
corporation, any predecessor thereof, and any successor thereof by merger,
consolidation or otherwise.

     1.8   "Company Contribution" shall mean a contribution to a Participant's
            --------------------                                
Tax Deferred Account made pursuant to Section 2.5 of this Plan.

     1.9   "Company Service Credit" shall mean the period of service determined
            ----------------------                
under Section 8.14 of this Plan.

     1.10  "Compensation" shall mean a Participant's regular, basic salary
            ------------                                                  
for his/her regularly scheduled hours, determined prior to any reduction in such
salary for Before Tax Contributions and Additional Contributions to this Plan or
any other plan maintained by the Company which meets the requirements of Code
section 125 and which provides for pre-tax contributions.  For purposes of this
Plan, a Participant's regular, basic salary shall include any shift bonus paid
to such Participant.

     1.11  "Credited Service" shall mean the period of service credited to
            ----------------                                              
an Employee for purposes of determining his/her eligibility to participate in
this Plan, as determined under Section 8.13 of this Plan.

     1.12  "Disability" shall mean a Participant's total physical or mental
            ----------                                                     
inability to perform any work for compensation or profit in any occupation for
which he/she is reasonably qualified by reason of training, education or
ability, and which is adjudged to be permanent, as determined by the Committee
on the basis of medical evidence satisfactory to it.

     1.13  "Earnings" shall mean total compensation actually paid or made
            --------                                                     
available by the Company and its Affiliates for such year, including, but not
limited to, bonuses, income from sources without the United States whether or
not excludable for Federal income tax

                                       2
<PAGE>
 
purposes, amounts related to the value of property transferred in connection
with the performance of services which are includable for Federal income tax
purposes under section 83(b) of the Code, and taxable income attributable to
employer-provided life insurance.  Earnings shall not include deferred
compensation (other than payments under an unfunded plan that are currently
includable in income), amounts realized from the exercise of a non-qualified
stock option or a stock appreciation right, exercise payments, amounts
contributed on behalf of a Participant to a plan which meets the requirements of
sections 401(a) and 401(k) of the Code, or other distributions which receive
special tax benefits.  A Participant's Earnings in excess of $200,000 shall not
be taken into account under the Plan for purposes of benefits accruing under the
Plan after December 31, 1988.  Such $200,000  limitation shall be adjusted at
the same time and in such manner as the limitation set forth in section
415(b)(1)(A) of the Code is adjusted under section 415(d) of the Code.

     1.14  "Eligible Employee" shall mean any Employee, other than an
            -----------------                                        
Employee who is a member of a class of Employees excluded from coverage under
this Plan pursuant to Section 2.2, if such individual:

          1.14.1 is compensated on a salaried basis;

          1.14.2 has at least one year of Credited Service; and

          1.14.3 is employed by Martin Marietta Energy Systems, Inc.

     1.15 "Employee" shall mean (a) any individual who, under the rules
           --------                                                    
applicable in determining the employer-employee relationship for purposes of
section 3121 of the Code, has the status of an employee of the Company or an
Affiliate; and (b) any officer of the Company or an Affiliate.

     1.16 "ERISA" shall mean the Employee Retirement Income Security Act of
           -----                                                           
1974, as from time to time amended.  Reference to a specific provision of ERISA
shall include

                                       3
<PAGE>
 
such provision, any valid regulation promulgated thereunder and any comparable
provision of future legislation that amends, supplements or supersedes such
provision.

     1.17 "Highly Compensated Employee" shall mean any Employee who, during
           --------------------------- 
the Plan Year or the preceding Plan Year,

            (i)  was at any time a five percent owner (as defined in Section
                 4.1.6.1) of the Employer;

           (ii)  received annual Compensation from an Employer in excess of
                 $75,000 (adjusted in accordance with Code section 414(q));

          (iii)  received annual Compensation from the Employer in excess of
                 $50,000 (adjusted in accordance with Code section 414(q)) and
                 was in the top 20 percent of Employees when ranked on the basis
                 of annual Compensation during such Plan Year;

           (iv)  was at any time an officer and received annual Compensation
                 greater than 150 percent of the amount in effect under Code
                 section 415(c)(1)(A) for such year; provided, however, that
                 notwithstanding the foregoing, not more than 50 Employees (or,
                 if lesser, the greater of 3 employees or 10 percent of all
                 Employees) shall be treated as officers;

            (v)  was the highest paid officer of an Employer for the Plan Year,
                 if no Employee is treated as an officer under subparagraph
                 (iv);

           (vi)  was a former Employee of the Employer, if such Employee was a
                 Highly Compensated Employee when such Employee separated from
                 service, or was a Highly Compensated Employee at any time after
                 attaining age 55.

     1.18  "Normal Retirement Date" shall mean a Participant's 65th birthday.
            ----------------------                                           

     1.19  "Participant" shall mean an Eligible Employee who becomes a
            -----------                                               
Participant in this Plan pursuant to Section 2.1.

     1.20  "Personal Investment Account" shall mean the Personal Investment
            ---------------------------                                    
Account established under the Savings Plan.

     1.21  "Plan" shall mean this Martin Marietta Energy Systems, Inc. 401(k)
            ----                                                             
Savings Plan for Salaried Employees, as from time to time in effect.

                                       4
<PAGE>
 
     1.22  "Plan Year" shall mean the twelve-month period starting January 1 and
            ---------                                                           
ending December 31.

     1.23  "Savings Plan" shall mean the Martin Marietta Energy Systems, Inc.
            ------------                                                     
Savings Plan for Salaried and Hourly Employees, as from time to time in effect.

     1.24  "Tax Deferred Account" shall mean an account setting forth a
            --------------------                                       
Participant's interest in the Trust Fund, as provided in Article III of this
Plan.

     1.25  "Termination of Employment" and similar references shall mean a
            -------------------------                                     
Participant's ceasing to be employed by the Company or an Affiliate for any
reason.  A transfer between employment by the Company and employment by an
Affiliate, between employment by Affiliates, or between employment compensated
on a salaried basis and employment compensated on an hourly basis shall not
constitute a termination of employment.

     1.26  "Trust Agreement" shall mean the agreement between the Company and
            ---------------                                                  
the Trustee under which this Plan is funded, as such agreement may be amended
from time to time.

     1.27  "Trust Fund" shall mean the fund created by the Trust Agreement.
            ----------                                                     

     1.28  "Trustee" shall mean the trustee or trustees from time to time
            -------                                                      
designated under the Trust Agreement.

     1.29  "Valuation Date" shall mean December 31, 1984, each succeeding
            --------------                                               
December 31, and any other date on or after January 1, 1984 as of which the
Committee, in its sole discretion, determines the value of all or any portion of
the Trust Fund or determines the actual deferral percentage, as defined in
section 401(k)(3)(B) of the Code, of any Employee or any group of Employees.

                                       5
<PAGE>
 
                                   ARTICLE II

                    PARTICIPATION, CONTRIBUTIONS AND VESTING
                    ----------------------------------------

     2.1  Participation.  An Eligible Employee shall become a Participant in
          -------------                                                     
this Plan upon the earlier of:

          2.1.1  his/her authorizing his/her Employer to reduce his/her
     Compensation for each pay period by an amount determined in accordance with
     Section 2.3 or Section 2.6; or

          2.1.2  the transfer of his/her entire account under any other plan
     maintained by an Employer or an Affiliate which meets the requirements of
     sections 401(a) and 401(k) of the Code to the Trustee for his/her Tax
     Deferred Account pursuant to Section 2.8.

An Eligible Employee shall cease to be a Participant in this Plan upon the
earlier of the complete distribution to him/her of his/her Tax Deferred Account
or the transfer of such account pursuant to Section 2.8 of this Plan to any
other plan maintained by the Company or an Affiliate which meets the
requirements of sections 401(a) and 401(k) of the Code.

     2.2  Exclusions.  (a) The following employees are not within the coverage
          ----------                                                          
of the Plan:

          (i) Individuals who perform services for the Company as leased
     employees.  For purposes of this Section (a)(i) the term "leased employee"
     shall mean any individual who:

          (1)  is not an independent contractor with respect to the Company;

                                       6
<PAGE>
 
          (2)  provides services pursuant to an agreement between the Company
               and any other person or entity (hereinafter referred to as "the
               leasing organization");

          (3)  has performed such services for the Company on a substantially
               full-time basis for a period of at least one year;

          (4)  performs services of a type historically performed in the
               business field of the Company by employees;

          (5)  is not a participant in a qualified money purchase plan
               maintained by the leasing organization which provides for a
               nonintegrated employer contribution of at least ten percent (10%)
               of such person's annual compensation and provides for immediate
               participation and full and immediate vesting; and

          (6)  meets such other requirements as may be set forth in section
               414(n) of the Code and the regulations promulgated thereunder.

          (ii) Individuals (if any) who are considered by the Company to be
     independent contractors and employees of such independent contractors, but
     who may be determined for any other purpose to be employees of the Company.
     The characterization by the Company on its books and records of the
     relationship of the individual and the Company shall be conclusive of the
     individual's status for purposes of this Plan.

     (b) The Committee reserves the right in its sole discretion to exclude from
     coverage as an Eligible Employee any class or classes of Employees,
     provided that any such exclusion does not discriminate in favor of
     Employees who are shareholders, officers, or highly compensated, as
     determined in accordance with section 410 of the Code.

                                       7
<PAGE>
 
     2.3  Before Tax Contributions.
          ------------------------ 

          2.3.1  A Participant may authorize his/her Employer to reduce his/her
     Compensation, the amount of which reduction shall be paid to the Trustee
     for such Participant's Tax Deferred Account as Before Tax Contributions.
     The reduction in Compensation authorized by a Participant as a Before Tax
     Contribution shall range from 1/2% to 6%, inclusive, of his/her
     Compensation, in multiples of 1/2%; provided, however, that the sum of a
     Participant's Before Tax Contributions under this Plan and his/her Basic
     Deductions under Section 2.3.2 of Article II of the Savings Plan shall be
     not less than 2 1/2% of his/her Compensation and not more than 6% of
     his/her Compensation.

          2.3.2  Within the limits of Section 2.3.1, a Participant may, at any
     time, increase or decrease the amount by which his/her Compensation is
     reduced for Before Tax Contributions for subsequent pay periods.

     2.4  Adjustment of Before Tax Contributions.
          -------------------------------------- 

          2.4.1  Notwithstanding anything to the contrary in this Article II,
     the Committee may prospectively decrease a Participant's authorized
     reduction in his/her Compensation at any time if the Participant is a
     Highly Compensated Employee and the Committee determines, in its sole
     discretion, that such action is necessary in order for the Plan to meet the
     actual deferral percentage tests under section 401(k)(3)(A) of the Code.

          2.4.2  If the Committee determines it is necessary to prospectively
     decrease any such Participant's authorized reduction under this Section
     2.4, it shall first decrease by 1/2% the authorized reductions of all such
     Participants who authorized the maximum reduction in their Compensation,
     determined without regard to this

                                       8
<PAGE>
 
     Section 2.4.  If the Committee determines further decreases are necessary,
     it shall decrease by 1/2% the authorized reductions of all such
     Participants whose authorized reductions in their Compensation are the
     largest, determined after taking all previous reductions under this Section
     2.4 into account.  The Committee shall continue to make such decreases in
     multiples of 1/2% until it determines that the actual deferral percentage
     tests in section 401(k)(3)(A) of the Code have been met.

          2.4.3  Any Before Tax Contributions which would have been made to this
     Plan on behalf of a Participant but for the decrease in his/her authorized
     Compensation reduction under this Section 2.4 shall be paid by the Company
     to the Savings Plan as a Basic Deduction as defined in Section 2.3.2 of
     Article II of the Savings Plan and the Company shall make a Company
     Contribution as defined in Section 2.5 of Article II of the Savings Plan on
     account of such Basic Deduction, in accordance with the provisions of the
     Savings Plan, unless otherwise directed by the Participant.  If the
     Participant is not a participant in the Savings Plan, then, unless
     otherwise directed by the Participant, such amounts shall be invested in a
     Personal Investment Account established for such Participant and shall be
     allocated among the investment options in such account in the same
     proportions as the latest Before Tax Contribution for his/her Tax Deferred
     Account.  If the Participant is a participant in the Savings Plan, then,
     unless otherwise directed by the Participant, such amounts shall be
     allocated to his/her Savings Plan account and among the various investment
     options in such account, in the same proportions as:

          2.4.3.1  his/her latest Basic Deductions for the Savings Plan, as
          defined in Section 2.3.2 of Article II of the Savings Plan; or

                                       9
<PAGE>
 
          2.4.3.2  if he/she has never made any such Basic Deductions for the
          Savings Plan, his/her latest Supplemental Deductions for the Savings
          Plan, as defined in Section 2.3.3 of Article II of the Savings Plan;
          or

          2.4.3.3  if he/she has never made any such Basic Deductions or
          Supplemental Deductions for the Savings Plan, his/her latest
          Supplemental Deposits for the Savings Plan, as defined in Section
          2.3.4 of Article II of the Savings Plan.

          2.4.4  If the Committee determines, in its sole discretion, that it is
     no longer necessary to decrease a Participant's authorized Compensation
     reduction under this Section 2.4, the Committee shall increase the
     authorized Compensation reductions of all Participants who had such
     reductions decreased, in multiples of 1/2%, until all such Participants
     have their authorized Compensation reductions restored to their originally
     authorized level or the Committee determines that the actual deferral
     percentage tests of  section 401(k)(3)(A) of the Code will not be met,
     whichever occurs first.

          2.4.5  When increasing or decreasing any Participant's authorized
     Compensation reduction under this Section 2.4, the Committee shall treat
     all Participants who authorized the same reduction in their Compensation in
     the same manner.

          2.4.6  Any action taken by the Committee under this Section 2.4 may be
     taken without the consent of, or prior notice to, the affected
     Participants, but such Participants shall be promptly informed in writing
     of the Committee's action.

     2.5  Company Contributions.
          --------------------- 

          2.5.1  At the time Before Tax Contributions are paid to the Trustee on
     behalf of a Participant, the Company shall pay to the Trustee as Company
     Contributions for

                                      10
<PAGE>
 
     such Participant's Tax Deferred Account an amount equal to the Applicable
     Percentage of the Before Tax Contributions paid to the Trustee on behalf of
     such Participant, in accordance with the following schedule:

<TABLE>
<CAPTION>
                                                  
       Number of Years of   
        Credited Service    Applicable Percentage 
      --------------------  ----------------------                       
      <S>                   <C>                   
               1                     15%           
               2                     30%           
               3                     40%           
           4 or more                 50%            
</TABLE>

          2.5.2  If the Company is prevented from making all or any portion of
     the Company Contribution it would otherwise make under Section 2.5.1
     because it has no current or accumulated earnings or profits, or because
     its current and accumulated earnings and profits are less than the Company
     Contributions it would otherwise make, then all or any of the other
     companies within the affiliated group of corporations within the meaning of
     section 1504 of the Code of which the Company is a member having sufficient
     current or accumulated earnings or profits may make the Company
     Contributions the Company could not make.  Any Company Contribution made by
     any such other company on behalf of the Company shall be allocated among
     the Participants as if the Company had itself made such Company
     Contribution.

     2.6  Additional Contributions.
          ------------------------ 

          2.6.1  If the Committee determines that contributions made under this
     Section 2.6 will not cause the Plan to fail to meet the actual deferral
     percentage tests in section 401(k)(3)(A) of the Code, the Committee, in its
     sole discretion, may permit Participants who have authorized the maximum
     allowable reduction in their Compensation for Before Tax Contributions to
     authorize additional reductions in their

                                      11
<PAGE>
 
     Compensation, the amount of which reductions shall be paid to the Trustee
     for such Participant's Tax Deferred Account as Additional Contributions.
     If permitted by the Committee, reductions for Additional Contributions
     shall range from 1/2% of the Participant's Compensation to such upper limit
     as the Committee may set, but in no event more than 10% of the
     Participant's Compensation, in multiples of 1/2%; provided, however, that
     the sum of a Participant's Additional Contributions under this Plan and
     his/her Supplemental Deductions under Section 2.3.3 of Article II of the
     Savings Plan shall not exceed 10% of his/her Compensation.  The Committee
     may suspend the right to authorize Additional Contributions and may raise
     or reduce the limit on Additional Contributions (subject to the maximum and
     minimum limits set forth in this Section 2.6) at any time.

          2.6.2  Within the limits of Section 2.6.1, a Participant may, at any
     time, increase or decrease the amount by which his/her Compensation is
     reduced for Additional Contributions.

          2.6.3  Additional Contributions shall not be taken into consideration
     in determining the Company Contribution to be allocated to any Participant.

     2.7  Transfers from the Savings Plan.  Immediately preceding a
          -------------------------------                          
Participant's termination of employment, other than on account of death, the
entire balance to the credit of the Participant under the Savings Plan, if any,
shall automatically be transferred to his/her Tax Deferred Account.  Amounts
transferred from the Personal Investment Account pursuant to this Section 2.7
shall be invested among the various investment options in his/her Tax Deferred
Account in the same proportion as they were invested among the various
investment options in his/her Personal Investment Account.

                                      12
<PAGE>
 
     2.8  Change from Eligible Employee to Ineligible Employee and from
          -------------------------------------------------------------    
Ineligible Employee to Eligible Employee.
- ---------------------------------------- 

          2.8.1  If an Employee ceases to be an Eligible Employee, other than on
     account of death or other termination of employment, his Tax Deferred
     Account shall automatically be transferred to the trust fund established in
     connection with any other plan maintained by the Company or an Affiliate
     which meets the requirements of sections 401(a) and 401(k) of the Code for
     his/her account under such other plan if such other plan provides for the
     acceptance of funds transferred from this Plan and if such Employee would
     be eligible to participate in such other plan on the date he/she ceases to
     be an Eligible Employee.  If such other plan does not provide for the
     acceptance of funds transferred from this Plan or if such Employee would
     not be eligible to participate in such other plan on such date, the
     Employee shall remain a Participant in this Plan except that his/her
     existing authorizations for reductions in his/her Compensation for Before
     Tax Contributions and Additional Contributions shall be deemed to have been
     revoked by such Participant and he/she shall not be able to authorize any
     future reductions in his/her Compensation for Before Tax Contributions or
     Additional Contributions.

          2.8.2  If an Employee who is a participant in any other plan
     maintained by the Company or an Affiliate which meets the requirements of
     sections 401(a) and 401(k) of the Code ceases to be eligible to participate
     in such other plan, other than on account of death or other termination of
     employment, and such other plan provides for the transfer of funds to this
     Plan, his/her account under such other plan shall automatically be
     transferred to the Trust Fund for the account of such Employee and

                                      13
<PAGE>
 
     such Employee shall become a Participant in this Plan if such Employee
     would be an Eligible Employee on the date he/she ceases to be a participant
     in such other plan.

     2.9  Revocation of Compensation Reduction.
          ------------------------------------ 

          2.9.1  A Participant may revoke his/her authorization for the
     reduction of his/her Compensation for Before Tax Contributions and
     Additional Contributions in a time and manner authorized by the Committee.
     If a Participant revokes his/her authorization for the reduction of his/her
     Compensation for Before Tax Contributions, the related Company
     Contributions will be suspended.

          2.9.2  Authorizations for a reduction in a Participant's Compensation
     for Before Tax Contributions and Additional Contributions which a
     Participant has revoked may be reinstated by the Participant in a time and
     manner authorized by the Committee.  If a Participant reinstates the
     authorization for a reduction in his/her Compensation for Before Tax
     Contributions, the related Company Contributions will be resumed.

          2.9.3  If the Committee relies upon Section 4.4.2 (b) to permit a
     hardship withdrawal by the Participant, such Participant's right to make
     Before Tax Contributions and Additional Contributions shall be suspended
     for a period of twelve (12) months after the hardship withdrawal is
     received by the Participant.

     2.10  Limitations on Contributions.  In no event shall the annual sum of
           ----------------------------                                      
the Before Tax Contributions, related Company Contributions and Additional
Contributions for a Participant's Tax Deferred Account in any Plan Year exceed
the lesser of $30,000 (or such other amount as the Secretary of the Treasury may
specify pursuant to section 415 of the Code) or 25 percent of the Participant's
Earnings for such Plan Year.

                                      14
<PAGE>
 
     2.11  Vesting.  A Participant's right to his/her Tax Deferred Account
           -------                                                        
derived from his/her Before Tax Contributions and Additional Contributions and
all earnings of the Tax Deferred Account is non-forfeitable (within the meaning
of section 411 of the Code) at all times.  A Participant's right to his/her Tax
Deferred Account derived from Company Contributions is non-forfeitable upon the
attainment of Normal Retirement Age, and in addition is non-forfeitable in the
case of a Participant who has at least three years of Credited Service.  Any
forfeitures under this Section 2.11 shall be used to reduce the amount the
Company is required to pay under Section 2.5 as Company Contributions.

     2.12  Limitations on Before Tax Contributions and Additional Contributions.
           --------------------------------------------------------------------
Notwithstanding the foregoing, in no event shall a Participant's Before Tax
Contributions for a Plan Year exceed $7,000 (adjusted annually for increases in
the cost of living in accordance with section 415 of the Code); provided,
however, that if the Committee relies upon Section 4.4.2(b) to permit a hardship
withdrawal by the Participant, such limitation shall be reduced for the year
following the year in which such withdrawal is made by the amount of the
Participant's Before Tax Contributions in the year such withdrawal is made.  If
any deferral in excess of such limitation is made, then the Committee may, in
its discretion, return to the Participant such excess deferral and any income
thereon not later than April 15 of the taxable year following the taxable year
in which such excess deferral occurred.

     2.13  401(m) Limitations.  The Committee shall ensure that the requirements
           ------------------                                                   
set forth in section 401(m) of the Code with respect to Participants' Before Tax
Contributions, Company  Contributions, and Additional Contributions are
satisfied.  The Plan shall not be treated as failing to meet such requirements
for any Plan Year, if before the close of the following Plan Year, the Committee
distributes "excess aggregate contributions," as defined

                                      15
<PAGE>
 
in section 401(m) of the Code, to Participants in accordance with procedures set
forth in section 401(m) of the Code and the Regulations promulgated thereunder.


                                      16
<PAGE>
 
                                  ARTICLE III

               INVESTMENT AND VALUATION OF TAX DEFERRED ACCOUNTS
               -------------------------------------------------

     3.1  General.  Before Tax Contributions, related Company Contributions, and
          -------                                                               
Additional Contributions authorized by a Participant and any amounts transferred
from the Participant's account in the Savings Plan pursuant to Section 2.7 of
this Plan or from his/her account in any other plan maintained by the Company or
an Affiliate which meets the requirements of sections 401(a) and 401(k) of the
Code pursuant to Section 2.8 of this Plan, shall be paid to the Trustee and held
in the Trust Fund in a Tax Deferred Account established for such Participant.

     3.2  Investment Options.  Each Participant shall direct that the entire
          ------------------                                                
amount of the Before Tax Contributions and Additional Contributions made to
his/her Tax Deferred Account be invested in one or more of the following
investment options, in multiples of 25 percent.  Company Contributions made to a
Participant's Tax Deferred Account shall be invested in the following investment
options in the same proportion as their related Before Tax Contributions.

          3.2.1  Government Bond Fund - A fund which invests only in United
                 --------------------                                      
     States Series "E" and Series "EE" Savings Bonds.

          3.2.2  Martin Marietta Corporation Stock Fund - A fund which invests
                 --------------------------------------                       
     only in common stock of Martin Marietta Corporation.

          3.2.3  Fixed Income Fund - A fund under which monies will be credited
                 -----------------                                             
     with monthly interest at a predetermined rate, not subject to change more
     than twice each calendar year.


                                      17
<PAGE>
 
          3.2.4  Equity Investment Fund - A fund under which monies will be
                 ----------------------                                    
     invested primarily in common stock and other equity-type investments.  The
     value of the Equity Investment Fund will vary to reflect the investment
     experience of the Fund.

Notwithstanding anything to the contrary in this Section 3.2, any monies
allocated to any Fund may be invested temporarily in obligations of a short-term
nature, including prime commercial obligations or part interests therein, or in
interests in any trust fund that has been or shall be created and maintained by
the Trustee or any other person or entity as trustee for the collective short-
term investment of funds of trusts for employee benefit plans qualified under
section 401(a) of the Code.  Any such earnings on such short-term investments
shall be allocated monthly to each Participant's account in proportion to the
amount of each Participant's account balance at the end of such month.

     3.3  Union Carbide Corporation Stock Fund.  From and after April 1, 1984,
          ------------------------------------                                
no monies may be allocated to purchase stock of Union Carbide Corporation;
provided, however, that any stock of Union Carbide Corporation existing in this
Fund on April l, 1984 shall remain in the Fund until such time as the
Participant directs that it shall be sold by the Trustee or it is distributed to
such Participant or his Beneficiary.

     Notwithstanding the preceding sentence, if, with regard to any Participant,
the number of shares of stock of Union Carbide Corporation existing in this
Fund, is less than 100, then the Participant (or his/her Beneficiary) shall
direct the sale of such shares no later than June 30, 1990; if, with regard to a
Participant, the number of such shares equals or exceeds 100, the Participant
(or his/her Beneficiary) shall direct the sale of such shares no later than June
30, 1991.  In the event a Participant (or his/her Beneficiary) shall fail to
direct the sale of his/her shares of stock of Union Carbide Corporation as
required herein by June 30, 1990 or June 30, 1991, as applicable, then the
Trustee shall sell such shares on the

                                      18
<PAGE>
 
next business day following June 30, 1990 or June 30, 1991, as applicable.
Unless a Participant shall elect otherwise, the proceeds of the sale of stock of
Union Carbide Corporation under this paragraph shall be allocated among the
funds in the same proportion as current contributions to such Participant's
Account are allocated to each fund.

     3.4  Investment Manager.  The Committee may appoint an investment manager
          ------------------                                                  
or managers, as defined in section 3(38) of ERISA, to manage (including the
power to acquire, invest and dispose of) any assets of the Plan.

     3.5  Change of Investments.  Subject to applicable rules and regulations
          ---------------------                                              
adopted by the Committee governing this Plan:

          3.5.1  A Participant may at any time change his/her investment options
     currently in effect with respect to subsequent Before Tax Contributions,
     related Company Contributions and Additional Contributions made to his/her
     Tax Deferred Account, subject to the percentage limitations of Section 3.2
     of this Plan.

          3.5.2  A Participant may direct, in whole or in part, the sale of
     his/her interest in the Martin Marietta Corporation Stock Fund, his/her
     stock in the Union Carbide Corporation Stock Fund and/or his/her Government
     Bonds, and the reinvestment of such proceeds in any other Investment
     Options in accordance with the percentage limitations of Section 3.2 of
     this Plan.

          3.5.3  A Participant may elect to liquidate his/her interest, in whole
     or in part, in the Fixed Income Fund and/or the Equity Investment Fund, and
     reinvest the proceeds in any other Investment Options in accordance with
     the percentage limitations of Section 3.2 of this Plan.  Only two such
     elections will be permitted in any 12-month period.


                                      19
<PAGE>
 
     3.6  Special Rules for Company Officers.
          ---------------------------------- 
     Notwithstanding any other provisions of this Plan, any Participant who is
an officer of the Company:

          3.6.1  may change the allocation of his Compensation between
     reductions for this Plan and contributions to the Savings Plan only once in
     any 12-month period if such change would affect the purchase of common
     stock of the Martin Marietta Corporation for his/her Tax Deferred Account;

          3.6.2  may change the allocation of Before Tax Contributions, related
     Company Contributions and Additional Contributions among the four
     investment options only once in any 12-month period if such change would
     affect the purchase of common stock of the Martin Marietta Corporation for
     his/her Tax Deferred Account;

          3.6.3  may direct the sale or redemption of his/her interest in
     his/her Tax Deferred Account and the reinvestment of the proceeds thereof
     in other investment options in his/her Tax Deferred Account only once in
     any 12-month period if such direction would affect the purchase or sale of
     common stock of the Martin Marietta Corporation for his/her Tax Deferred
     Account; and

          3.6.4  must make any such change in the allocation of his/her Before
     Tax Contributions, related Company Contributions and Additional
     Contributions and must give any such direction to sell or redeem on the
     same date in the 12-month period, which date must be the same date as the
     date on which he/she makes any change pursuant to Section 3.5 of Article
     III of the Savings Plan.

     3.7  Dividends.  Dividends received on stock held in the Martin Marietta
          ---------                                                          
Corporation Stock Fund for a Participant's Tax Deferred Account shall
automatically be reinvested in the Martin Marietta Corporation Stock Fund.

                                      20
<PAGE>
 
     Dividends received on Union Carbide Corporation stock are automatically
reinvested in the same investment options and in the same proportion as the
Participant's Before Tax Contributions.  Dividends will not be reinvested in
additional shares of stock in the Union Carbide Corporation Stock Fund.

     3.8  Rights, Warrants and Scrip.  If any rights, warrants or scrip are
          --------------------------                                       
issued on stock held in the Martin Marietta Corporation Stock Fund or Union
Carbide Corporation Stock for a Participant's Tax Deferred Account, the Trustee
shall automatically exercise the rights, warrants or scrip for whole shares,
which shares shall be for such Participant's Tax Deferred Account, and shall
automatically offer the rights, warrants, or scrip for fractional shares for
sale on the open market and shall reinvest the proceeds in additional units of
stock in the Martin Marietta Corporation Stock Fund or into the other designated
investment options.  Proceeds may not be reinvested in additional shares of
stock in Union Carbide Corporation Stock.

     3.9  Instructions By a Participant For His/Her Tax Deferred Account.  A
          --------------------------------------------------------------    
Participant shall give orders for the investment, reinvestment, sale or
redemption of his/her Tax Deferred Account, subject to the provisions of this
Article III,  in accordance with rules and regulations adopted by the Committee.

     3.10  Purchases and Sales.  Investment of amounts in Government Bonds or in
           -------------------                                                  
units of stock of Martin Marietta Corporation directed by a Participant shall be
made by the Trustee as expeditiously as possible, but not later than the last
day of the month following the month in which the order is made or the proceeds
are received by the Trustee, whichever is applicable, and as sufficient amounts
are available.  Investment of amounts in the Fixed Income Fund or the Equity
Investment Fund directed by a Participant shall be made as close as is
reasonably practicable to the first business day of the month following the
month in

                                      21
<PAGE>
 
which the order is made, or in which the proceeds are received by the Trustee,
whichever is applicable.  The sale of stock of Union Carbide Corporation, the
redemption of Government Bonds and the liquidation of a Participant's interest
in the Martin Marietta Corporation Stock Fund, the Fixed Income Fund and/or the
Equity Investment Fund shall be complied with as is reasonably practicable after
the receipt of the Participant's order by the Trustee.  The Trustee shall
purchase all shares of stock for the Martin Marietta Corporation Stock Fund on
the New York Stock Exchange or, if Martin Marietta Corporation elects, from
Martin Marietta Corporation.  If such stock is purchased from Martin Marietta
Corporation, it shall be purchased at a price equal to the last recorded sales
price on the last trading day of the month in which such purchase occurs,  as
reported in the New York Stock Exchange-Composite Transactions.

     3.11  Costs and Expenses.  In accordance with the rules and regulations
           ------------------                                               
adopted by the Committee, all costs and expenses, including transfer taxes and
brokerage commissions, incurred in connection with the purchase, sale and
redemption of United States Series "E" and Series "EE" Savings Bonds and stock
of Martin Marietta Corporation and in the case of the sale of Union Carbide
Corporation Stock, for a Participant's Tax Deferred Account shall be added to
the cost of such stock and bonds or deducted from the proceeds of such stock and
bonds, as the case may be, unless paid by the Company.

     3.12  Custody of Securities.  All cash, United States Series "E" and Series
           ---------------------                                                
"EE" Savings Bonds, certificates for shares of Martin Marietta Corporation
Stock, certificates for shares of Union Carbide Corporation Stock, evidences of
ownership of Fixed Income Fund and Equity Investment Fund units and all other
Plan assets shall be held in the custody of the Trustee until disposed of under
the provisions of this Plan.

                                      22
<PAGE>
 
     3.13  Voting Rights.  The Company will make forms available to each
           -------------                                                
Participant to instruct the Trustee with regard to the voting of any shares of
Martin Marietta Corporation Stock pertaining to that Participant's Tax Deferred
Account or for Union Carbide Corporation Stock held in that Participant's Tax
Deferred Account.  The Trustee will vote such shares only as directed by the
Participant.  If a Participant  fails to give timely directions as to the voting
of such shares of stock, the Trustee will vote such shares in the same
proportion as it votes the shares for which the Trustee receives directions.

     3.14  Valuation of Tax Deferred Accounts.
           ---------------------------------- 

          3.14.1  As of January l, 1984, the unit values of the Fixed Income
     Fund and the Equity Investment Fund shall be equal to the unit values of
     the similar funds maintained under the Savings Plan.  On any Valuation Date
     the unit values of the Martin Marietta Corporation Stock Fund, Fixed Income
     Fund and the Equity Investment Fund shall be equal to the total value of
     such fund, as determined pursuant to Section 3.14.2, divided by the number
     of units in such fund outstanding on such Valuation Date.

          3.14.2  On any Valuation Date, the Martin Marietta Corporation Stock
     Fund, the Union Carbide Corporation Stock Fund and the Equity Investment
     Fund shall be valued at their fair market value on such Valuation Date, the
     Fixed Income Fund shall be valued at its book value plus accrued interest
     at the stated rate to such Valuation Date, and the Government Bond Fund
     shall be valued at its book value plus accrued interest to such Valuation
     Date, determined according to tables issued by the United States Department
     of the Treasury.

          3.14.3  On any Valuation Date, a Participant's interest in the Trust
     Fund shall be equal to the value of his/her Tax Deferred Account.  The
     value of a Participant's

                                      23
<PAGE>
 
     Tax Deferred Account immediately prior to January l, 1984 shall be zero.
     The value of a Participant's Tax Deferred Account on any Valuation Date
     shall equal the greater of zero or the value of his/her Tax Deferred
     Account as of the preceding Valuation Date, increased by:

          (a)  all Before Tax Contributions, related Company Contributions and
          Additional Contributions allocated to such account since the preceding
          Valuation Date;

          (b)  all amounts transferred to such account since the preceding
          Valuation Date from the Savings Plan, pursuant to Section 2.7 of this
          Plan, and from any other plan maintained by the Company or an
          Affiliate which meets the requirements of sections 401(a) and 401(k)
          of the Code, pursuant to Section 2.8 of this Plan; and

          (c)  any income and gains (realized and unrealized) since the
          preceding Valuation Date on savings bonds in the Government Bond Fund
          allocated to his/her Tax Deferred Account, stock in the Union Carbide
          Corporation Stock Fund allocated to his/her Tax Deferred Account and
          units in the Martin Marietta Corporation Stock Fund, Fixed Income Fund
          and Equity Investment Fund allocated to his/her Tax Deferred Account;

     and decreased by:

          (d)  any losses (realized and unrealized) since the preceding
          Valuation Date on savings bonds in the Government Bond Fund allocated
          to his/her Tax Deferred Account, stock in the Union Carbide
          Corporation Stock Fund allocated to his/her Tax Deferred Account and
          units in the Martin Marietta Corporation


                                      24
<PAGE>
 
          Stock Fund, Fixed Income Fund and Equity Investment Fund allocated to
          his/her Tax Deferred Account;

          (e)  the amount of any distributions to such Participant under Section
          4.1 and withdrawals by such Participant under Section 4.4 since the
          preceding Valuation Date;

          (f)  any amounts transferred from this Plan pursuant to Section 2.8.1
          to any other plan maintained by the Company or an Affiliate which
          meets the requirements of sections 401(a) and 401(k) of the Code; and

          (g)  any expenses, taxes or other amounts charged to the Trust Fund
          since the preceding Valuation Date pursuant to Sections 7.2, 8.3, 8.7,
          8.12 and 9.3 of this Plan and allocated to his/her Tax Deferred
          Account.

     3.15  Statements Furnished Participants.  A Participant shall be furnished
           ---------------------------------                                   
an annual statement of his/her Tax Deferred Account by the Company.

                                      25
<PAGE>
 
                                   ARTICLE IV

                      DISTRIBUTIONS, WITHDRAWALS AND LOANS
                      ------------------------------------

     4.1  Distribution on Termination of Employment.
          ----------------------------------------- 

          4.1.1  Termination Other Than Death.  If the value of the Tax Deferred
                 ----------------------------                                   
     Account of a Participant whose employment terminates for any reason
     (including termination on account of disability) other than death is thirty
     five hundred dollars ($3,500) or less, or the value exceeds thirty five
     hundred dollars ($3,500) and such Participant consents in writing, then,
     such Participant shall receive the entire value of such Participant's Tax
     Deferred Account, valued as of the last Valuation Date preceding such
     Participant's termination, in a single-sum payment.  Subject to Section
     4.3, the payment shall be made to the Participant as soon after such
     Participant's employment terminates as the Committee shall determine to be
     administratively practicable.  For purposes of Section 4.1, a Participant
     who terminates employment during or after the calendar year in which such
     Participant attains age fifty-five (55) shall be deemed to have terminated
     employment on account of early retirement under the Plan.

          4.1.2  Deferred Single-Sum Payment.  If the value of the Tax Deferred
                 ---------------------------                                   
     Account of a Participant whose employment terminates for any reason
     (including termination on account of disability) other than death exceeds
     thirty five hundred dollars ($3,500) and such Participant does not consent
     in writing to receive the entire value of such Participant's Tax Deferred
     Account in accordance with Section 4.1.1, then unless such Participant
     shall have made an election under Section 4.1.3 or

                                      26
<PAGE>
 
     Section 4.1.4 hereof, such Participant shall be deemed to have deferred
     receipt of the entire value of such Participant's Tax Deferred Account
     until such Participant attains age seventy and one-half (70 1/2).  Such a
     Participant may elect, in accordance with procedures determined by the
     Committee, to receive the entire value (but not part) of such Participant's
     Tax Deferred Account in a single-sum payment at any time prior to the
     Participant's attainment of age seventy and one-half (70 1/2).  After the
     month of such Participant's birth in the calendar year following his
     retirement or termination of employment, such Participant's account can no
     longer be invested in the Fixed Income Fund.  The Participant may direct
     that his account be invested in the other Investment Options or in the
     Fixed Income Fund for Retirees which shall be a fund under which monies
     will be credited with monthly interest at a predetermined rate, not subject
     to change more than twice each calendar year.

          The entire value of such Participant's Tax Deferred Account shall be
     distributed to such Participant in a single-sum payment as soon after such
     Participant attains age seventy and one-half (70 1/2) or such earlier date
     selected by the Participant as provided above, as the Committee shall
     determine to be administratively practicable.  If a Participant who has
     been deemed to have deferred receipt of the entire value of such
     Participant's Tax Deferred Account under this Section 4.1.2 dies after such
     Participant's termination of employment, but prior to such Participant's
     attainment of age seventy and one-half (70 1/2), then the Participant shall
     be deemed to have terminated employment on account of death and the entire
     value of such Participant's Tax Deferred Account shall be paid to such
     Participant's Beneficiary in accordance with Section 4.1.3.

                                      27
<PAGE>
 
          4.1.3  Election of Partial Distributions.  Upon prior written notice
                 ---------------------------------                            
     to the Committee, given in a time and manner determined by the Committee, a
     Participant who: (1) has deferred receipt of the Participant's Tax Deferred
     Account pursuant to Section 4.1.2 and (2) is eligible to receive an
     immediate pension upon termination of employment or is disabled under the
     terms of the Company's long term disability plan, may elect to receive in
     lieu of a single-sum payment, partial distributions in accordance with this
     Section 4.1.3.  No election to take a partial distribution under this
     Section 4.1.3 may be made, however, if the total balance remaining in the
     Participant's Tax Deferred Account and the Participant's Personal
     Investment Account under the Savings Plan after such withdrawal will be
     less than $10,000.  A Participant may not take more than one partial
     distribution under this Section 4.1.3 in any one Plan Year.  If a
     Participant who has made an election under this Section 4.1.3 dies prior to
     receiving the full value of his/her Tax Deferred Account, the full
     remaining value of his/her Tax Deferred Account, valued as of the Valuation
     Date following the receipt of notice of the Participant's death, shall be
     paid in accordance with Section 4.1.5.

          4.1.4  Election of Annual Installments.  Upon prior written notice to
                 -------------------------------                               
     the Committee, given in a time and manner determined by the Committee, a
     Participant who is eligible to receive an immediate pension upon
     termination of employment or is disabled under the terms of the Company's
     long term disability plan, may elect to receive the entire value of his/her
     Tax Deferred Account, valued as of the last Valuation Date preceding such
     election, in one of the following forms of payment:

          (a)  monthly payments over the life of the Participant, computed as
               set forth below; or

                                      28
<PAGE>
 
          (b)  monthly payments over the joint lives of the Participant and the
               Participant's spouse, computed as set forth below; or

          (c)  monthly payments for a period certain of 10, 15 or 20 years,
               computed as set forth below.

     If a Participant elects to receive payments under Section 4.1.4(a) or (b)
     above, the annual amount to be paid to the Participant (or his/her spouse)
     shall be determined by dividing the entire value of the Tax Deferred
     Account at the beginning of each year by the then life expectancy of the
     Participant (or the joint life and last survivor expectancy of the
     Participant and the Participant's spouse.)  For purposes of this
     calculation, the life expectancy of the Participant, and his/her spouse if
     applicable, shall be recalculated annually.

          If a Participant elects to receive payments under Section 4.1.4(c)
     above, the annual amount to be paid to the Participant (or his/her
     Beneficiary) shall be determined by dividing the entire value of the Tax
     Deferred Account at the beginning of each year by the then remaining number
     of years in the term.

          For purposes of electing one of the options under this Section 4.1.4,
     a married Participant may not elect option (a) or (c) unless the
     Participant's spouse consents in writing to such election, as provided in
     Section 4.1.5.

          If a Participant who has made an election under Section 4.1.4(a) or
     (c) dies prior to receiving the full value of his/her Tax Deferred Account,
     the full remaining value of the Tax Deferred Account, valued as of the
     Valuation Date following the receipt of notice of the Participant's death,
     shall be paid in accordance with Section 4.1.5.

                                      29
<PAGE>
 
          With regard to a Participant who has made an election under Section
     4.1.4(b):  (i) upon the death of such Participant payments shall continue,
     as computed above, to the Participant's spouse, and (ii) if the
     Participant's spouse dies prior to receiving the full remaining value of
     the Participant's Tax Deferred Account, the full remaining value of the Tax
     Deferred Account, valued as of the Valuation Date following the spouse's
     death, shall be paid in full to such spouse's beneficiary or, if the spouse
     shall not have named a beneficiary, to the estate of the deceased spouse.

          4.1.4.1  Waiver.
                   ------ 
               A married Participant who has made an election under Section
          4.1.4 (a) or (b) may waive such election at any time during the 90 day
          period ending on the annuity starting date.

               No such waiver under this Section 4.1.4.1 shall be effective
          unless the Participant's spouse consents in writing to such waiver,
          the terms of such consent acknowledge the effect of the waiver, and
          the waiver is witnessed by a representative of the Company or a notary
          public.  Such consent shall be irrevocable.

               The provisions of the preceding paragraph shall not be applicable
          if the Company is satisfied that the required consent cannot be
          obtained because either (a) the Participant does not have a spouse,
          (b) the spouse cannot be located, or (c) by reason of such other
          circumstances as the Secretary of the Treasury may prescribe by
          regulations.  Any consent by a spouse or the establishment that the
          consent of a spouse cannot be obtained shall only be effective with
          respect to such spouse.

                                      30
<PAGE>
 
          4.1.4.2  Required Information.
                   -------------------- 

               The Company shall provide to each Participant who has made an
          election under Section 4.1.4 (a) or (b), within a reasonable time
          before the annuity starting date (pursuant to such regulations as may
          be prescribed by the Secretary of the Treasury) a written explanation
          of:  (i) the terms and conditions of the annuity elected; (ii) the
          Participant's right to make, and the effect of, an election to waive
          such annuity election; and (iii) the rights of the Participant's
          spouse under Section 4.1.4.1.

          4.1.4.3 One-Year Marriage Requirement.
                  ----------------------------- 

               Notwithstanding the foregoing, the spousal requirements set forth
          in this Section 4.1.4 shall not apply unless the Participant and
          his/her spouse were married throughout the one-year period ending on
          the Participant's annuity starting date.

          4.1.5  Termination on Death.  If a Participant's employment terminates
                 --------------------                                           
     on account of the Participant's death, the value of the Participant's Tax
     Deferred Account, valued as of the last Valuation Date preceding the
     Participant's death, shall be paid in a lump sum to the Participant's
     surviving spouse, unless such spouse has consented to the designation of an
     alternate beneficiary.  No consent under this Section 4.1.5 or Section
     4.1.4 shall be effective unless either (i) such consent is in writing, the
     terms of such consent acknowledge its effect, the execution of such consent
     is witnessed by a person representing the Plan or a notary public, as the
     Committee may determine, and such consent otherwise complies with such
     rules as the Committee may adopt, or (ii) it is established to the
     satisfaction of the Committee that the required consent cannot be obtained
     because the Participant does not have a

                                      31
<PAGE>
 
     spouse, because the spouse cannot be located, or because of such other
     circumstances as the Secretary of the Treasury may prescribe by
     regulations.  Any consent by a spouse (or establishment that the consent of
     a spouse cannot be obtained) shall only be effective with respect to such
     spouse.

          If a Participant's spouse has consented to the designation of an
     alternate beneficiary, then the Participant's Beneficiary shall be the
     Participant's beneficiary under the Savings Plan; provided, however, if (a)
     the Participant has not effectively designated a beneficiary under the
     Savings Plan, or (b) the beneficiary designated under the Savings Plan has
     not survived the Participant and no alternative designation of beneficiary
     shall be effective, the Participant's Beneficiary shall be the estate of
     the deceased Participant.  If the Participant's surviving spouse or
     Beneficiary cannot be located for a period of one year following death,
     despite mailing to his/her last known address, and if such surviving spouse
     or Beneficiary has not made a written claim for benefits within such period
     to the Committee, such surviving spouse or Beneficiary shall be treated as
     having predeceased the Participant.  The Committee may require such proof
     of death and such evidence of the right of any person to receive all or
     part of the benefit of a deceased Participant as the Committee may deem
     desirable.

          Subject to Section 4.3, the lump sum payment shall be made to the
     Participant's surviving spouse or Beneficiary as soon after the
     Participant's death as the Committee shall determine to be administratively
     practicable.  This Section 4.1.5 is effective August 23, 1984.

          4.1.6  Mandatory Distributions.  The Tax Deferred Account of a
                 -----------------------                                
     Participant shall be entirely distributed to such Participant or shall
     commence to be distributed not later than April 1 of the calendar year
     following:

                                      32
<PAGE>
 
          (i)  if the Participant is not a five percent owner, the later of the
               calendar year in which the Participant attains age seventy and
               one-half (70 1/2) or the calendar year in which the Participant
               retires; or

          (ii) if the Employee is a five percent owner at any time during the
               five (5) plan year period ending in the calendar year in which
               the Employee attains age seventy and one-half (70 1/2), the
               calendar year in which the Employee attains age seventy and one-
               half (70 1/2).

     Effective January 1, 1989, the Tax Deferred Account of a Participant shall
     be entirely distributed to such Participant or shall commence to be
     distributed not later than April 1 of the calendar year following the
     calendar year in which the Participant attains age seventy and one-half 
     (70 1/2); provided, however, that the rules set forth in the first
     paragraph of this Section 4.1.6 shall continue to apply in the case of a
     Participant who attained age seventy and one-half (70-1/2) by January 1,
     1988.

          4.1.6.1.  For purposes of this Section 4.1.6, the term "five percent
          owner" means:

               (1)  if an Employer is a corporation, any person who owns (or is
          considered as owning within the meaning of section 318 of the Code)
          more than five percent (5%) of the outstanding stock of the
          corporation or stock possessing more than five percent (5%) of the
          total combined voting power of all stock of the corporation, or

               (2)  if an Employer is not a corporation, any person who owns
          more than five percent (5%) of the capital or profits interest in the
          Employer.

          4.1.7  Form of Payment.  All payments made under this Section 4.1
                 ---------------                                           
     shall be made entirely in cash, unless the Participant or the Beneficiary,
     as the case may be,

                                      33
<PAGE>
 
     elects to receive any whole shares of stock in the Martin Marietta
     Corporation Stock Fund, the Union Carbide Corporation Stock Fund, the
     Equity Investment Fund, and/or any bonds in the Government Bond Fund in
     his/her Tax Deferred Account in lieu of the cash value of such stock and/or
     bonds.

     4.2  Rehire Prior to Distribution.  In the event that a Participant whose
          ----------------------------                                        
employment has terminated again becomes an Employee prior to the distribution of
his/her Tax Deferred Account, such distribution shall be deferred until the
subsequent termination of his/her employment.

     4.3  Commencement of Benefits.  Unless the Participant makes an election
          ------------------------                                           
under Section 4.1.2 of this Plan, benefits under this Plan will be paid to the
Participant not later than the 60th day after the close of the Plan Year in
which the latest of the following events occurs:

          4.3.1  the date on which the Participant attains Normal Retirement
     Age;

          4.3.2  the tenth anniversary of the year in which the Participant
     commenced participation in the Plan, or

          4.3.3  the Participant's most recent termination of employment.

     4.4  Withdrawal by Participant During Employment.  A Participant may make a
          -------------------------------------------                           
withdrawal from his/her Tax Deferred Account prior to his/her termination of
employment if and only if the withdrawal is made on account of an immediate and
heavy financial need of the Participant and is necessary to satisfy such
financial need.  (Notwithstanding the preceding sentence, for Participants who
have not yet attained age 59 1/2, no withdrawal under this Section 4.4 shall be
permitted with respect to that portion of the Participant's Tax Deferred Account
which is attributable to Company Contributions or  investment earnings on Before
Tax Contributions or Additional Contributions.)  The Committee shall determine

                                      34
<PAGE>
 
whether the withdrawal is made on account of an immediate and heavy financial
need and whether the withdrawal is necessary to satisfy such financial need in
accordance with uniform and non-discriminatory standards.  The Committee may, in
its discretion, adopt either or both of the standards set forth in Section
4.4.2(a) and Section 4.4.2(b) of the Plan to assist it in determining whether a
withdrawal is necessary to satisfy an immediate and heavy financial need.

          4.4.1.  A withdrawal will be deemed to be made on account of an
     immediate and heavy financial need of the Participant if the withdrawal is
     on account of:  (i) medical expenses described in section 213(d) of the
     Code incurred by the Participant, the Participant's spouse, or any
     dependents of the Participant, (ii) the purchase (excluding mortgage
     payment) of the Participant's principal residence, (iii) the payment of
     tuition for the next semester or quarter of post-secondary education for
     the Participant, the Participant's spouse or any dependents of the
     Participant, (iv) the need to prevent eviction of the Participant from
     his/her principal residence or the foreclosure on the mortgage of the
     Participant's principal residence, or (v) other pressing financial needs of
     the Participant.

          4.4.2.  A withdrawal may be treated by the Committee as necessary to
     satisfy a Participant's financial need if the requirements of either (a) or
     (b) are satisfied:

          (a)  The Committee may reasonably rely upon the Participant's
               representation that such need cannot be relieved

               (i)    through reimbursement or compensation by insurance or
                      otherwise;

                                      35
<PAGE>
 
               (ii)   by reasonable liquidation of the Participant's assets to
                      the extent such liquidation would not itself cause an
                      immediate and heavy financial need;

               (iii)  by cessation of Before Tax Contributions and Additional
                      Contributions under the Plan; or

               (iv)   by other distributions or nontaxable (at the time of the
                      loan) loans from plans maintained by the Company or by any
                      other employer, or by borrowing from commercial sources on
                      reasonable commercial terms.

          (b)  A withdrawal will be deemed to be necessary to satisfy an
               immediate and heavy financial need of a Participant if all of the
               following requirements are satisfied:

               (i)    the withdrawal is not in excess of the amount of the
                      immediate and heavy financial need of the Participant;

               (ii)   the Participant has obtained all withdrawals, other than
                      hardship withdrawals, and all nontaxable loans currently
                      available under all plans maintained by the Company;

               (iii)  the Plan, and all other plans maintained by the Company,
                      provides that the Participant's elective contributions and
                      Participant contributions will be suspended for at least
                      12 months after receipt of the hardship withdrawal; and

               (iv)   the Plan, and all other plans maintained by the Company,
                      provide that the Participant may not make elective
                      contributions for the Participant's taxable year
                      immediately following the

                                      36
<PAGE>
 
                      taxable year of the hardship withdrawal in excess of the
                      limitation set forth in section 402(g) of the Code for
                      such next taxable year less the amount of such
                      Participant's elective contributions for the taxable year
                      of the hardship withdrawal.

     4.5  Loans.
          ----- 

          4.5.1  Loans Authorized.  Beginning with the Plan Year commencing on
                 ----------------                                             
     January 1, 1988, a Participant may apply to the Committee for a loan under
     this Plan.  Upon receipt of a Participant's application, the Committee may
     in its discretion instruct the Trustee to make a loan to such Participant
     out of the Trust Fund, effective as of such date as the Committee shall
     designate, if such loan meets the requirements of Section 4.5.2.  In
     determining whether to grant a loan under this Section 4.5, the Committee
     shall consider only those factors which would be considered in a normal
     commercial setting of an entity in the business of making loans, and shall
     act in accordance with uniform and non-discriminatory standards.

          4.5.2  Loan Requirements.  A loan shall not be made to a Participant
                 -----------------                                            
     pursuant to this Section 4.5 unless such loan:

          (a) Does not exceed the lesser of (i) $50,000, reduced by the excess
          (if any) of (I) the highest outstanding balance of loans from the Plan
          during the 1-year period ending on the day before the date on which
          such loan is made, over (II) the outstanding balance of loans from the
          Plan on the date on which such loan is made, or (ii) the greater of
          (I) one-half of the present value of the Participant's Tax Deferred
          Account (determined as of the last Valuation Date preceding the
          Participant's application for a loan), or (II) $10,000.  For purposes
          of clause (ii), the present value of the Participant's Tax Deferred


                                      37
<PAGE>
 
          Account shall be determined without regard to any accumulated
          deductible employee contributions as defined in section 72(o)(5)(B) of
          the Code;

          (b) Is exempt from the tax imposed by section 4975 of the Code by
          reason of section 4975(d)(1) of the Code;

          (c) Is adequately secured by (i) a portion (not in excess of fifty
          percent (50%) of the present value) of the Participant's Tax Deferred
          Account, and/or (ii) such other or additional security as the
          Committee may in its sole discretion require;

          (d) Bears interest, payable annually to the Trust Fund or to such
          account or accounts in the Trust Fund as the Committee shall determine
          and at such rate as the Committee shall determine;

          (e) Is, by its terms, required (i) to be amortized in level payments,
          made at least quarterly, over the term of the loan (except that this
          requirement of level amortization shall not apply to a period when the
          Participant is on leave of absence without pay for up to 1 year) and
          (ii) to be repaid upon the earlier of the date the Participant's
          employment terminates, the date of the Participant's death, or the
          expiration of a fixed term of not more than five years; provided,
          however, that the Committee may extend the five year term in the case
          of loans used to acquire any dwelling unit which within a reasonable
          time is to be used (determined at the time the loan is made) as the
          principal residence of the Participant;

          (f) Is made pursuant to a loan agreement to be executed by the
          Participant and the Trustee, on a form containing such terms and
          provisions as the Committee shall in its sole discretion determine;
          and


                                      38
<PAGE>
 
          (g) Satisfies the requirements of section 408(b)(1) of ERISA and the
          Department of Labor's regulations promulgated thereunder;
          (h) Is made in accordance with specific provisions set out by the
          Committee;
          (i) Meets such other requirements as the Committee may set.

          4.5.3  If any loan granted to a Participant pursuant to this Section
     4.5 is not repaid on the date required under Section 4.5.2(e), the
     Committee may, without prior notice to the Participant, direct the Trustee
     to sell, redeem or otherwise dispose of such collateral as the Participant
     has given for the loan and apply the proceeds thereof to the repayment of
     the loan.

          4.5.4  If a Participant receives a loan under this Section 4.5,
     his/her status as a Participant in the Plan and his/her rights with respect
     to his/her Plan benefits shall not be affected, except to the extent that
     the Participant has used his/her interest in his/her Tax Deferred Account
     as security for the loan, pursuant to Section 4.5.2.

                                      39
<PAGE>
 
                                   ARTICLE V

                      LIMITATION ON MAXIMUM CONTRIBUTIONS
                      -----------------------------------
                          AND BENEFITS UNDER ALL PLANS
                          ----------------------------


     5.1  General.  By reason of Section 2.10, Before Tax Contributions, related
          -------                                                               
Company Contributions, and Additional Contributions for a Participant under this
Plan will not exceed the maximum limitations imposed by section 415 of the Code,
if all other defined contribution plans and all defined benefit plans of all
Employers and Affiliates are disregarded.  It is intended that any limitation
imposed by section 415 of the Code arising by reason of a Participant's
participation in one or more other such plans shall be implemented as provided
in this Article V, notwithstanding any contrary provision of the Plan.

     5.2  Affiliate.  For purposes of this Article V, the definition of
          ---------                                                    
"Affiliate" in Section 1.2 shall be applied by substituting the phrase "more
than 50 percent" for the phrase "at least 80 percent" wherever the phrase "at
least 80 percent" would otherwise be applicable under said provision.

     5.3  Limitation Year.  For purposes of this Article V, the limitation year
          ---------------                                                      
shall be the Plan Year.

     5.4  Annual Additions.  "Annual Addition" means for each Participant the
          ----------------                                                   
sum for any year of (i) contributions made by the Company or an Affiliate
allocable to the Participant under all Defined Contribution Plans maintained by
the Company or an Affiliate, (ii) forfeitures allocable to the Participant under
all such plans, (iii) the amount of the Participant's  contributions to all such
plans, and (iv) any amount attributable to post-retirement medical benefits
allocated to a separate account after March 31, 1984 on behalf of a Participant
under section 415(l)(1) and section 419A(d) of the Code.

                                      40
<PAGE>
 
Notwithstanding the foregoing, for Plan Years beginning prior to January 1,
1987, only that portion of a Participant's contributions to all such plans equal
to the lesser of (A) the Participant's contributions to all such plans in excess
of six percent (6%) of the Participant Earnings, or (B) one-half (1/2) of the
Participant's contributions to all such plans for the year shall be considered
"Annual Additions."  The Participant's contributions described in clause (iii)
of the first sentence and in the second sentence of this Section 5.4 shall not
include any rollover amounts (as defined in section 402(a)(5) of the Code), any
repayments of loans, any amounts transferred directly from a trust qualified
under section 401(a) of the Code pursuant to Section 7.3, or any prior
distributions repaid to a plan upon the exercise of buy-back rights under the
Savings Plan and Retirement Program Plan for Employees of Martin Marietta Energy
Systems, Inc.  A contribution shall be taken into account as an Annual Addition
for purposes of this Article V for the Limitation Year in which it is allocated
to the Participant's account under the applicable plan.

     5.5  Defined Benefit and Defined Contribution Plans.  For purposes of this
          ----------------------------------------------                       
Article V, the term "Defined Benefit Plan" or "Defined Contribution Plan" means
whichever of the following  is applicable:  a defined benefit plan or a defined
contribution plan described in section 401(a) of the Code, which includes a
trust which is exempt from income tax under section 501(a) of the Code; provided
that a Participant's contributions under a plan which otherwise qualifies as a
defined benefit plan shall be treated as a defined contribution plan.

     5.6  Aggregation of Defined Contribution Plans.  In applying the limitation
          -----------------------------------------                             
on annual additions provided in this Article V, all defined contribution plans
maintained by the Company and Affiliates shall be aggregated.

     5.7  Defined Contribution Plan Limitation.  In no event may the annual
          ------------------------------------                             
additions made to a Participant's accounts in all defined contribution plans
maintained by the Company

                                      41
<PAGE>
 
and Affiliates exceed the lesser of (1) thirty thousand dollars ($30,000) (or,
if greater, 1/4 of the dollar limitation in effect under section 415(b)(1)(A) of
the Code,) or (2) twenty-five percent of such Participant's Earnings for such
year.

     5.8  Defined Contribution Plan Fraction Determination.  For purposes of
          ------------------------------------------------                  
this Section 5.8, a Participant's "Defined Contribution Plan Fraction" shall be
determined as follows:

          (A)  Numerator.  For any Limitation Year, the numerator shall be the
               ---------                                                      
     sum of the Annual Additions to the Participant's accounts under all Defined
     Contribution Plans maintained by the Company or an Affiliate in such year
     and in all prior Limitation Years.

          (B)  Denominator.  For any Limitation Year, the denominator shall be
               -----------                                                    
     the lesser of the following amounts, determined for such year and for each
     prior Limitation Year of the Participant's Credited Services with the
     Company or an Affiliate:

               (I)  One hundred and twenty-five percent (125%) of the maximum
          Dollar Limit for such year determined under Section 5.7 of this Plan,
          or

               (II)  thirty-five percent (35%) of the Participant's Earnings for
          such year.

Notwithstanding the foregoing, in computing the denominator of the Defined
Contribution Plan Fraction for any Limitation Year ending after December 31,
1982, the Committee may elect to determine the portion of such denominator which
relates to 1982 and prior years under the method described in section 415(e)(6)
of the Code in lieu of the method described above.  Such election may be made at
such time and in such manner as may be provided in applicable regulations issued
by the Secretary of the Treasury or his/her delegate.

                                      42
<PAGE>
 
     5.9  Defined Benefit Plan Fraction Determination.  For purposes of this
          -------------------------------------------                       
Section 5.9, a Participant's "Defined Benefit Plan Fraction" shall be determined
as follows for any Limitation Year:

          (A)  Numerator.  The numerator shall be the sum of the projected
               ---------                                                  
     annual benefits (as defined in section 415(e)(2) of the Code) of the
     Participant under all  Defined Benefit Plans maintained by the Company or
     an Affiliate as of the close of such year, disregarding benefits derived
     from the Participant's contributions, if any.

          (B)  Denominator.  The denominator shall be the lesser of the
               -----------                                             
     following amounts:

               (I)  one hundred and twenty-five percent (125%) of the maximum
          dollar limitation applicable to Defined Benefit Plans for such year
          under sections 415(b)(1)(A) and 415(d) of the Code, or

               (II)  one hundred forty percent (140%) of the Participant's
          average annual Earnings for the three (3) consecutive years in which
          the Participant's Earnings were highest.

     5.10  Combined Limitation.  If a Participant participates in one or more
           -------------------                                               
Defined Benefit Plans maintained by the Company or an Affiliate, the sum of the
Participant's Defined Contribution Plan Fraction and Defined Benefit Plan
Fraction as of the close of any Limitation Year may not exceed 1.0.  In order to
prevent such sum from exceeding 1.0, benefits under any Defined Benefit Plan in
which the Participant participates shall be reduced to the extent necessary for
that purpose.

     5.11  Alternative Method.  The Committee may, in its discretion, determine
           ------------------                                                  
any amounts required to be taken into account under this Article V by such
alternative methods

                                      43
<PAGE>
 
as shall be permitted under applicable regulations or rulings issued by the
United States Department of the Treasury.

     5.12  Participation in Multiple Plans.
           ------------------------------- 

          5.12.1  If amounts contributed to any Defined Contribution Plan by or
     on behalf of a Participant must be reduced in any Limitation Year to comply
     with the limit on Annual Additions in Section 5.7 of this Plan, the amounts
     contributed to such Defined Contribution Plans shall be reduced in the
     following order:

          (a)  Supplemental Deposits made under the Savings Plan;

          (b)  Supplemental Deductions made under the Savings Plan;

          (c)  Additional Contributions made under Section 2.6 of this Plan;

          (d)  Forfeitures under the Savings Plan;

          (e)  Company Contributions made under Section 2.5 of this Plan;

          (f)  Before Tax Contributions made under Section 2.3 of this Plan;

          (g)  Company Contributions made under the Savings Plan;

          (h)  Basic Deductions made under the Savings Plan; and

          (i)  Contributions to any Defined Benefit Plan treated as a Defined
          Contribution Plan.

     Amounts contributed by or on behalf of a Participant in one category above
shall be reduced to zero before any reduction is made to any such amounts
contributed in the next following category.

          5.12.2  The amount of Company Contributions which may not be allocated
     to a Participant's Tax Deferred Account because of the limitations of this
     Article V or of Section 2.10 of this Plan shall be considered to have been
     made by a mistake of fact and shall be returned to the Employer making such
     contributions.

                                      44
<PAGE>
 
     5.13  Notice of Reduction.  The Committee shall give prompt notice to any
           -------------------                                                
Participant whose benefit is reduced pursuant to the provisions of this 
Article V.

                                      45
<PAGE>
 
                                   ARTICLE VI

                                TOP-HEAVY RULES
                                ---------------

     6.1  Top-Heavy Plan.
          -------------- 

          6.1.1  Top-Heavy Plan Defined.
                 ---------------------- 

          (a) The Plan will be considered to be Top-Heavy for a Plan Year if, on
          the last day of any Plan Year (hereinafter referred to as the
          Determination Date):  (i) the aggregate value of the Tax Deferred
          Accounts of all Key Employees under the Plan exceeds sixty percent
          (60%) of the aggregate value of the Tax Deferred Accounts of all
          Participants in the Plan; provided, however, that for purposes of
          determining whether this Plan is a top-heavy plan under this Section
          6.1, this Plan may be aggregated with any other plan of the Company or
          an Affiliate, in accordance with the provisions of section 416 of the
          Code or (ii) the Plan is part of a required aggregation group of plans
          and the required aggregation group is Top-Heavy.  The term "required
          aggregation group" shall mean (1) each plan of the Company or an
          Affiliate which qualifies under section 401(a) of the Code in which at
          least one Key Employee is a Participant, and (2) any other plan which
          enables a plan described in the preceding subsection (1) to meet the
          requirements of sections 401(a)(4) or 410 of the Code.

          (b) If an Employer maintains or has maintained a Defined Benefit Plan
          (as defined in Section 5.5) which has covered or could cover a
          Participant in this Plan, the Top-Heavy percentage shall be determined
          by applying a fraction, the numerator of which is the sum of the Tax
          Deferred Accounts of all Key

                                      46
<PAGE>
 
          Employees under this Plan and the present value of the Accrued
          Benefits of all Key Employees under the Defined Benefit Plan, and the
          denominator of which is the sum of the Tax Deferred Accounts of all
          Participants under this Plan and the present value of the Accrued
          Benefits of all Participants under the Defined Benefit Plan.  For
          purposes of this paragraph, the aggregate value of the Tax Deferred
          Accounts and the present value of the Accrued Benefits shall be
          calculated with reference to Determination Dates which occur within
          the same calendar year.  The provisions of subparagraphs (a) and (b)
          above shall apply in constructing such fraction.

          If the plans are determined to be Top-Heavy, an Employer shall be
     required to provide either a minimum contribution under this Plan equal to
     at least five percent (5%) (7.5% if Section 6.4 applies) of the total
     annual compensation of each Participant who is not a Key Employee, or the
     minimum benefit under the applicable provisions of the Defined Benefit
     Plan.

          6.1.2  Amounts Included in Tax Deferred Account.  For purposes of
                 ----------------------------------------                  
     determining whether this Plan is top-heavy, the value of a Participant's
     Tax Deferred Account includes the amount of any distribution made to such
     Participant pursuant to Section 4.1, any withdrawal made by such
     Participant pursuant to Section 4.4 and any transfers to such Participant's
     Tax Deferred Account pursuant to Sections 2.7 and 2.8.2 if such
     distributions, withdrawals or transfers were made during the Plan Year or
     the preceding four Plan Years.  However, amounts transferred from the
     Participant's Tax Deferred Account during such Plan Years pursuant to
     Section 2.8.1 shall not be taken into account for purposes of this Section
     6.1.  The value of a Participant's Tax Deferred Account shall not be taken
     into account if such Participant

                                      47
<PAGE>
 
     has not received any Compensation from the Company or an Affiliate (other
     than a distribution or withdrawal from the Plan) at any time during the
     five year period ending on the determination date.

     6.2  Minimum Top-Heavy Benefits.  If the Plan is top-heavy under Section
          --------------------------                                         
6.1, the Company Contribution for each Participant, other than a Participant who
is a Key Employee, shall be increased by an amount that, when added to the sum
of the Participant's Before Tax Contributions, related Company Contributions and
Additional Contributions made under this Plan  without regard to this Section
6.2, shall bring the total amount contributed for such Participant under this
Plan to three percent (3%) of such Participant's Earnings.

     6.3  Reduction in Combined Limitation.  If the Plan is top-heavy under
          --------------------------------                                 
Section 6.1, the Participant's defined contribution plan fraction and defined
benefit plan fraction, determined under Sections 5.8 and 5.9, respectively,
shall be determined by substituting "one hundred percent (100%)" for "one
hundred and twenty-five percent (125%)" in each place "one hundred and twenty-
five (125%)" appears in such sections unless, on the last day of the Plan Year
in which the Plan is found to be top-heavy under Section 6.1, the aggregate
value of the Tax Deferred Accounts of Key Employees under the Plan does not
exceed 90 percent of the aggregate value of the Tax Deferred Accounts for all
Participants in the Plan and the Company elects to substitute "four percent
(4%)" for "three percent (3%)" in Section 6.2.

     6.4  Key Employee.  For purposes of this Article VI, a "Key Employee" shall
          ------------                                                          
be any Employee of the Company or an Affiliate who, at any time during the Plan
Year or any of the four preceding Plan Years, is:

          6.4.1  one of the 50 Employees of the Company or an Affiliate who has
     the highest Earnings during the Plan Year or any of the preceding four Plan
     Years of all Employees of the Company and Affiliates if such Employee is
     also an officer of the

                                      48
<PAGE>
 
     Company or an Affiliate; provided, however, that such Employee shall not be
     a Key Employee unless such Employee's Earnings exceed 150% of the dollar
     limitation in effect under section 415(c)(1)(A) of the Code for the Plan
     Year;

          6.4.2  one of the 10 Employees owning (or considered as owning within
     the meaning of section 318 of the Code) the largest interests in the
     Company or an Affiliate among all Employees of the Company and Affiliates;
     provided, however, that such Employee shall not be a Key Employee unless
     such Employee's Earnings exceed $30,000 or such other dollar limitation in
     effect under section 415(c)(1)(A) of the Code for the Plan Year; and
     further provided that if two or more Employees own equal interests in the
     Company or an Affiliate, the Employee with greater Earnings shall be
     treated as owning a larger interest;

          6.4.3  a five percent (5%) owner of the Company or an Affiliate;

          6.4.4  a one percent (1%) owner of the Company or an Affiliate if such
     owner's annual Earnings exceed $150,000; or

          6.4.5  a Beneficiary of a Key Employee described in Sections 6.4.1
     through 6.4.4, inclusive.

     6.5  Automatic Removal.  In the event that it shall be determined by
          -----------------                                              
statute, regulation or ruling of the Internal Revenue Service that the
provisions of this Article VI are no  longer necessary in whole or in part to
qualify this Plan under the Code, this Article VI shall be ineffective to such
extent without amendment to the Plan.

                                      49
<PAGE>
 
                                  ARTICLE VII

                                     TRUST
                                     -----

     7.1  Trustee.  To provide for the administration of the Plan, the Company
          -------                                                             
will enter into a Trust Agreement with a Trustee appointed by the Company.  The
Trust Agreement shall be in such form and contain such provisions as the Company
may deem appropriate, including, but not limited to, provisions with respect to
the powers and authority of the Trustee (including the management of funds
and/or providing investment options and retirement elections under this Plan by
some other institution or institutions, as directed by the Committee from time
to time), the authority of the Company to amend the Trust Agreement and to
terminate the Trust Fund, and the authority of the Company to settle the
accounts of the Trustee on behalf of all persons having an interest in the Plan,
and a provision that, except as provided in Section 10.11 of this Plan, it shall
be impossible at any time for any part of the corpus or income of the Trust Fund
to be used for or diverted to purposes other than for the exclusive benefit of
Eligible Employees or their Beneficiaries.

     7.2  Trust Expenses.  Costs and expenses of administering the Trust Fund,
          --------------                                                      
including Trustee's fees and investment manager's fees, shall be paid from the
Trust Fund, unless they are paid by the Company.

     7.3  Plan-to-Plan Transfers.  The Trustee may transfer all funds in a
          ----------------------                                          
Participant's Tax Deferred Account to the trustees of any trust qualified under
section 401(a) of the Code.  The Trustee may make such a transfer only at the
direction of the Committee.

     The Trustee may accept as part of the Trust Fund property transferred from
a trust qualified under section 401(a) of the Code.  The Trustee may accept such
a transfer only at

                                      50
<PAGE>
 
the direction of the Committee.  Such property shall at all times remain in a
segregated account maintained by the Trustee.  Such property shall be
distributed to the Participant or his/her Beneficiary in accordance with the
provisions of Article IV.

                                      51
<PAGE>
 
                                  ARTICLE VIII

                                 ADMINISTRATION
                                 --------------

     8.1  Administrative Committee.  There is hereby created an Administrative
          ------------------------                                            
Committee (the "Committee") which shall consist of not less than three (3)
members appointed by the Board of Directors of the Company or pursuant to the
authorities granted by them.  The general administration of the Plan will be the
responsibility of the Administrative Committee.  The Vice President and Chief
Financial Officer of Martin Marietta Corporation may, at any time, fill
vacancies or require the resignation of one or more of the members of the
Committee with or without cause.  In the event that a vacancy or vacancies shall
occur on the Committee, the remaining member or members shall act as the
Committee until the Vice President and Chief Financial Officer of Martin
Marietta Corporation fills such vacancy or vacancies.  No person shall be
ineligible to be a member of a Committee because he/she is, was or may become
entitled to benefits under the Plan or because he/she is a director and/or
officer of the Company or an Affiliate or a Trustee; provided, that no
Participant who is a member of the Committee shall participate in any
determination by the Committee specifically relating to the disposition of
his/her own Tax Deferred Account (including any determination with respect to a
hardship withdrawal or a loan pursuant to Sections 4.4 and 4.5, respectively).

     8.2  Limitation of Liability; Indemnity.
          ---------------------------------- 

          8.2.1  Except as otherwise provided by law, no person who is a member
     of the Committee, or any employee, director or officer of the Company or an
     Affiliate,

                                      52
<PAGE>
 
     may incur any liability whatsoever on account of any matter connected with
     or related to the Plan or the administration of the Plan.

          8.2.2  The Company shall indemnify and save harmless each member of
     the Committee, and each employee, director or officer of the Company or an
     Affiliate, from and against any and all loss, liability, claim, damage,
     cost and expense which may arise by reason of, or be based upon, any matter
     connected with or related to the Plan or the administration of the Plan
     (including, but not limited to, any and all expenses whatsoever reasonably
     incurred in investigating, preparing or defending against any litigation,
     commenced or threatened, or in settlement of any such claim whatsoever),
     unless such person shall have acted in bad faith or been guilty of willful
     misconduct or gross negligence in respect of his/her duties, actions or
     omissions in respect of the Plan.

     8.3  Compensation and Expenses.  The members of the Committee shall serve
          -------------------------                                           
without compensation for their services as such members.  All expenses
reasonably incurred by the Committee shall be treated as an expense of the Trust
Fund unless paid by the Company.  The members of the Committee shall serve
without bond unless the Company or the provisions of any applicable laws shall
require otherwise, in which event the Company shall pay the premium thereon.

     8.4  Voting, Chairman, Subcommittees.
          ------------------------------- 

          8.4.1  If there are fewer than three members of the Committee at any
     time, the Committee may do any act which the Plan authorizes or requires
     the Committee to do only upon the unanimous consent of the members of the
     Committee eligible to vote on such act.  If there are three or more members
     of the Committee at any time, a majority of the members of the Committee at
     the time in office may do any act

                                      53
<PAGE>
 
     which the Plan authorizes or requires the Committee to do.  The action of
     such majority of the members expressed from time to time by a vote at a
     meeting, or in writing without a meeting, or by conference telephone or
     similar communications equipment allowing all persons participating in the
     meeting to hear each other at the same time, shall constitute the action of
     the Committee and shall have the same effect for all purposes as if
     assented to by all members at the time in office.  Where action is taken by
     members of the Committee by conference telephone or similar communications
     equipment, such action shall be confirmed in writing by such members as
     soon as practicable thereafter.

          The Secretary shall maintain minutes reflecting Committee meetings and
     shall cause each action taken in writing without a meeting, and each
     written confirmation of action taken by conference telephone or similar
     communications equipment, to be included in the minutes of the Committee.

          8.4.2  The Plan Administrator, as appointed pursuant to Section 8.10,
     shall serve as Chairman of the Committee.  The members of the Committee
     shall elect a Secretary who may, but need not be, a member of the
     Committee, and they may appoint from their number such subcommittees as
     they shall determine.

     8.5  Payment of Benefits.  The Committee shall advise the Trustee in
          -------------------                                            
writing with respect to all benefits which become payable under the terms of the
Plan and shall direct the Trustee to pay such benefits to or on order of the
Committee.  In the event that the Trust Fund shall be invested in whole or in
part in one or more insurance contracts, the Committee shall be authorized to
give to any such insurance company such instructions as may be necessary or
appropriate in order to provide for the payment of benefits in accordance with
the Plan.


                                      54
<PAGE>
 
     8.6  Powers and Authority; Action Conclusive.  Except as otherwise
          ---------------------------------------                      
expressly provided in the Plan or in the Trust Agreement, or by the Board of
Directors of the Company:

          8.6.1  The Committee shall be responsible for the administration of
     the Plan.

          8.6.2  The Committee shall have all powers necessary or helpful for
     the carrying out of its responsibilities, and the decisions or action of
     the Committee in good faith in respect of any matter hereunder shall be
     conclusive and binding upon all parties concerned.

          8.6.3  The Committee may delegate to one or more of its members or any
     other person the right to act on its behalf in all matters connected with
     the administration of the Plan.

          8.6.4  Without limiting the generality of the foregoing, the Committee
     shall have full discretionary authority to:

          8.6.4.1  Determine all questions arising out of or in connection with
          the terms and provisions of the Plan except as otherwise expressly
          provided herein;

          8.6.4.2  Make rules and regulations for the administration of the Plan
          which are not inconsistent with the terms and provisions of the Plan,
          and fix the annual accounting period of the trust established under
          the Trust Agreement as required for tax purposes;

          8.6.4.3  Construe all terms, provisions, conditions and limitations to
          the Plan;

          8.6.4.4  Determine all questions relating to (i) the eligibility of
          persons to receive benefits hereunder, (ii) the years of Credited
          Service, years of Company Service Credit and the amount of
          Compensation and Earnings of a Participant during any period
          hereunder, and (iii) all other matters upon which

                                      55
<PAGE>
 
          the benefits or other rights of a Participant or other person shall be
          based hereunder;

          8.6.4.5  Determine all questions relating to the administration of the
          Plan (i) when disputes arise between the Company and a Participant or
          his/her Beneficiary, spouse or legal representative), and (ii)
          whenever the Committee deems it advisable to determine such questions
          in order to promote the uniform administration of the Plan.

The foregoing list of powers is not intended to be either complete or exclusive,
and the Committee shall, in addition, have such powers as may be necessary for
the performance of its duties under the Plan and the Trust Agreement.

     8.7  Counsel and Agents.  The Committee may employ such counsel, including
          ------------------                                                   
legal counsel, accountants, investment advisors, physicians, agents and such
clerical and other services as it may require in carrying out the provisions of
the Plan, and shall charge the fees, charges and costs resulting  from such
employment as an expense of the Trust Fund unless paid by the Company.  Unless
otherwise provided by law, any person so employed by the Committee may be legal
or other counsel to the Company, an Affiliate, a member of the Committee or an
officer or member of the Board of Directors of the Company or an Affiliate.

     8.8  Reliance on Information.  The members of the Committee and the Company
          -----------------------                                               
and its officers, directors and employees shall be entitled to rely upon all
tables, valuations, certificates, opinions and reports furnished by any
accountant, trustee, insurance company, counsel or other expert who shall be
engaged by the Company or the Committee, and the members of the Committee and
the Company and its officers, directors and employees shall be fully protected
in respect of any action taken or suffered by them in good faith in reliance

                                      56
<PAGE>
 
thereon, and all action so taken or suffered shall be conclusive upon all
persons affected thereby.

     8.9  Fiduciaries.  The provisions of this Section 8.9 shall apply
          -----------                                                 
notwithstanding any contrary provisions of the Plan or the Trust Agreement.

          8.9.1  The named fiduciaries under the Plan shall be the members of
     the Committee, who shall be named fiduciaries with respect to control or
     management of the assets of the Plan, and who shall have authority to
     control or manage the operation and administration of the Plan, except with
     respect to those matters which  under the Plan or the Trust Agreement are
     the responsibility, or subject to the authority, of the Trustee.

          8.9.2  The named fiduciaries under the Plan shall have the right,
     which shall be exercised in accordance with the procedures set forth in
     Section 8.4.1 and/or in the Trust Agreement for action by the Committee, to
     allocate responsibilities, fiduciary or otherwise, among named fiduciaries,
     and the named fiduciaries (or any of them to whom such right shall be
     allocated) shall have the right to designate persons other than named
     fiduciaries to carry out responsibilities, fiduciary or otherwise, under
     the Plan.

          8.9.3  The members of the Committee shall together establish and carry
     out, or cause to be provided by those persons (including without
     limitation, any investment manager, trustee or insurance company) to whom
     responsibility or authority therefor has been allocated or delegated in
     accordance with this Plan or the Trust Agreement, a funding policy and
     method consistent with the objectives of the Plan and the requirements of
     ERISA.  For such purposes, the Committee shall, at a meeting duly called
     for the purpose, establish a funding policy and method which satisfies the

                                      57
<PAGE>
 
     requirements of ERISA, and shall meet annually at a stated time of the year
     to review such funding policy and method.  All actions taken with respect
     to such funding policy and method and the reasons therefor shall be
     recorded in the minutes of the meetings of the Committee.

          8.9.4  Any person or group of persons may serve in more than one
     fiduciary capacity with respect to the Plan.

          8.9.5  Any named fiduciary under the Plan, and any fiduciary
     designated by a named fiduciary pursuant to Section 8.9.2 to whom such
     power is granted by a named fiduciary under the Plan, may employ one or
     more persons to render advice with regard to any responsibility such
     fiduciary has under the Plan.

          8.9.6  The Board of Directors of the Company, or any director to whom
     such right shall be allocated, may appoint an investment manager or
     managers, as defined in section 3(38) of ERISA, to manage (including the
     power to acquire, invest and dispose of) any assets of the Plan.

          8.9.7  Except to the extent otherwise provided by law, if any duty or
     responsibility of a named fiduciary has been allocated or delegated to any
     other person in accordance with any provision of this Plan or of the Trust
     Agreement, then such named fiduciary shall not be liable for an act or
     omission of such person in carrying out such duty or responsibility.

     8.10  Plan Administrator.  The Vice President and Chief Financial Officer
           ------------------                                                 
of Martin Marietta Corporation shall appoint a person to serve as Administrator
of the Plan, as defined in section 3(16)(A) of ERISA.

     8.11  Notices and Elections.  An Employee shall deliver to the Committee
           ---------------------                                             
all directions, orders, designations, notices or other communications on
appropriate forms to be

                                      58
<PAGE>
 
furnished by the Committee.  The Committee shall also receive notices or other
communications for Participants from the Trustee and transmit them to the
Participants.  All elections which may be made by an Employee under this Plan
shall be made in a time, manner and form determined by the Committee unless a
specific time, manner or form is set forth in the Plan.

     8.12  Taxes Payable by Trustee.  Taxes, if any, other than transfer taxes,
           ------------------------                                            
payable by the Trustee shall be charged against the Tax Deferred Accounts pro
rata to the values of the cash and/or securities affected.

     8.13  Credited Service.  "Credited Service" means for any Employee his/her
           ----------------                                                    
Company Service Credit; provided, however, that in any case where it will
produce a result more favorable to the Employee, an Employee's Credited Service
shall be determined in accordance with the following provisions:

          8.13.1  Credited Service is the total of the period of elapsed time
     which begins as of the date an Employee first performs an hour of service
     with the Company or, prior to April l, 1984, Union Carbide Corporation and,
     except as otherwise provided in this Section 8.13, ends as of his/her
     severance from service date, as provided in Section 8.13.2.  An "hour of
     service" is each hour for which an Employee is paid, or entitled to
     payment, for the performance of duties for the Company, an Affiliate, or,
     prior to April 1, 1984, Union Carbide Corporation.

          8.13.2  An Employee's severance from service date shall be the earlier
     of:

          (a)  the date the Employee quits, retires, is discharged or dies; or

          (b)  the first anniversary of the first date of the Employee's absence
          for any other reason.

                                      59
<PAGE>
 
          8.13.3  If an Employee performs an hour of service with the Company
     or, prior to April 1, 1984, Union Carbide Corporation within twelve months
     of the date he/she quits, retires, is discharged, or is first absent for
     any other reason, such Employee shall be deemed not to have severed his
     service due to such quit, retirement, discharge or absence.

          8.13.4  Credited Service shall be the aggregate of all an Employee's
     periods of Credited Service, provided that periods of Credited Service
     before and after a period of severance will be aggregated only when:

          (a)  an Employee's number of consecutive one-year periods of severance
          is less than the greater of (A) 5 years or (B) the aggregate number of
          years of Credited Service that occurred before the period of
          severance; and

          (b)  such Employee has at least one year of service after such period
          of severance.

          8.13.5  A "period of severance" is the period of time commencing on an
     Employee's severance from service date and ending on the date on which the
     Employee again performs an "hour of service" as defined in Section 8.13.1;
     provided, however, that, effective as of January l, 1985, if an Employee is
     absent from service because of pregnancy, the birth of the Employee's
     child, the placement of a child with the Employee for adoption, or the need
     to care for such child during the period immediately following such birth
     or placement, such Employee shall be deemed to have had continuous service
     during such absence, subject to regulations adopted by the Committee in
     conformance with sections 410(A)(5)(E) and 411(a)(6)(E) of the Code and
     regulations thereunder.

                                      60
<PAGE>
 
     8.14  Company Service Credit.  "Company Service Credit" is based upon
           ----------------------                                         
employment by the Company and by any subsidiary of the Company, by any
predecessor of such a subsidiary and by any company acquired by the Company or
by any subsidiary of the  Company or, prior to April 1, 1984, by Union Carbide
Corporation.  Company Service Credit of all Employees who were on the payroll on
the date the Retirement Program Plan for Employees of Union Carbide Corporation
and its Participating Subsidiary Companies became effective has been established
with respect to their employment prior to that date.  Company Service Credit for
employment subsequent to that date and Company Service Credit of all new
Employees hired after that date will be determined under the following rules:

          8.14.1  If an Employee receives salary, wages or commission from the
     Company, a subsidiary of the Company, or, prior to April l, 1984, Union
     Carbide Corporation, without interruption, his/her Company Service Credit
     begins as of the date such salary, wages or commission is first paid to
     such Employee.

          8.14.2  If an Employee is laid off by the Company, a subsidiary of the
     Company, or, prior to April l, 1984, Union Carbide Corporation on account
     of a reduction in force and through no fault of his/her own:

          (a)  if such layoff continues not more than three (3) consecutive
          years, Company Service Credit will be given for service prior to such
          layoff; and

          (b)  if such layoff continues more than three (3) consecutive years,
          no Company Service Credit will be given for service prior to such
          layoff.

          8.14.3  In case of absence caused by temporary suspension of work
     (other than "layoff" as in Section 8.14.2), or absence-with-leave (except
     long term disability) which is authorized by the Company, any subsidiary of
     the Company, or, prior to

                                      61
<PAGE>
 
     April l, 1984, Union Carbide Corporation, and does not exceed three months,
     employment will be considered as continuous without any reduction for such
     absence.  However, in case such absence does exceed three months, the
     period of absence in excess of three months will not be considered as
     Company Service Credit unless Company Service Credit is otherwise
     authorized by the Company, a subsidiary of the Company, or, prior to April
     1, 1984, Union Carbide Corporation for such period.  If an Employee who is
     thus absent fails to return to work when able to do so, and at the time
     designated by the Company or a subsidiary of the Company or, prior to April
     1, 1984, Union Carbide Corporation, he/she will be considered as
     voluntarily terminating his/her employment and his/her Company Service
     Credit shall end as of the date on which such absence commenced.

          8.14.4  In case of rehire or reinstatement subsequent to discharge for
     cause or resignation at the request of the Company, a subsidiary of the
     Company, or, prior to April l, 1984, Union Carbide Corporation, Company
     Service Credit will be given for service only since the last date of rehire
     or reinstatement by the Company or the subsidiary, unless Company Service
     Credit is otherwise authorized by the Company or the subsidiary or, prior
     to April 1, 1984, Union Carbide Corporation, for the period prior to such
     rehire or reinstatement.

          8.14.5  An Employee on the active payroll of Union Carbide Corporation
     on January l, 1973, or rehired thereafter, who had been credited with
     Company Service Credit for one or more periods of prior employment but who
     had lost such credit because

          (a)  a layoff lasted for more than three years, or

          (b)  termination was for any other cause,

                                      62
<PAGE>
 
     will have such prior Company Service Credit restored upon completing a
     total of two years of currently accredited Company Service Credit following
     reemployment.

     8.15  Transfer of a Subsidiary, Division, Branch or Business Unit.
           -----------------------------------------------------------  
Notwithstanding anything herein to the contrary, if at any time any subsidiary
or any division, branch or business unit of the Company shall be transferred as
a going business and on that account certain Participants shall remain in the
employ of any such subsidiary or shall transfer to the acquiring company, the
Board of Directors may, if they so determine, provide for the withdrawal and
segregation of the  assets of the 401(k) Plan Trust Fund attributable to such
Participants, based on the value of their respective accrued benefits including
Company payments in the 401(k) Plan Trust Fund determined as though such
Participants had terminated employment as of the date of such transfer as a
going business.  Provided the subsidiary or acquiring company continues the Plan
or adopts a similar 401(k) Plan, as the case may be, a proportionate amount of
the assets of the 401(k) Plan Trust Fund equivalent to the value of such accrued
benefits as so determined may be transferred to the 401(k) Plan Trust Fund
created by the subsidiary or acquiring company for the benefit of such
Participants.

                                      63
<PAGE>
 
                                   ARTICLE IX

                  AMENDMENT, TERMINATION, ADOPTION AND MERGER
                  -------------------------------------------

     9.1  Modification or Amendment of Plan.  The Company reserves the right at
          ---------------------------------                                    
any time and from time to time to amend the Plan in whole or in part; provided
that, except as provided in Section 9.4 or as otherwise permitted by law, no
amendment shall be made which (a) would cause or permit any part of the corpus
of the Trust Fund to be diverted to purposes other than for the exclusive
benefit of Participants or their Beneficiaries, (b) would cause or permit any
portion of the assets of the Trust Fund to revert to or become the property of
the Company or an Affiliate at any time, or (c) would divest any Participant of
any amount previously credited to his/her Tax Deferred Account.

     9.2  Termination of Plan or Discontinuance of Contributions.  The Plan may
          ------------------------------------------------------               
be terminated by the Company at any time in the Company's sole discretion, in
whole or in part.  Notwithstanding any other provision of the Plan, upon
complete termination of the Plan or the complete discontinuance of contributions
thereunder, 100 percent of each Participant's Tax Deferred Account shall be non-
forfeitable.  Upon any such termination, the Committee shall instruct the
Trustee either (a) to distribute or dispose of the net assets of the Trust Fund
(remaining after payment of or provision for all expenses of final
administration and liquidation) exclusively for the  benefit of all Participants
(or their Beneficiaries, as the case may be) according to their respective
shares of the Trust Fund as of the date of such termination or discontinuance,
or (b) to continue the Trust Fund with distributions to be made at the time and
in the manner provided for by Article IV.  In the event of any partial
termination of the Plan (within the meaning of section 411(d)(3) of the Code),
100 percent of

                                      64
<PAGE>
 
the Tax Deferred Account of each Participant affected by such partial
termination shall be non-forfeitable

     9.3  Expenses of Termination.  In the event of the complete or partial
          -----------------------                                          
termination of the Plan, the expenses incident thereto shall be a prior claim
and lien upon the assets of the Trust Fund and shall be paid or provided for
prior to the distribution of any benefits pursuant to such termination, unless
such expenses are paid by the Company.

     9.4  Amendments Required for Qualification.  All provisions of this Plan,
          -------------------------------------                               
and all benefits and rights granted hereunder, are subject to any amendments,
modifications or alterations which are necessary from time to time to qualify
the Plan under section 401(a) of the Code or corresponding provisions of
subsequent law, to continue the Plan as so qualified, to meet the requirements
of section 401(k) of the Code or to comply with any other provision of law.
Accordingly, notwithstanding any other provisions of this Plan, the Company may
amend, modify or alter the Plan with retroactive effect in any respect or manner
necessary to qualify the Plan under  section 401(a) of the Code, to continue the
Plan as so qualified, to meet the requirements of section 401(k) of the Code, or
to comply with any other provision of law.

     9.5  Merger.  Subject to the provisions of this Section 9.5, the Plan may
          ------                                                              
be amended to provide for the merger of the Plan, in whole or in part, or a
transfer of all or a part of its assets or liabilities, to any other qualified
plan within the meaning of section 401(a) or 403(a) of the Code, including such
a merger or transfer in lieu of a distribution which might otherwise be required
under the Plan.  In the event of such a merger or consolidation of this Plan or
transfer of its assets or liabilities to any other plan in whole or in part,
each Participant shall be entitled to a benefit immediately after the merger,
consolidation or transfer (if such other plan then terminated) which is equal to
or greater than the benefit

                                      65
<PAGE>
 
he/she would have been entitled to receive immediately before the merger,
consolidation or transfer (if the Plan had then been terminated).

     9.6  Portsmouth, Ohio.  Effective January 1, 1989 with respect to any
          ----------------                                                
Employee of the Company who was a participant in the Savings Plan for Salaried
Employees at the Portsmouth Uranium Enrichment Plant or the Savings Plan for
Bargaining Unit Employees at the Portsmouth Uranium Enrichment Plant, Company
Service Credit under the Plan shall include all service which was recognized for
the purpose of determining benefits under said plans as in effect prior to their
merger into this Plan.

                                      66
<PAGE>
 
                                   ARTICLE X

                                 MISCELLANEOUS
                                 -------------

     10.1  Claims Procedure.  If a claim for benefits under this Plan is wholly
           ----------------                                                    
or partially denied, the claimant shall be provided with a notice setting forth
the specific reason or reasons for the denial, specific reference to pertinent
Plan provisions on which the denial is based, a description of any additional
material or information necessary for the claimant to perfect the claim, an
explanation of why such material or information is necessary, and an explanation
of the Plan's claim review procedure.  Within 60 days after notification of a
denial of benefits, such claimant may, upon written application, appeal such
denial to the Administrator, Martin Marietta Energy Systems, Inc., for a review.
Such claimant (or his/her duly authorized representative) may review pertinent
documents and submit issues and comments in writing.  Within 60 days of receipt
of such written application for review, the Administrator shall make a decision
in writing, including specific reasons for the decision, with references to the
pertinent Plan provisions.  Under special circumstances, the Administrator may
extend the time for processing such a review, but a decision shall be rendered
not later than 120 days after receipt of the request for review.  In the event
that government regulations shall impose a different standard for review, such
required standard shall be followed in lieu of the above.

     10.2  Plan Not an Employment Contract.  Neither the adoption of this Plan
           -------------------------------                                    
by the Company nor any action of the Company, the Committee, or the Trustee
under this Plan, nor participation in this Plan or failure to participate in
this Plan by any person, shall be held or construed to confer upon any person
any legal right to be continued as an employee of the Company or an Affiliate.
All employees, whether or not they participate in this Plan, shall

                                      67
<PAGE>
 
be subject to discharge to the same extent as they would have been if this Plan
had never been adopted.

     10.3  Consent to Terms of Plan and Trust Agreement.  An Employee by
           --------------------------------------------                 
becoming a Participant in this Plan consents and agrees to all the terms and
provisions of this Plan, the Trust Agreement, and any rules and regulations
adopted by the Committee pursuant to the provisions of this Plan, as they may
each be amended from time to time.

     10.4  Transfer of Interest Not Permitted.  Except as respects any
           ----------------------------------                         
assignment or encumbrance to secure a loan from the Trust Fund which is made
pursuant to Section 4.5, or an assignment of an interest in the Trust Fund made
pursuant to a domestic relations order, described in Section 10.4.1, no person
shall have any power to assign, transfer, pledge, encumber, commute, or
anticipate any interest in the Trust Fund or in any payment to be made under
this Plan, and any attempt to assign, transfer, pledge, encumber, commute or
anticipate the same shall be void; nor shall any such interest be in any way
liable for or  subject to the debts, contracts, liabilities, engagements or
torts of the person entitled to such benefit or payment or subject to levy,
garnishment, attachment, execution or other legal or equitable process.

          10.4.1  Exception For Qualified Domestic Relations Order
                  ------------------------------------------------

          10.4.1.1.  Definitions
                     -----------

               The term "qualified domestic relations order" means any judgment,
          decree, or order (including approval of a property settlement
          agreement) which:

               (a) relates to the provision of child support, alimony payments,
               or marital property rights to a spouse, former spouse, child, or
               other dependent of a Participant;

                                      68
<PAGE>
 
               (b) is made pursuant to a state domestic relations law (including
               a community property law); and

               (c) which meets the requirements of subparagraph 10.4.1.2.

          10.4.1.2  Requirements For a Qualified Domestic Relations Order
                    -----------------------------------------------------

               The provisions of Section 10.4 shall not be applicable to a
          domestic relations order and payment of the right or interest of a
          Participant in the Plan or in his accounts thereunder shall be made in
          accordance with the terms of such order provided that such order:

               (a) creates or recognizes the existence of an alternate payee's
               (as hereinafter defined) right to, or assigns to an alternate
               payee the right to, receive all or a portion of the right or
               interest of a Participant in the Plan or in his accounts
               thereunder;

               (b) clearly specifies

                    (i) the name and the last known mailing address (if any) of
                    the Participant and the name and mailing address of each
                    alternate payee covered by the order;

                    (ii) the amount or percentage of the right or interest of
                    the Participant to be paid by the Plan to each such
                    alternate payee or the manner in which such amount or
                    percentage is to be determined;

                    (iii) the number of payments or period to which such order
                    applies; and

                    (iv) the name of each plan to which such order applies;

                                      69
<PAGE>
 
               (c) does not require the Plan to provide any type or form of
               benefit, or any option, not otherwise provided under the Plan;

               (d) does not require the Plan to provide increased benefits
               (determined on the basis of actuarial value); and

               (e) does not require the payment of the right or interest of the
               Participant to an alternate payee which is required to be paid to
               another alternate payee under another order previously determined
               to be a qualified domestic relations order.

          10.4.1.3  Payments Prior to Termination of Employment
                    -------------------------------------------

               In the case of any payment made before a Participant has
          terminated employment with the Company, a qualified domestic relations
          order shall not be considered as failing to meet the requirements of
          subsection (c) of subparagraph 10.4.1.2 solely because such order
          requires that payment of the right or interest of the Participant be
          made to an alternate payee:

               (a) on or after the date on which the Participant attains (or
          would have attained) the earliest retirement age which shall be
          defined, for purposes of this Section 10.4.1, as the earlier of (1)
          the date on which the Participant is entitled to a distribution under
          the Plan, or (2) the later of (x) the date the Participant attains age
          50 or (y) the earliest date on which the Participant could begin
          receiving benefits under the Plan if the Participant terminated
          employment with the Company;

               (b) as if the Participant had retired on the date on which such
          payment is to begin under such order (but taking into account only the
          present value of the right or interest of the Participant actually
          accrued and not taking into


                                      70
<PAGE>
 
          account the present value of any subsidy of the Employer for early
          retirement); and

               (c) in any form in which such right or interest may be paid under
          the Plan to the Participant (other than in the form of a joint and
          survivor annuity with respect to the alternate payee and his
          subsequent spouse).

     For purposes of subsection (b) above, the interest rate assumption used in
determining the present value of a Participant's benefits shall be determined
from time to time by the Committee on a non-discriminatory basis.

          10.4.1.4  Former Spouse
                    -------------
               To the extent provided in any qualified domestic relations order:

               (a) the former spouse of a Participant shall be treated as a
               surviving spouse of such Participant for purposes of section
               401(a)(11) of the Code; and

               (b) if married for at least one year to the Participant, such
               former spouse shall be treated as meeting the requirements of
               section 401(a)(11)(d) of the Code.

          10.4.1.5  Notice
                    ------

               The Committee shall promptly notify a Participant and any other
          alternate payee of the receipt of a domestic relations order and of
          the Plan's procedure for determining whether the order satisfies the
          requirements of a qualified domestic relations order under this
          Section 10.4.1.  Within a reasonable period of time after the receipt
          of such order, the Committee, in accordance with such procedures as it
          shall from time to time establish, shall determine whether such order
          is a qualified domestic relations order under this


                                      71
<PAGE>
 
          Section 10.4.1 and shall notify the Participant and each alternate
          payee of such determination.  During any period of time in which the
          issue of whether a domestic relations order qualifies as a domestic
          relations order under this Section 10.4.1 is being determined by the
          Committee, by a court of competent jurisdiction, or otherwise, the
          Committee shall separately account for the amounts ("segregated
          amounts") which would have been payable to the alternate payee during
          such period if the order had been determined to be a domestic
          relations order under this Section 10.4.1.  If within the eighteen
          (18) month period beginning on the date on which the first payment
          would be required to be made under the domestic relations order such
          order is determined to be a domestic relations order under this
          Section 10.4.1, the Committee shall pay the segregated amounts (plus
          any interest thereon) to the person or persons entitled thereto.  If
          within such eighteen (18) month period it is determined that such
          order is not a domestic relations order under this Section 10.4.1, or
          the issue as to whether such order so qualifies is not resolved, then
          the Committee shall pay the segregated amounts (plus any interest
          thereon) to the person or persons who would have been entitled to such
          amounts if there had been no order.  Any determination that an order
          is a domestic relations order under this Section 10.4.1 which is made
          after the end of such eighteen-month period shall be applied
          prospectively only.

          10.4.1.6  Definition of Alternate Payee
                    -----------------------------

               The term "alternate payee" means any spouse, former spouse,
          child, or other dependent of a Participant who is recognized by a
          qualified domestic


                                      72
<PAGE>
 
          relations order as having a right to receive all, or a portion of, the
          benefits payable under the Plan with respect to such Participant.

          10.4.1.7  Transitional Rules
                    ------------------

               The provisions of this Section 10.4.1 shall become effective as
          of January l, 1985; provided however, that in the case of a domestic
          relations order entered before such date, the Committee:

               (a) shall treat such order as a qualified domestic relations
               order under this Section 10.4.1 if the Trustees are paying
               benefits pursuant to such order on January 1, 1985; and

               (b) may treat any other domestic relations order entered before
               January l, 1985 as a qualified domestic relations order under
               this Section 10.4.1 even if such order does not meet the
               requirements of the preceding provisions of this Section 10.4.1.

     10.5  Obligations of Company Limited.  The Company assumes no obligations
           ------------------------------                                     
under this Plan except those specifically stated in this Plan.  No person shall
have any right to participate in profits by reason of this Plan except to the
extent expressly set forth herein.  The Company shall be under no legal
obligation to make any contributions to the Trust Fund except as expressly
provided herein.

     10.6  Separation of Invalid Provisions.  If any provision of this Plan or
           --------------------------------                                   
the Trust Agreement is held invalid, the remainder of the Plan or Trust
Agreement shall not be affected thereby.

     10.7  Payment to a Minor or Incompetent.  In the event that any amount is
           ---------------------------------                                  
payable to a minor or other legally incompetent person, such amount may be paid
in any of the following ways, as the Committee in its sole discretion shall
determine:


                                      73
<PAGE>
 
          10.7.1  To the legal representative of such minor or other incompetent
     person;

          10.7.2  Directly to such minor or other incompetent person;

          10.7.3  To a parent or guardian of such minor, or to a custodian for
     such minor under the Uniform Gifts to Minors Act (or similar statute) of
     any jurisdiction or to the person with whom such minor shall reside.

Payment to such minor or incompetent person, or to such other person as may be
determined by the Committee, as above provided, shall discharge the Company, the
Committee, the Trustee and any insurance company or other person or corporation
making such payment pursuant to the direction of the Committee, and none of the
foregoing shall be required to see to the proper application of any such payment
to such person pursuant to the provisions of this Section 10.7.

     10.8  Doubt as to Right to Payment.  If at any time any doubt exists as to
           ----------------------------                                        
the right of any person to any payment hereunder or as to the amount or time of
such payment (including, without limitation, any doubt as to identity, or any
case in which any notice has been received from any other person claiming any
interest in amounts payable hereunder, or any case in which a claim from other
persons may exist by reason of community property or similar laws), the
Committee shall be entitled, in its discretion, to direct the Trustee (or any
insurance company) to hold such sum as a segregated amount in trust until such
right or amount or time is determined or until order of a court of competent
jurisdiction, or to pay  such sum into court in accordance with appropriate
rules of law in such case then provided, or to make payment only upon receipt of
a bond or similar indemnification (in such amount and in such form as is
satisfactory to the Committee).

     10.9  Forfeiture Upon Inability to Locate Distributee.  Notwithstanding any
           -----------------------------------------------                      
other provision of the Plan, in the event that the Committee cannot locate any
person to whom a

                                      74
<PAGE>
 
payment is due under the Plan, and no other payee has become entitled thereto
pursuant to any provision of the Plan, the benefit in respect of which such
payment is to be made shall be forfeited at such time as the Committee shall
determine in its sole discretion (but in all events prior to the time such
benefit would otherwise escheat under any applicable state law); provided that
any benefit so forfeited shall be restored if such person subsequently makes a
valid claim for such benefit.

     10.10  Contributions Conditioned on Initial Qualification and
            ------------------------------------------------------
Deductibility.  Notwithstanding any other provision of this Plan, each Before
- -------------
Tax Contribution, related Company Contribution and Additional Contribution made
by the Company under this Plan is conditioned on:

          10.10.1  A determination by the Internal Revenue Service that the Plan
     qualifies under section 401 of the Code for the Plan Year as to which the
     Company first makes a contribution hereunder; and

          10.10.2  The deductibility of such contribution under section 404 of
     the Code.

     10.11  No Diversion of Trust Fund.  It shall be impossible at any time for
            --------------------------                                         
any part of the Trust Fund to be (within the taxable year or thereafter) used
for or diverted to purposes other than for the exclusive benefit of Participants
and their Beneficiaries (including the payment of the expenses of the
administration of the Plan and of the Trust); provided that:

          10.11.1  A contribution that is made by the Company by a mistake of
     fact shall be returned to the Company upon its request within one year
     after the payment of the contribution; or

          10.11.2  A contribution that is conditioned upon its deductibility
     under section 404 of the Code shall be returned to the Company upon its
     request, to the extent that

                                      75
<PAGE>
 
     the contribution is disallowed as a deduction, within one year after such
     disallowance; or

          10.11.3  A contribution that is conditioned on qualification of the
     Plan under section 401 of the Code shall, if the Plan does not so qualify,
     be returned to the Company within one year after the date of denial of
     qualification of the Plan.

Subject to Article IX, the Trust shall continue for such time as may be
necessary to accomplish the purpose for which it is created.

     10.12  Usage.  Whenever applicable the masculine gender, when used in the
            -----                                                             
Plan, shall include the feminine and neuter genders, and the singular shall
include the plural.

     10.13  Governing Law.  The Plan shall be governed by, construed and
            -------------                                               
administered under the law of the State of Tennessee without regard to the
principles of conflict of laws, to the extent not preempted by Federal law.

     10.14  Captions.  The captions contained herein are inserted only as a
            --------                                                       
matter of convenience and for reference and in no way define, limit, enlarge or
describe the scope or intent of the Plan and in no way shall affect the Plan or
the construction of any provision thereof.

                                      76
<PAGE>
 
     IN WITNESS WHEREOF, and as evidence of the adoption of this Plan, the
Company has caused this instrument to be signed by its duly authorized officer
and its corporate seal to be hereunto affixed and attested this ____ day of
____________ 1993.

                              MARTIN MARIETTA ENERGY
                              SYSTEMS, INC.


                              By__________________________________
                                 (title)

[Seal]

ATTEST:

__________________________ 
(title)



                                      77

<PAGE>

                                                                     EXHIBIT 4-B
 
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.

                    401(k) SAVINGS PLAN FOR HOURLY EMPLOYEES

                            Effective April 1, 1984

                   (Amended and Restated as of April 1, 1990)
<PAGE>
 
                               TABLE OF CONTENTS
                               -----------------

                                                                          Page
                                                                          ----
ARTICLE I
DEFINITIONS..............................................................   1
      1.1  "Additional Contribution".....................................   1
      1.2  "Affiliate"...................................................   1
      1.3  "Before Tax Contribution".....................................   1
      1.4  "Beneficiary".................................................   1
      1.5  "Code"........................................................   1
      1.6  "Committee"...................................................   1
      1.7  "Company".....................................................   2
      1.8  "Company Contribution"........................................   2
      1.9  "Company Service Credit"......................................   2
     1.10  "Compensation"................................................   2
     1.11  "Credited Service"............................................   2
     1.12  "Disability"..................................................   2
     1.13  "Earnings"....................................................   2
     1.14  "Eligible Employee"...........................................   3
     1.15  "Employee"....................................................   3
     1.16  "ERISA".......................................................   3
     1.17  "Highly Compensated Employee".................................   4
     1.18  "Normal Retirement Date"......................................   4
     1.19  "Participant".................................................   4
     1.20  "Personal Investment Account".................................   5
     1.21  "Plan"........................................................   5
     1.22  "Plan Year"...................................................   5
     1.23  "Savings Plan"................................................   5
     1.24  "Tax Deferred Account"........................................   5
     1.25  "Termination of Employment"...................................   5
     1.26  "Trust Agreement".............................................   5
     1.27  "Trust Fund"..................................................   5
     1.28  "Trustee".....................................................   5
     1.29  "Valuation Date"..............................................   5
 
ARTICLE II
PARTICIPATION, CONTRIBUTIONS AND VESTING.................................   7
     2.1   Participation.................................................   7
     2.2   Exclusions....................................................   7
     2.3   Before Tax Contributions......................................   8
     2.4   Adjustment of Before Tax Contributions........................   9
     2.5   Company Contributions.........................................  12
     2.6   Additional Contributions......................................  12
     2.7   Transfers from the Savings Plan...............................  13
 
<PAGE>
 
     2.8   Change from Eligible Employee to Ineligible Employee and from
           Ineligible Employee to Eligible Employee......................  14
     2.9   Revocation of Compensation Reduction..........................  15
     2.10  Limitations on Contributions..................................  15
     2.11  Vesting.......................................................  16
     2.12  Limitations on Before Tax Contributions and Additional 
           Contributions.................................................  16
     2.13  401(m) Limitations............................................  16
 
ARTICLE III
INVESTMENT AND VALUATION OF TAX DEFERRED ACCOUNTS........................  18
     3.1   General.......................................................  18
     3.2   Investment Options............................................  18
     3.3   Union Carbide Corporation Stock Fund..........................  19
     3.4   Investment Manager............................................  20
     3.5   Change of Investments.........................................  20
     3.6   Special Rules for Company Officers............................  20
     3.7   Dividends.....................................................  21
     3.8   Rights, Warrants and Scrip....................................  22
     3.9   Instructions By a Participant For His/Her Tax Deferred 
           Account.......................................................  22
     3.10  Purchases and Sales...........................................  22
     3.11  Costs and Expenses............................................  23
     3.12  Custody of Securities.........................................  23
     3.13  Voting Rights.................................................  23
     3.14  Valuation of Tax Deferred Accounts............................  24
     3.15  Statements Furnished Participants.............................  26
 
ARTICLE IV
DISTRIBUTIONS, WITHDRAWALS AND LOANS.....................................  27
     4.1   Distribution on Termination of Employment.....................  27
     4.2   Rehire Prior to Distribution..................................  34
     4.3   Commencement of Benefits......................................  35
     4.4   Withdrawal by Participant During Employment...................  35
     4.5   Loans.........................................................  37
 
ARTICLE V
LIMITATION ON MAXIMUM CONTRIBUTIONS AND BENEFITS UNDER ALL PLANS.........  41
     5.1   General.......................................................  41
     5.2   Affiliate.....................................................  41
     5.3   Limitation Year...............................................  41
     5.4   Annual Additions..............................................  41
     5.5   Defined Benefit and Defined Contribution Plans................  42
     5.6   Aggregation of Defined Contribution Plans.....................  42
     5.7   Defined Contribution Plan Limitation..........................  42
     5.8   Defined Contribution Plan Fraction Determination..............  43
     5.9   Defined Benefit Plan Fraction Determination...................  43

                                      ii
<PAGE>
 
     5.10  Combined Limitation...........................................  44
     5.11  Alternative Method............................................  44
     5.12  Participation in Multiple Plans...............................  44
     5.13  Notice of Reduction...........................................  45
 
ARTICLE VI 
TOP-HEAVY RULES..........................................................  46
     6.1   Top-Heavy Plan................................................  46
     6.2   Minimum Top-Heavy Benefits....................................  48
     6.3   Reduction in Combined Limitation..............................  48
     6.4   Key Employee..................................................  48
     6.5   Automatic Removal.............................................  49
 
ARTICLE VII 
TRUST....................................................................  50
     7.1   Trustee.......................................................  50
     7.2   Trust Expenses................................................  50
     7.3   Plan-to-Plan Transfers........................................  50
 
ARTICLE VIII 
ADMINISTRATION..........................................................   52
     8.1   Administrative Committee......................................  52
     8.2   Limitation of Liability; Indemnity............................  52
     8.3   Compensation and Expenses.....................................  53
     8.4   Voting, Chairman, Subcommittees...............................  53
     8.5   Payment of Benefits...........................................  54
     8.6   Powers and Authority; Action Conclusive.......................  54
     8.7   Counsel and Agents............................................  56
     8.8   Reliance on Information.......................................  56
     8.9   Fiduciaries...................................................  56
     8.10  Plan Administrator............................................  58
     8.11  Notices and Elections.........................................  58
     8.12  Taxes Payable by Trustee......................................  59
     8.13  Credited Service..............................................  59
     8.14  Company Service Credit........................................  60
     8.15  Transfer of a Subsidiary, Division, Branch or Business Unit...  63
 
ARTICLE IX
AMENDMENT, TERMINATION, ADOPTION AND MERGER..............................  64
     9.1   Modification or Amendment of Plan.............................  64
     9.2   Termination of Plan or Discontinuance of Contributions........  64
     9.3   Expenses of Termination.......................................  65
     9.4   Amendments Required for Qualification.........................  65
     9.5   Merger........................................................  65
     9.6   S.C. Security, Inc............................................  66
 
                                     iii 
<PAGE>
 
ARTICLE X
MISCELLANEOUS............................................................ 67
     10.1  Claims Procedure.............................................. 67
     10.2  Plan Not an Employment Contract............................... 67
     10.3  Consent to Terms of Plan and Trust Agreement.................. 68
     10.4  Transfer of Interest Not Permitted............................ 68
     10.5  Obligations of Company Limited................................ 73
     10.6  Separation of Invalid Provisions.............................. 73
     10.7  Payment to a Minor or Incompetent............................. 73
     10.8  Doubt as to Right to Payment.................................. 74
     10.9  Forfeiture Upon Inability to Locate Distributee............... 74
     10.10 Contributions Conditioned on Initial Qualification           
           and Deductibility............................................. 74
     10.11 No Diversion of Trust Fund.................................... 75
     10.12 Usage......................................................... 76
     10.13 Governing Law................................................. 76
     10.14 Captions...................................................... 76

                                      iv
<PAGE>
 
                    THE MARTIN MARIETTA ENERGY SYSTEMS, INC.
                    401(k) SAVINGS PLAN FOR HOURLY EMPLOYEES

                                  INTRODUCTION
                                  ------------

          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Hourly Employees is the successor plan to the 401(k) Opportunity Plan for Hourly
Nuclear Division Employees of Union Carbide Corporation.  The transfer of the
Plan occurred pursuant to the assumption by Martin Marietta Energy Systems, Inc.
from Union Carbide Corporation of the contract to operate the Department of
Energy facilities in Oak Ridge, Tennessee and Paducah, Kentucky.  The Plan was
adopted in its current form effective April 1, 1984.  Any provision regarding a
date prior to April l, 1984 refers either to employment with Union Carbide
Corporation or to participation in the predecessor plan as in effect at that
time.  The Plan as in effect on April 1, 1984 shall apply to employees covered
by collective bargaining agreements, until such date as the Plan shall have been
accepted for such employees by collective bargaining.

          This Plan is established by Martin Marietta Energy Systems, Inc., a
Delaware Corporation and a subsidiary of Martin Marietta Corporation, for the
exclusive benefit of its eligible employees and their beneficiaries.
Participation in this Plan by employees is entirely voluntary.

                                       v
<PAGE>
 
                                   ARTICLE I

                                  DEFINITIONS
                                  -----------
          1.   Definitions.  As used in this Plan, the following terms shall
               -----------                                                  
have the designated meaning:

          1.1  "Additional Contribution" shall mean a contribution to a
                -----------------------                                
Participant's Tax Deferred Account made pursuant to Section 2.6 of this Plan.

          1.2  "Affiliate" shall mean, except as otherwise provided in Article
                ---------                                                     
V, each of (a) any corporation (other than the Company) of which at least 80% of
the total combined voting power of all classes of stock entitled to vote is
owned at the time of reference, either directly or indirectly, by the Company,
(b) any other trade or business (other than the Company), whether or not
incorporated, which, at the time of reference, is controlled by or under common
control with the Company, within the meaning of section 414(c) of the Code or
(c) any member (other than the Company), at the time of reference, of an
affiliated service group within the meaning of section 414(m) of the Code, which
includes the Company.

          1.3  "Before Tax Contribution" shall mean a contribution to a
                -----------------------                                
Participant's Tax Deferred Account made pursuant to Section 2.3 of this Plan.

          1.4  "Beneficiary" shall mean the person, persons or estate entitled
                -----------                                                   
under Section 4.1.5 to receive any amount under this Plan in the event of a
Participant's death.

          1.5  "Code" shall mean the Internal Revenue Code of 1986, as from time
                ----                                                            
to time amended.

          1.6  "Committee" shall mean the Administrative Committee provided for
                ---------                                                      
in Article VIII of this Plan.
<PAGE>
 
          1.7  "Company" shall mean Martin Marietta Energy Systems, Inc., a
                -------                                                    
Delaware corporation, any predecessor thereof, and any successor thereof by
merger, consolidation or otherwise.

          1.8  "Company Contribution" shall mean a contribution to a
                --------------------                                
Participant's Tax Deferred Account made pursuant to Section 2.5 of this Plan.

          1.9  "Company Service Credit" shall mean the period of service
                ----------------------                                  
determined under Section 8.14 of this Plan.

          1.10 "Compensation" shall mean a Participant's regular, basic hourly
                ------------                                                  
rate of pay (including any cost of living adjustments) for his/her regularly
scheduled hours, determined prior to any reduction in such hourly rate of pay
for Before Tax Contributions and Additional Contributions to this Plan or any
other plan maintained by the Company which meets the requirements of Code
section 125 and which provides for pre-tax contributions.  For purposes of this
Plan, a Participant's regular, basic hourly rate of pay shall include any shift
premium paid to such Participant.

          1.11 "Credited Service" shall mean the period of service credited to
                ----------------                                              
an Employee for purposes of determining his/her eligibility to participate in
this Plan, as determined under Section 8.13 of this Plan.

          1.12 "Disability" shall mean a Participant's total physical or mental
                ----------                                                     
inability to perform any work for compensation or profit in any occupation for
which he/she is reasonably qualified by reason of training, education or
ability, and which is adjudged to be permanent, as determined by the Committee
on the basis of medical evidence satisfactory to it.

          1.13 "Earnings" shall mean total compensation actually paid or made
                --------                                                     
available by the Company and its Affiliates for such year, including, but not
limited to, bonuses, income from sources without the United States whether or
not excludable for Federal income tax

                                       2
<PAGE>
 
purposes, amounts related to the value of property transferred in connection
with the performance of services which are includable for Federal income tax
purposes under section 83(b) of the Code, and taxable income attributable to
employer-provided life insurance.  Earnings shall not include deferred
compensation (other than payments under an unfunded plan that are currently
includable in income,) amounts realized from the exercise of a non-qualified
stock option or a stock appreciation right, exercise payments, amounts
contributed on behalf of a Participant to a plan which meets the requirements of
sections 401(a), and 401(k) of the Code, or other distributions which receive
special tax benefits.  A Participant's Earnings in excess of $200,000 shall not
be taken into account under the Plan for purposes of benefits accruing under the
Plan after December 31, 1988.  Such $200,000  limitation shall be adjusted at
the same time and in such manner as the limitation set forth in section
415(b)(1)(A) of the Code is adjusted under section 415(d) of the Code.

          1.14 "Eligible Employee" shall mean any Employee, other than an
                -----------------                                        
Employee who is a member of a class of Employees excluded from coverage under
this Plan pursuant to Section 2.2, if such individual:

               1.14.1  is compensated on an hourly basis;

               1.14.2  has at least one year of Credited Service; and

               1.14.3  is employed by Martin Marietta Energy Systems, Inc.

          1.15 "Employee" shall mean (a) any individual who, under the rules
                --------                                                    
applicable in determining the employer-employee relationship for purposes of
section 3121 of the Code, has the status of an employee of the Company or an
Affiliate; and (b) any officer of the Company or an Affiliate.

          1.16 "ERISA" shall mean the Employee Retirement Income Security Act of
                -----                                                           
1974, as from time to time amended.  Reference to a specific provision of ERISA
shall include

                                       3
<PAGE>
 
such provision, any valid regulation promulgated thereunder and any comparable
provision of future legislation that amends, supplements or supersedes such
provision.

          1.17 "Highly Compensated Employee" shall mean any Employee who, during
                ---------------------------                                     
the Plan Year or the preceding Plan Year,

               (i)   was at any time a five percent owner (as defined in Section
                     4.1.6.1) of the Employer;

               (ii)  received annual Compensation from an Employer in excess of
                     $75,000 (adjusted in accordance with Code section 414(q));

               (iii) received annual Compensation from the Employer in excess of
                     $50,000 (adjusted in accordance with Code section 414(q))
                     and was in the top 20 percent of Employees when ranked on
                     the basis of annual Compensation during such Plan Year;

               (iv)  was at any time an officer and received annual Compensation
                     greater that 150 percent of the amount in effect under Code
                     section 415(c)(1)(A) for such year; provided, however, that
                     notwithstanding the foregoing, not more than 50 Employees
                     (or, if lesser, the greater of 3 employees or 10 percent of
                     all Employees) shall be treated as officers;

               (v)   was the highest paid officer of an Employer for the Plan
                     Year, if no Employee is treated as an officer under
                     subparagraph (iv);

               (vi)  was a former Employee of the Employer, if such Employee was
                     a Highly Compensated Employee when such Employee separated
                     from service, or was a Highly Compensated Employee at any
                     time after attaining age 55.

          1.18  "Normal Retirement Date" shall mean a Participant's 65th
                 ----------------------                                 
birthday.

          1.19  "Participant" shall mean an Eligible Employee who becomes a
                 -----------                                               
Participant in this Plan pursuant to Section 2.1.

                                       4
<PAGE>
 
          1.20  "Personal Investment Account" shall mean the Personal Investment
                 ---------------------------                                    
Account established under the Savings Plan.

          1.21  "Plan" shall mean this Martin Marietta Energy Systems, Inc.
                 ----                                                      
401(k) Savings Plan for Hourly Employees, as from time to time in effect.

          1.22  "Plan Year" shall mean the twelve-month period starting January
                 ---------                                                     
1 and ending December 31.

          1.23  "Savings Plan" shall mean the Martin Marietta Energy Systems,
                 ------------                                                
Inc. Savings Plan for Salaried and Hourly Employees, as from time to time in
effect.

          1.24  "Tax Deferred Account" shall mean an account setting forth a
                 --------------------                                       
Participant's interest in the Trust Fund, as provided in Article III of this
Plan.

          1.25  "Termination of Employment" and similar references shall mean a
                 -------------------------                                     
Participant's ceasing to be employed by the Company or an Affiliate for any
reason.  A transfer between employment by the Company and employment by an
Affiliate, between employment by Affiliates, or between employment compensated
on a salaried basis and employment compensated on an hourly basis shall not
constitute a termination of employment.

          1.26  "Trust Agreement" shall mean the agreement between the Company
                 ---------------                                              
and the Trustee under which this Plan is funded, as such agreement may be
amended from time to time.

          1.27  "Trust Fund" shall mean the fund created by the Trust Agreement.
                 ----------                                                     

          1.28  "Trustee" shall mean the trustee or trustees from time to time
                 -------                                                      
designated under the Trust Agreement.

          1.29  "Valuation Date" shall mean December 31, 1984, each succeeding
                 --------------                                               
December 31, and any other date on or after January 1, 1984 as of which the
Committee, in its sole discretion, determines the value of all or any portion of
the Trust Fund or determines the

                                       5
<PAGE>
 
actual deferral percentage, as defined in section 401(k)(3)(B) of the Code, of
any Employee or any group of Employees.
 
                                       6
<PAGE>
 
                                   ARTICLE II

                    PARTICIPATION, CONTRIBUTIONS AND VESTING
                    ----------------------------------------

          2.1  Participation.  An Eligible Employee shall become a Participant
               -------------                                                  
in this Plan upon the earlier of:

               2.1.1  his/her authorizing his/her Employer to reduce his/her
          Compensation for each pay period by an amount determined in accordance
          with Section 2.3 or Section 2.6; or

               2.1.2  the transfer of his/her entire account under any other
          plan maintained by an Employer or an affiliate which meets the
          requirements of sections 401(a) and 401(k) of the Code to the Trustee
          for his/her Tax Deferred Account pursuant to Section 2.8.

An Eligible Employee shall cease to be a Participant in this Plan upon the
earlier of the complete distribution to him/her of his/her Tax Deferred Account
or the transfer of such account pursuant to Section 2.8 of this Plan to any
other plan maintained by the Company or an Affiliate which meets the
requirements of sections 401(a) and 401(k) of the Code.

          2.2  Exclusions.  (a) The following employees are not within the
               ----------                                                 
coverage of the Plan:

               (i) Individuals who perform services for the Company as leased
          employees.  For purposes of this Section (a)(i) the term "leased
          employee" shall mean any individual who:

               (1)  is not an independent contractor with respect to the
               Company;

               (2)  provides services pursuant to an agreement between the
               Company and any other person or entity (hereinafter referred to
               as "the leasing organization");

                                       7
<PAGE>
 
               (3)  has performed such services for the Company on a
               substantially full-time basis for a period of at least one year;

               (4)  performs services of a type historically performed in the
               business field of the Company by employees;

               (5)  is not a participant in a qualified money purchase plan
               maintained by the leasing organization which provides for a
               nonintegrated employer contribution of at least ten percent (10%)
               of such person's annual compensation and provides for immediate
               participation and full and immediate vesting; and

               (6)  meets such other requirements as may be set forth in section
               414(n) of the Code and the regulations promulgated thereunder.

               (ii)  Individuals (if any) who are considered by the Company to
          be independent contractors and employees of such independent
          contractors, but who may be determined for any other purpose to be
          employees of the Company.  The characterization by the Company on its
          books and records of the relationship of the individual and the
          Company shall be conclusive of the individual's status for purposes of
          this Plan.

               (b)  The Committee reserves the right in its sole discretion to
          exclude from coverage as an Eligible Employee any class or classes of
          Employees, provided that any such exclusion does not discriminate in
          favor of Employees who are shareholders, officers, or highly
          compensated, as determined in accordance with section 410 of the Code.

          2.3  Before Tax Contributions.
               ------------------------ 

                                       8
<PAGE>
 
               2.3.1  A Participant may authorize his/her Employer to reduce
          his/her Compensation, the amount of which reduction shall be paid to
          the Trustee for such Participant's Tax Deferred Account as Before Tax
          Contributions.  The reduction in Compensation authorized by a
          Participant as a Before Tax Contribution shall range from 1/2% to 6%,
          inclusive, of his/her Compensation, in multiples of 1/2%; provided,
          however, that the sum of a Participant's Before Tax Contributions
          under this Plan and his/her Basic Deductions under Section 2.3.2 of
          Article II of the Savings Plan shall be not less than 2 1/2% of
          his/her Compensation and not more than 6% of his/her Compensation.

               2.3.2  Within the limits of Section 2.3.1, a Participant may, at
          any time, increase or decrease the amount by which his/her
          Compensation is reduced for Before Tax Contributions for subsequent
          pay periods.

          2.4  Adjustment of Before Tax Contributions.
               -------------------------------------- 

               2.4.1  Notwithstanding anything to the contrary in this Article
          II, the Committee may prospectively decrease a Participant's
          authorized reduction in his/her Compensation at any time if the
          Participant is a Highly Compensated Employee and the Committee
          determines, in its sole discretion, that such action is necessary in
          order for the Plan to meet the actual deferral percentage tests under
          section 401(k)(3)(A) of the Code.

               2.4.2  If the Committee determines it is necessary to
          prospectively decrease any such Participant's authorized reduction
          under this Section 2.4, it shall first decrease by 1/2% the authorized
          reductions of all such Participants who authorized the maximum
          reduction in their Compensation, determined without regard to this
          Section 2.4.  If the Committee determines further decreases are

                                       9
<PAGE>
 
          necessary, it shall decrease by 1/2% the authorized reductions of all
          such Participants whose authorized reductions in their Compensation
          are the largest, determined after taking all previous reductions under
          this Section 2.4 into account.  The Committee shall continue to make
          such decreases in multiples of 1/2% until it determines that the
          actual deferral percentage tests in section 401(k)(3)(A) of the Code
          have been met.

               2.4.3  Any Before Tax Contributions which would have been made to
          this Plan on behalf of a Participant but for the decrease in his/her
          authorized Compensation reduction under this Section 2.4 shall be paid
          by the Company to the Savings Plan as a Basic Deduction as defined in
          Section 2.3.2 of Article II of the Savings Plan and the Company shall
          make a Company Contribution as defined in Section 2.5 of Article II of
          the Savings Plan on account of such Basic Deduction, in accordance
          with the provisions of the Savings Plan, unless otherwise directed by
          the Participant.  If the Participant is not a participant in the
          Savings Plan, then, unless otherwise directed by the Participant, such
          amounts shall be invested in a Personal Investment Account established
          for such Participant and shall be allocated among the investment
          options in such account in the same proportions as the latest Before
          Tax Contribution for his/her Tax Deferred Account.  If the Participant
          is a participant in the Savings Plan, then, unless otherwise directed
          by the Participant, such amounts shall be allocated to his/her Savings
          Plan account and among the various investment options in such account,
          in the same proportions as:

               2.4.3.1  his/her latest Basic Deductions for the Savings Plan, as
               defined in Section 2.3.2 of Article II of the Savings Plan; or

                                      10
<PAGE>
 
               2.4.3.2 if he/she has never made any such Basic Deductions for
               the Savings Plan, his/her latest Supplemental Deductions for the
               Savings Plan, as defined in Section 2.3.3 of Article II of the
               Savings Plan; or

               2.4.3.3  if he/she has never made any such Basic Deductions or
               Supplemental Deductions for the Savings Plan, his/her latest
               Supplemental Deposits for the Savings Plan, as defined in Section
               2.3.4 of Article II of the Savings Plan.

               2.4.4  If the Committee determines, in its sole discretion, that
          it is no longer necessary to decrease a Participant's authorized
          Compensation reduction under this Section 2.4, the Committee shall
          increase the authorized Compensation reductions of all Participants
          who had such reductions decreased, in multiples of 1/2%, until all
          such Participants have their authorized Compensation reductions
          restored to their originally authorized level or the Committee
          determines that the actual deferral percentage tests of section
          401(k)(3)(A) of the Code will not be met, whichever occurs first.

               2.4.5  When increasing or decreasing any Participant's authorized
          Compensation reduction under this Section 2.4, the Committee shall
          treat all Participants who authorized the same reduction in their
          Compensation in the same manner.

               2.4.6  Any action taken by the Committee under this Section 2.4
          may be taken without the consent of, or prior notice to, the affected
          Participants, but such Participants shall be promptly informed in
          writing of the Committee's action.

                                      11
<PAGE>
 
          2.5  Company Contributions.
               --------------------- 

               2.5.1  At the time Before Tax Contributions are paid to the
          Trustee on behalf of a Participant, the Company shall pay to the
          Trustee as Company Contributions for such Participant's Tax Deferred
          Account an amount equal to the Applicable Percentage of the Before tax
          Contributions paid to the Trustee on behalf of such Participant, in
          accordance with the following schedule:

          
<TABLE> 
<CAPTION> 

            Number of Years of
             Credited Service                      Applicable Percentage
           --------------------                    ---------------------
           <S>                                     <C> 
                    1                                       15%
                    2                                       30%
                    3                                       40%
                    4 or more                               50%
</TABLE> 

               2.5.2  If the Company is prevented from making all or any portion
          of the Company Contribution it would otherwise make under Section
          2.5.1 because it has no current or accumulated earnings or profits, or
          because its current and accumulated earnings and profits are less than
          the Company Contributions it would otherwise make, then all or any of
          the other companies within the affiliated group of corporations within
          the meaning of section 1504 of the Code of which the Company is a
          member having sufficient current or accumulated earnings or profits
          may make the Company Contributions the Company could not make.  Any
          Company Contribution made by any such other company on behalf of the
          Company shall be allocated among the Participants as if the Company
          had itself made such Company Contribution.

          2.6  Additional Contributions.
               ------------------------ 

               2.6.1  If the Committee determines that contributions made under
          this Section 2.6 will not cause the Plan to fail to meet the actual
          deferral percentage

                                      12
<PAGE>
 
          tests in section 401(k)(3)(A) of the Code, the Committee, in its sole
          discretion, may permit Participants who have authorized the maximum
          allowable reduction in their Compensation for Before Tax Contributions
          to authorize additional reductions in their Compensation, the amount
          of which reductions shall be paid to the Trustee for such
          Participant's Tax Deferred Account as Additional Contributions.  If
          permitted by the Committee, reductions for Additional Contributions
          shall range from 1/2% of the Participant's Compensation to such upper
          limit as the Committee may set, but in no event more than 10% of the
          Participant's Compensation, in multiples of 1/2%; provided, however,
          that the sum of a Participant's Additional Contributions under this
          Plan and his/her Supplemental Deductions under Section 2.3.3 of
          Article II of the Savings Plan shall not exceed 10% of his/her
          Compensation.  The Committee may suspend the right to authorize
          Additional Contributions and may raise or reduce the limit on
          Additional Contributions (subject to the maximum and minimum limits
          set forth in this Section 2.6) at any time.

               2.6.2  Within the limits of Section 2.6.1, a Participant may, at
          any time, increase or decrease the amount by which his/her
          Compensation is reduced for Additional Contributions.

               2.6.3  Additional Contributions shall not be taken into
          consideration in determining the Company Contribution to be allocated
          to any Participant.

          2.7  Transfers from the Savings Plan.  Immediately preceding a
               -------------------------------                          
Participant's termination of employment, other than on account of death, the
entire balance to the credit of the Participant under the Savings Plan, if any,
shall automatically be transferred to his/her Tax Deferred Account.  Amounts
transferred from the Personal Investment Account pursuant to this

                                      13
<PAGE>
 
Section 2.7 shall be invested among the various investment options in his/her
Tax Deferred Account in the same proportion as they were invested among the
various investment options in his/her Personal Investment Account.

          2.8  Change from Eligible Employee to Ineligible
               Employee and from Ineligible Employee to
               Eligible Employee.
               -------------------------------------------

               2.8.1  If an Employee ceases to be an Eligible Employee, other
          than on account of death or other termination of employment, his Tax
          Deferred Account shall automatically be transferred to the trust fund
          established in connection with any other plan maintained by the
          Company or an Affiliate which meets the requirements of sections
          401(a) and 401(k) of the Code for his/her account under such other
          plan if such other plan provides for the acceptance of funds
          transferred from this Plan and if such Employee would be eligible to
          participate in such other plan on the date he/she ceases to be an
          Eligible Employee.  If such other plan does not provide for the
          acceptance of funds transferred from this Plan or if such Employee
          would not be eligible to participate in such other plan on such date,
          the Employee shall remain a Participant in this Plan except that
          his/her existing authorizations for reductions in his/her Compensation
          for Before Tax Contributions and Additional Contributions shall be
          deemed to have been revoked by such Participant and he/she shall not
          be able to authorize any future reductions in his/her Compensation for
          Before Tax Contributions or Additional Contributions.

               2.8.2  If an Employee who is a participant in any other plan
          maintained by the Company or an Affiliate which meets the requirements
          of sections 401(a) and 401(k) of the Code ceases to be eligible to
          participate in such other plan,

                                      14
<PAGE>
 
          other than on account of death or other termination of employment, and
          such other plan provides for the transfer of funds to this Plan,
          his/her account under such other plan shall automatically be
          transferred to the Trust Fund for the account of such Employee and
          such Employee shall become a Participant in this Plan if such Employee
          would be an Eligible Employee on the date he/she ceases to be a
          participant in such other plan.

          2.9  Revocation of Compensation Reduction.
               ------------------------------------ 

               2.9.1  A Participant may revoke his/her authorization for the
          reduction of his/her Compensation for Before Tax Contributions and
          Additional Contributions in a time and manner authorized by the
          Committee.  If a Participant revokes his/her authorization for the
          reduction of his/her Compensation for Before Tax Contributions, the
          related Company Contributions will be suspended.

               2.9.2  Authorizations for a reduction in a Participant's
          Compensation for Before Tax Contributions and Additional Contributions
          which a Participant has revoked may be reinstated by the Participant
          in a time and manner authorized by the Committee.  If a Participant
          reinstates the authorization for a reduction in his/her Compensation
          for Before Tax Contributions, the related Company Contributions will
          be resumed.

               2.9.3  If the Committee relies upon Section 4.4.2(b) to permit a
          hardship withdrawal by the Participant, such Participant's right to
          make Before Tax Contributions and Additional Contributions shall be
          suspended for a period of twelve (12) months after the hardship
          withdrawal is received by the Participant.

          2.10 Limitations on Contributions.  In no event shall the annual sum
               ----------------------------                                   
of the Before Tax Contributions, related Company Contributions and Additional
Contributions for a

                                      15
<PAGE>
 
Participant's Tax Deferred Account in any Plan Year exceed the lesser of $30,000
(or such other amount as the Secretary of the Treasury  may specify pursuant to
section 415 of the Code) or 25 percent of the Participant's Earnings for such
Plan Year.

          2.11 Vesting.  A Participant's right to his/her Tax Deferred Account
               -------                                                        
derived from his/her Before Tax Contributions and Additional Contributions and
all earnings of the Tax Deferred Account is non-forfeitable (within the meaning
of section 411 of the Code) at all times.  A Participant's right to his/her Tax
Deferred Account derived from Company Contributions is non-forfeitable upon the
attainment of Normal Retirement Age, and in addition is non-forfeitable in the
case of a Participant who has at least three years of Credited Service.  Any
forfeitures under this Section 2.11 shall be used to reduce the amount the
Company is required to pay under Section 2.5 as Company Contributions.

          2.12 Limitations on Before Tax Contributions and Additional
               ------------------------------------------------------
Contributions.  Notwithstanding the foregoing, in no event shall a Participant's
- -------------                                                                   
Before Tax Contributions for a Plan Year exceed $7,000 (adjusted annually for
increases in the cost of living in accordance with section 415 of the Code);
provided, however, that if the Committee relies upon Section 4.4.2(b) to permit
a hardship withdrawal by the Participant, such limitation shall be reduced for
the year following the year in which such withdrawal is made by the amount of
the Participant's Before Tax Contributions in the year such withdrawal is made.
If any deferral in excess of such limitation is made, then the Committee may, in
its discretion, return to the Participant such  excess deferral and any income
thereon not later than April 15 of the taxable year following the taxable year
in which such excess deferral occurred.

          2.13 401(m) Limitations.  The Committee shall ensure that the
               ------------------                                      
requirements set forth in section 401(m) of the Code with respect to
Participants' Before Tax Contributions, Company Contributions, and Additional
Contributions are satisfied.  The Plan shall not be

                                      16
<PAGE>
 
treated as failing to meet such requirements for any Plan Year, if before the
close of the following Plan Year, the Committee distributes "excess aggregate
contributions," as defined in section 401(m) of the Code, to Participants in
accordance with procedures set forth in section 401(m) of the Code and the
Regulations promulgated thereunder.

                                      17
<PAGE>
 
                                  ARTICLE III

               INVESTMENT AND VALUATION OF TAX DEFERRED ACCOUNTS
               -------------------------------------------------

          3.1  General.  Before Tax Contributions, related Company
               -------                                            
Contributions, and Additional Contributions authorized by a Participant and any
amounts transferred from the Participant's account in the Savings Plan pursuant
to Section 2.7 of this Plan or from his/her account in any other plan maintained
by the Company or an Affiliate which meets the requirements of sections 401(a)
and 401(k) of the Code pursuant to Section 2.8 of this Plan, shall be paid to
the Trustee and held in the Trust Fund in a Tax Deferred Account established for
such Participant.

          3.2  Investment Options.  Each Participant shall direct that the
               ------------------                                         
entire amount of the Before Tax Contributions and Additional Contributions made
to his/her Tax Deferred Account be invested in one or more of the following
investment options, in multiples of 25 percent.  Company Contributions made to a
Participant's Tax Deferred Account shall be invested in the following investment
options in the same proportion as their related Before Tax Contributions.

               3.2.1  Government Bond Fund - A fund which invests only in United
                      --------------------                                      
          States Series "E" and Series "EE" Savings Bonds.

               3.2.2  Martin Marietta Corporation Stock Fund - A fund which
                      --------------------------------------               
          invests only in common stock of Martin Marietta Corporation.

               3.2.3  Fixed Income Fund - A fund under which monies will be
                      -----------------                                    
          credited with monthly interest at a predetermined rate, not subject to
          change more than twice each calendar year.

               3.2.4  Equity Investment Fund - A fund under which monies will be
                      ----------------------                                    
          invested primarily in common stock and other equity-type investments.
          The value

                                      18
<PAGE>
 
          of the Equity Investment Fund will vary to reflect the investment
          experience of the Fund.

Notwithstanding anything to the contrary in this Section 3.2, any monies
allocated to any Fund may be invested temporarily in obligations of a short-term
nature, including prime commercial obligations or part interests therein, or in
interests in any trust fund that has been or shall be created and maintained by
the Trustee or any other person or entity as trustee for the collective short-
term investment of funds of trusts for employee benefit plans qualified under
section 401(a) of the Code.  Any such earnings on such short-term investments
shall be allocated monthly to each Participant's account in proportion to the
amount of each Participant's account balance at the end of such month.

          3.3  Union Carbide Corporation Stock Fund.  From and after April l,
               ------------------------------------                          
1984, no monies may be allocated to purchase stock of Union Carbide Corporation;
provided, however, that any stock of Union Carbide Corporation existing in this
Fund on April 1, 1984 shall remain in the Fund until such time as the
Participant directs that it shall be sold by the Trustee or it is distributed to
such Participant or his Beneficiary.  Notwithstanding the preceding sentence,
if, with regard to any Participant, the number of shares of stock of Union
Carbide Corporation existing in this Fund, is less than 100, then the
Participant (or his/her Beneficiary) shall direct the sale of such shares no
later than June 30, 1990; if, with regard to a Participant, the number of such
shares equals or exceeds 100, the Participant (or his/her Beneficiary) shall
direct the sale of such shares no later than June 30, 1991.  In the event a
Participant (or his/her Beneficiary) shall fail to direct the sale of his/her
shares of stock of Union Carbide Corporation as required herein by June 30, 1990
or June 30, 1991, as applicable, then the Trustee shall sell such shares on the
next business day following June 30, 1990 or June 30, 1991, as applicable.
Unless a Participant shall elect otherwise, the proceeds of the sale of stock of
Union Carbide

                                      19
<PAGE>
 
Corporation under this paragraph shall be allocated among the funds in the same
proportion as current contributions to such Participant's Account are allocated
to each fund.

          3.4  Investment Manager.  The Committee may appoint an investment
               ------------------                                          
manager or managers, as defined in section 3(38) of ERISA, to manage (including
the power to acquire, invest and dispose of) any assets of the Plan.

          3.5  Change of Investments.  Subject to applicable rules and
               ---------------------                                  
regulations adopted by the Committee governing this Plan:

               3.5.1  A Participant may at any time change his/her investment
          options currently in effect with respect to subsequent Before Tax
          Contributions, related Company Contributions and Additional
          Contributions made to his/her Tax Deferred Account, subject to the
          percentage limitations of Section 3.2 of this Plan.

               3.5.2  A Participant may direct, in whole or in part, the sale of
          his/her interest in the Martin Marietta Corporation Stock Fund,
          his/her stock in the Union Carbide Corporation Stock Fund and/or
          his/her Government Bonds, and the reinvestment of such proceeds in any
          other Investment Options in accordance with the percentage limitations
          of Section 3.2 of this Plan.

               3.5.3  A Participant may elect to liquidate his/her interest, in
          whole or in part, in the Fixed Income Fund and/or the Equity
          Investment Fund, and reinvest the proceeds in any other Investment
          Options in accordance with the percentage limitations of Section 3.2
          of this Plan.  Only two such elections will be permitted in any 12-
          month period.

          3.6  Special Rules for Company Officers.  Notwithstanding any other
               ----------------------------------                            
provisions of this Plan, any Participant who is an officer of the Company:

                                      20
<PAGE>
 
               3.6.1  may change the allocation of his Compensation between
          reductions for this Plan and contributions to the Savings Plan only
          once in any 12-month period if such change would affect the purchase
          of common stock of the Martin Marietta Corporation for his/her Tax
          Deferred Account;

               3.6.2  may change the allocation of Before Tax Contributions,
          related Company Contributions and Additional Contributions among the
          four investment options only once in any 12-month period if such
          change would affect the purchase of common stock of the Martin
          Marietta Corporation for his/her Tax Deferred Account;

               3.6.3  may direct the sale or redemption of his/her interest in
          his/her Tax Deferred Account and the reinvestment of the proceeds
          thereof in other investment options in his/her Tax Deferred Account
          only once in any 12-month period if such direction would affect the
          purchase or sale of common stock of the Martin Marietta Corporation
          for his/her Tax Deferred Account; and

               3.6.4  must make any such change in the allocation of his/her
          Before Tax Contributions, related Company Contributions and Additional
          Contributions and must give any such direction to sell or redeem on
          the same date in the 12-month period, which date must be the same date
          as the date on which he/she makes any change pursuant to Section 3.5
          of Article III of the Savings Plan.

          3.7  Dividends.  Dividends received on stock held in the Martin
               ---------                                                 
Marietta Corporation Stock Fund for a Participant's Tax Deferred Account shall
automatically be reinvested in the Martin Marietta Corporation Stock Fund.

          Dividends received on Union Carbide Corporation stock are
automatically reinvested in the same investment options and in the same
proportion as the Participant's Before

                                      21
<PAGE>
 
Tax Contributions.  Dividends will not be reinvested in additional shares of
stock in the Union Carbide Corporation Stock Fund.

          3.8  Rights, Warrants and Scrip.  If any rights, warrants or scrip are
               --------------------------                                       
issued on stock held in the Martin Marietta Corporation Stock Fund or Union
Carbide Corporation Stock for a Participant's Tax Deferred Account, the Trustee
shall automatically exercise the rights, warrants or scrip for whole shares,
which shares shall be for such Participant's Tax Deferred Account, and shall
automatically offer the rights, warrants, or scrip for fractional shares for
sale on the open market and shall reinvest the proceeds in additional units of
stock in the Martin Marietta Corporation Stock Fund or into the other designated
investment options.  Proceeds may not be reinvested in additional shares of
stock in Union Carbide Corporation Stock.

          3.9  Instructions By a Participant For His/Her Tax Deferred Account.
               --------------------------------------------------------------  
A Participant shall give orders for the investment, reinvestment, sale or
redemption of his/her Tax Deferred Account, subject to the provisions of this
Article III, in accordance with rules and regulations adopted by the Committee.

          3.10 Purchases and Sales.  Investment of amounts in Government Bonds
               -------------------                                            
or in units of stock of Martin Marietta Corporation directed by a Participant
shall be made by the Trustee as expeditiously as possible, but not later than
the last day of the month following the month in which the order is made or the
proceeds are received by the Trustee whichever is applicable, and as sufficient
amounts are available.  Investment of amounts in the Fixed Income Fund or the
Equity Investment Fund directed by a Participant shall be made as close as is
reasonably practicable to the first business day of the month following the
month in which the order is made, or in which the proceeds are received by the
Trustee, whichever is applicable.  The sale of stock of Union Carbide
Corporation, the redemption of Government Bonds and the

                                      22
<PAGE>
 
liquidation of a Participant's interest in the Martin Marietta Corporation Stock
Fund, the Fixed Income Fund and/or the Equity Investment Fund shall be complied
with as is reasonably practicable after the receipt of the Participant's order
by the Trustee.  The Trustee shall purchase all shares of stock for the Martin
Marietta Corporation Stock Fund on the New York Stock Exchange or, if Martin
Marietta Corporation elects, from Martin Marietta Corporation.  If such stock is
purchased from Martin Marietta Corporation, it shall be purchased at a price
equal to the last recorded sales price on the last trading day of the month in
which such purchase occurs, as reported in the New York Stock Exchange-Composite
Transactions.

          3.11 Costs and Expenses.  In accordance with the rules and regulations
               ------------------                                               
adopted by the Committee, all costs and expenses, including transfer taxes and
brokerage commissions, incurred in connection with the purchase, sale and
redemption of United States Series "E" and Series "EE" Savings Bonds and stock
of Martin Marietta Corporation and in the case of the sale of Union Carbide
Corporation Stock, for a Participant's Tax Deferred Account shall be added to
the cost of such stock and bonds or deducted from the proceeds of such stock and
bonds, as the case may be, unless paid by the Company.

          3.12 Custody of Securities.  All cash, United States Series "E" and
               ---------------------                                         
Series "EE" Savings Bonds, certificates for shares of Martin Marietta
Corporation Stock, certificates for shares of Union Carbide Corporation Stock,
evidences of ownership of Fixed Income Fund and Equity Investment Fund units and
all other Plan assets shall be held in the custody of the Trustee until disposed
of under the provisions of this Plan.

          3.13 Voting Rights.  The Company will make forms available to each
               -------------                                                
Participant to instruct the Trustee with regard to the voting of any shares of
Martin Marietta Corporation Stock pertaining to that Participant's Tax Deferred
Account or for Union Carbide Corporation Stock held in that  Participant's Tax
Deferred Account.  The Trustee will vote such

                                      23
<PAGE>
 
shares only as directed by the Participant.  If a Participant fails to give
timely directions as to the voting of such shares of stock, the Trustee will
vote such shares in the same proportion as it votes the shares for which the
Trustee receives directions.

          3.14 Valuation of Tax Deferred Accounts.
               ---------------------------------- 

               3.14.1  As of January 1, 1984, the unit values of the Fixed
          Income Fund and the Equity Investment Fund shall be equal to the unit
          values of the similar funds maintained under the Savings Plan.  On any
          Valuation Date the unit values of the Martin Marietta Corporation
          Stock Fund, Fixed Income Fund and the Equity Investment Fund shall be
          equal to the total value of such fund, as determined pursuant to
          Section 3.14.2, divided by the number of units in such fund
          outstanding on such Valuation Date.

               3.14.2  On any Valuation Date, the Martin Marietta Corporation
          Stock Fund, the Union Carbide Corporation Stock Fund and the Equity
          Investment Fund shall be valued at their fair market value on such
          Valuation Date, the Fixed Income Fund shall be valued at its book
          value plus accrued interest at the stated rate to such Valuation Date,
          and the Government Bond Fund shall be valued at its book value plus
          accrued interest to such Valuation Date, determined according to
          tables issued by the United States Department of the Treasury.

               3.14.3  On any Valuation Date, a Participant's interest in the
          Trust Fund shall be equal to the value of his/her Tax Deferred
          Account.  The value of a Participant's Tax Deferred Account
          immediately prior to January 1, 1984 shall be zero.  The value of a
          Participant's Tax Deferred Account on any Valuation Date shall equal
          the greater of zero or the value of his/her Tax Deferred Account as of
          the preceding Valuation Date, increased by:

                                      24
<PAGE>
 
                    (a) all Before Tax Contributions, related Company
               Contributions and Additional Contributions allocated to such
               account since the preceding Valuation Date;

                    (b) all amounts transferred to such account since the
               preceding Valuation Date from the Savings Plan, pursuant to
               Section 2.7 of this Plan, and from any other plan maintained by
               an the Company or an Affiliate which meets the requirements of
               sections 401(a) and 401(k) of the Code, pursuant to section 2.8
               of this Plan; and

                    (c) any income and gains (realized and unrealized) since the
               preceding Valuation Date on savings bonds in the Government Bond
               Fund allocated to his/her Tax Deferred Account, stock in the
               Union Carbide Corporation Stock Fund allocated to his/her Tax
               Deferred Account and units in the Martin Marietta Corporation
               Stock Fund, Fixed Income Fund and Equity Investment Fund
               allocated to his/her Tax Deferred Account; and

          decreased by:

                    (d) any losses (realized and unrealized) since the preceding
               Valuation Date on savings bonds in the Government Bond Fund
               allocated to his/her Tax Deferred Account, stock in the Union
               Carbide Corporation Stock Fund allocated to his/her Tax Deferred
               Account and units in the Martin Marietta Corporation Stock Fund,
               Fixed Income Fund and Equity Investment Fund allocated to his/her
               Tax Deferred Account;

                                      25
<PAGE>
 
                    (e) the amount of any distributions to such Participant
               under Section 4.1 and withdrawals by such Participant under
               Section 4.4 since the preceding Valuation Date;

                    (f) any amounts transferred from this Plan pursuant to
               Section 2.8.1 to any other plan maintained by the Company or an
               Affiliate which meets the requirements of sections 401(a) and
               401(k) of the Code; and

                    (g) any expenses, taxes or other amounts charged to the
               Trust Fund since the preceding Valuation Date pursuant to
               Sections 7.2, 8.3, 8.7, 8.12 and 9.3 of this Plan and allocated
               to his/her Tax Deferred Account.

          3.15 Statements Furnished Participants.  A Participant shall be
               ---------------------------------                         
furnished an annual statement of his/her Tax Deferred Account by the Company.

                                      26
<PAGE>
 
                                   ARTICLE IV

                      DISTRIBUTIONS, WITHDRAWALS AND LOANS
                      ------------------------------------
          4.1  Distribution on Termination of Employment.
               ----------------------------------------- 

               4.1.1  Termination Other Than Death.  If the value of the Tax
                      ----------------------------                          
          Deferred Account of a Participant whose employment terminates for any
          reason (including termination on account of disability) other than
          death is thirty five hundred dollars ($3,500) or less, or the value
          exceeds thirty five hundred dollars ($3,500) and such Participant
          consents in writing, then, such Participant shall receive the entire
          value of such Participant's Tax Deferred Account, valued as of the
          last Valuation Date preceding such Participant's termination, in a
          single-sum payment.  Subject to Section 4.3, the payment shall be made
          to the Participant as soon after such Participant's employment
          terminates as the Committee shall determine to be administratively
          practicable.  For purposes of Section 4.1, a Participant who
          terminates employment during or after the calendar year in which such
          Participant attains age fifty-five (55) shall be deemed to have
          terminated employment on account of early retirement under the Plan.

               4.1.2  Deferred Single-Sum Payment.  If the value of the Tax
                      ---------------------------                          
          Deferred Account of a Participant whose employment terminates for any
          reason (including termination on account of disability) other than
          death exceeds thirty five hundred dollars ($3,500) and such
          Participant does not consent in writing to receive the entire value of
          such Participant's Tax Deferred Account in accordance with Section
          4.1.1, then unless such Participant shall have made an election under
          Section 4.1.3 or Section 4.1.4 hereof, such Participant shall be
          deemed to have deferred receipt of the entire value of such
          Participant's Tax Deferred Account

                                      27
<PAGE>
 
          until such Participant attains age seventy and one-half (70 1/2).
          Such a Participant may elect, in accordance with procedures determined
          by the Committee, to receive the entire value (but not part) of such
          Participant's Tax Deferred Account in a single-sum payment at any time
          prior to the Participant's attainment of age seventy and one-half (70
          1/2).  After the month of such Participant's birth in the calendar
          year following his retirement or termination of employment, such
          Participant's account can no longer be invested in the Fixed Income
          Fund.  The Participant may direct that his account be invested in the
          other Investment Options or in the Fixed Income Fund for Retirees
          which shall be a fund under which monies will be credited with monthly
          interest at a predetermined rate, not subject to change more than
          twice each calendar year.

               The entire value of such Participant's Tax Deferred Account shall
          be distributed to such Participant in a single-sum payment as soon
          after such Participant attains age seventy and one-half (70 1/2) or
          such earlier date selected by the Participant as provided above, as
          the Committee shall determine to be administratively practicable.  If
          a Participant who has been deemed to have deferred receipt of the
          entire value of such Participant's Tax Deferred Account under this
          Section 4.1.2 dies after such Participant's termination of employment,
          but prior to such Participant's attainment of age seventy and one-half
          (70 1/2), then the Participant shall be deemed to have terminated
          employment on account of death and the entire value of such
          Participant's Tax Deferred Account shall be paid to such Participant's
          Beneficiary in accordance with Section 4.1.3.

               4.1.3  Election of Partial Distributions.  Upon prior written
                      ---------------------------------                     
          notice to the Committee, given in a time and manner determined by the
          Committee, a

                                      28
<PAGE>
 
          Participant who: (1) has deferred receipt of the Participant's Tax
          Deferred Account pursuant to Section 4.1.2 and (2) is eligible to
          receive an immediate pension upon termination of employment or is
          disabled under the terms of the Company's long term disability plan,
          may elect to receive in lieu of a single-sum payment, partial
          distributions in accordance with this Section 4.1.3.  No election to
          take a partial distribution under this Section 4.1.3 may be made,
          however, if the total balance remaining in the Participant's Tax
          Deferred Account and the Participant's Personal Investment Account
          under the Savings Plan after such withdrawal will be less than
          $10,000.  A Participant may not take more than one partial
          distribution under this Section 4.1.3 in any one Plan Year.  If a
          Participant who has made an election under this Section 4.1.3 dies
          prior to receiving the full value of his/her Tax Deferred Account, the
          full remaining value of his/her Tax Deferred Account, valued as of the
          Valuation Date following the receipt of notice of the Participant's
          death, shall be paid in accordance with Section 4.1.5.

               4.1.4  Election of Annual Installments.  Upon prior written
                      -------------------------------                     
          notice to the Committee, given in a time and manner determined by the
          Committee, a Participant who is eligible to receive an immediate
          pension upon termination of employment or is disabled under the terms
          of the Company's long term disability plan, may elect to receive the
          entire value of his/her Tax Deferred Account, valued as of the last
          Valuation Date preceding such election, in one of the following forms
          of payment:

               (a)  monthly payments over the life of the Participant, computed
                    as set forth below; or

               (b)  monthly payments over the joint lives of the Participant and
                    the Participant's spouse, computed as set forth below; or

                                      29
<PAGE>
 
               (c) monthly payments for a period certain of 10, 15 or 20 years,
                   computed as set forth below.

               If a Participant elects to receive payments under Section
          4.1.4(a) or (b) above, the annual amount to be paid to the Participant
          (or his/her spouse) shall be determined by dividing the entire value
          of the Tax Deferred Account at the beginning of each year by the then
          life expectancy of the Participant (or the joint life and last
          survivor expectancy of the Participant and the Participant's spouse.)
          For purposes of this calculation, the life expectancy of the
          Participant, and his/her spouse if applicable, shall be recalculated
          annually.

               If a Participant elects to receive payments under Section
          4.1.4(c) above, the annual amount to be paid to the Participant (or
          his/her Beneficiary) shall be determined by dividing the entire value
          of the Tax Deferred Account at the beginning of each year by the then
          remaining number of years in the term.

               For purposes of electing one of the options under this Section
          4.1.4, a married Participant may not elect option (a) or (c) unless
          the Participant's spouse consents in writing to such election, as
          provided in Section 4.1.5.

               If a Participant who has made an election under Section 4.1.4(a)
          or (c) dies prior to receiving the full value of his/her Tax Deferred
          Account, the full remaining value of the Tax Deferred Account, valued
          as of the Valuation Date following the receipt of notice of the
          Participant's death, shall be paid in accordance with Section 4.1.5.

               With regard to a Participant who has made an election under
          Section 4.1.4(b):  (i) upon the death of such Participant payments
          shall continue, as computed above, to the Participant's spouse, and
          (ii) if the Participant's spouse

                                      30
<PAGE>
 
          dies prior to receiving the full remaining value of the Participant's
          Tax Deferred Account, the full remaining value of the Tax Deferred
          Account, valued as of the Valuation Date following the spouse's death,
          shall be paid in full to such spouse's beneficiary or, if the spouse
          shall not have named a beneficiary, to the estate of the deceased
          spouse.

               4.1.4.1  Waiver.  A married Participant who has made an election
                        ------                                                 
          under Section 4.1.4 (a) or (b) may waive such election at any time
          during the 90 day period ending on the annuity starting date.

               No such waiver under this Section 4.1.4.1 shall be effective
          unless the Participant's spouse consents in writing to such waiver,
          the terms of such consent acknowledge the effect of the waiver, and
          the waiver is witnessed by a representative of the Company or a notary
          public.  Such consent shall be irrevocable.

               The provisions of the preceding paragraph shall not be applicable
          if the Company is satisfied that the required consent cannot be
          obtained because either (a) the Participant does not have a spouse,
          (b) the spouse cannot be located, or (c) by reason of such other
          circumstances as the Secretary of the Treasury may prescribe by
          regulations.  Any consent by a spouse or the establishment that the
          consent of a spouse cannot be obtained shall only be effective with
          respect to such spouse.

               4.1.4.2  Required Information.  The Company shall provide to each
                        --------------------                                    
          Participant who has made an election under Section 4.1.4 (a) or (b),
          within a reasonable time before the annuity starting date (pursuant to
          such regulations as may be prescribed by the Secretary of the
          Treasury) a written explanation of: (i)

                                      31
<PAGE>
 
          the terms and conditions of the annuity elected; (ii) the
          Participant's right to make, and the effect of, an election to waive
          such annuity election; and (iii) the rights of the Participant's
          spouse under Section 4.1.4.1.

               4.1.4.3  One-Year Marriage Requirement.  Notwithstanding the
                        -----------------------------                      
          foregoing, the spousal requirements set forth in this Section 4.1.4
          shall not apply unless the Participant and his/her spouse were married
          throughout the one-year period ending on the Participant's annuity
          starting date.

               4.1.5  Termination on Death.  If a Participant's employment
                      --------------------                                
          terminates on account of the Participant's death, the value of the
          Participant's Tax Deferred Account, valued as of the last Valuation
          Date preceding the Participant's death, shall be paid in a lump sum to
          the Participant's surviving spouse, unless such spouse has consented
          to the designation of an alternate beneficiary.  No consent under this
          Section 4.1.5 or Section 4.1.4 shall be effective unless either (i)
          such consent is in writing, the terms of such consent acknowledge its
          effect, the execution of such consent is witnessed by a person
          representing the Plan or a notary public, as the Committee may
          determine, and such consent otherwise complies with such rules as the
          Committee may adopt, or (ii) it is established to the satisfaction of
          the Committee that the required consent cannot be obtained because the
          Participant does not have a spouse, because the spouse cannot be
          located, or because of such other circumstances as the Secretary of
          the Treasury may prescribe by regulations.  Any consent by a spouse
          (or establishment that the consent of a spouse cannot be obtained)
          shall only be effective with respect to such spouse.

                                      32
<PAGE>
 
               If a Participant's spouse has consented to the designation of an
          alternate beneficiary, then the Participant's Beneficiary shall be the
          Participant's beneficiary under the Savings Plan; provided, however,
          if (a) the Participant has not effectively designated a beneficiary
          under the Savings Plan, or (b) the beneficiary designated under the
          Savings Plan has not survived the Participant and no alternative
          designation of beneficiary shall be effective, the Participant's
          Beneficiary shall be the estate of the deceased Participant.  If the
          Participant's surviving spouse or Beneficiary cannot be located for a
          period of one year following death, despite mailing to his/her last
          known address, and if such surviving spouse or Beneficiary has not
          made a written claim for benefits within such period to the Committee,
          such surviving spouse or Beneficiary shall be treated as having
          predeceased the Participant.  The Committee may require such proof of
          death and such evidence of the right of any person to receive all or
          part of the benefit of a deceased Participant as the Committee may
          deem desirable.  Subject to Section 4.3, the lump sum payment shall be
          made to the Participant's surviving spouse or Beneficiary as soon
          after the Participant's death as the Committee shall determine to be
          administratively practicable.  This Section 4.1.5 is effective August
          23, 1984.

                    4.1.6  Mandatory Distributions.  The Tax Deferred Account of
                           -----------------------                              
               a Participant shall be entirely distributed to such Participant
               or shall commence to be distributed not later than April 1 of the
               calendar year following:

               (i)  if the Participant is not a five percent owner, the later of
               the calendar year in which the Participant attains age seventy
               and one-half (70 1/2) or the calendar year in which the
               Participant retires; or

                                      33
<PAGE>
 
               (ii)  if the Employee is a five percent owner at any time during
               the five (5) plan year period ending in the calendar year in
               which the Employee attains age seventy and one-half (70 1/2), the
               calendar year in which the Employee attains age seventy and one-
               half (70 1/2).

               For purposes of this Section 4.1.6, the term "five percent owner"
               means:

               (1)  if an Employer is a corporation, any person who owns (or is
               considered as owning within the meaning of section 318 of the
               Code) more than five percent (5%) of the outstanding stock of the
               corporation or stock possessing more than five percent (5%) of
               the total combined voting power of all stock of the corporation,
               or

               (2)  if an Employer is not a corporation, any person who owns
               more than five percent (5%) of the capital or profits interest in
               the Employer.

          Effective January 1, 1989, the Tax Deferred Account of a Participant
          shall be entirely distributed to such Participant or shall commence to
          be distributed not later than April 1 of the calendar year following
          the calendar year in which the Participant attains age seventy and
          one-half (70 1/2); provided, however, that the rules set forth in the
          first paragraph of this Section 4.1.6 shall continue to apply in the
          case of a Participant who attained age seventy and one-half (70 1/2)
          by January 1, 1988.

               4.1.7  Form of Payment.  All payments made under this Section 4.1
                      ---------------                                           
          shall be made entirely in cash, unless the Participant or the
          Beneficiary, as the case may be, elects to receive any whole shares of
          stock in the Martin Marietta Corporation Stock Fund, the Union Carbide
          Corporation Stock Fund, the Equity Investment Fund, and/or any bonds
          in the Government Bond Fund in his/her Tax Deferred Account in lieu of
          the cash value of such stock and/or bonds.

          4.2  Rehire Prior to Distribution.  In the event that a Participant
               ----------------------------                                  
whose employment has terminated again becomes an Employee prior to the
distribution of his/her Tax

                                      34
<PAGE>
 
Deferred Account, such distribution shall be deferred until the subsequent
termination of his/her employment.

          4.3  Commencement of Benefits.  Unless the Participant makes an
               ------------------------                                  
election under Section 4.1.2 of this Plan, benefits under this Plan will be paid
to the Participant not later than the 60th day after the close of the Plan Year
in which the latest of the following events occurs:

               4.3.1  the date on which the Participant attains
          Normal Retirement Age;

               4.3.2  the tenth anniversary of the year in which
          the Participant commenced participation in the Plan; or

               4.3.3  the Participant's most recent termination of employment.

          4.4  Withdrawal by Participant During Employment.  A Participant may
               -------------------------------------------                    
make a withdrawal from his/her Tax Deferred Account prior to his/her termination
of employment if and only if the withdrawal is made on account of an immediate
and heavy financial need of the Participant and is necessary to satisfy such
financial need.  (Notwithstanding the preceding sentence, for Participants who
have not yet attained age 59 1/2, no withdrawal under this Section 4.4 shall be
permitted with respect to that portion of the Participant's Tax Deferred Account
which is attributable to Company Contributions or investment earnings on Before
Tax Contributions or Additional Contributions.)  The Committee shall determine
whether the withdrawal is made on account of an immediate and heavy financial
need and whether the withdrawal is necessary to satisfy such financial need in
accordance with uniform and non-discriminatory standards.  The Committee may, in
its discretion, adopt either or both of the standards set forth in Section
4.4.2(a) and Section 4.4.2(b) of the Plan to assist it in determining whether a
withdrawal is necessary to satisfy an immediate and heavy financial need.

                                      35
<PAGE>
 
               4.4.1.  A withdrawal will be deemed to be made on account of an
          immediate and heavy financial need of the Participant if the
          withdrawal is on account of:  (i) medical expenses described in
          section 213(d) of the Code incurred by the Participant, the
          Participant's spouse, or any dependents of the Participant, (ii) the
          purchase (excluding mortgage payment) of the Participant's principal
          residence, (iii) the payment of tuition for the next semester or
          quarter of post-secondary education for the Participant, the
          Participant's spouse or any dependents of the Participant, (iv) the
          need to prevent eviction of the Participant from his/her principal
          residence or the foreclosure on the mortgage of the Participant's
          principal residence, or (v) other pressing financial needs of the
          Participant.

               4.4.2.  A withdrawal may be treated by the Committee as necessary
          to satisfy a Participant's financial need if the requirements of
          either (a) or (b) are satisfied:

               (a)  The Committee may reasonably rely upon the Participant's
                    representation that such need cannot be relieved

                       (i)   through reimbursement or compensation by insurance
                             or otherwise;
                            
                       (ii)  by reasonable liquidation of the Participant's
                             assets to the extent such liquidation would not
                             itself cause an immediate and heavy financial need;

                       (iii) by cessation of Before Tax Contributions and
                             Additional Contributions under the Plan; or

                       (iv)  by other distributions or nontaxable (at the time
                             of the loan) loans from plans maintained by the
                             Company or by any other employer, or by borrowing
                             from commercial sources on reasonable commercial
                             terms.

                                      36
<PAGE>
 
               (b)  A withdrawal will be deemed to be necessary to satisfy an
                    immediate and heavy financial need of a Participant if all
                    of the following requirements are satisfied:

                       (i)   the withdrawal is not in excess of the amount of
                             the immediate and heavy financial need of the
                             Participant;

                       (ii)  the Participant has obtained all withdrawals, other
                             than hardship withdrawals, and all nontaxable loans
                             currently available under all plans maintained by
                             the Company;

                       (iii) the Plan, and all other plans maintained by the
                             Company, provides that the Participant's elective
                             contributions and Participant contributions will be
                             suspended for at least 12 months after receipt of
                             the hardship withdrawal; and

                       (iv)  the Plan, and all other plans maintained by the
                             Company, provide that the Participant may not make
                             elective contributions for the Participant's
                             taxable year immediately following the taxable year
                             of the hardship withdrawal in excess of the
                             limitation set forth in section 402(g) of the Code
                             for such next taxable year less the amount of such
                             Participant's elective contributions for the
                             taxable year of the hardship withdrawal.

          4.5  Loans.
               ----- 

               4.5.1  Loans Authorized.  Beginning with the Plan Year commencing
                      ----------------                                          
          on January 1, 1988, a Participant may apply to the Committee for a
          loan under this Plan.  Upon receipt of a Participant's application,
          the Committee may in its discretion instruct the Trustee to make a
          loan to such Participant out of the Trust Fund, effective as of such
          date as the Committee shall designate, if such loan meets the
          requirements of Section 4.5.2.  In determining whether to grant a loan
          under this Section 4.5, the Committee shall consider only those
          factors which would be considered in a normal commercial setting of an
          entity in the business of making loans, and shall act in accordance
          with uniform and non-discriminatory standards.

                                      37
<PAGE>
 
               4.5.2  Loan Requirements.  A loan shall not be made to a
                      -----------------                                
          Participant pursuant to this Section 4.5 unless such loan:

                    (a)  Does not exceed the lesser of (i) $50,000, reduced by
               the excess (if any) of - (I) the highest outstanding balance of
               loans from the Plan during the 1-year period ending on the day
               before the date on which such loan is made, over (II) the
               outstanding balance of loans from the Plan on the date on which
               such loan is made, or (ii) the greater of (I) one-half of the
               present value of the Participant's Tax Deferred Account
               (determined as of the last Valuation Date preceding the
               Participant's application for a loan), or (II) $10,000.  For
               purposes of clause (ii), the present value of the Participant's
               Tax Deferred Account shall be determined without regard to any
               accumulated deductible employee contributions as defined in
               section 72(o)(5)(B) of the Code;

                    (b)  Is exempt from the tax imposed by section 4975 of the
               Code by reason of section 4975(d)(1) of the Code;

                    (c)  Is adequately secured by (i) a portion (not in excess
               of fifty percent (50%) of the present value) of the Participant's
               Tax Deferred Account, and/or (ii) such other or additional
               security as the Committee may in its sole discretion require;

                    (d)  Bears interest, payable annually to the Trust Fund or
               to such account or accounts in the Trust Fund as the Committee
               shall determine and at such rate as the Committee shall
               determine;

                    (e)  Is, by its terms, required (i) to be amortized in level
               payments, made at least quarterly, over the term of the loan
               (except that

                                      38
<PAGE>
 
               this requirement of level amortization shall not apply to a
               period when the Participant is on leave of absence without pay
               for up to 1 year) and (ii) to be repaid upon the earlier of the
               date the Participant's employment terminates, the date of the
               Participant's death, or the expiration of a fixed term of not
               more than five years; provided, however, that the Committee may
               extend the five year term in the case of loans used to acquire
               any dwelling unit which within a reasonable time is to be used
               (determined at the time the loan is made) as the principal
               residence of the Participant;

                    (f)  Is made pursuant to a loan agreement to be executed by
               the Participant and the Trustee, on a form containing such terms
               and provisions as the Committee shall in its sole discretion
               determine;

                    (g)  Satisfies the requirements of section 408(b)(1) of
               ERISA and the Department of Labor's regulations promulgated
               thereunder;

                    (h)  Is made in accordance with specific provisions set out
               by the Committee; and

                    (i)  Meets such other requirements as the Committee may set.

               4.5.3  If any loan granted to a Participant pursuant to this
          Section 4.5 is not repaid on the date required under Section 4.5.2(e),
          the Committee may, without prior notice to the Participant, direct the
          Trustee to sell, redeem or otherwise dispose of such collateral as the
          Participant has given for the loan and apply the proceeds thereof to
          the repayment of the loan.

                    4.5.4  If a Participant receives a loan under this Section
          4.5, his/her status as a Participant in the Plan and his/her rights
          with respect to his/her Plan benefits shall not be affected, except to
          the extent that the Participant has used

                                      39
<PAGE>
 
          his/her interest in his/her Tax Deferred Account as security for the
          loan, pursuant to Section 4.5.2.

                                      40
<PAGE>
 
                                   ARTICLE V

                      LIMITATION ON MAXIMUM CONTRIBUTIONS
                      -----------------------------------
                          AND BENEFITS UNDER ALL PLANS
                          ----------------------------

          5.1  General.  By reason of Section 2.10, Before Tax Contributions,
               -------                                                       
related Company Contributions, and Additional Contributions for a Participant
under this Plan will not exceed the maximum limitations imposed by section 415
of the Code, if all other defined contribution plans and all defined benefit
plans of all Employers and Affiliates are disregarded.  It is intended that any
limitation imposed by section 415 of the Code arising by reason of a
Participant's participation in one or more other such plans shall be implemented
as provided in this Article V, notwithstanding any contrary provision of the
Plan.

          5.2  Affiliate.  For purposes of this Article V, the definition of
               ---------                                                    
"Affiliate" in Section 1.2 shall be applied by substituting the phrase "more
than 50 percent" for the phrase "at least 80 percent" wherever the phrase "at
least 80 percent" would otherwise be applicable under said provision.

          5.3  Limitation Year.  For purposes of this Article V, the limitation
               ---------------                                                 
year shall be the Plan Year.

          5.4  Annual Additions.  "Annual Addition" means for each Participant
               ----------------                                               
the sum for any year of (i) contributions made by the Company or an Affiliate
allocable to the Participant under all Defined Contribution Plans maintained by
the Company  or an Affiliate, (ii) forfeitures allocable to the Participant
under all such plans, (iii) the amount of the Participant's contributions to all
such plans, and (iv) any amount attributable to post-retirement medical benefits
allocated to a separate account after March 31, 1984 on behalf of a Participant
under section 415(1)(1) and section 419A(d) of the Code.  Notwithstanding the
foregoing, for Plan Years beginning prior to January 1, 1987, only that portion
of a Participant's contributions to

                                      41
<PAGE>
 
all such plans equal to the lesser of (A) the Participant's contributions to all
such plans in excess of six percent (6%) of the Participant's Earnings, or (B)
one-half (1/2) of the Participant's contributions to all such plans for the year
shall be considered "Annual Additions."  The Participant's contributions
described in clause (iii) of the first sentence and in the second sentence of
this Section 5.4 shall not include any rollover amounts (as defined in section
402(a)(5) of the Code), any repayments of loans, any amounts transferred
directly from a trust qualified under section 401(a) of the Code pursuant to
Section 7.3, or any prior distributions repaid to a plan upon the exercise of
buy-back rights under the Savings Plan and Retirement Program Plan for Employees
of Martin Marietta Energy Systems, Inc.

          5.5  Defined Benefit and Defined Contribution Plans.  For purposes of
               ----------------------------------------------                  
this Article V, the term "Defined Benefit Plan" or "Defined Contribution Plan"
means whichever of the following is applicable:  a defined benefit plan or a
defined contribution plan described in section 401(a) of the Code, which
includes a trust which is exempt from income tax under section 501(a) of the
Code; provided that a Participant's contributions under a plan which otherwise
qualifies as a defined benefit plan shall be treated as a defined contribution
plan.

          5.6  Aggregation of Defined Contribution Plans.  In applying the
               -----------------------------------------                  
limitation on annual additions provided in this Article V, all defined
contribution plans maintained by the Company and Affiliates shall be aggregated.

          5.7  Defined Contribution Plan Limitation.  In no event may the annual
               ------------------------------------                             
additions made to a Participant's accounts in all defined contribution plans
maintained by the Company and Affiliates exceed the lesser of (1) thirty
thousand dollars ($30,000) (or, if greater, 1/4 of the dollar limitation in
effect under section 415(b)(1)(A) of the Code,) or (2) twenty-five percent of
such Participant's Earnings for such year.

                                      42
<PAGE>
 
          5.8  Defined Contribution Plan Fraction Determination.  For purposes
               ------------------------------------------------               
of this Section 5.8, a Participant's "Defined Contribution Plan Fraction" shall
be determined as follows:

               (A)  Numerator.  For any Limitation Year, the numerator shall be
                    ---------                                                  
          the sum of the Annual Additions to the Participant's accounts under
          all Defined Contribution Plans maintained by the Company or an
          Affiliate in such year and in all prior Limitation Years.

               (B)  Denominator.  For any Limitation Year, the denominator shall
                    -----------                                                 
          be the lesser of the following amounts, determined for such year and
          for each prior Limitation Year of the Participant's Credited Services
          with the Company or an Affiliate:

                    (I)  One hundred and twenty-five percent (125%) of the
               maximum Dollar Limit for such year determined under Section 5.7
               of this Plan, or

                    (II)  thirty-five percent (35%) of the Participant's
               Earnings for such year.

Notwithstanding the foregoing, in computing the denominator of the Defined
Contribution Plan Fraction for any Limitation Year ending after December 31,
1982, the Committee may elect to determine the portion of such denominator which
relates to 1982 and prior years under the method described in section 415(e)(6)
of the Code in lieu of the method described above.  Such election may be made at
such time and in such manner as may be provided in applicable regulations issued
by the Secretary of the Treasury or his/her delegate.

          5.9  Defined Benefit Plan Fraction Determination.  For purposes of
               -------------------------------------------                  
this Section 5.9, a Participant's "Defined Benefit Plan Fraction" shall be
determined as follows for any Limitation Year:

                                      43
<PAGE>
 
               (A)  Numerator.  The numerator shall be the sum of the projected
                    ---------                                                  
          annual benefits (as defined in section 415(e)(2) of the Code) of the
          Participant under all Defined Benefit Plans maintained by the Company
          or an Affiliate as of the close of such year, disregarding benefits
          derived from the Participant's contributions, if any.

               (B)  Denominator.  The denominator shall be the lesser of the
                    -----------                                             
          following amounts:

                    (I)  one hundred and twenty-five percent (125%) of the
               maximum dollar limitation applicable to Defined Benefit Plans for
               such year under sections 415(b)(1)(A) and 415(d) of the Code, or

                    (II)  one hundred forty percent (140%) of the Participant's
               average annual Earnings for the three (3) consecutive years in
               which the Participant's Earnings were highest.

          5.10 Combined Limitation.  If a Participant participates in one or
               -------------------                                          
more Defined Benefit Plans maintained by the Company or an Affiliate, the sum of
the Participant's Defined Contribution Plan Fraction and Defined Benefit Plan
Fraction as of the close of any Limitation Year may not exceed 1.0.  In order to
prevent such sum from exceeding 1.0, benefits under any Defined Benefit Plan in
which the Participant  participates shall be reduced to the extent necessary for
that purpose.

          5.11 Alternative Method.  The Committee may, in its discretion,
               ------------------                                        
determine any amounts required to be taken into account under this Article V by
such alternative methods as shall be permitted under applicable regulations or
rulings issued by the United States Department of the Treasury.

          5.12 Participation in Multiple Plans.
               ------------------------------- 

                                      44
<PAGE>
 
               5.12.1  If amounts contributed to any Defined Contribution Plan
          by or on behalf of a Participant must be reduced in any Limitation
          Year to comply with the limit on Annual Additions in Section 5.7 of
          this Plan, the amounts contributed to such Defined Contribution Plans
          shall be reduced in the following order:

                    (a)  Supplemental Deposits made under the Savings Plan;

                    (b)  Supplemental Deductions made under the Savings Plan;

                    (c)  Additional Contributions made under Section 2.6 of this
               Plan;

                    (d)  Forfeitures under the Savings Plan;

                    (e)  Company Contributions made under Section 2.5 of this
               Plan;

                    (f)  Before Tax Contributions made under Section 2.3 of this
               Plan;

                    (g)  Company Contributions made under the Savings Plan;

                    (h)  Basic Deductions made under the Savings Plan; and

                    (i)  Contributions to any Defined Benefit Plan treated as a
               Defined Contribution Plan.

          Amounts contributed by or on behalf of a Participant in one category
          above shall be reduced to zero before any reduction is made to any
          such amounts contributed in the next following category.

               5.12.2  The amount of Company Contributions which may not be
          allocated to a Participant's Tax Deferred Account because of the
          limitations of this Article V or of Section 2.10 of this Plan shall be
          considered to have been made by a mistake of fact and shall be
          returned to the Employer making such contributions.

          5.13 Notice of Reduction.  The Committee shall give prompt notice to
               -------------------                                            
any Participant whose benefit is reduced pursuant to the provisions of this
Article V.

                                      45
<PAGE>
 
                                   ARTICLE VI

                                TOP-HEAVY RULES
                                ---------------
          6.1  Top-Heavy Plan.
               -------------- 

               6.1.1  Top-Heavy Plan Defined.  (a) The Plan will be considered
                      ----------------------                                  
          to be Top-Heavy for a Plan Year if, on the last day of any Plan Year
          (hereinafter referred to as the Determination Date):  (i) the
          aggregate value of the Tax Deferred Accounts of all Key Employees
          under the Plan exceeds sixty percent (60%) of the aggregate value of
          the Tax Deferred Accounts of all Participants in the Plan; provided,
          however, that for purposes of determining whether this Plan is a top-
          heavy plan under this Section 6.1, this Plan may be aggregated with
          any other plan of the Company or an Affiliate, in accordance with the
          provisions of section 416 of the Code, or (ii) the Plan is part of a
          required aggregation group of plans and the required aggregation group
          is Top-Heavy.  The term "required aggregation group" shall mean (1)
          each plan of the Company or an Affiliate which qualifies under section
          401(a) of the Code in which at least one Key Employee is a
          Participant, and (2) any other plan which enables a plan described in
          the preceding subsection (1) to meet the requirements of section
          401(a)(4) or 410 of the Code.

               (b) If an Employer maintains or has maintained a Defined Benefit
          Plan (as defined in Section 5.5) which has covered or could cover a
          Participant in this Plan, the Top-Heavy percentage shall be determined
          by applying a fraction, the numerator of which is the sum of the Tax
          Deferred Accounts of all Key Employees under this Plan and the present
          value of the Accrued Benefits of all Key Employees under the Defined
          Benefit Plan, and the denominator of which

                                      46
<PAGE>
 
          is the sum of the Tax Deferred Accounts of all Participants under this
          Plan and the present value of the Accrued Benefits of all Participants
          under the Defined Benefit Plan.  For purposes of this paragraph, the
          aggregate value of the Tax Deferred Accounts and the present value of
          the Accrued Benefits shall be calculated with reference to
          Determination Dates which occur within the same calendar year.  The
          provisions of subparagraphs (a) and (b) above shall apply in
          constructing such fraction.

               If the plans are determined to be Top-Heavy, an Employer shall be
          required to provide either a minimum contribution under this Plan
          equal to at least five percent (5%) (7.5% if Section 6.4 applies) of
          the total annual compensation of each Participant who is not a Key
          Employee, or the minimum benefit under the applicable provisions of
          the Defined Benefit Plan.

               6.1.2  Amounts Included in Tax Deferred Account.  For purposes of
                      ----------------------------------------                  
          determining whether this Plan is top-heavy, the value of a
          Participant's Tax Deferred Account includes the amount of any
          distribution made to such Participant pursuant to Section 4.1, any
          withdrawal made by such Participant pursuant to Section 4.4 and any
          transfers to such Participant's Tax Deferred Account pursuant to
          Sections 2.7 and 2.8.2 if such distributions, withdrawals or transfers
          were made during the Plan Year or the preceding four Plan Years.
          However, amounts transferred from the Participant's Tax Deferred
          Account during such Plan Years pursuant to Section 2.8.1 shall not be
          taken into account for purposes of this Section 6.1.  The value of a
          Participant's Tax Deferred Account shall not be taken into account if
          such Participant has not received any Compensation from the Company or
          an Affiliate (other than a distribution or

                                      47
<PAGE>
 
          withdrawal from the Plan) at any time during the five year period
          ending on the determination date.

          6.2  Minimum Top-Heavy Benefits.  If the Plan is top-heavy under
               --------------------------                                 
Section 6.1, the Company Contribution for each Participant, other than a
Participant who is a Key Employee, shall be increased by an amount that, when
added to the sum of the Participant's Before Tax Contributions, related Company
Contributions and Additional Contributions made under this Plan  without regard
to this Section 6.2, shall bring the total amount contributed for such
Participant under this Plan to three percent (3%) of such Participant's
Earnings.

          6.3  Reduction in Combined Limitation.  If the Plan is top-heavy under
               --------------------------------                                 
Section 6.1, the Participant's defined contribution plan fraction and defined
benefit plan fraction, determined under Sections 5.8 and 5.9, respectively,
shall be determined by substituting "one hundred percent (100%)" for "one
hundred and twenty-five percent (125%)" in each place "one hundred and twenty-
five (125%)" appears in such sections unless, on the last day of the Plan Year
in which the Plan is found to be top-heavy under Section 6.1, the aggregate
value of the Tax Deferred Accounts of Key Employees under the Plan does not
exceed 90 percent of the aggregate value of the Tax Deferred Accounts for all
Participants in the Plan and the Company elects to substitute "four percent
(4%)" for "three percent (3%)" in Section 6.2.

          6.4  Key Employee.  For purposes of this Article VI, a "Key Employee"
               ------------                                                    
shall be any Employee of the Company or an Affiliate who, at any time during the
Plan Year or any of the four preceding Plan Years, is:

               6.4.1  one of the 50 Employees of the Company or an Affiliate who
          has the highest Earnings during the Plan Year or any of the preceding
          four Plan Years of all Employees of the Company and Affiliates if such
          Employee is also an officer of the Company or an Affiliate; provided,
          however, that such

                                      48
<PAGE>
 
          Employee shall not be a Key Employee unless such Employee's Earnings
          exceed 150% of the dollar limitation in effect under section
          415(c)(1)(A) of the Code for the Plan Year;

               6.4.2  one of the 10 Employees owning (or considered as owning
          within the meaning of section 318 of the Code) the largest interests
          in the Company or an Affiliate among all Employees of the Company and
          Affiliates; provided, however, that such Employee shall not be a Key
          Employee unless such Employee's Earnings exceed $30,000 or such other
          dollar limitation in effect under section 415(c)(1)(A) of the Code for
          the Plan Year; and further provided that if two or more Employees own
          equal interests in the Company or an Affiliate, the Employee with
          greater Earnings shall be treated as owning a larger interest;

               6.4.3  a five percent (5%) owner of the Company
          or an Affiliate;

               6.4.4  a one percent (1%) owner of the Company or an Affiliate if
          such owner's annual Earnings exceed $150,000; or

               6.4.5  a Beneficiary of a Key Employee described in Sections
          6.4.1 through 6.4.4, inclusive.

          6.5  Automatic Removal.  In the event that it shall be determined by
               -----------------                                              
statute, regulation or ruling of the Internal Revenue Service that the
provisions of this Article VI are no longer necessary in whole or in part to
qualify this Plan under the Code, this Article VI shall be ineffective to such
extent without amendment to the Plan.

                                      49
<PAGE>
 
                                  ARTICLE VII

                                     TRUST
                                     -----
          7.1  Trustee.  To provide for the administration of the Plan, the
               -------                                                     
Company will enter into a Trust Agreement with a Trustee appointed by the
Company.  The Trust Agreement shall be in such form and contain such provisions
as the Company may deem appropriate, including, but not limited to, provisions
with respect to the powers and authority of the Trustee (including the
management of funds and/or providing investment options and retirement elections
under this Plan by some other institution or institutions, as directed by the
Committee from time to time), the authority of the Company to amend the Trust
Agreement and to terminate the Trust Fund, and the authority of the Company to
settle the accounts of the Trustee on behalf of all persons having an interest
in the Plan, and a provision that, except as provided in Section 10.11 of this
Plan, it shall be impossible at any time for any part of the corpus or income of
the Trust Fund to be used for or diverted to purposes other than for the
exclusive benefit of Eligible Employees or their Beneficiaries.

          7.2  Trust Expenses.  Costs and expenses of administering the Trust
               --------------                                                
Fund, including Trustee's fees and investment manager's fees, shall be paid from
the Trust Fund, unless they are paid by the Company.

          7.3  Plan-to-Plan Transfers.  The Trustee may transfer all funds in a
               ----------------------                                          
Participant's Tax Deferred Account to the trustees of any trust qualified under
section 401(a) of the Code.  The Trustee may make such a transfer only at the
direction of the Committee.

          The Trustee may accept as part of the Trust Fund property transferred
from a trust qualified under section 401(a) of the Code.  The Trustee may accept
such a transfer only at the direction of the Committee.  Such property shall at
all times remain in a segregated


                                      50
<PAGE>
 
account maintained by the Trustee.  Such property shall be distributed to the
Participant or his/her Beneficiary in accordance with the provisions of Article
IV.

                                      51
<PAGE>
 
                                  ARTICLE VIII

                                 ADMINISTRATION
                                 --------------

          8.1  Administrative Committee.  There is hereby created an
               ------------------------                             
Administrative Committee (the "Committee") which shall consist of not less than
three (3) members appointed by the Board of Directors of the Company or pursuant
to the authorities granted by them.  The general administration of the Plan will
be the responsibility of the Administrative Committee.  The Vice President and
Chief Financial Officer of Martin Marietta Corporation may, at any time, fill
vacancies or require the resignation of one or more of the members of the
Committee with or without cause.  In the event that a vacancy or vacancies shall
occur on the Committee, the remaining member or members shall act as the
Committee until the Vice President and Chief Financial Officer of Martin
Marietta Corporation fills such vacancy or vacancies.  No person shall be
ineligible to be a member of a Committee because he/she is, was or may become
entitled to benefits under the Plan or because he/she is a director and/or
officer of the Company or an Affiliate or a Trustee; provided, that no
Participant who is a member of the Committee shall participate in any
determination by the Committee specifically relating to the disposition of
his/her own Tax Deferred Account (including any determination with respect to a
hardship withdrawal or a loan pursuant to Sections 4.4 and 4.5, respectively.)

          8.2  Limitation of Liability; Indemnity.
               ---------------------------------- 

               8.2.1  Except as otherwise provided by law, no person who is a
          member of the Committee, or any employee, director or officer of the
          Company or an Affiliate, may incur any liability whatsoever on account
          of any matter connected with or related to the Plan or the
          administration of the Plan.

               8.2.2  The Company shall indemnify and save harmless each member
          of the Committee, and each employee, director or officer of the
          Company or an

                                      52
<PAGE>
 
          Affiliate, from and against any and all loss, liability, claim,
          damage, cost and expense which may arise by reason of, or be based
          upon, any matter connected with or related to the Plan or the
          administration of the Plan (including, but not limited to, any and all
          expenses whatsoever reasonably incurred in investigating, preparing or
          defending against any litigation, commenced or threatened, or in
          settlement of any such claim whatsoever), unless such person shall
          have acted in bad faith or been guilty of willful misconduct or gross
          negligence in respect of his/her duties, actions or omissions in
          respect of the Plan.

          8.3  Compensation and Expenses.  The members of the Committee shall
               -------------------------                                     
serve without compensation for their services as such members.  All expenses
reasonably incurred by the Committee shall be treated as an expense of the Trust
Fund unless paid by the Company.  The members of the Committee shall serve
without bond unless the Company or the provisions of any applicable laws shall
require otherwise, in which event the Company shall pay the premium thereon.

          8.4  Voting, Chairman, Subcommittees.
               ------------------------------- 

               8.4.1  If there are fewer than three members of the Committee at
          any time, the Committee may do any act which the Plan authorizes or
          requires the Committee to do only upon the unanimous consent of the
          members of the Committee eligible to vote on such act.  If there are
          three or more members of the Committee at any time, a majority of the
          members of the Committee at the time in office may do any act which
          the Plan authorizes or requires the Committee to do.  The action of
          such majority of the members expressed from time to time by a vote at
          a meeting, or in writing without a meeting, or by conference telephone
          or similar communications equipment allowing all persons

                                      53
<PAGE>
 
          participating in the meeting to hear each other at the same time,
          shall constitute the action of the Committee and shall have the same
          effect for all purposes as if assented to by all members at the time
          in office.  Where action is taken by members of the Committee by
          conference telephone or similar communications equipment, such action
          shall be confirmed in writing by such members as soon as practicable
          thereafter.

               The Secretary shall maintain minutes reflecting Committee
          meetings and shall cause each action taken in writing without a
          meeting, and each written confirmation of action taken by conference
          telephone or similar communications equipment, to be included in the
          minutes of the Committee.

               8.4.2  The Plan Administrator, as appointed pursuant to Section
          8.10, shall serve as Chairman of the Committee.  The members of the
          Committee shall elect a Secretary who may, but need not be, a member
          of the Committee, and they may appoint from their number such
          subcommittees as they shall determine.

          8.5  Payment of Benefits.  The Committee shall advise the Trustee in
               -------------------                                            
writing with respect to all benefits which become payable under the terms of the
Plan and shall direct the Trustee to pay such benefits to or on order of the
Committee.  In the event that the Trust Fund shall be invested in whole or in
part in one or more insurance contracts, the Committee shall be authorized to
give to any such insurance company such instructions as may be necessary or
appropriate in order to provide for the payment of benefits in accordance with
the Plan.

          8.6  Powers and Authority; Action Conclusive.  Except as otherwise
               ---------------------------------------                      
expressly provided in the Plan or in the Trust Agreement, or by the Board of
Directors of the Company:

               8.6.1  The Committee shall be responsible for the administration
          of the Plan.

                                      54
<PAGE>
 
               8.6.2  The Committee shall have all powers necessary or helpful
          for the carrying out of its responsibilities, and the decisions or
          action of the Committee in good faith in respect of any matter
          hereunder shall be conclusive and binding upon all parties concerned.

               8.6.3  The Committee may delegate to one or more of its members
          or any other person the right to act on its behalf in all matters
          connected with the administration of the Plan.

               8.6.4  Without limiting the generality of the foregoing, the
          Committee shall have full discretionary authority to:

               8.6.4.1  Determine all questions arising out of or in connection
          with the terms and provisions of the Plan except as otherwise
          expressly provided herein;

               8.6.4.2  Make rules and regulations for the administration of the
          Plan which are not inconsistent with the terms and provisions of the
          Plan, and fix the annual accounting period of the trust established
          under the Trust Agreement as required for tax purposes;

               8.6.4.3  Construe all terms, provisions, conditions and
          limitations to the Plan;

               8.6.4.4  Determine all questions relating to (i) the eligibility
          of persons to receive benefits hereunder, (ii) the years of Credited
          Service, years of Company Service Credit and the amount of
          Compensation and Earnings of a Participant during any period
          hereunder, and (iii) all other matters upon which the benefits or
          other rights of a Participant or other person shall be based
          hereunder;

                                      55
<PAGE>
 
               8.6.4.5  Determine all questions relating to the administration
          of the Plan (i) when disputes arise between the Company and a
          Participant or his/her Beneficiary, spouse or legal representative,
          and (ii) whenever the Committee deems it advisable to determine such
          questions in order to promote the uniform administration of the Plan.

The foregoing list of powers is not intended to be either complete or exclusive,
and the Committee shall, in addition, have such powers as may be necessary for
the performance of its duties under the Plan and the Trust Agreement.

          8.7  Counsel and Agents.  The Committee may employ such counsel,
               ------------------                                         
including legal counsel, accountants, investment advisors, physicians, agents
and such clerical and other services as it may require in carrying out the
provisions of the Plan, and shall charge the fees, charges and costs resulting
from such employment as an expense of the Trust Fund unless paid by the Company.
Unless otherwise provided by law,  any person so employed by the Committee may
be legal or other counsel to the Company, an Affiliate, a member of the
Committee or an officer or member of the Board of Directors of the Company or an
Affiliate.

          8.8  Reliance on Information.  The members of the Committee and the
               -----------------------                                       
Company and its officers, directors and employees shall be entitled to rely upon
all tables, valuations, certificates, opinions and reports furnished by any
accountant, trustee, insurance company, counsel or other expert who shall be
engaged by the Company or the Committee, and the members of the Committee and
the Company and its officers, directors and employees shall be fully protected
in respect of any action taken or suffered by them in good faith in reliance
thereon, and all action so taken or suffered shall be conclusive upon all
persons affected thereby.

          8.9  Fiduciaries.  The provisions of this Section 8.9 shall apply
               -----------                                                 
notwithstanding any contrary provisions of the Plan or the Trust Agreement.

                                      56
<PAGE>
 
               8.9.1  The named fiduciaries under the Plan shall be the members
          of the Committee, who shall be named fiduciaries with respect to
          control or management of the assets of the Plan, and who shall have
          authority to control or manage the operation and administration of the
          Plan, except with respect to those matters which under the Plan or the
          Trust Agreement are the responsibility, or subject to the authority,
          of the Trustee.

               8.9.2  The named fiduciaries under the Plan shall have the right,
          which shall be exercised in accordance with the procedures set forth
          in Section 8.4.1 and/or in the Trust Agreement for action by the
          Committee, to allocate responsibilities, fiduciary or otherwise, among
          named fiduciaries, and the named fiduciaries (or any of them to whom
          such right shall be allocated) shall have the right to designate
          persons other than named fiduciaries to carry out responsibilities,
          fiduciary or otherwise, under the Plan.

               8.9.3  The members of the Committee shall together establish and
          carry out, or cause to be provided by those persons (including without
          limitation, any investment manager, trustee or insurance company) to
          whom responsibility or authority therefor has been allocated or
          delegated in accordance with this Plan or the Trust Agreement, a
          funding policy and method consistent with the objectives of the Plan
          and the requirements of ERISA.  For such purposes, the Committee
          shall, at a meeting duly called for the purpose, establish a funding
          policy and method which satisfies the requirements of ERISA, and shall
          meet annually at a stated time of the year to review such funding
          policy and method.  All actions taken with respect to such funding
          policy and method and the reasons therefor shall be recorded in the
          minutes of the meetings of the Committee.

                                      57
<PAGE>
 
               8.9.4  Any person or group of persons may serve in more than one
          fiduciary capacity with respect to the Plan.

               8.9.5  Any named fiduciary under the Plan, and any fiduciary
          designated by a named fiduciary pursuant to Section 8.9.2 to whom such
          power is granted by a named fiduciary under the Plan, may employ one
          or more persons to render advice with regard to any responsibility
          such fiduciary has under the Plan.

               8.9.6  The Board of Directors of the Company, or any director to
          whom such right shall be allocated, may appoint an investment manager
          or managers, as defined in section 3(38) of ERISA, to manage
          (including the power to acquire, invest and dispose of) any assets of
          the Plan.

               8.9.7  Except to the extent otherwise provided by law, if any
          duty or responsibility of a named fiduciary has been allocated or
          delegated to any other person in accordance with any provision of this
          Plan or of the Trust Agreement, then such named fiduciary shall not be
          liable for an act or omission of such person in carrying out such duty
          or responsibility.

          8.10 Plan Administrator.  The Vice President and Chief Financial
               ------------------                                         
Officer of Martin Marietta Corporation shall appoint a person to serve as
Administrator of the Plan, as defined in section 3(16)(A) of ERISA.

          8.11 Notices and Elections.  An Employee shall deliver to the
               ---------------------                                   
Committee all directions, orders, designations, notices or other communications
on appropriate forms to be furnished by the Committee.  The Committee shall also
receive notices or other communications for Participants from the Trustee and
transmit them to the Participants.  All elections which may be made by an
Employee under this Plan shall be made in a time, manner and form determined by
the Committee unless a specific time, manner or form is set forth in the Plan.

                                      58
<PAGE>
 
          8.12 Taxes Payable by Trustee.  Taxes, if any, other than transfer
               ------------------------                                     
taxes, payable by the Trustee shall be charged against the Tax Deferred Accounts
pro rata to the values of the cash and/or securities affected.

          8.13 Credited Service.  "Credited Service" means for any Employee
               ----------------                                            
his/her Company Service Credit; provided, however, that in any case where it
will produce a result more favorable to the Employee, an Employee's Credited
Service shall be determined in accordance with the following provisions:

               8.13.1  Credited Service is the total of the period of elapsed
          time which begins as of the date an Employee first performs an hour of
          service with the Company or, prior to April 1, 1984, Union Carbide
          Corporation and, except as otherwise provided in this Section 8.13,
          ends as of his/her severance from service date, as provided in Section
          8.13.2.  An "hour of service" is each hour for which an Employee is
          paid, or entitled to payment, for the performance of duties for the
          Company, an Affiliate, or, prior to April l, 1984, Union Carbide
          Corporation.

               8.13.2  An Employee's severance from service date
          shall be the earlier of:

                    (a)  the date the Employee quits, retires, is discharged or
               dies; or

                    (b)  the first anniversary of the first date of the
               Employee's absence for any other reason.

               8.13.3 If an Employee performs an hour of service with the
          Company or, prior to April l, 1984, Union Carbide Corporation within
          twelve months of the date he/she quits, retires, is discharged, or is
          first absent for any other reason, such Employee shall be deemed not
          to have severed his service due to such quit, retirement, discharge or
          absence.

                                      59
<PAGE>
 
               8.13.4  Credited Service shall be the aggregate of all an
          Employee's periods of Credited Service, provided that periods of
          Credited Service before and after a period of severance will be
          aggregated only when:

                    (a)  an Employee's number of consecutive one-year periods of
               severance is less than the greater of (A) 5 years or (B) the
               aggregate number of years of Credited Service that occurred
               before the period of severance; and

                    (b)  such Employee has at least one year of service after
               such period of severance.

               8.13.5  A "period of severance" is the period of time commencing
          on an Employee's severance from service date and ending on the date on
          which the Employee again performs an "hour of service" as defined in
          Section 8.13.1; provided, however, that, effective as of January 1,
          1985, if an Employee is absent from service because of pregnancy, the
          birth of the Employee's child, the placement of a child with the
          Employee for adoption, or the need to care for such child during the
          period immediately following such birth or placement, such Employee
          shall be deemed to have had continuous service during such absence,
          subject to regulations adopted by the Committee in conformance with
          sections 410(a)(5)(E) and 411(a)(6)(E) of the Code and regulations
          thereunder.

          8.14 Company Service Credit.  "Company Service Credit" is based upon
               ----------------------                                         
employment by the Company and by any subsidiary of the Company, by any
predecessor of such a subsidiary and by any Company acquired by the Company or
by any  subsidiary of the Company or, prior to April 1, 1984, by Union Carbide
Corporation.  Company Service Credit of all Employees who were on the payroll on
the date the Retirement Program Plan for

                                      60
<PAGE>
 
Employees of Union Carbide Corporation and its Participating Subsidiary
Companies became effective has been established with respect to their employment
prior to that date.  Company Service Credit for employment subsequent to that
date and Company Service Credit of all new Employees hired after that date will
be determined under the following rules:

               8.14.1  If an Employee receives salary, wages or commission from
          the Company, a subsidiary of the Company, or, prior to April 1, 1984,
          Union Carbide Corporation, without interruption, his/her Company
          Service Credit begins as of the date such salary, wages or commission
          is first paid to such Employee.

               8.14.2  If an Employee is laid off by the Company, a subsidiary
          of the Company, or, prior to April 1, 1984, Union Carbide Corporation
          on account of a reduction in force and through no fault of his/her
          own:

                    (a)  if such layoff continues not more than three (3)
               consecutive years, Company Service Credit will be given for
               service prior to such layoff; and

                    (b)  if such layoff continues more than three (3)
               consecutive years, no Company Service Credit will be given for
               service prior to such layoff.

               8.14.3  In case of absence caused by temporary suspension of work
          (other than "layoff" as in Section 8.14.2), or absence-with-leave
          (except long term disability) which is authorized by the Company, any
          subsidiary of the Company, or, prior to April 1, 1984, Union Carbide
          Corporation, and does not exceed three months, employment will be
          considered as continuous without any reduction for such absence.
          However, in case such absence does exceed three months, the period of
          absence in excess of three months will not be considered as Company

                                      61
<PAGE>
 
          Service Credit unless Company Service Credit is otherwise authorized
          by the Company, a subsidiary of the Company, or, prior to April 1,
          1984, Union Carbide Corporation for such period.  If an Employee who
          is thus absent fails to return to work when able to do so, and at the
          time designated by the Company or a subsidiary of the Company or,
          prior to April 1, 1984, Union Carbide Corporation, he/she will be
          considered as voluntarily terminating his/her employment and his/her
          Company Service Credit shall end as of the date on which such absence
          commenced.

               8.14.4  In case of rehire or reinstatement subsequent to
          discharge for cause or resignation at the request of the Company, a
          subsidiary of the Company, or, prior to April 1, 1984, Union Carbide
          Corporation, Company Service Credit will be given for service only
          since the last date of rehire or reinstatement by the Company or the
          subsidiary, unless Company Service Credit is otherwise authorized by
          the Company or the subsidiary or, prior to April 1, 1984, Union
          Carbide Corporation, for the period prior to such rehire or
          reinstatement.

               8.14.5  An Employee on the active payroll of Union Carbide
          Corporation on January 1, 1973, or rehired thereafter, who had been
          credited with Company Service Credit for one or more periods of prior
          employment but who had lost such credit because

                    (a)  a layoff lasted for more than three years, or

                    (b)  termination was for any other cause, will have such
               prior Company Service Credit restored upon completing a total of
               two years of currently accredited Company Service Credit
               following re-employment.

                                      62
<PAGE>
 
          8.15 Transfer of a Subsidiary, Division, Branch or Business Unit.
               -----------------------------------------------------------  
Notwithstanding anything herein to the contrary, if at any time any subsidiary
or any division, branch or business unit of the Company shall be transferred as
a going business and on that account certain Participants shall remain in the
employ of any such subsidiary or shall transfer to the  acquiring company, the
Board of Directors may, if they so determine, provide for the withdrawal and
segregation of the assets of the 401(k) Plan Trust Fund attributable to such
Participants, based on the value of their respective accrued benefits including
Company payments in the 401(k) Plan Trust Fund determined as though such
Participants had terminated employment as of the date of such transfer as a
going business.  Provided the subsidiary or acquiring company continues the Plan
or adopts a similar 401(k) Plan, as the case may be, a proportionate amount of
the assets of the 401(k) Plan Trust Fund equivalent to the value of such accrued
benefits as so determined may be transferred to the 401(k) Plan Trust Fund
created by the subsidiary or acquiring company for the benefit of such
Participants.

                                      63
<PAGE>
 
                                   ARTICLE IX

                  AMENDMENT, TERMINATION, ADOPTION AND MERGER
                  -------------------------------------------

          9.1  Modification or Amendment of Plan.  The Company reserves the
               ---------------------------------                           
right at any time and from time to time to amend the Plan in whole or in part;
provided that, except as provided in Section 9.4 or as otherwise permitted by
law, no amendment shall be made which (a) would cause or permit any part of the
corpus of the Trust Fund to be diverted to purposes other than for the exclusive
benefit of Participants or their Beneficiaries, (b) would cause or permit any
portion of the assets of the Trust Fund to revert to or become the property of
the Company or an Affiliate at any time, or (c) would divest any Participant of
any amount previously credited to his/her Tax Deferred Account.

          9.2  Termination of Plan or Discontinuance of Contributions.  The Plan
               ------------------------------------------------------           
may be terminated by the Company at any time in the Company's sole discretion,
in whole or in part.  Notwithstanding any other provision of the Plan, upon
complete termination of the Plan or the complete discontinuance of contributions
thereunder, 100 percent of each Participant's Tax Deferred Account shall be non-
forfeitable.  Upon any such termination, the Committee shall instruct the
Trustee either (a) to distribute or dispose of the net assets of the Trust Fund
(remaining after payment of or provision for all expenses of final
administration and liquidation) exclusively for the benefit of all Participants
(or their Beneficiaries, as the case may be) according to their respective
shares of the Trust Fund as of the date of such termination or discontinuance,
or (b) to continue the Trust Fund with distributions to be made at the time and
in the manner provided for by Article IV.  In the event of any partial
termination of the Plan (within the meaning of section 411(d)(3) of the Code),
100 percent of the Tax Deferred Account of each Participant affected by such
partial termination shall be non-forfeitable.

                                      64
<PAGE>
 
          9.3  Expenses of Termination.  In the event of the complete or partial
               -----------------------                                          
termination of the Plan, the expenses incident thereto shall be a prior claim
and lien upon the assets of the Trust Fund and shall be paid or provided for
prior to the distribution of any benefits pursuant to such termination, unless
such expenses are paid by the Company.

          9.4  Amendments Required for Qualification.  All provisions of this
               -------------------------------------                         
Plan, and all benefits and rights granted hereunder, are subject to any
amendments, modifications or alterations which are necessary from time to time
to qualify the Plan under section 401(a) of the Code or corresponding provisions
of subsequent law, to continue the Plan as so qualified, to meet the
requirements of section 401(k) of the Code or to comply with any other provision
of law.  Accordingly, notwithstanding any other provisions of this Plan, the
Company may amend, modify or alter the Plan with retroactive effect in any
respect or manner necessary to qualify the Plan under section 401(a) of the
Code, to continue the Plan as so qualified, to meet the requirements of section
401(k) of the Code, or to comply with any other provision of law.

          9.5  Merger.  Subject to the provisions of this Section 9.5, the Plan
               ------                                                          
may be amended to provide for the merger of the Plan, in whole or in part, or a
transfer of all or a part of its assets or liabilities, to any other qualified
plan within the meaning of section 401(a) or 403(a) of the Code, including such
a merger or transfer in lieu of a distribution which might otherwise be required
under the Plan.  In the event of such a merger or consolidation of this Plan or
transfer of its assets or liabilities to any other plan in whole or in part,
each Participant shall be entitled to a benefit immediately after the merger,
consolidation or transfer (if such other plan then terminated) which is equal to
or greater than the benefit he/she would have been entitled to receive
immediately before the merger, consolidation or transfer (if the Plan had then
been terminated.)

                                      65
<PAGE>
 
          9.6  S.C. Security, Inc.  Effective May 1, 1990, with respect to any
               -------------------                                            
Employee of the Company who was a participant in the S.C. Security, Inc. DOE ORO
Savings Plan, Company Service Credit under the Plan shall include all service
with S.C. Security, Inc. which was recognized for the purpose of determining
benefits under said plan as in effect prior to its merger into this Plan.
 
                                      66
<PAGE>
 
                                   ARTICLE X

                                 MISCELLANEOUS
                                 -------------

          10.1 Claims Procedure.  If a claim for benefits under this Plan is
               ----------------                                             
wholly or partially denied, the claimant shall be provided with a notice setting
forth the specific reason or reasons for the denial, specific reference to
pertinent Plan provisions on which the denial is based, a description of any
additional material or information necessary for the claimant to perfect the
claim, an explanation of why such material or information is necessary, and an
explanation of the Plan's claim review procedure.  Within 60 days after
notification of a denial of benefits, such claimant may, upon written
application, appeal such denial to the Administrator, Martin Marietta Energy
Systems, Inc. for a review.  Such claimant (or his/her duly authorized
representative) may review pertinent documents and submit issues and comments in
writing.  Within 60 days of receipt of such written application for review, the
Administrator shall make a decision in writing, including specific reasons for
the decision, with references to the pertinent Plan provisions.  Under special
circumstances, the Administrator may extend the time for processing such a
review, but a decision shall be rendered not later than 120 days after receipt
of the request for review.  In the event that government regulations shall
impose a different standard for review, such required standard shall be followed
in lieu of the above.

          10.2 Plan Not an Employment Contract.  Neither the adoption of this
               -------------------------------                               
Plan by the Company nor any action of the Company, the Committee, or the Trustee
under this Plan, nor participation in this Plan or failure to participate in
this Plan by any person, shall be held or construed to confer upon any person
any legal right to be continued as an employee of the Company or an Affiliate.
All employees, whether or not they participate in this Plan, shall be subject to
discharge to the same extent as they would have been if this Plan had never been
adopted.

                                      67
<PAGE>
 
          10.3 Consent to Terms of Plan and Trust Agreement.  An Employee by
               --------------------------------------------                 
becoming a Participant in this Plan consents and agrees to all the terms and
provisions of this Plan, the Trust Agreement, and any rules and regulations
adopted by the Committee pursuant to the provisions of this Plan, as they may
each be amended from time to time.

          10.4 Transfer of Interest Not Permitted.  Except as respects any
               ----------------------------------                         
assignment or encumbrance to secure a loan from the Trust Fund which is made
pursuant to Section 4.5, or an assignment of an interest in the Trust Fund made
pursuant to a domestic relations order described in Section 10.4.1, no person
shall have any power to assign, transfer, pledge, encumber, commute, or
anticipate any interest in the Trust Fund or in any payment to be made under
this Plan, and any attempt to assign, transfer, pledge, encumber, commute or
anticipate the same shall be void; nor shall any such interest be in any way
liable  for or subject to the debts, contracts, liabilities, engagements or
torts of the person entitled to such benefit or payment or subject to levy,
garnishment, attachment, execution or other legal or equitable process.

               10.4.1  Exception For Qualified Domestic Relations Order
                       ------------------------------------------------

               10.4.1.1  Definitions
                         -----------
          The term "qualified domestic relations order" means any judgment,
decree, or order (including approval of a property settlement agreement) which:

               (a)  relates to the provision of child support, alimony payments,
          or marital property rights to a spouse, former spouse, child, or other
          dependent of a Participant;

               (b)  is made pursuant to a state domestic relations law
          (including a community property law); and

               (c)  which meets the requirements of subparagraph 10.4.1.2.

                                      68
<PAGE>
 
               10.4.1.2  Requirements For a Qualified Domestic Relations Order
                         ------------------------------------- ---------------

          The provisions of Section 10.4 shall not be applicable to a domestic
relations order and payment of the right or interest of a Participant in the
Plan or in his accounts thereunder shall be made in accordance with the terms of
such order provided that such order:

               (a)  creates or recognizes the existence of an alternate payee's
          (as hereinafter defined) right to, or assigns to an alternate payee
          the right to, receive all or a portion of the right or interest of a
          Participant in the Plan or in his accounts thereunder;

               (b)  clearly specifies

                    (i)   the name and the last known mailing address (if any)
                          of the Participant and the name and mailing address of
                          each alternate payee covered by the order;

                    (ii)  the amount or percentage of the right or interest of
                          the Participant to be paid by the Plan to each such
                          alternate payee or the manner in which such amount or
                          percentage is to be determined;

                    (iii) the number of payments or period to which such order
                          applies; and

                    (iv)  the name of each plan to which such order applies;

               (c)  does not require the Plan to provide any type or form of
          benefit, or any option, not otherwise provided under the Plan;

               (d)  does not require the Plan to provide increased benefits
          (determined on the basis of actuarial value); and

                                      69
<PAGE>
 
               (e)  does not require the payment of the right or interest of the
          Participant to an alternate payee which is required to be paid to
          another alternate payee under another order previously determined to
          be a qualified domestic relations order.

               10.4.1.3  Payments Prior to Termination of Employment.  In the
                         -------------------------------------------         
          case of any payment made before a Participant has terminated
          employment with the Company, a qualified domestic relations order
          shall not be considered as failing to meet the requirements of
          subsection (c) of subparagraph 10.4.1.2 solely because such order
          requires that payment of the right or interest of the Participant be
          made to an alternate payee:

               (a)  on or after the date on which the Participant attains (or
          would have attained) the earliest retirement age which shall be
          defined, for purposes of this Section 10.4.1, as the earlier of (1)
          the date on which the Participant is entitled to a distribution under
          the Plan, or (2) the later of (x) the date the Participant attains age
          50 or (y) the earliest date on which the Participant could begin
          receiving benefits under the Plan if the Participant terminated
          employment with the Company;

               (b)  as if the Participant had retired on the date on which such
          payment is to begin under such order (but taking into account only the
          present value of the right or interest of the Participant actually
          accrued and not taking into account the present value of any subsidy
          of the Employer for early retirement); and

               (c)  in any form in which such right or interest may be paid
          under the Plan to the Participant (other than in the form of a joint
          and survivor annuity with respect to the alternate payee and his
          subsequent spouse).

                                      70
<PAGE>
 
               For purposes of subsection (b) above, the interest rate
          assumption used in determining the present value of a Participant's
          benefits shall be determined from time to time by the Committee on a
          non-discriminatory basis.

               10.4.1.4  Former Spouse
                         -------------
               To the extent provided in any qualified domestic relations order:

               (a)  the former spouse of a Participant shall be treated as a
          surviving spouse of such Participant for purposes of section
          401(a)(11) of the Code; and

               (b)  if married for at least one year to the Participant, such
          former spouse shall be treated as meeting the requirements of section
          401(a)(11)(d) of the Code.

               10.4.1.5  Notice
                         ------

               The Committee shall promptly notify a Participant and any other
          alternate payee of the receipt of a domestic relations order and of
          the Plan's procedure for determining whether the order satisfies the
          requirements of a qualified domestic relations order under this
          Section 10.4.1.  Within a reasonable period of time after the receipt
          of such order, the Committee, in accordance with such procedures as it
          shall from time to time establish, shall determine whether such order
          is a qualified domestic relations order under this Section 10.4.1 and
          shall notify the Participant and each alternate payee of such
          determination.

               During any period of time in which the issue of whether a
          domestic relations order qualifies as a domestic relations order under
          this Section 10.4.1 is being determined by the Committee, by a court
          of competent jurisdiction, or otherwise, the Committee shall
          separately account for the amounts ("segregated amounts") which would
          have been payable to the alternate payee during such period if the
          order had been determined to be a domestic relations order under

                                      71
<PAGE>
 
          this Section 10.4.1.  If within the eighteen (18) month period
          beginning on the date on which the first payment would be required to
          be made under the domestic relations order such order is determined to
          be a domestic relations order under this Section 10.4.1, the Committee
          shall pay the segregated amounts (plus any interest thereon) to the
          person or persons entitled thereto.  If within such eighteen (18)
          month period it is determined that such order is not a domestic
          relations order under this Section 10.4.1, or the issue as to whether
          such order so qualifies is not resolved, then the Committee shall pay
          the segregated amounts (plus any interest thereon) to the person or
          persons who would have been entitled to such amounts if there had been
          no order.  Any determination that an order is a domestic relations
          order under this Section 10.4.1 which is made after the end of such
          eighteen-month period shall be applied prospectively only.

               10.4.1.6  Definition of Alternate Payee
                         -----------------------------

               The term "alternate payee" means any spouse, former spouse,
          child, or other dependent of a Participant who is recognized by a
          qualified domestic relations order as having a right to receive all,
          or a portion of, the benefits payable under the Plan with respect to
          such Participant.

               10.4.1.7  Transitional Rules
                         ------------------

               The provisions of this Section 10.4.1 shall become effective as
          of January 1, 1985; provided however, that in the case of a domestic
          relations order entered before such date, the Committee:

               (a)  shall treat such order as a qualified domestic relations
          order under this Section 10.4.1 if the Trustees are paying benefits
          pursuant to such order on January 1, 1985; and

                                      72
<PAGE>
 
               (b)  may treat any other domestic relations order entered before
          January 1, 1985 as a qualified domestic relations order under this
          Section 10.4.1 even if such order does not meet the requirements of
          the preceding provisions of this Section 10.4.1.

          10.5 Obligations of Company Limited.  The Company assumes no
               ------------------------------                         
obligations under this Plan except those specifically stated in this Plan.  No
person shall have any right to participate in profits by reason of this Plan
except to the extent expressly set forth herein.  The Company shall be under no
legal obligation to make any contributions to the Trust Fund except as expressly
provided herein.

          10.6 Separation of Invalid Provisions.  If any provision of this Plan
               --------------------------------                                
or the Trust Agreement is held invalid, the remainder of the Plan or Trust
Agreement shall not be affected thereby.

          10.7 Payment to a Minor or Incompetent.  In the event that any amount
               ---------------------------------                               
is payable to a minor or other legally incompetent person, such amount may be
paid in any of the following ways, as the Committee in its sole discretion shall
determine:

               10.7.1  To the legal representative of such minor or other
          incompetent person;

               10.7.2  Directly to such minor or other incompetent person;

               10.7.3  To a parent or guardian of such minor, or to a custodian
          for such minor under the Uniform Gifts to Minors Act (or similar
          statute) of any jurisdiction or to the person with whom such minor
          shall reside.

Payment to such minor or incompetent person, or to such other person as may be
determined by the Committee, as above provided, shall discharge the Company, the
Committee, the Trustee and any insurance company or other person or corporation
making such payment pursuant to the

                                      73
<PAGE>
 
direction of the Committee, and none of the foregoing shall be required to see
to the proper application of any such payment to such person pursuant to the
provisions of this Section 10.7.

          10.8 Doubt as to Right to Payment.  If at any time any doubt exists as
               ----------------------------                                     
to the right of any person to any payment hereunder or as to the amount or time
of such payment (including, without limitation, any doubt as to identity, or any
case in which any notice has been received from any other person claiming any
interest in amounts payable hereunder, or any case in which a claim from other
persons may exist by reason of community property or similar laws,) the
Committee shall be entitled, in its discretion, to direct the Trustee (or any
insurance company) to hold such sum as a segregated amount in trust until such
right or amount or time is determined or until order of a court of competent
jurisdiction, or to pay such sum into court in accordance with appropriate rules
of law in such case then provided, or to make payment only upon  receipt of a
bond or similar indemnification (in such amount and in such form as is
satisfactory to the Committee.)

          10.9 Forfeiture Upon Inability to Locate Distributee.  Notwithstanding
               -----------------------------------------------                  
any other provision of the Plan, in the event that the Committee cannot locate
any person to whom a payment is due under the Plan, and no other payee has
become entitled thereto pursuant to any provision of the Plan, the benefit in
respect of which such payment is to be made shall be forfeited at such time as
the Committee shall determine in its sole discretion (but in all events prior to
the time such benefit would otherwise escheat under any applicable state law);
provided that any benefit so forfeited shall be restored if such person
subsequently makes a valid claim for such benefit.

          10.10  Contributions Conditioned on Initial Qualification and
                 ------------------------------------------------------
Deductibility.  Notwithstanding any other provision of this Plan, each Before
- -------------                                                                
Tax Contribution, related

                                      74
<PAGE>
 
Company Contribution and Additional Contribution made by the Company under this
Plan is conditioned on:

               10.10.1  A determination by the Internal Revenue Service that the
          Plan qualifies under section 401 of the Code for the Plan Year as to
          which the Company first makes a contribution hereunder; and

               10.10.2  The deductibility of such contribution under section 404
          of the Code.

          10.11  No Diversion of Trust Fund.  It shall be impossible at any time
                 --------------------------                                     
for any part of the Trust Fund to be (within the taxable year or thereafter)
used for or diverted to purposes other than for the exclusive benefit of
Participants and their Beneficiaries (including the payment of the expenses of
the administration of the Plan and of the Trust); provided that:

               10.11.1  A contribution that is made by the Company by a mistake
          of fact shall be returned to the Company upon its request within one
          year after the payment of the contribution; or

               10.11.2  A contribution that is conditioned upon its
          deductibility under section 404 of the Code shall be returned to the
          Company upon its request, to the extent that the contribution is
          disallowed as a deduction, within one year after such disallowance; or

               10.11.3  A contribution that is conditioned on qualification of
          the Plan under section 401 of the Code shall, if the Plan does not so
          qualify, be returned to the Company within one year after the date of
          denial of qualification of the Plan.

Subject to Article IX, the Trust shall continue for such time as may be
necessary to accomplish the purpose for which it is created.

                                      75
<PAGE>
 
          10.12  Usage.  Whenever applicable the masculine gender, when used in
                 -----                                                         
the Plan, shall include the feminine and neuter genders, and the singular shall
include the plural.

          10.13  Governing Law.  The Plan shall be governed by, construed and
                 -------------                                               
administered under the law of the State of Tennessee without regard to the
principles of conflict of laws, to the extent not preempted by Federal law.

          10.14  Captions.  The captions contained herein are inserted only as a
                 --------                                                       
matter of convenience and for reference and in no way define, limit, enlarge or
describe the scope or intent of the Plan and in no way shall affect the Plan or
the construction of any provision thereof.

          IN WITNESS WHEREOF, and as evidence of the adoption of this Plan, the
Company has caused this instrument to be signed by its duly authorized officer
and its corporate seal to be hereunto affixed and attested this ____ day of
___________ 1993.

                                 MARTIN MARIETTA ENERGY
                                 SYSTEMS, INC.


                                 By
                                   __________________________________________
                                   (title)
[Seal]

ATTEST:


____________________________
          (title)


                                      76

<PAGE>

                                                                   EXHIBIT 4-C 


                      MARTIN MARIETTA ENERGY SYSTEMS, INC.

                 SAVINGS PLAN FOR SALARIED AND HOURLY EMPLOYEES

                            Effective April 1, 1984



                   (Amended and Restated as of April 1, 1990)
<PAGE>
 
                               TABLE OF CONTENTS
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                 SAVINGS PLAN FOR SALARIED AND HOURLY EMPLOYEES



ARTICLE I - DEFINITIONS ....................................................  1
          1.    Definitions ................................................  1
          1.1   "Accrued Benefit"...........................................  1
          1.2   "Accrued Benefit Derived from Company Contributions" .......  1
          1.3   "Accrued Benefit Derived from Participant's Contributions"..  1
          1.4   "Affiliate".................................................  1
          1.5   "Beneficiary"...............................................  2
          1.6   "Code"......................................................  2
          1.7   "Company"...................................................  2
          1.8   "Compensation"..............................................  2
          1.9   "Corporation"...............................................  2
          1.10  "Employer"..................................................  2
          1.11  "ERISA".....................................................  2
          1.12  "401(k) Plan"...............................................  2
          1.13  "Mandatory Contribution"....................................  3
          1.14  "Normal Retirement Age".....................................  3
          1.15  "Period of Severance".......................................  3
          1.16  "Plan"......................................................  3
          1.17  "Plan Year".................................................  3
          1.18  "Regular Employee"..........................................  3
          1.19  "Subsidiary"................................................  3
          1.20  "Trust Agreement"...........................................  4
          1.21  "Trustee"...................................................  4
          1.22  "Vesting"...................................................  4
 
ARTICLE II - PARTICIPATION, CONTRIBUTIONS AND VESTING ......................  5
          2.1   Participation ..............................................  5
          2.2   Exclusions .................................................  5
          2.3   Basic Deductions ...........................................  6
          2.4   Supplemental Deposits ......................................  7
          2.5   Transfers from the 401(k) Plan..............................  7
          2.6   Company's Contributions ....................................  8
          2.7   Revocation of Basic Deductions .............................  9
          2.8   Vesting and Benefit Accrual ................................ 11
          2.9   401(m) Limitations ......................................... 12
 
ARTICLE III - INVESTMENT AND VALUATION OF PERSONAL
                INVESTMENT ACCOUNT ......................................... 13
          3.1   General .................................................... 13
          3.2   Investment Options ......................................... 13
          3.3   Union Carbide Corporation Stock Fund ....................... 14

                                       i
<PAGE>
 
<TABLE> 
           <C>   <S>                                                                        <C> 
           3.4   Rollover Deposits and Supplemental Deposits .............................. 15
           3.5   Rules for Investment Options ............................................. 15
           3.6   Short-term Investment of Funds ........................................... 17
           3.7   Dividends ................................................................ 17
           3.8   Investment Manager ....................................................... 17
           3.9   Instructions By A Participant For His/Her Personal Investment Account .... 17
           3.10  Purchases and Sales ...................................................... 18
           3.11  Value of Martin Marietta Corporation Stock Fund .......................... 20
           3.12  Proceeds of Martin Marietta Corporation Stock Fund ....................... 20
           3.13  Averaging Stock Purchases and/or Sales ................................... 21
           3.14  Cost of Bonds Purchased .................................................. 21
           3.15  Proceeds of Bonds Redeemed ............................................... 21
           3.16  Value of Fixed Income Fund ............................................... 21
           3.17  Proceeds of Fixed Income Fund ............................................ 22
           3.18  Value of Equity Investment Fund .......................................... 22
           3.19  Proceeds of Equity Investment Fund ....................................... 22
           3.20  Costs and Expenses ....................................................... 23
           3.21  Statements Furnished Participants ........................................ 23
           3.22  Custody Of Securities .................................................... 23
           3.23  Voting Rights ............................................................ 23
           3.24  Rights, Warrants and Scrip ............................................... 24
 
 ARTICLE IV - DISTRIBUTIONS, WITHDRAWALS AND LOANS ........................................ 25
           4.1   Withdrawal by Participant During Employment .............................. 25
           4.2   Retirement Elections ..................................................... 29
           4.3   Termination on Death ..................................................... 34
           4.4   Form of Payment .......................................................... 35
           4.5   Transfer to 401(k) Plan .................................................. 36
 
 ARTICLE V - LIMITATION ON MAXIMUM CONTRIBUTIONS
                 AND BENEFITS UNDER ALL PLANS ............................................. 37
           5.1   General .................................................................. 37
           5.2   Affiliate ................................................................ 37
           5.3   Limitation Year .......................................................... 37
           5.4   Annual Additions ......................................................... 37
           5.5   Defined Benefit and Defined Contribution Plans ........................... 38
           5.6   Aggregation of Defined Contribution Plans ................................ 38
           5.7   Defined Contribution Plan Limitation ..................................... 39
           5.8   Defined Contribution Plan Fraction Determination ......................... 39
           5.9   Defined Benefit Plan Fraction Determination .............................. 40
           5.10  Combined Limitation ...................................................... 40
           5.11  Alternative Method ....................................................... 41
           5.12  Participation in Multiple Plans .......................................... 41
           5.13  Notice of Reduction ...................................................... 42
</TABLE> 
                                      ii
<PAGE>
 
ARTICLE VI - TOP-HEAVY RULES ................................................ 42
          6.1   Top-Heavy Plan .............................................. 42
          6.2   Minimum Top-Heavy Benefits .................................. 42
          6.3   Reduction in Combined Limitation ............................ 43
          6.4   Key Employee ................................................ 43
          6.5   Automatic Removal ........................................... 44
          6.6   Amounts Included In Personal Investment Accounts ............ 44
          6.7   Earnings .................................................... 45
 
ARTICLE VII - TRUST ......................................................... 46
          7.1   Trustee ..................................................... 46
          7.2   Trust Expenses .............................................. 46
          7.3   Plan-to-Plan Transfers ...................................... 46
 
ARTICLE VIII - ADMINISTRATION ............................................... 48
          8.1   Administrative Committee .................................... 48
          8.2   Limitation of Liability; Indemnity .......................... 48
          8.3   Compensation ................................................ 49
          8.4   Voting, Chairman, Subcommittees ............................. 49
          8.5   Payment of Benefits ......................................... 50
          8.6   Powers and Authority; Action Conclusive ..................... 50
          8.7   Counsel and Agents .......................................... 52
          8.8   Reliance on Information ..................................... 52
          8.9   Fiduciaries ................................................. 53
          8.10  Plan Administrator .......................................... 54
          8.11  Notices and Elections ....................................... 54
          8.12  Credited Service ............................................ 55
          8.13  Company Service Credit ...................................... 56
          8.14  Taxes Payable by Trustee .................................... 58
          8.15  Costs of Administration ..................................... 59
          8.16  Transfer of a Subsidiary, Division, Branch or Business Unit.. 59
 
ARTICLE IX - AMENDMENT, TERMINATION, ADOPTION AND MERGER .................... 60
          9.1  Modification or Amendment of Plan ............................ 60
          9.2  Termination of Plan or Discontinuance of Contributions ....... 60
          9.3  Expenses of Termination ...................................... 61
          9.4  Amendments Required for Qualification ........................ 61
          9.5  Merger ....................................................... 61
          9.6  Portsmouth, Ohio ............................................. 61
 
ARTICLE X - MISCELLANEOUS ................................................... 63
          10.1  Claims Procedure ............................................ 63
          10.2  Alienation Prohibited ....................................... 63
          10.3  Exception For Qualified Domestic Relations Order ............ 64
          10.4  Consent to Terms of Plan and Trust Agreement ................ 68
          10.5  Obligations of Company Limited .............................. 69

                                      iii
<PAGE>
 
<TABLE> 
          <C>   <S>                                                                        <C> 
          10.6  Separation of Invalid Provisions ......................................... 69
          10.7  Payment to a Minor or Incompetent ........................................ 69
          10.8  Doubt as to Right to Payment ............................................. 70
          10.9  Forfeiture Upon Inability to Locate Distributee .......................... 70
          10.10  Contributions Conditioned on Initial Qualification and Deductibility .... 70
          10.11  No Diversion of Trust Fund .............................................. 71
          10.12  Usage ................................................................... 72
          10.13  Governing Law ........................................................... 72
          10.14  Captions ................................................................ 72
</TABLE> 

                                      iv
<PAGE>
 
                    THE MARTIN MARIETTA ENERGY SYSTEMS, INC.

                 SAVINGS PLAN FOR SALARIED AND HOURLY EMPLOYEES



                                  INTRODUCTION
                                  ------------


         The Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and
Hourly Employees was spun off from the Savings Plan for Employees of Union
Carbide Corporation and Participating Subsidiary Companies, pursuant to the
assumption by Martin Marietta Energy Systems, Inc. from Union Carbide
Corporation of the contract to operate the Department of Energy facilities in
Oak Ridge, Tennessee and Paducah, Kentucky.  The Plan was adopted in its current
form effective April l, 1984.  Any provision regarding a date prior to April l,
1984 refers either to employment with Union Carbide Corporation, or to
participation in the predecessor Union Carbide plan as in effect at that time.
The Plan as in effect on April 1, 1984 shall apply to employees covered by
collective bargaining agreements, until such date as the Plan shall have been
accepted for such employees by collective bargaining.

         This Plan is established by Martin Marietta Energy Systems, Inc., a
Delaware Corporation and a subsidiary of Martin Marietta Corporation, for the
exclusive benefit of its eligible employees and their beneficiaries.
Participation in this Plan by employees is entirely voluntary.
<PAGE>
 
                                   ARTICLE I

                                  DEFINITIONS
                                  -----------

          1.   Definitions.  As used in this Plan, the following terms shall
               -----------                                                  
have the designated meaning:

          1.1  "Accrued Benefit" shall mean the balance of an employee's
                ---------------                                         
account.

          1.2  "Accrued Benefit Derived from Company Contributions" shall mean,
                --------------------------------------------------             
as of any applicable date, the excess, if any, of the accrued benefit of a
Participant as of such applicable date over the accrued benefit derived from
contributions made by such Participant as of such date.

          1.3  "Accrued Benefit Derived from Participant's Contributions" shall
                --------------------------------------------------------       
mean, as of any applicable date, the balance of the Participant's separate
account consisting only of his/her contributions and the income, expenses, gains
and losses attributable thereto.

          1.4  Affiliate" shall mean, except as otherwise provided in Article V,
               ---------                                                        
each of (a) any corporation (other than the Company) of which at least 80% of
the total combined voting power of all classes of stock entitled to vote is
owned at the time of reference, either directly or indirectly, by the Company,
(b) any other trade or business (other than the Company), whether or not
incorporated, which, at the time of reference, is controlled by or under common
control with the  Company, within the meaning of section 414(c) of the Code or
(c) any member (other than the Company), at the time of reference, of an
affiliated service group within the meaning of section 414(m) of the Code, which
includes the Company.
<PAGE>
 
          1.5  "Beneficiary" shall mean the person, persons or estate entitled
                -----------                                                   
under Section 4.3 to receive any amount under this Plan in the event of the
Participant's death.

          1.6  "Code" shall mean the Internal Revenue Code of 1986, as from time
                ----                                                            
to time amended.

          1.7  "Company" shall mean Martin Marietta Energy Systems, Inc., a
                -------                                                    
Delaware corporation, any predecessor thereof, and any successor thereof by
merger, consolidation or otherwise.

          1.8  "Compensation" shall mean a Participant's regular basic salary or
                ------------                                                    
hourly rate of pay (including any cost of living adjustments) for the
Participant's regularly scheduled hours, determined prior to any reduction in
such salary or hourly rate of pay for any contributions to the 401(k) Plan made
on behalf of such Participant or any other plan maintained by the Company which
meets the requirements of Code section 125 and which provides for pre-tax
contributions.  For purposes of this Plan, a Participant's regular, basic salary
or hourly rate of pay shall include any shift bonus or premium, sales commission
or sales bonus paid to such Participant.

          1.9  "Corporation" shall mean Martin Marietta Corporation.
                -----------                                         

          1.10 "Employer" shall mean the Company.
                --------                         

          1.11 "ERISA" shall mean the Employee Retirement Income Security Act of
                -----                                                           
1974, as from time to time amended.  Reference to a specific provision of ERISA
shall include such provision, any valid regulation promulgated thereunder and
any comparable provision of any future legislation that amends, supplements or
supersedes such provision.

          1.12 "401(k) Plan" shall mean either the Martin Marietta Energy
                -----------                                              
Systems, Inc. 401(k) Savings Plan for Salaried Employees or the Martin Marietta
Energy Systems, Inc. 401(k) Savings Plan for Hourly Employees, whichever is
applicable.

                                       2
<PAGE>
 
          1.13 "Mandatory Contribution" shall mean an amount contributed to the
                ----------------------                                         
Plan by a Participant which is required as a condition of participation in the
Plan or as a condition of obtaining benefits under the Plan attributable to
Company contributions.

          1.14 "Normal Retirement Age" shall mean age 65.
                ---------------------                    

          1.15 "Period of Severance" shall mean a period of time commencing on
                -------------------                                           
the severance from service date and ending on the date on which the employee
again performs an "hour of service" as defined in Section 8.12(a); provided,
however, effective as of January 1, 1985, if an employee is absent from service
because of pregnancy, the birth of the employee's child, the placement of a
child with the employee for adoption, or the need to care for such child during
the period immediately following such birth or placement, such employee shall be
deemed to have had continuous employment during such  absence, subject to
regulations adopted by the Committee in conformance with sections 410(a)(5)(E)
and 411(a)(6)(E) of the Code and regulations thereunder.

          1.16 "Plan" shall mean the Martin Marietta Energy Systems, Inc.
                ----                                                     
Savings Plan for Salaried and Hourly Employees as from time to time in effect.

          1.17 "Plan Year" for the Plan shall mean the twelve month period
                ---------                                                 
starting January 1 and ending December 31.

          1.18 "Regular Employee" shall mean an employee of the Employer.
                ----------------                                         

          1.19 "Subsidiary" shall mean (a) any Affiliate as defined in Section
                ----------                                                    
1.4 of Article I of the Plan, and (b) any other corporation partnership or other
entity, other than an Affiliated Company, 20% or more of which is owned at the
time of reference, either directly or indirectly, by the Company.

                                       3
<PAGE>
 
          1.20 "Trust Agreement" shall mean the agreement between the Company
                ---------------                                              
and the Trustee under which this Plan is funded, as such agreement may be
amended from time to time.

          1.21 "Trustee" shall mean the trustee or trustees from time to time
                -------                                                      
designated under the Trust Agreement.

          1.22 "Vesting" refers to the non-forfeitable right of a participant to
                -------                                                         
the accrued benefit payable under the plan.

                                       4
<PAGE>
 
                                   ARTICLE II

                    PARTICIPATION, CONTRIBUTIONS AND VESTING
                    ----------------------------------------


          2.1  Participation.  Any regular employee of the Company who has at
               -------------                                                 
least one year of credited service shall be eligible to become a Participant in
this Plan effective as of the first day of the pay period in which such
Participant completes one year of credited service.

          2.2  Exclusions.  (a)  The following employees are not within the
               ----------                                                  
coverage of the Plan:

                (i) Individuals who perform services for the Company as leased
         employees.  For purposes of this Section 2.2, the term "leased
         employee" shall mean any individual who:

              (1)  is not an independent contractor with respect to the Company;

              (2)  provides services pursuant to an agreement between the
                   Company and any other person or entity (hereinafter referred
                   to as "the leasing organization");

              (3)  has performed such services for the Company on a
                   substantially full-time basis for a period of at least one
                   year;

              (4)  performs services of a type historically performed in the
                   business field of the Company by employees;

              (5)  is not a participant in a qualified money purchase plan
                   maintained by the leasing organization which provides for a
                   non-integrated employer contribution of at least ten percent
                   (10%) of such

                                       5
<PAGE>
 
                   person's annual compensation and provides for immediate
                   participation and full and immediate vesting; and

              (6)  meets such other requirements as may be set forth in section
                   414(n) of the Code and the regulations promulgated
                   thereunder; and

              (ii) Individuals (if any) who are considered by the Company to
         be independent contractors and employees of such independent
         contractors, but who may be determined for any other purpose to be
         employees of the Company.  The characterization by the Company on its
         books and records of the relationship of the individual and the Company
         shall be conclusive of the individual's status for purposes of the
         Plan.

         (b) The Company reserves the right to exclude from coverage under the
Plan a class or classes of employees, provided that any such exclusion does not
discriminate in favor of employees who are shareholders, officers, or highly
compensated, as determined in accordance with section 410 of the Code.

         2.3  Basic Deductions.
              ---------------- 

              2.3.1  Any eligible employee may become a Participant in the Plan
         by authorizing the Company to make Basic Deductions and, subject to the
         provisions of Section 2.3.3, Supplemental Deductions, on each pay day
         from his/her current Compensation, and to pay over such Deductions to
         the Trustee.

              2.3.2  The Basic Deductions authorized by a Participant shall
         range from 1/2% to 6%, inclusive, of the Participant's Compensation in
         multiples of 1/2%; provided, however, that the sum of a Participant's
         Basic Deductions under the Plan and Before Tax Contributions under
         Section 2.3 of the 401(k) Plan shall

                                       6
<PAGE>
 
         not be less than 2 1/2% of the Participant's Compensation and not more
         than 6% of the Participant's Compensation.

              2.3.3 The Supplemental Deductions authorized by a Participant
         shall range from 1/2% to 10%, inclusive, of the Participant's
         Compensation, in multiples of 1/2%; provided, however, that the sum of
         a Participant's Supplemental Deductions under this Plan and the
         Participant's Additional Contributions under Section 2.6 of the 401(k)
         Plan shall not exceed 10% of the Participant's Compensation.

              2.3.4  A Participant may increase or decrease
         his/her Deductions within these limits for subsequent pay periods.

         2.4  Supplemental Deposits.  In addition to any Deductions described
              ---------------------                                          
under Section 2.3 hereof, a Participant may make Supplemental Deposits to the
Trustee, in an amount of at least $500, but not in excess of 10% of the
aggregate current compensation paid to him/her while a Participant in the
Savings Plan.  However, in no event shall the sum of a Participant's
Supplemental Deductions, Supplemental Deposits, Additional Contributions under
Section 2.6 of the 401(k) Plan and voluntary contributions to all other
qualified plans of the Company exceed 10% of such Participant's aggregate
current compensation paid since July 1, 1973 while he/she was a Participant
making Basic Deductions in the Savings Plan.

         2.5  Transfers from the 401(k) Plan.  Any amounts which would have been
              ------------------------------                                    
contributed to the 401(k) Plan on behalf of an eligible employee but for the
provisions of Section 2.4 of the 401(k) Plan, shall be paid by the Company to
this Plan as a Basic Deduction, and the Company shall make a Company
Contribution to this Plan for such eligible employee on account of such Basic
Deduction in accordance with the provisions of this Plan, unless otherwise
directed by the Participant.  If the eligible employee is not a

                                       7
<PAGE>
 
Participant in this Plan at the time a Basic Deduction is made for such eligible
employee under this Section 2.5, then, unless otherwise directed by the
Participant, the amount of the Basic Deduction and Company Contribution shall be
invested in a Personal Investment Account established for such eligible employee
and shall be allocated  among the investment options in such account in the same
proportions as the latest Before Tax Contribution, as defined in Section 1.3 of
the 401(k) Plan, made to the 401(k) Plan on behalf of the Participant.  If the
eligible employee is a Participant in this Plan, then, unless otherwise directed
by the Participant, such amounts shall be allocated to the Participant's
Personal Investment Account account and among the various investment options in
the Participant's Personal Investment Account, in the same proportions as:

              (a) the Participant's latest Basic Deductions for the Plan; or

              (b) if the Participant has never made any such Basic Deductions
         for the Plan, the Participant's latest Supplemental Deductions for the
         Plan; or

              (c) if the Participant has never made any such Basic Deductions or
         Supplemental Deductions for the Plan, the Participant's latest
         Supplemental Deposits for the Plan.

         2.6  Company's Contributions.
              ----------------------- 
                  2.6.1  At the time a Participant's Basic Deduction is paid to 
the Trustee, the Company shall pay to the Trustee out of accumulated earnings 
and profits an amount equal to:

                   (i)  15% of the Participant's Basic Deduction if the
                        Participant has one year but less than two years of
                        credited service; or

                                       8
<PAGE>
 
                   (ii)  30% of the Participant's Basic Deduction if the
                         Participant has two years but less than three years of
                         credited service; or

                   (iii) 40% of the Participant's Basic Deduction if the
                         Participant has three years but less than four years
                         of credited service; or

                   (iv)  50% of the Participant's Basic Deduction if the
                         Participant has four years or more of credited service.

                   2.6.2  No Company Contributions shall be made on account of
                any Supplemental Deductions or Supplemental Deposits made by a
                Participant.

                2.7  Revocation of Basic Deductions.
                     ------------------------------ 
                     2.7.1  A Participant may at any time suspend his Basic
                Deductions in which event the related Company Contributions will
                be suspended.

                     2.7.2  Basic Deductions which a Participant has suspended 
                may be resumed by the Participant at any time, in which event 
                the Company Contributions will be resumed.

                     2.7.3  Supplemental Deductions are automatically suspended
                whenever Basic Deductions are suspended.

                     2.7.4  A Participant may suspend or resume Supplemental
                Deductions at any time.

                     2.7.5  If the 401(k) Plan Committee relies upon Section
                4.4.2(b) of the 401(k) Plan to permit a hardship withdrawal by
                the Participant

                                       9
<PAGE>
 
                under that Plan, a Participant's right to make Basic Deductions,
                Supplemental Deductions, and Supplemental Deposits under this
                Plan shall be suspended for a period of twelve (12) months after
                the hardship withdrawal is received by the Participant.

                                      10
<PAGE>
 
                2.8  Vesting and Benefit Accrual.
                     --------------------------- 
                     2.8.1  A Participant's right in the accrued benefit derived
                from his/her own contributions is non-forfeitable.

                     2.8.2  A Participant's right to, or derived from the
                contributions of the Company on his/her behalf to the Personal
                Investment Account is non-forfeitable upon the attainment of
                Normal Retirement Age, and in addition, is non-forfeitable in
                the case of a Participant who has three years or more of
                credited service.

                     2.8.3  If a Participant withdraws Basic Deductions before 
                the date that the corresponding Employer Contributions become 
                non-forfeitable, the Participant forfeits his/her accrued
                benefit from such Employer Contributions. A withdrawal of a
                Participant's contributions shall be treated as a withdrawal of
                such contributions on a plan year by plan year basis in
                succeeding order of time. Any accrued benefit forfeited under
                this Section 2.8 shall be restored upon repayment by the
                Participant of the full amount of the withdrawal described in
                this Section 2.8, but only if such repayment is made not later
                than the earliest of

                        (i)    the end of the two-year period beginning with the
                               employee's resumption of employment covered by
                               the Plan;

                        (ii)   the end of the five-year period beginning with
                               the date of withdrawal; or

                                      11
<PAGE>
 
                        (iii)  before the end of a 12-consecutive month period
                               beginning on the severance from service date or
                               any anniversary thereof and ending on the next
                               succeeding anniversary of such date during which
                               the employee does not complete any hours of
                               service for the Company.

                   2.8.4  Unless the Participant makes an election under Section
                4.2.2 of Article IV, the payment of benefits under this Plan to
                the Participant shall begin no later than the 60th day after the
                latest of the close of the Plan year in which

                   (i)   occurs the date on which the Participant attains Normal
                         Retirement Age;

                   (ii)  occurs the tenth anniversary of the year in which the
                         Participant commenced participation in the Plan, or

                   (iii) the Participant terminates his service with the
                         Company.

          2.9  401(m) Limitations.  The Administrators shall ensure that the
               ------------------                                           
requirements set forth in section 401(m) of the Code with respect to
Participants' Basic Deductions, Supplemental Deductions, Supplemental Deposits,
and Company Contributions are satisfied.  The Plan shall not be treated as
failing to meet such requirements for a year if, before the close of the
following year, the Committee distributes "excess aggregate contributions," as
defined in section 401(m) of the Code, to Participants in accordance with
procedures set forth in section 401(m) of the Code and the regulations
promulgated thereunder.

                                      12
<PAGE>
 
                                 ARTICLE III

            INVESTMENT AND VALUATION OF PERSONAL INVESTMENT ACCOUNT
            -------------------------------------------------------

          3.1  General.  A Participant's Personal Investment Account shall be
               -------                                                       
credited with the Participant's Basic Deductions made for his/her Personal
Investment Account, related Company Contributions, and Rollover Deposits,
Supplemental Deductions and Supplemental Deposits made by the Participant.

               3.1.1  Basic Contributions.  Effective July 1, 1987, each
                      -------------------                               
          Participant's Basic Deductions and the related Company Contributions
          made thereafter are to be paid to the Trustee exclusively for the
          Personal Investment Account.

               3.1.2 (a)  Each Participant may authorize the Company to make
          Supplemental Deductions, or he/she may make Supplemental Deposits, to 
          the Trustee for the Personal Investment Account.

                   (b) Supplemental Deductions may only be authorized by the
                Participant while maximum Basic Deductions are authorized.

          3.2  Investment Options.  Each Participant shall direct that the sum
               ------------------                                             
of the Participant's Basic Deductions made for the Participant's Personal
Investment Account, related  Company Contributions and the Participant's
Supplemental Deductions be invested in one or more of the following investment
options, in multiples of 25 percent:

               3.2.1  Government Bond Fund.  A fund which invests only in
                      --------------------                               
           United States Series "E" and Series "EE" Savings Bonds.

               3.2.2.  Martin Marietta Corporation Stock Fund.  A fund which
                       --------------------------------------               
           invests only in common stock of the Martin Marietta Corporation.

                                      13
<PAGE>
 
                   3.2.3  Fixed Income Fund.  A fund under which monies will be
                          -----------------                                    
                credited with monthly interest at a predetermined rate, not
                subject to change more than twice each calendar year.

                   3.2.4  Equity Investment Fund.  A fund under which monies
                          ----------------------                            
                will be invested primarily in common stock and other equity-type
                investments.  The value of the Equity Investment Fund will vary
                to reflect the investment experience of the Fund.

                If those Participants who participated only in the General 
Savings Fund prior to July 1, 1987 did not select one or more of the above
Investment Options, then their Basic Deductions and related Company
Contributions shall be invested in the Fixed Income Fund. For those Participants
who participated in both the General Savings Fund and the Personal Investment
Account prior to July 1, 1987 and who did not select one or more of the above
Investment Options for their Basic Deductions and related Company Contributions
previously made to the General Savings Fund, the Basic Deductions and related
Company Contributions previously invested in the General Savings Fund shall be
invested as directed for their investment of Basic Deductions and related
Company Contributions in their Personal Investment Accounts.

                3.3  Union Carbide Corporation Stock Fund.  From and after 
                     ------------------------------------
April 1, 1984, no monies may be allocated to purchase stock of Union Carbide
Corporation; provided, however, that any stock of Union Carbide Corporation
existing in this Fund on April l, 1984 shall remain in the Fund until such time
that the Participant directs that it shall be sold by the Trustee or until such
time that it is distributed to the Participant or his/her beneficiary.

                                      14
<PAGE>
 
          Notwithstanding the preceding sentence, if, with regard to any
Participant, the number of shares of stock of Union Carbide Corporation existing
in this Fund, is less than 100, then the Participant (or his/her Beneficiary)
shall direct the sale of such shares no later than June 30, 1990; if, with
regard to a Participant, the number of such shares equals or exceeds 100, the
Participant (or his/her Beneficiary) shall direct the sale of such shares no
later than June 30, 1991.  In the event a Participant (or his/her Beneficiary)
shall fail to direct the sale of his/her shares of stock of Union Carbide
Corporation as required herein by June 30, 1990 or June 30, 1991, as applicable,
then the Trustee shall sell such shares on the next business day following June
30, 1990 or June 30, 1991, as applicable.  Unless a participant shall elect
otherwise, the proceeds of the sale of stock of Union Carbide Corporation under
this paragraph shall be allocated among the funds in the same proportion as
current contributions to such Participant's Account are allocated to each fund.

          3.4  Rollover Deposits and Supplemental Deposits.  A Participant shall
               -------------------------------------------                      
direct that his/her Rollover Deposits and Supplemental Deposits be invested in
any or all of the Investment Options, in multiples of 25 percent.  The
Participant shall give such directions at the time he/she elects such Rollover
Deposit or makes such Supplemental Deposit.

          3.5  Rules for Investment Options.  Subject to applicable
               ----------------------------                        
administrative rules and regulations adopted by the Committee governing this
Plan:

          (a) A Participant may change his/her Investment Options currently in
effect with respect to subsequent Basic Deductions made for his/her Personal
Investment Account, related Company Contributions and Supplemental Deductions,
in accordance with the provisions of Section 3.2 above.

                                      15
<PAGE>
 
          (b) A Participant may direct, in whole or in part, the sale of his/her
interest in the Martin Marietta Corporation Stock Fund, his/her stock in the
Union Carbide Corporation  Stock Fund and/or his/her Government Bonds, and the
reinvestment of such proceeds in any other Investment Options in accordance with
the percentage limitations of Section 3.2 above.

          (c) A Participant may elect to liquidate his/her interest, in whole or
in part, in the Fixed Income Fund and/or the Equity Investment Fund, and
reinvest the proceeds in any other Investment Options in accordance with the
percentage limitations of Subsection (2) above.  Only two such elections will be
permitted in any 12-month period.

          (d) Notwithstanding any other provision of this Plan

                   (i)  any employee who is an officer of the Company may change
                        the allocation of his/her and the Company's
                        contributions between the Personal Investment Account
                        ("PIA") and the 401(k) Plan or among the four investment
                        options in the PIA only once in any 12-month period if
                        such change would affect the purchase of common stock of
                        the Corporation for his/her PIA;

                   (ii) any such officer may direct the sale or liquidation of
                        his/her holdings in the PIA and the reinvestment of the
                        proceeds thereof in other investment options in the PIA
                        only once in any 12-month period if such direction would
                        affect the purchase or sale of common stock of the
                        Corporation for his/her PIA; and

                                      16
<PAGE>
 
               (iii)  any such change in allocation of contributions and any
                      such direction to sell or liquidate must be made on 
                      the same date in the 12-month period.

          3.6  Short-term Investment of Funds.  Notwithstanding anything to the
               ------------------------------                                  
contrary in Section 3.2 of Article III of the Plan, any monies allocated to any
Fund may be invested temporarily in obligations of a short-term nature,
including prime commercial obligations or part interests therein, or in
interests in any trust fund that has been or shall be created and maintained by
the Trustee or any other person or entity as trustee for the collective short-
term investment of funds of trusts for employee benefit plans qualified under
section 401(a) of the Code.  Any such earnings on such short-term investments
shall be allocated monthly to each Participant's account in proportion to the
amount of each Participant's account balance at the end of such month.

          3.7  Dividends.  Dividends received on stock of Martin Marietta
               ---------                                                 
Corporation held for a Participant's Personal Investment Account shall be
automatically reinvested in the Martin Marietta Corporation Stock Fund.
Dividends received on stock of Union Carbide Corporation held for a
Participant's  Personal Investment Account shall be invested in Investment
Options of Section 3.2 in the same manner and proportions as the Basic
Deductions.

          3.8  Investment Manager.  The Committee may appoint an investment
               ------------------                                          
manager or managers, as defined in section 3(38) of ERISA to manage (including
the power to acquire, invest or dispose of) any assets of the Plan.

          3.9  Instructions By A Participant For His/Her Personal Investment
               -------------------------------------------------------------
Account.  A Participant shall give orders, subject to the provisions of Section
- -------                                                                        
3.1 of this Article III, for his/her Personal Investment Account as follows:

                                      17
<PAGE>
 
                   3.9.1  A Continuing Investment Order which shall direct the
                            ---------------------------                       
                application of his/her Basic Deductions thereafter made for
                his/her Personal Investment Account, the related Company
                Contributions and Supplemental Deductions to the purchase of any
                Investment Options as designated by the Participant in
                accordance with the provisions of Section 3.2 of Article III.  A
                Participant may for any month change his/her instructions by
                submitting a new Continuing Investment Order.

                   3.9.2  A Supplemental Deposit Investment Order which shall
                            -------------------------------------            
                direct the application of his/her Supplemental Deposit to the
                purchase of any Investment Options in the amounts designated by
                the Participant.

                   3.9.3  A Selling and Reinvestment Order which shall direct
                            ------------------------------                   
                the liquidation, in whole or in part, of any Investment Option
                held in his/her Personal Investment Account, and the
                reinvestment of the proceeds in any other Investment Options as
                designated by the Participant in accordance with the percentage
                limitations of Section 3.2 of Article III.

                3.10  Purchases and Sales.
                      ------------------- 

                   3.10.1  Investment of amounts in Government Bonds or in units
                of stock of Martin Marietta Corporation directed by a Continuing
                Investment Order shall be made by the Trustee as expeditiously
                as possible, but not later than the last day of the month
                following the month in which the Basic Deduction, related
                Company Contribution

                                      18
<PAGE>
 
                and Supplemental Deduction are made, and as sufficient amounts
                are available.

                   3.10.2  Investment of amounts in Government Bonds or in units
                of stock of Martin Marietta Corporation directed by a
                Supplemental Deposit Investment Order or a Selling and
                Reinvestment Order shall be made by the Trustee as expeditiously
                as possible, but not later than the last day of the month
                following the month in which the Supplemental Deposit Investment
                Order or the proceeds from a Selling and Reinvestment Order are
                received by the Trustee, and as sufficient amounts are
                available.

                   3.10.3  Investment of amounts in the Fixed Income Fund or the
                Equity Investment Fund directed by a Continuing Investment Order
                shall be made as close as is reasonably practicable to the first
                business day of the month following the month in which the Basic
                Deduction, related Company Contribution and Supplemental
                Deduction are made.

                   3.10.4  Investment of amounts in the Fixed Income Fund or the
                Equity Investment Fund directed by a Supplemental Deposit
                Investment Order or a Selling and Reinvestment Order shall be
                made no later than the last business day of the month following
                the month in which the proceeds from such Supplemental Deposit
                Investment Order or Selling and Reinvestment Order are received
                by the Trustee.

                   3.10.5  The sale of stock of Union Carbide Corporation, the
                redemption of Government Bonds and the liquidation of a
                Participant's interest in the Martin Marietta Corporation Stock
                Fund,

                                      19
<PAGE>
 
                the Fixed Income Fund and/or the Equity Investment Fund under a
                Selling and Reinvestment Order shall be complied with as is
                reasonably practicable after its receipt by the Trustee.

                   3.10.6  All purchases of shares of stock of Martin Marietta
                Corporation shall be made on the New York Stock Exchange or
                shall be purchased from Martin Marietta Corporation at a price
                equivalent to the last recorded sales price on the last trading
                day of the month in which such purchase occurs, as reported in
                the New York Stock Exchange Composite-Transactions.

                3.11  Value of Martin Marietta Corporation Stock Fund.  Basic
                      -----------------------------------------------        
Deductions, related Company Contributions, Supplemental Deductions and
Supplemental Deposits allocated by a Participant to the Martin Marietta
Corporation Stock Fund shall be converted into investment units.  The value of
an investment unit will be increased or decreased based on the investment
experience of the Martin Marietta Corporation Stock Fund.  The value of an
investment unit in the Martin Marietta Corporation Stock Fund was $10.00 on May
31, 1984.  Thereafter the value of an investment unit will be the total value of
the Martin Marietta Corporation Stock Fund divided by the total number of
investment units outstanding in such Fund.  Monies allocated to the Martin
Marietta Corporation Stock Fund will be converted into investment units on the
valuation date (the last business day of a month) coincident with or next
following the date such amounts are paid to the Trustee.  No interest or other
earnings will accrue prior to the date of conversion.

                3.12  Proceeds of Martin Marietta Corporation Stock Fund.  A
                      --------------------------------------------------    
Participant requesting the liquidation of his/her  interest in the Martin
Marietta Corporation Stock Fund shall be credited with the net proceeds received
by the Trustee from the

                                      20
<PAGE>
 
liquidation of such interest.  The value of all investment units will be
determined by the Trustee as of the last business day of the month in which such
request is received by the Trustee.

          3.13  Averaging Stock Purchases and/or Sales.  Notwithstanding
                --------------------------------------                  
anything herein to the contrary, if, in the discretion of the Trustee, it is
necessary to limit the daily volume of purchases and/or sales of stock of Martin
Marietta Corporation or sales of stock in Union Carbide Corporation in the best
interests of the Participants directing investment in and/or liquidation of
interests in the Martin Marietta Corporation Stock Fund and/or sales of stock of
Union Carbide Corporation, then such investments, liquidations and/or sales may
be made over a period of up to 30 days, and the Participants directing such
investments, liquidations and/or sales shall be deemed to have paid or received,
as the case may be, the average price paid or received by the Trustee for all
stock of Martin Marietta Corporation or Union Carbide Corporation purchased
and/or sold during such period.

          3.14  Cost of Bonds Purchased.  The cost of Government Bonds purchased
                -----------------------                                         
for a Participant's Personal Investment Account shall be based on the actual
price paid by the Trustee for such Bonds.

          3.15  Proceeds of Bonds Redeemed.  A Participant directing the
                --------------------------                              
redemption of Government Bonds in his/her Personal Investment Account shall be
credited with the actual proceeds received by the Trustee from such redemption.

          3.16  Value of Fixed Income Fund.  Basic Deductions, related Company
                --------------------------                                    
Contributions, Supplemental Deductions and Supplemental Deposits allocated by a
Participant to the Fixed Income Fund shall be converted into fixed income
investment units.  The value of an investment unit in the Fixed Income Fund was
$10 on July l, 1973.  Thereafter the value of an investment unit will be the
total value of the Fixed Income Fund

                                      21
<PAGE>
 
divided by the total number of investment units outstanding in such Fund.
Monies allocated to the Fixed Income Fund will be converted into investment
units on the valuation date (the last business day of a month) coincident with
or next following the date such amounts are paid to the Trustee.  No interest or
other earnings will accrue prior to the date of conversion.

          3.17  Proceeds of Fixed Income Fund.  A Participant requesting the
                -----------------------------                               
liquidation of his/her interest in the Fixed Income Fund shall be credited with
the net proceeds received by the Trustee from the liquidation of such Fund.  The
value of all investment units will be determined by the Trustee as of the last
business day of the month in which such request is received by the Trustee.

          3.18  Value of Equity Investment Fund.  Basic Deductions, related
                -------------------------------                            
Company Contributions, Supplemental Deductions and Supplemental Deposits
allocated by a Participant to the Equity Investment Fund shall be converted into
equity investment units.  The value of an equity investment unit will be
increased or decreased based on the investment experience of the Equity
Investment Fund.  The value of an investment unit in the Equity Investment Fund
was $10 on July l, 1973.  Thereafter the value of an investment unit will be the
total value of the Equity Investment Fund divided by the total number of
investment units outstanding in such Fund.  Monies allocated to the Equity
Investment Fund will be converted into investment units on the valuation date
(the last business day of a month) coincident with or next following the date
such amounts are paid to the Trustee.  No interest or other earnings will accrue
prior to the date of conversion.

          3.19  Proceeds of Equity Investment Fund.  A Participant requesting
                ----------------------------------                           
the liquidation of his/her interest in the Equity Investment Fund shall be
credited with the net proceeds received by the Trustee from the liquidation of
such Fund.  The value

                                      22
<PAGE>
 
of all investment units will be determined by the Trustee as of the last
business day of the month in which such request is received by the Trustee.

          3.20  Costs and Expenses.  Costs and expenses, including transfer
                ------------------                                         
taxes and brokerage commissions, associated  with the purchase, sale and
transfer of United States Government Bonds and stock of Martin Marietta
Corporation or sale of stock of Union Carbide Corporation for a Participant's
interest in the Personal Investment Account shall be added to the cost of such
stock and bonds or deducted from the proceeds of such stock and bonds, as the
case may be, unless paid by the Company.  Unless paid by the Company, brokerage
commissions will be prorated to the extent applicable.  Unless paid by the
Company, any applicable taxes on annuity considerations will be charged against
the amount to be so applied.

          3.21  Statements Furnished Participants.  A Participant shall be
                ---------------------------------                         
furnished a statement of his/her Personal Investment Account at least annually
or upon written request to the Company.

          3.22  Custody Of Securities.  All cash, bonds and certificates for
                ---------------------                                       
shares of stock of Martin Marietta Corporation and certificates for shares of
stock of Union Carbide Corporation shall be held in the custody of the Trustee
until disposed of under the provisions of the Plan.

          3.23  Voting Rights.  The Company will make forms available to each
                -------------                                                
Participant to instruct the Trustee with regard to the voting of any shares of
the Corporation pertaining to units held in that Participant's Personal
Investment Account.  The Trustee will vote such shares only as directed by the
Participant.  If a Participant fails to give  timely directions as to the voting
of shares of stock of the Corporation pertaining to

                                      23
<PAGE>
 
units held in that Participant's Personal Investment Account, the Trustee will
vote such shares in the same proportion as it votes the shares for which the
Trustee receives directions.

          3.24  Rights, Warrants and Scrip.  If any rights, warrants or scrip
                --------------------------                                   
are issued on stock held in the Martin Marietta Corporation Stock Fund or Union
Carbide Corporation Stock for a Participant's Personal Investment Account, the
Trustee shall automatically exercise the rights, warrants or scrip for whole
shares, which shares shall be for such Participant's Personal Investment
Account, and shall automatically offer the rights, warrants, or scrip for
fractional shares for sale on the open market and shall reinvest the proceeds in
additional units of stock in the Martin Marietta Corporation Stock Fund or into
the other designated investment options.  Proceeds may not be reinvested in
additional shares of stock in Union Carbide Corporation Stock.

                                      24
<PAGE>
 
                                   ARTICLE IV

                      DISTRIBUTIONS, WITHDRAWALS AND LOANS
                      ------------------------------------

                4.1  Withdrawal by Participant During Employment.
                     ------------------------------------------- 

                     4.1.1  Withdrawals Without Suspensions.  Company
                            -------------------------------          
                Contributions for the Personal Investment Account of
                Participants shall be exclusively for the benefit of such
                Participants.  A Participant remaining in the employment of the
                Company may make the following withdrawals from his/her Personal
                Investment Account, on 60 days prior written notice to the
                Company, without incurring a suspension of Company Contributions
                under this Section 4.1:

                        (i)    Up to the entire current value of his/her
                               Personal Investment Account, less the sum of the
                               Company Contributions made to his/her Personal
                               Investment Account during the preceding twenty-
                               four month period, if at least twenty-four months
                               have elapsed since the Participant first made
                               Basic Deductions for his/her Personal Investment
                               Account or, if he/she has made a prior withdrawal
                               under Section 4.1, at least twenty-four months
                               have elapsed since such last withdrawal.  Company
                               Contributions made to the Participant's Personal

                                      25
<PAGE>
 
                               Investment Account during the twenty-four month
                               period preceding the Participant's withdrawal
                               will remain in the Participant's Personal
                               Investment Account.

                        (ii)   Up to the sum of his/her Supplemental Deductions
                               and Supplemental Deposits, less the sum of any
                               Supplemental Deductions or Supplemental Deposits
                               previously withdrawn, but not more than the
                               entire current value of his/her Personal
                               Investment Account, if at least twelve months
                               have elapsed since the Participant first made
                               Supplemental Deductions or Supplemental Deposits
                               or, if he/she has made a prior withdrawal under
                               this Section 4.1, at least twelve months have
                               elapsed since such last withdrawal.

                        (iii)  Up to the sum of his/her Rollover Deposits, less
                               the sum of any Rollover Deposits previously
                               withdrawn, but not more than the entire current
                               value of his/her Personal Investment Account;
                               provided, however, if he/she has made a prior
                               withdrawal under this Section 4.1, at least
                               twenty-four months have elapsed since such last
                               withdrawal.

                                      26
<PAGE>
 
            If a Participant making a withdrawal under this Section 4.1 does not
withdraw the entire withdrawable amount in his/her Personal Investment Account,
the unwithdrawn balance will remain in the Participant's Personal Investment
Account.

            4.1.2  Withdrawal With Suspensions.  A Participant who is not
                   ---------------------------                           
         eligible to make a withdrawal under Section 4.1 may, on 60 days prior
         written notice to the Company, make a withdrawal of an amount up to the
         entire current value of his/her Personal Investment Account, less the
         sum of Company Contributions made during the preceding twenty-four
         month period; provided, however, that his/her Company Contributions
         shall be suspended as provided in Section 4.1.3.

            4.1.3  Suspensions.  If a Participant makes a withdrawal from
                   -----------                                           
         his/her Personal Investment Account under Section 4.1.2, his/her
         Company Contributions under the Plan for the Personal Investment
         Account, shall be automatically suspended until:

                   (i)  the end of the third calendar month following such
                        withdrawal if such withdrawal exceeds the sum of the
                        Participant's unwithdrawn Supplemental Deductions and
                        Supplemental Deposits and the withdrawal was made at
                        least twelve months, but less than twenty-four months,
                        following the date the Participant first made Basic
                        Deductions for his/her Personal Investment Account or
                        the date of the Participant's last withdrawal of an
                        amount in excess of such sum;

                   (ii) the end of the sixth calendar month following such
                        withdrawal if such withdrawal exceeds the sum of the

                                      27
<PAGE>
 
                         Participant's unwithdrawn Supplemental Deductions and
                         Supplemental Deposits and the withdrawal was made less
                         than twelve months following the date the Participant
                         first made Basic Deductions for his/her Personal
                         Investment Account or the date of the Participant's
                         last withdrawal of an amount in excess of such sum; and

                  (iii)  the end of the third month following the withdrawal,
                         regardless of the frequency of such withdrawals, if the
                         amount of such withdrawal does not exceed the sum of
                         the Participant's unwithdrawn Supplemental Deductions
                         and Supplemental Deposits.

              At the end of such three month or six month period, as the case
         may be, Company Contributions will be automatically resumed and
         allocated according to the Continuing Investment Order in effect prior
         to such withdrawal, unless the Participant gives other instructions.

              4.1.4  Withdrawals Prior to July l, 1983.  Any Participant who
                     ---------------------------------                      
         made a withdrawal under this Section 4.1.4 as in existence prior to
         July 1, 1983 shall, as of July 1, 1983:

                (i)  be permitted to resume making Basic Deductions, 
                     Supplemental Deductions and Supplemental Deposits for both 
                     the General Savings Fund and the Personal Investment 
                     Account;

                (ii) have his/her Company Contributions resume on the later of
                     July 1, 1983 or the date they would have resumed had the
                     suspension

                                      28
<PAGE>
 
                       period for withdrawals prior to July 1, 1983 been the 
                       same as the suspension period for withdrawals after 
                       July l, 1983; and

                (iii)  be permitted to make another withdrawal under this
                       Section 4.1.4 on the later of July 1, 1983 or the date
                       he/she would have been permitted to make a subsequent
                       withdrawal had the minimum period between withdrawals
                       prior to July 1, 1983 been the same as the minimum period
                       between withdrawals after July 1, 1983.

         4.2  Retirement Elections.
              -------------------- 

              4.2.1  If the total value of the Personal Investment Account of a
         Participant whose employment terminates for any reason (including
         termination on account of disability) other than death is thirty five
         hundred dollars ($3,500) or less, or the value exceeds thirty five
         hundred dollars ($3,500) and such Participant consents in writing,
         then, such Participant shall receive such amounts in a single-sum
         payment made to such Participant as soon after such Participant's
         employment terminates as the Committee shall determine to be
         administratively practicable.  For purposes of Section 4.2 of Article
         IV, a Participant who terminates employment during or after the
         calendar year in which such Participant attains age fifty-five (55)
         shall be deemed to have terminated employment on account of early
         retirement under the Plan.

              4.2.2  If the total value of the Personal Investment Account of a
         Participant whose employment terminates for any reason (including
         termination on account of disability) other than death exceeds thirty
         five hundred dollars ($3,500) and such Participant does not consent in
         writing to receive the entire value of such account, then unless such
         Participant shall have made an election

                                      29
<PAGE>
 
         under Section 4.2.3 or 4.2.4 hereof, such Participant shall be deemed
         to have deferred receipt of the entire value of such account until such
         Participant attains seventy and one-half (70 1/2).  Such a Participant
         may elect, in accordance with procedures determined by the Committee,
         to receive the entire value (but not part) of his/her account in a
         single-sum payment at any time prior to the Participant's attainment of
         seventy and one-half (70 1/2).  After the month of such Participant's
         birth in the calendar year following his/her retirement or termination
         of employment, such Participant's account can no longer be invested in
         the Fixed Income Fund.  The Participant may direct that his/her account
         be invested in the other Investment Options or in The Fixed Income Fund
         for Retirees which shall be a fund under which monies will be credited
         with monthly interest at a predetermined rate, not subject to change
         more than twice each calendar year.  The entire value of a
         Participant's Personal Investment Account shall be distributed to such
         Participant in a single-sum payment as soon after such Participant
         attains age seventy and one-half (70 1/2) or such earlier date selected
         by the Participant as provided above, as the Committee shall determine
         to be administratively practicable.  If a Participant who has been
         deemed to have deferred receipt of the entire value of his/her account
         under this Section 4.2.2 dies after such Participant's termination of
         employment, but prior to such Participant's attainment of age seventy
         and one-half (70 1/2), then the Participant shall be deemed to have
         terminated employment on account of death and such amounts shall be
         paid to such Participant's Beneficiary in accordance with Section 4.3
         hereof.

                                      30
<PAGE>
 
              4.2.3  Upon prior written notice to the Committee, given in a time
         and manner determined by the Committee, a Participant who: (1) has
         deferred receipt of his/her Personal Investment Account pursuant to
         Section 4.2.2 and (2) is eligible to receive an immediate pension upon
         termination of employment or is disabled under the terms of the
         Company's long term disability plan, may elect to receive in lieu of a
         single-sum payment, partial distributions in accordance with this
         Section 4.2.3.  No election to take a partial distribution under this
         Section 4.2.3 may be made, however, if the total balance remaining in
         the Participant's Personal Investment Account and the Participant's Tax
         Deferred Account under the 401(k) Plan, if any, after such withdrawal
         will be less than $10,000.  A Participant may not take more than one
         partial distribution under this Section 4.2.3 in any one Plan Year.  If
         a Participant who has made an election under this Section 4.2.3 dies
         prior to receiving the full value of his/her Personal Investment
         Account, the full remaining value of his/her Personal Investment
         Account, valued as of the Valuation Date following the receipt of
         notice of the Participant's death, shall be paid in accordance with
         Section 4.3. hereof.

              4.2.4  Upon prior written notice to the Committee, given in a time
         and manner determined by the Committee, a Participant who is eligible
         to receive an immediate pension upon termination of employment or is
         disabled under the terms of the Company's long term disability plan,
         may elect to receive the entire value of his/her Personal Investment
         Account, valued as of the last Valuation Date preceding such election,
         in one of the following forms of payment:

                                      31
<PAGE>
 
                   (i)    monthly payments over the life of the Participant,
                          computed as set forth below; or

                   (ii)   monthly payments over the joint lives of the
                          Participant and the Participant's spouse, computed as
                          set forth below; or

                   (iii)  monthly payments for a period certain of 10, 15 or 20
                          years, computed as set forth below.

              If a Participant elects to receive payments under subsection
         4.2.4(i) or (ii) above, the annual amount to be paid to the Participant
         (or his/her spouse) shall be determined by dividing the entire value of
         the Personal Investment Account at the beginning of each year by the
         then life expectancy of the Participant (or the joint life and last
         survivor expectancy of the Participant and the Participant's spouse).
         For purposes of this calculation, the life expectancy of the
         Participant, and his/her spouse if applicable, shall be recalculated
         annually.

              If a Participant elects to receive payments under subsection
         4.2.4(iii) above, the annual amount to be paid to the Participant (or
         his/her Beneficiary) shall be determined by dividing the entire value
         of the Personal Investment Account at the beginning of each year by the
         then remaining number of years in the term.

              For purposes of electing one of the options under this Section
         4.2.4, a married Participant may not elect option (i) or (iii) unless
         the Participant's spouse consents in writing to such election, as
         provided in Section 4.3. hereof.

                                      32
<PAGE>
 
              If a Participant who has made an election under subsection 4.2.4
         (i) or (iii) dies prior to receiving the full value of his/her Personal
         Investment Account, the full remaining value of the Personal Investment
         Account, valued as of the Valuation Date following the receipt of
         notice of the Participant's death, shall be paid in accordance with
         Section 4.3.

              With regard to a Participant who has made an election under
         subsection 4.2.4 (ii): (a) upon the death of such Participant payments
         shall continue, as computed above, to the Participant's spouse, and (b)
         if the Participant's spouse dies prior to receiving the full remaining
         value of the Participant's Personal Investment Account, the full
         remaining value of the Personal Investment Account, valued as of the
         Valuation Date following the spouse's death, shall be paid in full to
         such spouse's beneficiary or, if the spouse shall not have named a
         beneficiary, to the estate of the deceased spouse.

              4.2.5  A married Participant who has made an election under
         subsection 4.2.4 (i) or (ii) of this Section 4.2 may waive such
         election at any time during the 90 day period ending on the annuity
         starting date.

              No such waiver under this Section 4.2.5 shall be effective unless
         the Participant's spouse consents in writing to such waiver, the terms
         of such consent acknowledge the effect of the waiver, and the waiver is
         witnessed by a representative of the Company or a notary public.  Such
         consent shall be irrevocable.

              The provisions of the preceding paragraph shall not be applicable
         if the Company is satisfied that the required consent cannot be
         obtained because either (a) the Participant does not have a spouse, (b)
         the spouse cannot be located, or

                                      33
<PAGE>
 
         (c) by reason of such other circumstances as the Secretary of the
         Treasury may prescribe by regulations.  Any consent by a spouse or the
         establishment that the consent of a spouse cannot be obtained shall
         only be effective with respect to such spouse.

              4.2.6  The Company shall provide to each Participant who has made
         an election under subsection 4.2.4 (i) or (ii), within a reasonable
         time before the annuity starting date (pursuant to such regulations as
         may be prescribed by the Secretary of the Treasury) a written
         explanation of: (i) the terms and conditions of the annuity elected;
         (ii) the Participant's right to make, and the effect of, an election to
         waive such annuity election; and (iii) the rights of the Participant's
         spouse under Section 4.2.5.

              4.2.7  Notwithstanding the provisions of Sections 4.2.4 through
         4.2.6 above, the spousal requirements set forth in Sections 4.2.4
         through 4.2.6 shall not apply unless the Participant and his/her spouse
         were married throughout the one-year period ending on the Participant's
         annuity starting date.

         4.3  Termination on Death.  If a Participant's employment terminates on
              --------------------                                              
account of the Participant's death, the Personal Investment Account of the
Participant shall be paid to the Participant's beneficiary as hereinafter
provided.  If a Participant's employment terminates on account of the
Participant's death, then the value of the Participant's Personal Investment
Account shall be paid to the Participant's surviving spouse, unless such spouse
has consented to the designation of an alternate beneficiary.  No consent under
this Section or Section 4.2 shall be effective unless either (a) such consent is
in writing, the terms of such consent acknowledge its effect, the execution of
such consent is witnessed by a person representing the Plan or a notary public,
as the Committee may

                                      34
<PAGE>
 
determine, and such consent otherwise complies with such rules as the Committee
may adopt, or (b) it is established to the satisfaction of the Committee that
the required consent cannot be obtained because the Participant does not have a
spouse, because the spouse cannot be located, or because of such other
circumstances as the Secretary of the Treasury may prescribe by regulations.
Any such consent by a Participant's spouse (or the establishment that the
consent of a spouse cannot be obtained) shall only be effective with respect to
such spouse.  If a Participant's spouse has consented to the designation of an
alternate beneficiary, then the Participant shall designate such beneficiary in
a time and manner determined by the Committee; provided, however, if (a)  the
Participant has not effectively designated a beneficiary, or (b) the beneficiary
designated by the Participant has not survived the Participant and no
alternative designation of beneficiary shall be effective, then the
Participant's beneficiary shall be deemed to be the estate of the deceased
Participant.  If the Participant's beneficiary cannot be located for a period of
one year following death, despite mailing to his/her last known address, and if
such surviving spouse or beneficiary has not made a written claim for benefits
within such period to the Committee, such surviving spouse or beneficiary shall
be treated as having predeceased the Participant.  The Committee may require
such proof of death and such evidence of the right of any person to receive all
or part of the benefit of a deceased Participant as the Committee may deem
desirable.  The payment shall be made to the Participant's surviving spouse or
beneficiary, as the case may be, as soon after the Participant's death as the
Committee shall determine to be administratively practicable.

         4.4  Form of Payment.  All payments made under Sections 4.2 and 4.3 of
              ---------------                                                  
this Article IV shall be made entirely in cash, unless the Participant or the
Beneficiary as the case may be, elects to receive any whole shares of stock in
the Martin Marietta Corporation

                                      35
<PAGE>
 
Stock Fund or the Union Carbide Corporation Stock Fund or the Equity Investment
Fund and/or any bonds in the Government Bond Fund in the Participant's Personal
Investment Account in lieu of the cash value of such stock and/or bonds.

         4.5  Transfer to 401(k) Plan.  Notwithstanding anything to the contrary
              -----------------------                                           
in this Plan, if the Participant is a participant in the 401(k) Plan, the
Participant's account in the Personal Investment Account shall be transferred to
the 401(k) Plan immediately prior to the Participant's termination of employment
and shall be paid to the Participant in accordance with the provisions of the
401(k) Plan.

                                      36
<PAGE>
 
                                   ARTICLE V

                      LIMITATION ON MAXIMUM CONTRIBUTIONS
                           AND BENEFITS UNDER ALL PLANS
                      -----------------------------------------


         5.1  General.  By reason of Section 5.7 Company Contributions for a
              -------                                                       
Participant under this Plan will not exceed the maximum limitations imposed by
section 415 of the Code, if all other defined contribution plans and all defined
benefit plans of all Employers and Affiliates are disregarded.  It is intended
that any limitation imposed by section 415 of the Code arising by reason of a
Participant's participation in one or more other such plans shall be implemented
as provided in this Article V, notwithstanding any contrary provision of the
Plan.

         5.2  Affiliate.  For purposes of this Article V, the definition of
              ---------                                                    
"Affiliate" in Section 1.2 shall be applied by substituting the phrase "more
than 50 percent" for the phrase "at least 80 percent" wherever the phrase "at
least 80 percent" would otherwise be applicable under said provision.

         5.3  Limitation Year.  For purposes of this Article V, the limitation
              ---------------                                                 
year shall be the Plan Year.

         5.4  Annual Additions.  "Annual Addition" means for each Participant
              ----------------                                               
the sum for any year of (i) contributions made by the Company or an Affiliate
allocable to the Participant under all Defined Contribution Plans maintained by
the Company or an Affiliate, (ii) forfeitures allocable to the Participant under
all such plans, (iii) the amount of the Participant's contributions to all such
plans, and (iv) any amount attributable to post-retirement medical benefits
allocated to a separate account after March 31, 1984 on behalf of a Participant
under section 415(l)(1) and section 419A(d) of the Code.

                                      37
<PAGE>
 
Notwithstanding the foregoing, for Plan Years beginning prior to January 1,
1987, only that portion of a Participant's contributions to all such plans equal
to the lesser of (A) the Participant's contributions to all such plans in excess
of six percent (6%) of the Participant Earnings, or (B) one-half (1/2) of the
Participant's contributions to all such plans for the year shall be considered
"Annual Additions."  The Participant's contributions described in clause (iii)
of the first sentence and in the second sentence of this Section 5.4 shall not
include any rollover amounts (as defined in section 402(a)(5) of the Code), any
repayments of loans, any amounts transferred directly from a trust qualified
under section 401(a) of the Code pursuant to Section 7.3, or any prior
distributions repaid to a plan upon the exercise of buy-back rights under the
401(k) Plans and Retirement Program Plan for Employees of Martin Marietta Energy
Systems, Inc.  A contribution shall be taken into account as an Annual Addition
for purposes of this Article V for the Limitation Year in which it is allocated
to the Participant's account under the applicable plan.

         5.5  Defined Benefit and Defined Contribution Plans.  For purposes of
              ----------------------------------------------                  
this Article V, the term "Defined Benefit Plan" or "Defined Contribution Plan"
means whichever of the following  is applicable:  a defined benefit plan or a
defined contribution plan described in section 401(a) of the Code, which
includes a trust which is exempt from income tax under section 501(a) of the
Code; provided that a Participant's contributions under a plan which otherwise
qualifies as a defined benefit plan shall be treated as a defined contribution
plan.

         5.6  Aggregation of Defined Contribution Plans.  In applying the
              -----------------------------------------                  
limitation on annual additions provided in this Article V, all defined
contribution plans maintained by the Company and Affiliates shall be aggregated.

                                      38
<PAGE>
 
         5.7  Defined Contribution Plan Limitation.  In no event may the annual
              ------------------------------------                             
additions made to a Participant's accounts in all defined contribution plans
maintained by the Company and Affiliates exceed the lesser of (1) thirty
thousand dollars ($30,000) (or, if greater, 1/4 of the dollar limitation in
effect under section 415(b)(1)(A) of the Code,) or (2) twenty-five percent of
such Participant's Earnings for such year.

         5.8  Defined Contribution Plan Fraction Determination.  For purposes of
              ------------------------------------------------                  
this Section 5.8, a Participant's "Defined Contribution Plan Fraction" shall be
determined as follows:

              (A)  Numerator.  For any Limitation Year, the numerator shall be
                   ---------                                                  
         the sum of the Annual Additions to the Participant's accounts under all
         Defined Contribution Plans maintained by the Company or an Affiliate in
         such year and in all prior Limitation Years.

              (B)  Denominator.  For any Limitation Year, the denominator shall
                   -----------                                                 
         be the lesser of the following amounts, determined for such year and
         for each prior Limitation Year of the Participant's Credited Services
         with the Company or an Affiliate:

                   (I)  One hundred and twenty-five percent (125%) of the
              maximum Dollar Limit for such year determined under Section 5.7 of
              this Plan, or

                   (II)  thirty-five percent (35%) of the Participant's Earnings
              for such year.

Notwithstanding the foregoing, in computing the denominator of the Defined
Contribution Plan Fraction for any Limitation Year ending after December 31,
1982, the Committee may elect to determine the portion of such denominator which
relates to 1982 and prior years under the method described in section 415(e)(6)
of the Code in lieu of the method described

                                      39
<PAGE>
 
above.  Such election may be made at such time and in such manner as may be
provided in applicable regulations issued by the Secretary of the Treasury or
his/her delegate.

         5.9  Defined Benefit Plan Fraction Determination.  For purposes of this
              -------------------------------------------                       
Section 5.9, a Participant's "Defined Benefit Plan Fraction" shall be determined
as follows for any Limitation Year:

              (A)  Numerator.  The numerator shall be the sum of the projected
                   ---------                                                  
              annual benefits (as defined in section 415(e)(2) of the Code) of
              the Participant under all   Defined Benefit Plans maintained by
              the Company or an Affiliate as of the close of such year,
              disregarding benefits derived from the Participant's
              contributions, if any.

              (B)  Denominator.  The denominator shall be the lesser of the
                   -----------                                             
         following amounts:

                   (I)  one hundred and twenty-five percent (125%) of the
              maximum dollar limitation applicable to Defined Benefit Plans for
              such year under sections 415(b)(1)(A) and 415(d) of the Code, or

                   (II)  one hundred forty percent (140%) of the Participant's
              average annual Earnings for the three (3) consecutive years in
              which the Participant's Compensation was highest.

         5.10 Combined Limitation.  If a Participant participates in one or more
              -------------------                                               
Defined Benefit Plans maintained by the Company or an Affiliate, the sum of the
Participant's Defined Contribution Plan Fraction and Defined Benefit Plan
Fraction as of the close of any Limitation Year may not exceed 1.0.  In order to
prevent such sum from exceeding 1.0, benefits under any Defined Benefit Plan in
which the Participant participates shall be reduced to the extent necessary for
that purpose.

                                      40
<PAGE>
 
         5.11 Alternative Method.  The Committee may, in its discretion,
              ------------------                                        
determine any amounts required to be taken into account under this Article V by
such alternative methods as  shall be permitted under applicable regulations or
rulings issued by the United States Department of the Treasury.

         5.12 Participation in Multiple Plans.
              ------------------------------- 

              5.12.1  If amounts contributed to any Defined Contribution Plan by
         or on behalf of a Participant must be reduced in any Limitation Year to
         comply with the limit on Annual Additions in Section 5.7 of this Plan,
         the amounts contributed to such Defined Contribution Plans shall be
         reduced in the following order:

                   (a)  Supplemental Deposits made under the Savings Plan;

                   (b)  Supplemental Deductions made under the Savings Plan;

                   (c)  Additional Contributions made under Section 2.6 of this
              Plan;

                   (d)  Forfeitures under the 401(k) Plan;

                   (e) Company Contributions made under Section 2.5 of this Plan
              and for the 401(k) Plan;

                   (f)  Before Tax Contributions made under Section 2.3 of the
              401(k) Plan;

                   (g)  Company Contributions made under this Plan;

                   (h)  Basic Deductions made under this Plan; and

                   (i)  Contributions to any Defined Benefit Plan treated as a
              Defined Contribution Plan.

                                      41
<PAGE>
 
         Amounts contributed by or on behalf of a Participant in one category
above shall be reduced to zero before any reduction is made to any such amounts
contributed in the next following category.

              5.12.2  The amount of Company Contributions which may not be
         allocated to a Participant's Account because of the limitations of this
         Article V or of Section 5.7 of this Plan shall be considered to have
         been made by a mistake of fact and shall be returned to the Employer
         making such contributions.

         5.13 Notice of Reduction.  The Committee shall give prompt notice to
              -------------------                                            
any Participant whose benefit is reduced pursuant to the provisions of this
Article V.

                                   ARTICLE VI

                                TOP-HEAVY RULES
                                ---------------

         6.1  Top-Heavy Plan.  If, on the last day of any Plan Year, the
              --------------                                            
aggregate value of the Personal Investment Accounts of Key Employees under the
Plan exceeds 60 percent of the aggregate value of the Personal Investment
Accounts of all Participants in the Plan, the Plan shall be top-heavy and the
provisions of this Article VI shall apply for the following Plan Year; provided,
however, that for purposes of determining whether the Plan is a top-heavy plan
under this Section 6.1, the Plan may be aggregated with any other plan of the
Company or an Affiliate, in accordance with the provisions of section 416 of the
Code.

         6.2  Minimum Top-Heavy Benefits.  If the Plan is top-heavy under
              --------------------------                                 
Section 6.1, the Company Contribution for each Participant, other than a
Participant who is a Key Employee, shall be increased by an amount that, when
added to the Company Contributions made under this Plan without regard to this
Section 6.2, shall bring the total amount

                                      42
<PAGE>
 
contributed for such Participant under this Plan to three percent (3%) of such
Participant's Earnings.

         6.3  Reduction in Combined Limitation.  If the Plan is top-heavy under
              --------------------------------                                 
Section 6.1, the Participant's Defined Contribution Plan Fraction and Defined
Benefit Plan Fraction,  determined under Section 5.5, shall be determined by
substituting "one hundred percent (100%)" for "one hundred and twenty-five
percent (125%)" in each place "one hundred and twenty-five percent (125%)"
appears in such sections unless, on the last day of the Plan Year in which the
Plan is found to be top-heavy under Section 6.1, the aggregate value of the
Personal Investment Accounts of Key Employees under the Plan does not exceed 90
percent (90%) of the aggregate value of the Personal Investment Accounts for all
Participants in the Plan and the Company elects to substitute "four percent
(4%)" for "three percent (3%)" in Section 6.2.

         6.4  Key Employee.  For purposes of this Article VI, a "Key Employee"
              ------------                                                    
shall be any employee of the Company or an Affiliate who at any time during the
Plan Year or any of the four preceding Plan Years, is:

              (a) one of the 50 employees of the Company or an Affiliate who has
         the highest Earnings during the Plan Year or any of the preceding four
         Plan Years of all employees of the Company and Affiliates if such
         employee is also an officer of the Company or an Affiliate; provided
         that such employee shall not be a Key Employee unless he/she has an
         annual Earnings greater than 150% of the dollar limitation in effect
         under Code section 415(c)(1)(A) for the Plan Year;

              (b) one of the 10 employees owning (or considered as owning within
         the meaning of section 318 of the Code) the largest interests in the
         Company or an Affiliate among all employees of the Company and
         Affiliates; provided,

                                      43
<PAGE>
 
         however, that such employee shall not be a Key Employee unless he/she
         has annual Earnings greater than $30,000 or such other dollar
         limitation in effect under section 415(C)(1)(A) of the Code for the
         Plan Year; and further provided that if two or more employees own equal
         interests in the Company or an Affiliate, the employee with greater
         annual Earnings shall be treated as owning a larger interest;

              (c) a five percent (5%) owner of the Company or an Affiliate;

              (d) a one percent (1%) owner of the Company or an Affiliate if
         such owner's annual Earnings exceed $150,000; or

              (e) a Beneficiary of a Key Employee described in Sections 6.4(a)
         through 6.4(d), inclusive.

         6.5  Automatic Removal.  In the event that it shall be determined by
              -----------------                                              
statute, regulation or ruling of the Internal Revenue Service that the
provisions of this Article VI are no longer necessary in whole or in part to
qualify the Plan under the Code, this Article VI shall be ineffective to such
extent without amendment to the Plan.

         6.6  Amounts Included In Personal Investment Accounts.  For purposes of
              ------------------------------------------------                  
determining whether the Plan is  top-heavy, the value of a Participant's
Personal Investment Accounts includes the amount of any distribution made to
such Participant pursuant to Sections 4.2 and 4.3, any withdrawal made by such
Participant pursuant to Section 4.1 if such distributions or withdrawals were
made during the Plan Year or the preceding four Plan Years; provided, however,
that if any Participant has not received any Earnings from the Company or an
Affiliate (other than distributions or withdrawals from the plan) at any time
during the five year period ending on the determination date, the Accounts of
such Participant shall not be taken into account.

                                      44
<PAGE>
 
         6.7  Earnings.  For purposes of this Article VI, Earnings shall have
              --------                                                       
the meaning as set forth in Section 5.2(vi) of the Plan.

                                      45
<PAGE>
 
                                  ARTICLE VII

                                     TRUST
                                     -----

         7.1  Trustee.  To provide for the administration of the Personal
              -------                                                    
Investment Account, the Company will enter into a Trust Agreement with a Trustee
appointed by the Company.  The Trust Agreement shall be in such form and contain
such provisions as the Company may deem appropriate, including, but not limited
to, provisions with respect to the powers and authority of the Trustee
(including the management of funds and/or providing investment options and
retirement elections under this Plan by some other institution or institutions,
as directed by the Committee from time to time,) the authority of the Company to
amend the Trust Agreement and to terminate the Trust, and the authority of the
Company to settle the accounts of the Trustee on behalf of all persons having an
interest in the Personal Investment Account, and a provision that it shall be
impossible at any time for any part of the corpus or income of the Personal
Investment Account to be used for or diverted to purposes other than for the
exclusive benefit of employees of the Company or their beneficiaries.

         7.2  Trust Expenses.  Costs and expenses of administering the Trust
              --------------                                                
Fund, including Trustee's fees and investment manager's fees, shall be paid from
the Trust Fund, unless they are paid by the Company.

         7.3  Plan-to-Plan Transfers.  The Trustee may transfer all of the
              ----------------------                                      
amounts in a Participant's account in the Personal Investment Account to the
trustees of any trust qualified under section 401(a) of the Code.  The Trustee
may make such a transfer only at the direction of the Committee.

                                      46
<PAGE>
 
         The Trustee may accept as part of the Trust Fund property transferred
from a trust qualified under section 401(a) of the Code.  The Trustee may accept
such a transfer only at the direction of the Committee.  Any property so
transferred shall be placed in a segregated account to be maintained by the
Trustee.  Such property shall be distributed to the Participant or his/her
Beneficiary in accordance with the applicable provisions of the Plan.

                                      47
<PAGE>
 
                                  ARTICLE VIII

                                 ADMINISTRATION
                                 --------------

         8.1  Administrative Committee.  There is hereby created an
              ------------------------                             
Administrative Committee (the "Committee") which shall consist of not less than
three (3) members appointed by the Board of Directors of the Company or pursuant
to the authorities granted by them.  The general administration of the Plan will
be the responsibility of the Administrative Committee.  The Vice President and
Chief Financial Officer of Martin Marietta Corporation may, at any time, fill
vacancies or require the resignation of one or more of the members of a
Committee with or without cause.  In the event that a vacancy or vacancies shall
occur on the Committee, the remaining member or members shall act as the
Committee until the Vice President and Chief Financial Officer of Martin
Marietta Corporation fills such vacancy or vacancies.  No person shall be
ineligible to be a member of a Committee because he/she is, was or may become
entitled to benefits under the Plan or because he/she is a director and/or
officer of the Company or an Affiliate or a Trustee; provided, that no
Participant who is a member of the Committee shall participate in any
determination by the Committee specifically relating to the disposition of
his/her own interest in the Plan.

         8.2  Limitation of Liability; Indemnity.  (a)  Except as otherwise
              ----------------------------------                           
provided by law, no person who is a member of the Committee, or any employee,
director or officer of the Company or an Affiliate, may incur any liability
whatsoever on account of any matter connected with or related to the Plan or the
administration of the Plan.

         (b) The Company shall indemnify and save harmless each member of the
Committee, and each employee, director or officer of the Company or an
Affiliate, from and against any and all loss, liability, claim, damage, cost and
expense which may arise by

                                      48
<PAGE>
 
reason of, or be based upon, any matter connected with or related to the Plan or
the administration of the Plan (including, but not limited to, any and all
expenses whatsoever reasonably incurred in investigating, preparing or defending
against any litigation, commenced or threatened, or in settlement of any such
claim whatsoever), unless such person shall have acted in bad faith or been
guilty of willful misconduct or gross negligence in respect of his/her duties,
actions or omissions in respect of the Plan.

         8.3  Compensation.  The members of the Committee shall serve without
              ------------                                                   
compensation for their services as such members.  The members of the Committee
shall serve without bond unless the Company or the provisions of any applicable
laws shall require otherwise, in which event the Company shall pay the premium
thereon.

         8.4  Voting, Chairman, Subcommittees.
              ------------------------------- 

              (a) If there are fewer than three members of the Committee at any
         time, the Committee may do any act which the Plan authorizes or
         requires the Committee to do only upon the unanimous consent of the
         members of the Committee eligible to vote on such act.  If there are
         three or more members of the Committee at any time, a majority of the
         members of the Committee at the time in office may do any act which the
         Plan authorizes or requires the Committee to do.  The action of such
         majority of the members expressed from time to time by a vote at a
         meeting, or in writing without a meeting, or by conference telephone or
         similar communications equipment allowing all persons participating in
         the meeting to hear each other at the same time, shall constitute the
         action of the Committee and shall have the same effect for all purposes
         as if assented to by all members at the time in office.  Where action
         is taken by members of the Committee by conference telephone or similar
         communications

                                      49
<PAGE>
 
         equipment, such action shall be confirmed in writing by such members as
         soon as practicable thereafter.

              The Secretary shall maintain minutes reflecting Committee meetings
         and shall cause each action taken in writing without a meeting, and
         each written confirmation of action taken by conference telephone or
         similar communications equipment, to be included in the minutes of the
         Committee.

              (b) The Plan Administrator, as appointed pursuant to Section 8.10,
         shall serve as Chairman of the Committee.  The members of the Committee
         shall elect a Secretary who may, but need not be, a member of the
         Committee, and they may appoint from their number such subcommittees as
         they shall determine.

         8.5  Payment of Benefits.  The Committee shall advise the Trustee in
              -------------------                                            
writing with respect to all benefits which become payable under the terms of the
Plan and shall direct the Trustee to pay such benefits to or on order of the
Committee.  In the event that the Trust Fund shall be invested in whole or in
part in one or more insurance contracts, the Committee shall be authorized to
give to any such insurance company such instructions as may be necessary or
appropriate in order to provide for the payment of benefits in accordance with
the Plan.

         8.6  Powers and Authority; Action Conclusive.  Except as otherwise
              ---------------------------------------                      
expressly provided in the Plan or in the Trust Agreement, or by the Board of
Directors of the Company:

              (a) The Committee shall be responsible for the administration of
         the Plan.

                                      50
<PAGE>
 
              (b) The Committee shall have all powers necessary or helpful for
         the carrying out of its responsibilities, and the decisions or action
         of the Committee in good faith in respect of any matter hereunder shall
         be conclusive and binding upon all parties concerned.

              (c) The Committee may delegate to one or more of its members or
         any other person the right to act on its behalf in all matters
         connected with the administration of the Plan.

              (d) Without limiting the generality of the foregoing, the
         Committee shall:

                (i)    Determine all questions arising out of or in connection 
                       with the terms and provisions of the Plan except as
                       otherwise expressly provided herein;

                (ii)   Make rules and regulations for the administration of the
                       Plan which are not inconsistent with the terms and
                       provisions of the Plan, and fix the annual accounting
                       period of the trust established under the Trust Agreement
                       as required for tax purposes;

                (iii)  Have full discretionary authority to construe all terms,
                       provisions, conditions and limitations to the Plan;

                (iv)   Have full discretionary authority to determine all
                       questions relating to (A) the eligibility of persons to
                       receive benefits hereunder, (B) the years of Credited
                       Service, years of Company Service Credit and the amount
                       of Compensation and Earnings of a Participant during any
                       period hereunder, and (C) all other matters upon which
                       the benefits or other rights of a Participant or other
                       person shall be based hereunder;

                                      51
<PAGE>
 
                (v) Determine all questions relating to the administration of
                    the Plan (A) when disputes arise between the Company and a
                    Participant or his/her Beneficiary, spouse or legal
                    representative, and (B) whenever the Committee deems it
                    advisable to determine such questions in order to promote
                    the uniform administration of the Plan.

         The foregoing list of powers is not intended to be either complete or
         exclusive, and the Committee shall, in addition, have such powers as
         may be necessary for the performance of its duties under the Plan and
         the Trust Agreement.

         8.7  Counsel and Agents.  The Committee may employ such counsel,
              ------------------                                         
including legal counsel, accountants, investment advisors, physicians, agents
and such clerical and other services as it may require in carrying out the
provisions of the Plan, and shall charge the fees, charges and costs resulting
from such employment as an expense of the Trust Fund  unless paid by the
Company.  Unless otherwise provided by law, any person so employed by the
Committee may be legal or other counsel to the Company, an Affiliate, a member
of a Committee or an officer or member of the Board of Directors of the Company
or an Affiliate.

         8.8  Reliance on Information.  The members of the Committee and the
              -----------------------                                       
Company and its officers, directors and employees shall be entitled to rely upon
all tables, valuations, certificates, opinions and reports furnished by any
accountant, trustee, insurance company, counsel or other expert who shall be
engaged by the Company or the Committee, and the members of the Committee and
the Company and its officers, directors and employees shall be fully protected
in respect of any action taken or suffered by them in good

                                      52
<PAGE>
 
faith in reliance thereon, and all action so taken or suffered shall be
conclusive upon all persons affected thereby.

         8.9  Fiduciaries.  The provisions of this Section 8.9 shall apply
              -----------                                                 
notwithstanding any contrary provisions of the Plan or the Trust Agreement.

              (a) The named fiduciaries under the Plan shall be the members of
         the Committee, who shall be named fiduciaries with respect to control
         or management of the assets of the Plan, and who shall have authority
         to control or manage the operation and administration of the Plan,
         except with respect to those matters which under the Plan or the Trust
         Agreement are the responsibility, or subject to the authority, of the
         Trustee.

              (b) The named fiduciaries under the Plan shall have the right,
         which shall be exercised in accordance with the procedures set forth in
         Section 8.4 and/or in the Trust Agreement for action by the Committee,
         to allocate responsibilities, fiduciary or otherwise, among named
         fiduciaries, and the named fiduciaries (or any of them to whom such
         right shall be allocated) shall have the right to designate persons
         other than named fiduciaries to carry out responsibilities, fiduciary
         or otherwise, under the Plan.

              (c) The members of the Committee shall together establish and
         carry out, or cause to be provided by those persons (including without
         limitation, any investment manager, trustee or insurance company) to
         whom responsibility or authority therefor has been allocated or
         delegated in accordance with this Plan or the Trust Agreement, a
         funding policy and method consistent with the objectives of the Plan
         and the requirements of ERISA.  For such purposes, the Committee shall,
         at a meeting duly called for the purpose, establish a funding

                                      53
<PAGE>
 
         policy and method which satisfies the requirements of ERISA, and shall
         meet annually at a stated time of the year to review such funding
         policy and method.  All actions taken with respect to such funding
         policy and method and the reasons therefor shall be recorded in the
         minutes of the meetings of the Committee.

              (d) Any person or group of persons may serve in more than one
         fiduciary capacity with respect to the Plan.

              (e) Any named fiduciary under the Plan, and any fiduciary
         designated by a named fiduciary pursuant to Section 8.9(b) to whom such
         power is granted by a named fiduciary under the Plan, may employ one or
         more persons to render advice with regard to any responsibility such
         fiduciary has under the Plan.

              (f) Except to the extent otherwise provided by law, if any duty or
         responsibility of a named fiduciary has been allocated or delegated to
         any other person in accordance with any provision of this Plan or of
         the Trust Agreement, then such named fiduciary shall not be liable for
         an act or omission of such person in carrying out such duty or
         responsibility.

         8.10 Plan Administrator.  The Vice President and Chief Financial
              ------------------                                         
Officer of Martin Marietta Corporation shall appoint a person to serve as
Administrator of the Plan, as defined in section 3(16)(A) of ERISA.

         8.11 Notices and Elections.  An employee shall deliver to the Committee
              ---------------------                                             
all directions, orders, designations, notices or other communications on
appropriate forms to be  furnished by the Committee.  The Committee shall also
receive notices or other communications for Participants from the Trustee and
transmit them to the Participants.  All elections which may be made by an
employee under this Plan shall be made in a time,

                                      54
<PAGE>
 
manner and form determined by the Committee unless a specific time, manner or
form is set forth in the Plan.

         8.12 Credited Service.  "Credited Service" shall mean employment in
              ----------------                                              
Martin Marietta Energy Systems, Inc. and/or a subsidiary corporation and/or any
predecessor corporation (herein collectively referred to as the "Corporation")
and employment in Union Carbide Corporation prior to April 1, 1984 in accordance
with the "Company Service Credit Rules" of the Corporation as now promulgated
and as hereafter amended from time to time; provided, however, that solely for
the purpose of determining eligibility to participate and vesting, in any case
where it will produce a result more favorable to the employee, all "Credited
Service" shall be determined in accordance with the following provisions:

              (a) Credited Service is the total of the period of elapsed time
         which begins as of the date an employee first performs an hour of
         service with an employer maintaining this plan and, except as otherwise
         provided in this Section 8.12, ends as of the severance from service
         date, as provided in (b) below.  An "hour of service" is (i) each hour
         for which an employee is paid, or entitled to payment, for the
         performance of duties for the employer.

              (b) The severance from service date of an employee shall be deemed
         to be the earlier of:

                   (i)  the date the employee quits, retires, is discharged or
                        dies; or
                   (ii) the first anniversary of the first date of absence for
                        any other reason.

                                      55
<PAGE>
 
              (c) If an employee returns to service with an employer maintaining
         this plan within twelve months of his severance from service date, such
         employee shall be deemed to have had continuous employment.

              (d) Credited Service shall be the aggregate of all periods of
         Credited Service, provided that pre- and post-period of severance
         credited service will be aggregated only when

                   (i)    an employee's number of consecutive one-year periods 
                          of severance is less than the greater of (A) 5 years
                          or (B) the aggregate number of years of credited
                          service that occurred before the period of severance;

                   (ii)   such employee has one year of service after such 
                          period of severance; and

                   (iii)  (for aggregating pre-1976 service) such service would
                          not have been disregarded under the plan rules 
                          relating to periods of severance as in effect before 
                          1976.

              (e) For plan years after 1975, credited service includes credited
         service with other related employers who are members of a controlled
         group of corporations as defined in section 1563(a) of the Code without
         regard to subsections (a)(4) and (i)(3)(c).

         8.13 Company Service Credit.  "Company Service Credit" is based upon
              ----------------------                                         
employment by Union Carbide Corporation and by any of its subsidiary companies
prior to April 1, 1984, and based upon employment by Martin Marietta Energy
Systems, Inc., by any subsidiary company of the Company and by any predecessor
company of a subsidiary, and by any company acquired by the Company or by any
subsidiary thereof.  Company Service

                                      56
<PAGE>
 
Credit of all employees who were on the payroll on the date the Company
Retirement Plan or Union Carbide Corporation Plan became effective has been
established with respect to their employment prior to that date.  Company
Service Credit for employment subsequent to that date and Company Service Credit
of all new employees hired after that date will be determined under the
following rules:

              (a) In case an employee receives salary, wages or commission, from
         some subsidiary of Martin Marietta Energy Systems, Inc., or, prior to
         April l, 1984, from some subsidiary of Union Carbide Corporation
         without interruption, his/her Company Service Credit begins as of the
         date such salary, wages or commission becomes effective.

              (b) In case an employee is laid off by the Company, or by Union
         Carbide Corporation prior to April l, 1984, on account of reduction in
         force and through no fault of his/her own:

                   (i)  If such layoff continues not more than three (3)
                        consecutive years - Company Service Credit will be given
                        for service prior to such layoff;

                   (ii) If such layoff continues more than three (3) years - no
                        Company Service Credit will be given for service prior
                        to such layoff.

              (c) In case of absence caused by temporary suspension of work
         (other than "layoff" as in paragraph (b) above), disability or absence-
         with-leave (except long term disability) which is authorized by the
         management, employment will be considered as continuous without any
         deduction if it does not exceed three months.  However, in case such
         absence does exceed three

                                      57
<PAGE>
 
         months, the period of absence in excess of three months will not be
         considered as Company Service unless otherwise authorized by the
         management.  If an employee who is thus absent fails to return to work
         when able to do so, and at the time designated by the Company, he/she
         will be considered as voluntarily terminating his/her employment and
         his/her Company Service Credit shall end as of the date on which such
         absence commenced.

              (d) In case of rehire or reinstatement subsequent to discharge for
         cause or resignation at the Company's request, credit will be given for
         service only since last date of rehire or reinstatement by the Company,
         unless otherwise authorized by the management.

              (e) An employee on the active payroll of Union Carbide Corporation
         on January l, 1973, or rehired thereafter, who had been credited with
         Union Carbide Corporation Service Credit for one or more periods of
         prior employment but who had lost such credit because

                   (i) a layoff lasted for more than three years, or

                   (ii) termination was for any other cause, will have such
         prior Service Credit with Union Carbide Corporation restored upon
         completing a total of two years of currently accredited Company Service
         Credit with Union Carbide Corporation prior to April 1, 1984, or Martin
         Marietta Energy Systems, Inc. following reemployment.

         8.14 Taxes Payable by Trustee.  Taxes, if any, other than Transfer
              ------------------------                                     
Taxes, payable by the Trustee shall be charged against the Personal Investment
Accounts pro rata to the values of the cash and/or securities affected.

                                      58
<PAGE>
 
         8.15 Costs of Administration.  Costs and expenses of administering the
              -----------------------                                          
Plan, including Trustee's and investment manager's fees shall be paid from the
Trust Fund, unless they are paid by the Company.

         8.16 Transfer of a Subsidiary, Division, Branch or Business Unit.
              -----------------------------------------------------------  
Notwithstanding anything herein to the contrary, if at any time any subsidiary
or any division, branch or business unit of the Company shall be transferred as
a going business and on that account certain Participants shall remain in the
employ of any such subsidiary or shall transfer to the acquiring company, the
Board of Directors may, if they so determine, provide for the withdrawal and
segregation of the assets of the Savings Plan Trust Fund attributable to such
Participants, based on the value of their respective accrued benefits including
Company payments in the Savings Plan Trust Fund determined as though such
Participants had terminated employment as of the date of such transfer as a
going business.  Provided the subsidiary or acquiring company continues the Plan
or adopts a similar Savings Plan, as the case may be, a proportionate amount of
the assets of the Savings Plan Trust Fund equivalent to the value of such
accrued benefits as so determined may be transferred to the Savings Plan Trust
Fund created by the subsidiary or acquiring company for the benefit of such
Participants.

                                      59
<PAGE>
 
                                   ARTICLE IX

                  AMENDMENT, TERMINATION, ADOPTION AND MERGER
                  -------------------------------------------

         9.1  Modification or Amendment of Plan.  The Board shall have the right
              ---------------------------------                                 
at any time to terminate the Plan or to amend any of the provisions of the Plan.
No amendment shall decrease the accrued benefit of a Participant, and no
amendment shall change the vesting provisions to provide that the non-
forfeitable percentage of the accrued benefit derived from Employer
contributions (determined as of the later of the date such amendment is adopted,
or the date such amendment becomes effective) of any Participant is less than
such non-forfeitable percentage computed under the Plan without regard to such
amendment.

         9.2  Termination of Plan or Discontinuance of Contributions.  The Plan
              ------------------------------------------------------           
may be terminated by the Company at any time in the Company's sole discretion,
in whole or in part.  Notwithstanding any other provision of the Plan, upon
complete termination of the Plan or the complete discontinuance of contributions
thereunder, 100 percent of each Participant's accounts shall be non-forfeitable.
Upon any such termination, the Committee shall instruct the Trustee either (a)
to distribute or dispose of the net assets of the Trust Fund (remaining after
payment of or provision for all expenses of  final administration and
liquidation) exclusively for the benefit of all Participants (or their
Beneficiaries, as the case may be) according to their respective shares of the
Trust Fund as of the date of such termination or discontinuance, or (b) to
continue the Trust Fund with distributions to be made at the time and in the
manner provided for by Article IV.  In the event of any partial termination of
the Plan (within the meaning of section 411(d)(3) of the Code), 100 percent of
the accounts of each Participant affected by such partial termination shall be
non-forfeitable

                                      60
<PAGE>
 
         9.3  Expenses of Termination.  In the event of the complete or partial
              -----------------------                                          
termination of the Plan, the expenses incident thereto shall be a prior claim
and lien upon the assets of the Trust Fund and shall be paid or provided for
prior to the distribution of any benefits pursuant to such termination, unless
such expenses are paid by the Company.

         9.4  Amendments Required for Qualification.  All provisions of this
              -------------------------------------                         
Plan, and all benefits and rights granted hereunder, are subject to any
amendments, modifications or alterations which are necessary from time to time
to qualify the Plan under section 401(a) of the Code or corresponding provisions
of subsequent law, or to comply with any other provision of law.  Accordingly,
notwithstanding any other provisions of this Plan, the Company may amend, modify
or alter the Plan with retroactive effect in any respect or manner necessary to
qualify the Plan under section 401(a) of the Code,  to continue the Plan as so
qualified, or to comply with any other provision of law.

         9.5  Merger.  Subject to the provisions of this Section 9.5, the Plan
              -------                                                         
may be amended to provide for the merger of the Plan, in whole or in part, or a
transfer of all or a part of its assets or liabilities, to any other qualified
plan within the meaning of section 401(a) or 403(a) of the Code, including such
a merger or transfer in lieu of a distribution which might otherwise be required
under the Plan.  In the event of such a merger or consolidation of this Plan or
transfer of its assets or liabilities to any other plan in whole or in part,
each Participant shall be entitled to a benefit immediately after the merger,
consolidation or transfer (if such other plan then terminated) which is equal to
or greater than the benefit he/she would have been entitled to receive
immediately before the merger, consolidation or transfer (if the Plan had then
been terminated).

         9.6  Portsmouth, Ohio.  Effective January 1, 1989, with respect to any
              ----------------                                                 
Employee of the Company who was a participant in the Savings Plan for Salaried
Employees

                                      61
<PAGE>
 
at the Portsmouth Uranium Enrichment Plan or the Savings Plan for Bargaining
Unit Employees at the Portsmouth Uranium Enrichment Plant, Company Service
Credit under the Plan shall include all service which was recognized for the
purpose of determining benefits under said plans as in effect prior to their
merger into this Plan.

                                      62
<PAGE>
 
                                   ARTICLE X

                                 MISCELLANEOUS
                                 -------------

         10.1 Claims Procedure.  If a claim for benefits under the Plan is
              ----------------                                            
wholly or partially denied, the claimant shall be provided with a notice setting
forth the specific reason or reasons for the denial; specific reference to
pertinent plan provisions on which the denial is based; a description of any
additional material or information necessary for the claimant to perfect the
claim and an explanation of why such material is necessary; and an explanation
of the Plan's Claim Review Procedure.  Within 60 days after notification of a
denial of benefits, such claimant may, upon written application, appeal such
denial to an Administrator appointed pursuant to Section 8.10 of Article VIII
for a full and fair review.  Such claimant (or his/her duly authorized
representatives) may review pertinent documents and submit issues and comments
in writing.  Within 60 days of receipt of such written application for review,
the Administrator shall make a decision in writing, including specific reasons
for the decision, with references to the pertinent plan provisions.  Under
special circumstances, the Administrator may extend the time for processing such
a review, but a decision shall be rendered not later than 120 days after receipt
of request for review.  In the event that government regulation shall impose a
different standard for  review, such required standard shall be followed in lieu
of the above.

         10.2 Alienation Prohibited.  Except as provided in Section 10.3, to the
              ---------------------                                             
extent permitted by law no right or interest of any Participant in the Plan or
in his/her account thereunder shall be assignable or transferable in whole or in
part either directly or by operation of law or otherwise, including, but without
limitation, execution, levy, garnishment, attachment, pledge, bankruptcy, or in
any other manner but excluding

                                      63
<PAGE>
 
devolution by death or mental incompetency, and no right or interest in any
Participant in the Plan or in his/her accounts thereunder shall be liable for or
subject to any obligation or liability of such Participant.

         10.3 Exception For Qualified Domestic Relations Order.
              ------------------------------------------------ 

              10.3.1 Definitions
                     -----------

              The term "qualified domestic relations order" means any judgment,
         decree, or order (including approval of a property settlement
         agreement) which:

                   (a)  relates to the provision of child support, alimony
              payments, or marital property rights to a spouse, former spouse,
              child, or other dependent of a Participant;

                   (b)  is made pursuant to a state domestic relations law
              (including a community property law); and

                   (c)  which meets the requirements of subparagraph 10.4.1.2.

              10.3.2  Requirements
                      ------------

              The provisions of Section 10.2 shall not be applicable to a
         domestic relations order and payment of the right or interest of a
         Participant in the Plan or in his/her account thereunder shall be made
         in accordance with the terms of such order provided that such order:

                   (a)  creates or recognizes the existence of an alternate
              payee's (as hereinafter defined) right to, or assigns to an
              alternate payee the right to, receive all or a portion of the
              right or interest of a Participant in the Plan or in his/her
              account thereunder;

                   (b)  clearly specifies

                                      64
<PAGE>
 
                 (i)    the name and the last known mailing address (if any) of
                        the Participant and the name and mailing address of each
                        alternate payee covered by the order;

                 (ii)   the amount or percentage of the right or interest of
                        the Participant to be paid by the Plan to each such
                        alternate payee or the manner in which such amount or
                        percentage is to be determined;

                 (iii)  the number of payments or period to which such order
                        applies; and

                 (iv)   the name of each plan to which such order applies;

                    (c) does not require the Plan to provide any type or form of
              benefit, or any option, not otherwise provided under the Plan;

                    (d) does not require the Plan to provide increased benefits
              (determined on the basis of actuarial value); and

                    (e) does not require the payment of the right or interest of
              the Participant to an alternate payee which is required to be paid
              to another alternate payee under another order previously
              determined to be a qualified domestic relations order.

              10.3.3.  Payments Prior to Termination of Employment
                       -------------------------------------------

              In the case of any payment made before a Participant has
         terminated employment with the Company, a qualified domestic relations
         order shall not be considered as failing to meet the requirements of
         Section 10.3.2 solely because such order requires that payment of the
         right or interest of the Participant be made to an alternate payee:

                                      65
<PAGE>
 
              (a) on or after the date on which the Participant attains (or
         would have attained) the earliest retirement age, which for purposes of
         this Section 10.3 shall mean the earlier of:

                    (I)   the date on which the Participant is entitled to a
                          distribution under the Plan, or

                    (II)  the later of:

                          (A) the date the Participant attains age 50, or

                          (B) the earlier date on which the Participant could 
                              begin receiving benefits under the Plan if the
                              Participant separated from service;

              (b) as if the Participant had retired on the date on which such
         payment is to begin under such order (but taking into account only the
         present value of the right or interest of the Participant actually
         accrued and not taking into account the present value of any subsidy of
         the Employer for early retirement); and

              (c) in any form in which such right or interest may be paid under
         the Plan to the Participant (other than in the form of a joint and
         survivor annuity with respect to the alternate payee and his/her
         subsequent spouse).

              For purposes of Section 10.3.3(b) above, the interest rate
         assumption used in determining the present value of a Participant's
         benefits shall be determined from time to time by the Committee on a
         non-discriminatory basis.

              10.3.4  Former Spouse.  To the extent provided in any qualified
                      -------------                                          
domestic relations order:

              (a) the former spouse of a Participant shall be treated as a
         surviving spouse of such Participant for purposes of section 401(a)(11)
         of the Code; and

                                      66
<PAGE>
 
              (b) if married for at least one year to the Participant, such
         former spouse shall be treated as meeting the requirements of section
         401(a)(11)(d) of the Code.

              10.3.5  Notice.  The Committee shall promptly notify a 
                      ------
Participant and any other alternate payee of the receipt of a domestic relations
order and of the Plan's procedure for determining whether the order is a
qualified domestic relations order under this Section 10.3. Within a reasonable
period of time after the receipt of such order, the Committee, in accordance
with such procedures as it shall from time to time establish, shall determine
whether such order is a qualified domestic relations order under this Section
10.3 and shall notify the Participant and each alternate payee of such
determination.

              During any period of time in which the issue of whether a domestic
         relations order is a qualified domestic relations order under this
         Section 10.3 is being determined by the Committee, by a court of
         competent jurisdiction, or otherwise, the Committee shall separately
         account for the amounts which would have been payable to the alternate
         payee during such period if the order had been determined to be a
         qualified domestic relations order under this Section 10.3.  If within
         the eighteen (18) month period beginning on the date on which the first
         payment would be required to be made under the domestic relations order
         such order is determined to be a qualified domestic relations order
         under this Section 10.3, the Committee shall pay such amounts to the
         person or persons entitled thereto.  If within such eighteen (18) month
         period it is determined that such order is not a qualified domestic
         relations order under this Section 10.3, or the issue as to whether
         such order so qualifies is not resolved, then the Committee shall pay
         such amounts to the person or persons who would have been entitled to

                                      67
<PAGE>
 
         such amounts if there had been no order.  Any determination that an
         order is a qualified domestic relations order under this Section 10.3
         which is made after the end of such eighteen-month period shall be
         applied prospectively only.

          10.3.6  Definition of Alternate Payee.  The term "alternate payee"
                  -----------------------------                             
means any spouse, former spouse, child, or other dependent of a Participant who
is recognized by a domestic relations order as having a right to receive all, or
a portion of, the benefits payable under the Plan with respect to such
Participant.  The term "qualified domestic relations order" means a domestic
relations order which meets the requirements of Section 10.3.2.

          10.3.7  Transitional Rules.  The provisions of this Section 10.3.
                  ------------------                                       
shall become effective as of January 1, 1985; provided however, that in the case
of a domestic relations order entered before such date, the Committee:

          (a) shall treat such order as a qualified domestic relations order
        under this Section 10.3 if the Trustee is paying benefits pursuant to
        such order on January 1, 1985; and

          (b) may treat any other domestic relations order entered before
        January l, 1985 as a qualified domestic relations order under this
        Section 10.3 even if such order does not meet the requirements of the
        preceding provisions of this Section 10.3.

        10.4 Consent to Terms of Plan and Trust Agreement.
             -------------------------------------------- 

        An employee by becoming a Participant in the Plan consents and agrees
to all the terms and provisions of the Plan and of the Trust Agreement and as
they may be amended from time to time.

                                      68
<PAGE>
 
         10.5 Obligations of Company Limited.  The Company assumes no
              ------------------------------                         
obligations under this Plan except those specifically stated in this Plan.  No
person shall have any right to participate in profits by reason of this Plan
except to the extent expressly set forth herein.  The Company shall be  under no
legal obligation to make any contributions to the Trust Fund except as expressly
provided herein.

         10.6 Separation of Invalid Provisions.  If any provision of this Plan
              --------------------------------                                
or the Trust Agreement is held invalid, the remainder of the Plan or Trust
Agreement shall not be affected thereby.

         10.7 Payment to a Minor or Incompetent.  In the event that any amount
              ---------------------------------                               
is payable to a minor or other legally incompetent person, such amount may be
paid in any of the following ways, as the Committee in its sole discretion shall
determine:

              10.7.1  To the legal representative of such minor or other
         incompetent person;

              10.7.2  Directly to such minor or other incompetent person;

              10.7.3  To a parent or guardian of such minor, or to a custodian
         for such minor under the Uniform Gifts to Minors Act (or similar
         statute) of any jurisdiction or to the person with whom such minor
         shall reside.

Payment to such minor or incompetent person, or to such other person as may be
determined by the Committee, as above provided, shall discharge the Company, the
Committee, the Trustee and any insurance company or other person or corporation
making such payment pursuant to the direction of the Committee, and none of the
foregoing shall be required to see to the proper application of any such payment
to such person pursuant to the provisions of this Section 10.7.

                                      69
<PAGE>
 
         10.8   Doubt as to Right to Payment.  If at any time any doubt exists
                ----------------------------                               
as to the right of any person to any payment hereunder or as to the amount or
time of such payment (including, without limitation, any doubt as to identity,
or any case in which any notice has been received from any other person claiming
any interest in amounts payable hereunder, or any case in which a claim from
other persons may exist by reason of community property or similar laws), the
Committee shall be entitled, in its discretion, to direct the Trustee (or any
insurance company) to hold such sum as a segregated amount in trust until such
right or amount or time is determined or until order of a court of competent
jurisdiction, or to pay such sum into court in accordance with appropriate rules
of law in such case then provided, or to make payment only upon receipt of a
bond or similar indemnification (in such amount and in such form as is
satisfactory to the Committee).

         10.9   Forfeiture Upon Inability to Locate Distributee.  
                -----------------------------------------------       
Notwithstanding any other provision of the Plan, in the event that the Committee
cannot locate any person to whom a payment is due under the Plan, and no other
payee has become entitled thereto pursuant to any provision of the Plan, the
benefit in respect of which such payment is to be made shall be forfeited at
such time as the Committee shall determine in its sole discretion (but in all
events prior to the time such benefit would otherwise escheat under any
applicable state law); provided that any benefit so forfeited shall be restored
if such person subsequently makes a valid claim for such benefit.

         10.10  Contributions Conditioned on Initial Qualification and
                ------------------------------------------------------
Deductibility.  Notwithstanding any other provision of this Plan, each Basic
- -------------                                                               
Deduction, and related Company Contribution by the Company under this Plan is
conditioned on:

                                      70
<PAGE>
 
              10.10.1  A determination by the Internal Revenue Service that the
         Plan qualifies under section 401 of the Code for the Plan Year as to
         which the Company first makes a contribution hereunder; and

              10.10.2  The deductibility of such contribution under section 404
         of the Code.

         10.11  No Diversion of Trust Fund.  It shall be impossible at any time
                --------------------------                                     
for any part of the Trust Fund to be (within the taxable year or thereafter)
used for or diverted to purposes other than for the exclusive benefit of
Participants and their Beneficiaries (including the payment of the expenses of
the administration of the Plan and of the Trust); provided that:

              10.11.1  A contribution that is made by the Company by a mistake
         of fact shall be returned to the Company upon its request within one
         year after the payment of the contribution; or

              10.11.2  A contribution that is conditioned upon its deductibility
         under section 404 of the Code shall be returned to the Company upon its
         request, to the extent that the contribution is disallowed as a
         deduction, within one year after such disallowance; or

              10.11.3  A contribution that is conditioned on qualification of
         the Plan under section 401 of the Code shall, if the Plan does not so
         qualify, be returned to the Company within one year after the date of
         denial of qualification of the Plan.

Subject to Article IX, the Trust shall continue for such time as may be
necessary to accomplish the purpose for which it is created.

                                      71
<PAGE>
 
         10.12  Usage.  Whenever applicable the masculine gender, when used in
                -----                                                         
the Plan, shall include the feminine and neuter genders, and the singular shall
include the plural.

         10.13  Governing Law.  The Plan shall be governed by, construed and
                -------------                                               
administered under the law of the State of Tennessee without regard to the
principles of conflict of laws, to the extent not preempted by Federal law.

         10.14  Captions.  The captions contained herein are inserted only as a
                --------                                                       
matter of convenience and for reference and in no way define, limit, enlarge or
describe the scope or intent of the Plan and in no way shall affect the Plan or
the construction of any provision thereof.

         IN WITNESS WHEREOF, and as evidence of the adoption of this Plan, the
Company has caused this instrument to be signed by its duly authorized officer
and its corporate seal to be hereunto affixed and attested this _____ day of
______________ 1993.

                               MARTIN MARIETTA ENERGY
                               SYSTEMS, INC.


                               By 
                                 ---------------------
                                 (title)

[Seal]

ATTEST:


- ------------------
    (title)

                                      72

<PAGE>

                                                                     EXHIBIT 4-D
 
                            FIRST AMENDMENT TO THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                   401(k) SAVINGS PLAN FOR SALARIED EMPLOYEES
                   ------------------------------------------


          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Salaried Employees (the "Plan") is amended as follows:
          
          1.   The Plan is amended by adding a new Article XI to read in its
entirety as follows:

                                  "ARTICLE XI

                          SUSPENSION OF CONTRIBUTIONS
                          ---------------------------

          11.1 Override of Other Plan Provisions.  To the extent that this
               ---------------------------------                          
               Article XI is inconsistent with any other part of the Plan, this
               Article XI shall apply in lieu of such other part.  This override
               shall take precedence over any contrary language in other parts
               of the Plan, such as language providing that a part of the Plan
               shall apply "notwithstanding any contrary provision of the Plan."

          11.2 Suspension of Contributions.
               --------------------------- 

          (a)  With respect to any calendar month described in Section 11.2(b),
               an individual shall not be entitled to have Before Tax
               Contributions or Additional Contributions made to the Trustee on
               his/her behalf.

          (b)  A calendar month shall be considered to be described in this
               Section 11.2(b) with respect to an individual if such individual
               is not entitled to have Basic Deductions or Supplemental
               Deductions made to the Trustee on his/her behalf with respect to
               such calendar month, pursuant to Section 11.4(b) of the Savings
               Plan.  For purposes of this Section 11.2(b), the terms "Basic
               Deductions," "Supplemental Deductions, " and "Trustee," shall
               have the meanings given such terms under the Savings Plan.

          11.3 Interaction with Legal Requirements.
               ----------------------------------- 

          (a)  For purposes of Sections 2.4, 2.6, and 2.13 of the Plan and for
               all purposes under the Code, an individual shall not fail to be
               treated as eligible to benefit under the Plan solely by reason of
               not being entitled
<PAGE>
 
               to have Before Tax Contributions or Additional Contributions made
               to the Trustee on his/her behalf, pursuant to Section 11.2(a).

          (b)  Section 11.5(e) of the Savings Plan shall apply for purposes of
               determining whether a distribution under the Plan is an "eligible
               rollover distribution" under the Code.

          11.4 Transfers to Savings Plan.  This Plan shall make any transfer of
               -------------------------                                       
               assets that it would be required to make under the terms of
               Section 11.5(g) of the Savings Plan.  With respect to an
               individual, such transfers shall be made from the following Funds
               within the individual's Tax Deferred Account in the following
               order:  Fixed Income Fund, Equity Investment Fund, Martin
               Marietta Corporation Stock Fund, and Government Bond Fund.  A
               Fund within an individual's Tax Deferred Account shall be reduced
               to zero prior to any reduction of a Fund subsequently listed."

          2.   This Amendment shall be effective as of January 1, 1993 (except
that any provision of this Amendment shall be effective as of such earlier date
or dates as are necessary to carry out the purposes of such provision).

                                       MARTIN MARIETTA ENERGY SYSTEMS, INC.



                                       By: ________________________________

 

<PAGE>
 

                                                                     EXHIBIT 4-E

                            SECOND AMENDMENT TO THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                   401(k) SAVINGS PLAN FOR SALARIED EMPLOYEES

          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Salaried Employees (the "Plan") is amended as follows:

          1.  Section 1.10 of the Plan is amended by adding the following
sentences to the end thereof:

               A Participant's Compensation in excess of $200,000
               shall not be taken into account under the Plan for any purpose.
               Such $200,000 limitation shall be adjusted at the same time and
               in the same manner as the limitation set forth in Section
               415(b)(1)(A) of the Code is adjusted under Section 415(d) of the
               Code.

          2.  Section 1.13 of the Plan is amended by adding ", 125" after
"401(a)" therein.

          3.  Section 2.4.6 of the Plan is renumbered 2.4.7.

          4.  A new Section 2.4.6 is added to the Plan to read as follows:

               2.4.6  Notwithstanding anything to the contrary in this
               Article II, in the event the Committee determines that the Plan
               does not meet the actual deferral percentage tests under Section
               401(k)(3)(A) of the Code for a Plan Year, the Committee may
               adjust Before Tax Contributions and/or Additional Contributions
               made to the Plan for such Plan Year as set forth below:

               (i)  On or before the fifteenth day of the third month
               following the end of the Plan Year, the excess contributions of
               the Highly Compensated Employee(s) with the highest actual
               deferral percentage(s) shall be distributed to him or her until
               one of the actual deferral percentage tests is satisfied, or
               until his or her actual deferral
<PAGE>
 
               percentage equals the actual deferral percentage(s) of the Highly
               Compensated Employee(s) having the next highest actual deferral
               percentage.  This process shall continue until one of the actual
               deferral percentage tests is satisfied.

                    (ii)  Highly Compensated Employee's excess contributions
               shall mean such Employee's Before Tax Contributions or Additional
               Contributions which must be reduced for the Employee's actual
               deferral percentage to equal the highest permitted actual
               deferral percentage under the Plan.  In determining the amount of
               excess contributions to be distributed with respect to an
               affected Highly Compensated Employee as determined herein, such
               amount shall be reduced by any excess contributions previously
               distributed to such Highly Compensated Employee for the taxable
               year ending with or within such Plan Year, and any Company
               Contributions which relate to such excess contributions.

                    (iii) The distribution of excess contributions:

                    (a)   may be postponed but not later than the close of the
                          Plan Year following the Plan Year to which the excess
                          contributions are allocable;

                    (b)   shall be made first from Additional Contributions and,
                          thereafter, from Before Tax Contributions. Company
                          Contributions which relate to such Before Tax
                          Contributions shall be forfeited;

                    (c)   shall be adjusted for income; and

                    (d)   shall be designated by the Committee as a distribution
                          of excess contributions and income.

          5.  Section 3.2 of the Plan is amended by amending the last sentence
to read as follows:

               Any such earnings on such short-term investments of monies
               in a Fund shall be allocated monthly to the account of each 
               Participant having an 

                                      -2-
<PAGE>
 
               investment in such Fund in proportion to the amount of each 
               Participant's account balance invested in such Fund at the 
               end of such month.

          6.  Section 4.1.1 of the Plan is amended by adding the words ",
subject to Section 4.1.8," after the word "then" in the first sentence thereof:

          7.  Section 4.1.2 of the Plan is amended by adding the words "or elect
to have an eligible rollover distribution transferred from the Plan to an
eligible retirement plan pursuant to Section 4.1.8" after the words "Section
4.1.1" in the first sentence thereof.

          8.  Section 4.1.5 of the Plan is amended by adding the following
sentence to the end thereof:

               Such payment shall be made within five years after the
               Participant's death, or, where the distribution of payments to
               the Participant had commenced before the Participant's death, at
               least as rapidly as the method of distribution used as of the
               date of the Participant's death.

          9.  A new Section 4.1.8 is added to the Plan to read as follows:

               4.1.8.  This section applies to distributions made on or
               after January 1, 1993.  Notwithstanding any provision of the Plan
               to the contrary that would otherwise  limit a Participant's
               election under this Section 4.1.8, a Participant may elect, at
               the time and in the manner prescribed by the Committee and
               subject to the following sentence, to have all or any portion of
               an eligible rollover distribution paid in a direct rollover
               directly to an eligible retirement plan specified by the
               Participant.  The Participant's right to make such an election
               shall be limited by the following rules:  (i) a Participant with
               an eligible rollover distribution amounting to less than $200
               shall not have the right to elect a direct rollover pursuant to
               this Section 4.1.8; (ii) a Participant may elect a direct
               rollover for a portion of an eligible rollover distribution only
               if such portion equals or exceeds $500; and (iii) a Participant
               may only elect one direct rollover for each eligible rollover 
               distribution.

                                      -3-
<PAGE>
 
               An "eligible rollover distribution" is any distribution of
               all or any portion of the balance to the credit of the
               Participant, except that an eligible rollover distribution does
               not include: any distribution that is one of a series of
               substantially equal periodic payments (not less frequently than
               annually) made for the life (or life expectancy) of the
               Participant or the joint lives (or joint life expectancies) of
               the Participant and the Participant's designated beneficiary, or
               for a specified period of ten years or more; any distribution to
               the extent such distribution is required under code section
               401(a)(9); the portion of any distribution that is not includible
               in gross income (determined without regard to the exclusion for
               net unrealized appreciation with respect to employer securities);
               and other items designated not to be eligible rollover
               distributions by regulation, revenue ruling, notice, or other
               guidance issued by the Department of the Treasury.

               An "eligible retirement plan" is an individual retirement
               account described in Code section 408(a), an individual
               retirement annuity described in Code section 408(b), an annuity
               plan described in Code section 403(a), or a qualified trust
               described in Code section 401(a), that accepts the Participant's
               eligible rollover distribution.  However, in the case of an
               eligible rollover distribution to a surviving spouse, an eligible
               retirement plan is an individual retirement account or individual
               retirement annuity.  The Participant's surviving spouse and the
               Participant's spouse or former spouse who is the alternate payee
               under a qualified domestic relations order, as defined in Code
               section 414(p), are considered Participants with regard to the
               interest of the spouse or former spouse.

          10. Section 4.2 of the Plan is amended by adding the phrase "Subject
to Section 4.1.6" to the beginning thereof.
 
          11. Section 4.5 of the Plan is amended by adding the following 
sentence

                                      -4-
<PAGE>
 
at the beginning thereof:

               The following loan provisions will not be implemented until
               the Administrative Committee determines that such provisions will
               be effective.

          12.  Section 5.12.2 of the Plan is amended by adding the words "If
permitted by law" at the beginning of the existing sentence therein and by
adding the following sentence before such existing sentence:

               If, notwithstanding subparagraphs (a) through (i) of Section
               5.12.1, a Before Tax Contribution or Additional Contribution is
               made on behalf of a Participant which results in the limitations
               set forth in Section 5.7 of this Article V being exceeded, then
               such excess and any earnings thereon may be returned to the
               Participant.

          13.  Section 5.12.2 of the Plan is further amended by adding the
following sentences at the end thereof:

               If such a return is not permitted under the law, then these
               amounts (including forfeitures) shall be used to reduce Company
               Contributions for the following Limitation Year (and succeeding
               Limitation Years, if necessary) for the Participant if that
               Participant is covered by the Plan as of the end of the
               Limitation Year.  If the Participant is not covered by the Plan
               as of the end of the Limitation Year, such excess Company
               Contributions shall be held unallocated in a suspense account for
               the Limitation Year.  The amounts in such suspense account shall
               be used to reduce Company Contributions on behalf of each
               Participant to whom such amounts are allocated or reallocated,
               for the Limitation Year in which such amounts are allocated or
               reallocated, and shall be allocated and reallocated in the 
               following manner:

                                      -5-
<PAGE>
 
                         (i)   The amounts in such suspense account shall be
               allocated and reallocated in the following Limitation Year to the
               accounts of the remaining Participants in the Plan.

                         (ii)  If the allocation or reallocation of the amounts
               in such suspense account causes the limitations set forth in
               Article V to be exceeded with respect to all Participants'
               accounts for that Limitation Year, then the amounts which may not
               be allocated as the result of such limitations shall be held
               unallocated in the suspense account.  All amounts so remaining in
               the suspense account must be allocated and reallocated among the
               accounts of the remaining Participants (subject to the
               limitations set forth in this Article V) in the following
               Limitation Year, and succeeding Limitation Years, if necessary.

          14.  Section 6.1.1 of the Plan is amended by amending subdivision
(ii) of the first sentence of subsection (a) to read as follows:

                         (ii)  The Plan is part of a required aggregation group
               and the sum of the present value of the cumulative accrued
               benefits for Key Employees under all defined benefit plans
               included in the required aggregation group and the aggregate of
               the accounts of Key Employees under all defined contribution
               plans included in the required aggregation group exceeds 60
               percent of a similar sum determined for all employees.

          15.  Section 6.1.1 of the Plan further amended by replacing the words
"if Section 6.4 applies" with "if the 125% figure is utilized pursuant to
Section 6.3" in the second paragraph of subsection (b) thereof.

          16.  Section 6.2 of the Plan is amended by adding the words "and is
not a member of a required aggregation group as described in Section 6.1.1"
after the words "Section 6.1" therein.

                                      -6-
<PAGE>
 
          17.  Section 6.4.1 of the Plan is amended by changing "415(c)(1)(A)"
to "415(b)(1)(A)" therein.

          18.  Section 6.4.2 of the Plan is amended by adding the words "both
more than a one-half (1/2) percent interest and" before the words "the largest
interests" therein.

          19.  Section 8.13.1 of the Plan is amended by inserting the words "and
hours during which no duties are performed due to layoff, vacation, holiday,
illness, military duty, incapacity (including Disability), jury duty, or leave
of absence, and hours for which back pay is awarded or agreed to by the Company,
an Affiliate, or, prior to April 1, 1984, Union Carbide Corporation" at the end
thereof.

          20.  Section 8.13.4 of the Plan is further amended by deleting the
words "his/her" and by adding the words "for an Employee who does not have a
nonforfeitable right to his/her Tax Deferred Account derived from Company
Contributions" before the words "only when" therein.

          21.  Section 9.1 of the Plan is amended by adding the words "or
income" after the word "corpus" therein.

          22.  The title of Section 10.4.1.1 of the Plan is amended to read
"Definitions."

          23.  Section 10.4.1.1 of the Plan is amended by deleting the word
"qualified" therein, by adding the word "and" after the word "Participant" in
subsection (a) therein, by deleting " ; and " from subsection (b) therein and by
deleting subsection (c) in its entirety.

          24.  Section 10.4.1.1 of the Plan is further amended by adding the
following paragraph to read as follows:

               The term "qualified domestic relations order" means a domestic
               relations order which meets the requirements of Section 10.4.1.2.

                                      -7-
<PAGE>
 
          25. Section 10.4.1.6 of the Plan is amended by deleting the word
"qualified" therein.


                             MARTIN MARIETTA ENERGY SYSTEMS, INC.


                             By: 
                                ---------------------------------

                                      -8-

<PAGE>

                                                                     EXHIBIT 4-F
 
                            THIRD AMENDMENT TO THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                   401(k) SAVINGS PLAN FOR SALARIED EMPLOYEES
                   ------------------------------------------


          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Salaried Employees (the "Plan") is amended as follows:

1.  The following new definition is added to Article I:

          "1.30  "Employer" shall mean (a) the Company, and (b) any Affiliate
                  --------                                                   
          who adopts the Plan pursuant to Section 9.7.  With respect to any
          Participants employed by an Employer, references in this Plan to
          employment with the Company or Compensation received from the Company
          shall mean employment with, or Compensation received from, the
          Employer.  In addition, any references in the Plan to its adoption by
          the Company, or to contributions and expenses paid by the Company,
          shall mean the adoption by, and contributions and expenses paid by, an
          Employer, as applicable."

2.  New Sections 9.7 and 9.8 are added to the Plan to read as follows:

     "9.7.   Adoption of Plan by Employers.
             ----------------------------- 

          9.7.1  With the consent of the Company, any Affiliate may adopt the
                 Plan and the Trust Agreement for any of its divisions or
                 locations as it may specify by delivering to the Committee and
                 the Trustee:

                 9.7.1.1  A written instrument, duly executed and acknowledged:

                          (a)  adopting and assuming, jointly and severally, the
                          obligations of the Company under the Plan and Trust
                          Agreement;

                          (b)  appointing the Company and the Committee as its
                          agents and attorneys-in-fact for all purposes with
                          respect to the Plan and Trust Agreement, including
                          amending or terminating the Plan and Trust Agreement
                          and giving or receiving notices, instructions,
                          directions and other communications to the Trustee;
                          and

                          (c)  specifying the divisions or locations for which
                          it is adopting the Plan and Trust Agreement.


                                       1
<PAGE>
 
                 9.7.1.2  A duly certified copy of resolutions of the board of
                          directors of the adopting corporation, or a similar
                          document from the person or persons having the power
                          to bind the partnership or other entity, authorizing
                          the adoption of the Plan and the Trust Agreement and
                          approving and authorizing the execution,
                          acknowledgement and delivery of the written instrument
                          described in Section 9.7.1.1; and

                 9.7.1.3  A copy of a document evidencing the Company's consent
                          to the adoption of the Plan and the Trust Agreement by
                          such Affiliate.

          9.7.2  The Company's consent to any adoption of this Plan and Trust
                 Agreement shall be evidenced by:

                 9.7.2.1  written approval and consent to such adoption by the
                          Committee if such adoption would add fewer than 100
                          Eligible Employees, or

                 9.7.2.2  a resolution of the Company's Board of Directors
                          approving and consenting to such adoption if such
                          adoption would add 100 or more Eligible Employees on
                          its effective date.

          9.7.3  In giving its consent to any adoption of the Plan and Trust
                 Agreement under Section 9.7.2, the Company or the Committee may
                 make its consent subject to such terms and conditions as it may
                 prescribe.

     9.8  Discontinuance of Participation.  An Employer's discontinuance of its
          -------------------------------                                      
participation under the Plan may be voluntary or involuntary, partial or
complete, as described below:

          9.8.1  Any Employer may, with the approval of the Committee, elect,
                 at any time, to discontinue its participation hereunder in
                 whole or in part with respect to any of its divisions or
                 locations by filing written notice thereof with the Committee
                 and specifying the group or groups of Participants affected by
                 such election.

          9.8.2  The Plan shall discontinue as to all Participants of any
                 Employer which shall be declared bankrupt or which makes any
                 general assignment for the benefit of creditors.

                                       2
<PAGE>
 
          9.8.3  The Plan shall discontinue as to Participants of any Employer
                 in the event of the dissolution, merger, consolidation, or sale
                 or other disposition of the business and assets or stock of
                 such Employer, unless provision is made for the continuance of
                 the Plan by a successor.  In the event the Plan is discontinued
                 pursuant to this Section 9.8.3, the Committee shall make such
                 current or deferred distribution to the Participants affected
                 by such discontinuance as it shall deem appropriate and in
                 accordance with section 9.5 and the other provisions of the
                 Plan; provided, however, if provision is made for the
                 continuance of the Plan by a successor, the Board of Directors
                 of the Company or, if such disposition of the business is
                 either approved by the Board of Directors of the Company or is
                 a disposition for which no approval by the Board of Directors
                 is required, the Committee may, if they so determine, direct
                 that the portion of the Trust Fund allocable to such
                 Participants be transferred to a successor qualified plan or
                 funding medium covering such Participants.  The Committee, in
                 its sole discretion, may permit the value of such Participants'
                 Tax Deferred Accounts to remain in the Plan pending the
                 completion of the dissolution, merger, consolidation or sale or
                 other disposition of the business and assets or stock of such
                 Participants' Employer, as the case may be, for such a period
                 of time as shall be designated by the Committee."


                            MARTIN MARIETTA ENERGY SYSTEMS, INC.


                            By: ______________________________________



                                       3

<PAGE>
 
                                                                     EXHIBIT 4-G

                            FOURTH AMENDMENT OF THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                   401(k) SAVINGS PLAN FOR SALARIED EMPLOYEES
                   ------------------------------------------


          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Salaried Employees ("Plan") is hereby amended as follows:

          1.   Section 1.14.2 of Article I of the Plan is deleted in its
entirety.

          2.   Section 1.14.3 of Article I of the Plan is redesignated to read
"1.14.2".

          3.   Section 2.5.1 of Article II of the Plan is amended and restated
in its entirety to read as follows:

                   "At the time a Participant's Before Tax Contribution is paid
               to the Trustee, the Company shall pay to the Trustee out of
               accumulated earnings and profits an amount equal to 50% of the
               Basic Deduction paid to the Trustee on behalf of such
               Participant."

          4.   The provisions of this Fourth Amendment shall be effective as of
January 1, 1994.

                            Signed this ____ day of _______________________,1993

                            MARTIN MARIETTA ENERGY SYSTEMS, INC.


                            By:_________________________________________________

<PAGE>

                                                                     EXHIBIT 4-H
 
                             FIFTH AMENDMENT TO THE

                      MARTIN MARIETTA ENERGY SYSTEMS, INC.

                       401(k) PLAN FOR SALARIED EMPLOYEES
           _________________________________________________________

          The Martin Marietta Energy Systems, Inc. 401(k) Plan for Salaried
Employees (the "Plan") is hereby amended as follows:

          1.   Sections 1.10 and 1.13 of the Plan are amended by adding the
following sentences to the end thereof:

               "Notwithstanding the foregoing, a Participant's Compensation in
               excess of $150,000, or such greater amount as determined by the
               Secretary of the Treasury pursuant to Section 401(a)(17) of the
               Code, in any Plan Year beginning on or after January 1, 1994
               shall not be considered for any purpose under this Plan. In
               determining a Participant's Compensation, the family unit of a
               Participant who is a 5% owner or who is both a Highly Compensated
               Employee and one of the ten most highly compensated employees
               will be treated as a single Employee with one Compensation. For
               this purpose, a family unit is the Participant, the Participant's
               spouse, and the Participant's lineal descendants who have not
               attained age 19 on or before the last day of the year."

          2.   Section 1.17 of the Plan is amended by adding the following
sentences to the end therof:

               "For the purposes of Code section 401(k), the family
               unit of a Highly Compensated Employee
<PAGE>
 
               who is either a 5% owner or one of the ten most highly
               compensated employees will be considered as a single Employee.
               For this purpose, a family unit is the Employee, the Employee's
               spouse, and the lineal ascendants and descendants, and spouses of
               such ascendants and descendants, of any Employee or former
               Employee."

          3.   Sections 2.1 and 2.3.1 of the Plan are amended by adding the
following sentence to the end thereof:

               "An Employee's election to reduce his/her Compensation may only
               be made with respect to amounts which are not currently available
               to the Employee at the time of the election and which would
               otherwise be payable in cash."

          4.   Section 2.4.3 of the Plan is amended by adding the following
sentence to the end thereof:

               "No amounts shall be recharacterized as described in this Section
               2.4.3 with respect to a Highly Compensated Employee to the extent
               that the recharacterized amounts, in combination with Employee
               contributions actually made by the Employee, exceed the maximum
               amount of Employee contributions (determined prior to applying
               Code section 401(m)(2)(A)) that the Employee is permitted to make
               under the Plan in the absence of such recharacterization.
               Recharacterized excess contributions shall remain subject to the
               nonforfeitability requirements and distribution limitations that
               apply to elective contributions."

          5.   Section 2.4.6 of the Plan is amended by adding the words "and
excess contributions previously distributed for the Plan Year beginning in such
taxable year" after

                                      -2-
<PAGE>
 
the words "such Plan Year" in the second sentence of subsection (ii) thereof,
and by adding the following to the end of subparagraph (ii) thereof:

               "If a Highly Compensated Employee's actual deferral ratio (ADR)
               is determined under the family aggregation rules, the ADR shall
               be reduced in accordance with the "leveling" method described in
               Treasury regulations section 1.401(k)-1(f)(2) and the excess
               contributions shall be allocated among the family members in
               proportion to the contributions of each family member that have
               been combined."


          6.   Section 2.4.6 is further amended by adding the following sentence
to the end thereof:

               "The income allocable to excess contributions shall be equal to
               the sum of the allocable gain and loss for the Plan Year and the
               allocable gain and loss for the period between the end of the
               Plan Year and the date of distribution."


          7.   Section 2.13 of the Plan is amended by replacing the second
sentence therein with the following sentences:

               "Such contributions shall meet the nondiscriminatory test
               regarding employee and matching contributions set forth in Code
               section 401(m)(2)(A) of the Code. Excess aggregate contributions
               on behalf of Highly Compensated Employees, and income allocable
               to these contributions (as determined below), shall be
               distributed in a manner consistent with Code section 401(a) to
               the Highly Compensated Employees on the basis of the respective
               portions of such amounts attributable to each Highly Compensated
               Employee after the close of the Plan

                                      -3-
<PAGE>
 
               Year in which the excess aggregate contributions arose and within
               2 1/2 months after the close of the Plan Year (the distribution
               may be postponed but not later than the Plan Year following the
               Plan Year to which the excess contributions are allocable).

               The amount of excess aggregate contributions for a
               Highly Compensated Employee shall be equal to the total
               contribution taken into account for the actual contribution
               percentage test under Code section 401(m) minus the product of
               the Employee's contribution ratio and the Employee's
               Compensation.  If a Highly Compensated Employee's actual
               contribution ration (ACR) is determined under the family
               aggregation rules, the ACR shall be reduced in accordance with
               the "leveling" method described in Treasury regulations section
               1.401(m)-1(e)(2) and the excess aggregate contributions shall be
               allocated among the family members in proportion to the
               contributions of each family member that have been combined.

               The amount of excess aggregate contributions for a Plan
               Year shall be determined after determining the excess
               contributions that are treated as Employee contributions due to
               recharacterization pursuant to Treasury regulation section
               1.401(m)-1(e)(2)(ii).

               For the purposes of this section 2.13, the multiple use
               of the alternative limitation described in Treasury regulation
               section 1.401(m)-2(b) shall apply.  In the event this Plan
               exceeds this limitation, the actual deferral ratio or the actual
               contribution ratio shall be reduced accordingly for all Highly
               Compensated Employees or for only those Highly Compensated
               Employees who are eligible in both the 401(k) and 401(m)
               arrangements."

                                      -4-
<PAGE>
 
          8.   Section 2.13 of the Plan is further amended by adding the
following sentence to the end thereof:

               "The income allocable to excess aggregate contributions shall
               be equal to the sumj of the allocable gain or loss for the Plan
               Year and the allocable gain and loss for the period between the
               end of the Plan Year and the date of distribution. Matching
               Contributions attributable to distributed excess aggregate
               contributions shall be forfeited."



                                 MARTIN MARIETTA ENERGY SYSTEMS, INC.


                                 -----------------------------------------



                                      -5-

<PAGE>

                                                                     EXHIBIT 4-I
 
                             FIRST AMENDMENT TO THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                    401(k) SAVINGS PLAN FOR HOURLY EMPLOYEES
                    ----------------------------------------


          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Hourly Employees (the "Plan") is amended as follows:

          1.   The Plan is amended by adding a new Article XI to read in its
entirety as follows:

                                  "ARTICLE XI

                          SUSPENSION OF CONTRIBUTIONS
                          ---------------------------

          11.1 Override of Other Plan Provisions.  To the extent that this
               ---------------------------------                          
               Article XI is inconsistent with any other part of the Plan, this
               Article XI shall apply in lieu of such other part.  This override
               shall take precedence over any contrary language in other parts
               of the Plan, such as language providing that a part of the Plan
               shall apply "notwithstanding any contrary provision of the Plan."

          11.2 Suspension of Contributions.
               --------------------------- 

          (a)  With respect to any calendar month described in Section 11.2(b),
               an individual shall not be entitled to have Before Tax
               Contributions or Additional Contributions made to the Trustee on
               his/her behalf.

          (b)  A calendar month shall be considered to be described in this
               Section 11.2(b) with respect to an individual if such individual
               is not entitled to have Basic Deductions or Supplemental
               Deductions made to the Trustee on his/her behalf with respect to
               such calendar month, pursuant to Section 11.4(b) of the Savings
               Plan.  For purposes of this Section 11.2(b), the terms "Basic
               Deductions," "Supplemental Deductions, " and "Trustee," shall
               have the meanings given such terms under the Savings Plan.

          11.3 Interaction with Legal Requirements.
               ----------------------------------- 

          (a)  For purposes of Sections 2.4, 2.6, and 2.13 of the Plan and for
               all purposes under the Code, an individual shall not fail to be
               treated as eligible to benefit under the Plan solely by reason of
               not being entitled

<PAGE>
 
 
               to have Before Tax Contributions or Additional Contributions made
               to the Trustee on his/her behalf, pursuant to Section 11.2(a).

          (b)  Section 11.5(e) of the Savings Plan shall apply for purposes of
               determining whether a distribution under the Plan is an "eligible
               rollover distribution" under the Code.

          11.4 Transfers to Savings Plan.  This Plan shall make any transfer of
               -------------------------                                       
               assets that it would be required to make under the terms of
               Section 11.5(g) of the Savings Plan.  With respect to an
               individual, such transfers shall be made from the following Funds
               within the individual's Tax Deferred Account in the following
               order:  Fixed Income Fund, Equity Investment Fund, Martin
               Marietta Corporation Stock Fund, and Government Bond Fund.  A
               Fund within an individual's Tax Deferred Account shall be reduced
               to zero prior to any reduction of a Fund subsequently listed."

          2.   This Amendment shall be effective as of January 1, 1993 (except
that any provision of this Amendment shall be effective as of such earlier date
or dates as are necessary to carry out the purposes of such provision).


                       MARTIN MARIETTA ENERGY SYSTEMS, INC.



                       By: ________________________________

 


<PAGE>

                                                                     EXHIBIT 4-J

 
                            SECOND AMENDMENT TO THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                    401(k) SAVINGS PLAN FOR HOURLY EMPLOYEES

          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Hourly Employees (the "Plan") is amended as follows:

          1.  Section 1.10 of the Plan is amended by adding the following
sentences to the end thereof:

               A Participant's Compensation in excess of $200,000 shall not be
               taken into account under the Plan for any purpose. Such $200,000
               limitation shall be adjusted at the same time and in the same
               manner as the limitation set forth in Section 415(b)(1)(A) of the
               Code is adjusted under Section 415(d) of the Code.

          2.  Section 1.13 of the Plan is amended by adding ", 125" after
"401(a)" therein.

          3.  Section 2.4.6 of the Plan is renumbered 2.4.7.

          4.  A new Section 2.4.6 is added to the Plan to read as follows:

               2.4.6 Notwithstanding anything to the contrary in this Article
               II, in the event the Committee determines that the Plan does not
               meet the actual deferral percentage tests under Section
               401(k)(3)(A) of the Code for a Plan Year, the Committee may
               adjust Before Tax Contributions and/or Additional Contributions
               made to the Plan for such Plan Year as set forth below:

               (i) On or before the fifteenth day of the third month following
               the end of the Plan Year, the excess contributions of the Highly
               Compensated Employee(s) with the highest actual deferral
               percentage(s) shall be distributed to him or her until one of the
               actual deferral percentage tests is satisfied, or until his or
               her actual deferral
<PAGE>
 
               percentage equals the actual deferral percentage(s) of the Highly
               Compensated Employee(s) having the next highest actual deferral
               percentage.  This process shall continue until one of the actual
               deferral percentage tests is satisfied.

                    (ii)  Highly Compensated Employee's excess contributions
               shall mean such Employee's Before Tax Contributions or Additional
               Contributions which must be reduced for the Employee's actual
               deferral percentage to equal the highest permitted actual
               deferral percentage under the Plan. In determining the amount of
               excess contributions to be distributed with respect to an
               affected Highly Compensated Employee as determined herein, such
               amount shall be reduced by any excess contributions previously
               distributed to such Highly Compensated Employee for the taxable
               year ending with or within such Plan Year, and any Company
               Contributions which relate to such excess contributions.

                    (iii) The distribution of excess contributions:

                    (a)   may be postponed but not later than the close of the
                          Plan Year following the Plan Year to which the excess
                          contributions are allocable;

                    (b)   shall be made first from Additional Contributions and,
                          thereafter, from Before Tax Contributions.  Company
                          Contributions which relate to such Before Tax
                          Contributions shall be forfeited;

                    (c)   shall be adjusted for income; and

                    (d)   shall be designated by the Committee as a distribution
                          of excess contributions and income.

          5.  Section 3.2 of the Plan is amended by amending the last sentence
to read as follows:

               Any such earnings on such short-term investments of monies in a
               Fund shall be allocated monthly to the account of each
               Participant having

                                      -2-
<PAGE>
 
               an investment in such Fund in proportion to the amount of each
               Participant's account balance invested in such Fund at the end of
               such month.

          6.  Section 4.1.1 of the Plan is amended by adding the words ",
subject to Section 4.1.8," after the word "then" in the first sentence thereof.

          7.  Section 4.1.2 of the Plan is amended by adding the words "or elect
to have an eligible rollover distribution transferred from the Plan to an
eligible retirement plan pusuant to Section 4.1.8" after the words "Section
4.1.1" in the first sentence thereof and by changing "4.1.3" at the end thereof
to "4.1.5."

          8.  Section 4.1.5 of the Plan is amended by adding the following
sentencen to the end thereof:

               Such payment shall be made within five years after the
               Participant's death, or, where the distribution of payments to
               the Participant had commenced before the Participant's death, at
               least as rapidly as the method of distribution used as of the
               date of the Participant's death.

          9.  A new Section 4.1.8 is added to the Plan to read as follows:

               4.1.8. This section applies to distributions made on or after
               January 1, 1993. Notwithstanding any provision of the Plan to the
               contrary that would otherwise limit a Participant's election
               under this Section 4.1.8, a Participant may elect, at the time
               and in the manner prescribed by the Committee and subject to the
               following sentence, to have all or any portion of an eligible
               rollover distribution paid in a direct rollover directly to an
               eligible retirement plan specified by the Participant. The
               Participant's right to make such an election shall be limited by
               the following rules: (i) a Participant with an eligible rollover
               distribution amounting to less than $200 shall not have the right
               to elect a direct rollover pursuant to this Section 4.1.8; (ii) a
               Participant may elect a direct rollover for a portion of an
               eligible rollover distribution only if such portion equals or
               exceeds $500; and (iii) a Participant may only elect one

                                      -3-
<PAGE>
 
               direct rollover for each eligible rollover distribution.

               An "eligible rollover distribution" is any distribution of all or
               any portion of the balance to the credit of the Participant,
               except that an eligible rollover distribution does not include:
               any distribution that is one of a series of substantially equal
               periodic payments (not less frequently than annually) made for
               the life (or life expectancy) of the Participant or the joint
               lives (or joint life expectancies) of the Participant and the
               Participant's designated beneficiary, or for a specified period
               of ten years or more; any distribution to the extent such
               distribution is required under code section 401(a)(9); the
               portion of any distribution that is not includible in gross
               income (determined without regard to the exclusion for net
               unrealized appreciation with respect to employer securities); and
               other items designated not to be eligible rollover distributions
               by regulation, revenue ruling, notice, or other guidance issued
               by the Department of the Treasury.

               An "eligible retirement plan" is an individual retirement account
               described in Code section 408(a), an individual retirement
               annuity described in Code section 408(b), an annuity plan
               described in Code section 403(a), or a qualified trust described
               in Code section 401(a), that accepts the Participant's eligible
               rollover distribution. However, in the case of an eligible
               rollover distribution to a surviving spouse, an eligible
               retirement plan is an individual retirement account or individual
               retirement annuity. The Participant's surviving spouse and the
               Participant's spouse or former spouse who is the alternate payee
               under a qualified domestic relations order, as defined in Code
               section 414(p), are considered Participants with regard to the
               interest of the spouse or former spouse.

          10.  Section 4.2 of the Plan is amended by adding the phrase "Subject
to Section 4.1.6" to the beginning thereof.

                                      -4-
<PAGE>
 
          11.  Section 4.5 of the Plan is amended by adding the following
sentence at the beginning thereof:

               The following loan provisions will not be implemented until the
               Administrative Committee determines that such provisions will be
               effective.

          12.  Section 5.12.2 of the Plan is amended by adding the words "If
permitted by law" at the beginning of the existing sentence therein and by
adding the following sentence before such existing sentence:

               If, notwithstanding subparagraphs (a) through (i) of Section
               5.12.1, a Before Tax Contribution or Additional Contribution is
               made on behalf of a Participant which results in the limitations
               set forth in Section 5.7 of this Article V being exceeded, then
               such excess and any earnings thereon may be returned to the
               Participant.

          13.  Section 5.12.2 of the Plan is further amended by adding the
following sentences at the end thereof:

               If such a return is not permitted under the law, then these
               amounts (including forfeitures) shall be used to reduce Company
               Contributions for the following Limitation Year (and succeeding
               Limitation Years, if necessary) for the Participant if that
               Participant is covered by the Plan as of the end of the
               Limitation Year.  If the Participant is not covered by the Plan
               as of the end of the Limitation Year, such excess Company
               Contributions shall be held unallocated in a suspense account for
               the Limitation Year.  The amounts in such suspense account shall
               be used to reduce Company Contributions on behalf of each
               Participant to whom such amounts are allocated or reallocated,
               for the Limitation Year in which such amounts are allocated or
               reallocated, and shall be allocated and reallocated in the
               following manner:

                                      -5-
<PAGE>
 
                         (i)  The amounts in such suspense account shall be
               allocated and reallocated in the following Limitation Year to the
               accounts of the remaining Participants in the Plan.

                         (ii)  If the allocation or reallocation of the amounts
               in such suspense account causes the limitations set forth in
               Article V to be exceeded with respect to all Participants'
               accounts for that Limitation Year, then the amounts which may not
               be allocated as the result of such limitations shall be held
               unallocated in the suspense account.  All amounts so remaining in
               the suspense account must be allocated and reallocated among the
               accounts of the remaining Participants (subject to the
               limitations set forth in this Article V) in the following
               Limitation Year, and succeeding Limitation Years, if necessary.

          14.  Section 6.1.1 of the Plan is amended by amending subdivision
(ii) of the first sentence of subsection (a) to read as follows:

                         (ii)  The Plan is part of a required aggregation group
               and the sum of the present value of the cumulative accrued
               benefits for Key Employees under all defined benefit plans
               included in the required aggregation group and the aggregate of
               the accounts of Key Employees under all defined contribution
               plans included in the required aggregation group exceeds 60
               percent of a similar sum determined for all employees.

          15.  Section 6.1.1 of the Plan further amended by replacing the words
"if Section 6.4 applies" with "if the 125% figure is utilized pursuant to
Section 6.3" in the second paragraph of subsection (b) thereof.
 
          16.  Section 6.2 of the Plan is amended by adding the words "and is
not a member of a required aggregation group as described in Section 6.1.1"
after the words "Section 6.1" therein.

                                      -6-
<PAGE>
 
          17.  Section 6.4.1 of the Plan is amended by changing "415(c)(1)(A)"
to "415(b)(1)(A)" therein.

          18.  Section 6.4.2 of the Plan is amended by adding the words "both
more than a one-half (1/2) percent interest and" before the words "the largest
interests" therein.

          19.  Section 8.13.1 of the Plan is amended by inserting the words "and
hours during which no duties are performed due to layoff, vacation, holiday,
illness, military duty, incapacity (including Disability), jury duty, or leave
of absence, and hours for which back pay is awarded or agreed to by the Company,
an Affiliate, or, prior to April 1, 1984, Union Carbide Corporation" at the end
thereof.

          20.  Section 8.13.4 of the Plan is further amended by deleting the
words "his/her" and by adding the words "for an Employee who does not have a
nonforfeitable right to his/her Tax Deferred Account derived from Company
Contributions" before the words "only when" therein.

          21.  Section 9.1 of the Plan is amended by adding the words "or
income" after the word "corpus" therein.

          22.  The title of Section 10.4.1.1 of the Plan is amended to read
"Definitions."

          23.  Section 10.4.1.1 of the Plan is amended by deleting the word
"qualified" therein, by adding the word "and" after the word "Participant" in
subsection (a) therein, by deleting " ; and " from subsection (b) therein and by
deleting subsection (c) in its entirety.

          24.  Section 10.4.1.1 of the Plan is further amended by adding the
following paragraph to read as follows:

               The term "qualified domestic relations order" means a domestic
               relations order which meets the requirements of Section 10.4.1.2.

                                      -7-
<PAGE>
 
          25. Section 10.4.1.6 of the Plan is amended by deleting the word
"qualified" therein.


                    MARTIN MARIETTA ENERGY SYSTEMS, INC.


                    By: ________________________________________



                                      -8-

<PAGE>
                                                                     EXHIBIT 4-K
 
                             THIRD AMENDMENT TO THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                    401(k) SAVINGS PLAN FOR HOURLY EMPLOYEES
                    ----------------------------------------


          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Hourly Employees (the "Plan") is amended as follows:

1.  The following new definition is added to Article I:

          "1.30  "Employer" shall mean (a) the Company, and (b) any Affiliate
                  --------                                                   
          who adopts the Plan pursuant to Section 9.7.  With respect to any
          Participants employed by an Employer, references in this Plan to
          employment with the Company or Compensation received from the Company
          shall mean employment with, or Compensation received from, the
          Employer.  In addition, any references in the Plan to its adoption by
          the Company, or to contributions and expenses paid by the Company,
          shall mean the adoption by, and contributions and expenses paid by, an
          Employer, as applicable."


2.  New Sections 9.7 and 9.8 are added to the Plan to read as follows:

     "9.7.   Adoption of Plan by Employers.
             ----------------------------- 

          9.7.1  With the consent of the Company, any Affiliate may adopt the
                 Plan and the Trust Agreement for any of its divisions or
                 locations as it may specify by delivering to the Committee and
                 the Trustee:

                 9.7.1.1  A written instrument, duly executed and acknowledged:

                        (a)  adopting and assuming, jointly and severally, the
                        obligations of the Company under the Plan and Trust
                        Agreement;

                        (b)  appointing the Company and the Committee as its
                        agents and attorneys-in-fact for all purposes with
                        respect to the Plan and Trust Agreement, including
                        amending or terminating the Plan and Trust Agreement and
                        giving or receiving notices, instructions, directions
                        and other communications to the Trustee; and

                        (c)  specifying the divisions or locations for which it
                        is adopting the Plan and Trust Agreement.

                                       1

<PAGE>
 
 
                 9.7.1.2  A duly certified copy of resolutions of the board of
                          directors of the adopting corporation, or a similar
                          document from the person or persons having the power
                          to bind the partnership or other entity, authorizing
                          the adoption of the Plan and the Trust Agreement and
                          approving and authorizing the execution,
                          acknowledgement and delivery of the written instrument
                          described in Section 9.7.1.1; and

                 9.7.1.3  A copy of a document evidencing the Company's consent
                          to the adoption of the Plan and the Trust Agreement by
                          such Affiliate.

          9.7.2  The Company's consent to any adoption of this Plan and Trust
                 Agreement shall be evidenced by:

                 9.7.2.1  written approval and consent to such adoption by the
                          Committee if such adoption would add fewer than 100
                          Eligible Employees, or

                 9.7.2.2  a resolution of the Company's Board of Directors
                          approving and consenting to such adoption if such
                          adoption would add 100 or more Eligible Employees on
                          its effective date.

          9.7.3  In giving its consent to any adoption of the Plan and Trust
                 Agreement under Section 9.7.2, the Company or the Committee may
                 make its consent subject to such terms and conditions as it may
                 prescribe.

     9.8  Discontinuance of Participation.  An Employer's discontinuance of its
          -------------------------------                                      
participation under the Plan may be voluntary or involuntary, partial or
complete, as described below:

          9.8.1  Any Employer may, with the approval of the Committee, elect,
                 at any time, to discontinue its participation hereunder in
                 whole or in part with respect to any of its divisions or
                 locations by filing written notice thereof with the Committee
                 and specifying the group or groups of Participants affected by
                 such election.

          9.8.2  The Plan shall discontinue as to all Participants of any
                 Employer which shall be declared bankrupt or which makes any
                 general assignment for the benefit of creditors.


                                       2

<PAGE>
 
 
          9.8.3  The Plan shall discontinue as to Participants of any Employer
                 in the event of the dissolution, merger, consolidation, or sale
                 or other disposition of the business and assets or stock of
                 such Employer, unless provision is made for the continuance of
                 the Plan by a successor.  In the event the Plan is discontinued
                 pursuant to this Section 9.8.3, the Committee shall make such
                 current or deferred distribution to the Participants affected
                 by such discontinuance as it shall deem appropriate and in
                 accordance with section 9.5 and the other provisions of the
                 Plan; provided, however, if provision is made for the
                 continuance of the Plan by a successor, the Board of Directors
                 of the Company or, if such disposition of the business is
                 either approved by the Board of Directors of the Company or is
                 a disposition for which no approval by the Board of Directors
                 is required, the Committee may, if they so determine, direct
                 that the portion of the Trust Fund allocable to such
                 Participants be transferred to a successor qualified plan or
                 funding medium covering such Participants.  The Committee, in
                 its sole discretion, may permit the value of such Participants'
                 Tax Deferred Accounts to remain in the Plan pending the
                 completion of the dissolution, merger, consolidation or sale or
                 other disposition of the business and assets or stock of such
                 Participants' Employer, as the case may be, for such a period
                 of time as shall be designated by the Committee."


                            MARTIN MARIETTA ENERGY SYSTEMS, INC.


                            By: ____________________________________


                                       3


<PAGE>
                                                                     EXHIBIT 4-L
 
                            FOURTH AMENDMENT OF THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                    401(k) SAVINGS PLAN FOR HOURLY EMPLOYEES
                    ----------------------------------------


          The Martin Marietta Energy Systems, Inc. 401(k) Savings Plan for
Hourly Employees ("Plan") is hereby amended as follows:

          1.   Section 1.14.2 of Article I of the Plan is deleted in its
entirety.

          2.   Section 1.14.3 of Article I of the Plan is redesignated to read
"1.14.2".

          3.   Section 2.5.1 of Article II of the Plan is amended and restated
in its entirety to read as follows:

                   "At the time a Participant's Before Tax Contribution is paid
               to the Trustee, the Company shall pay to the Trustee out of
               accumulated earnings and profits an amount equal to 50% of the
               Basic Deduction paid to the Trustee on behalf of such
               Participant."

          4.   The provisions of this Fourth Amendment shall be effective as of
January 1, 1994.

                            Signed this ____ day of _______________________,1993

                            MARTIN MARIETTA ENERGY SYSTEMS, INC.


                            By:_________________________________________________

<PAGE>
                                                                     EXHIBIT 4-M
 
                             FIFTH AMENDMENT TO THE

                      MARTIN MARIETTA ENERGY SYSTEMS, INC.

                        401(k) PLAN FOR HOURLY EMPLOYEES
           _________________________________________________________

          The Martin Marietta Energy Systems, Inc. 401(k) Plan for Hourly
Employees (the "Plan") is hereby amended as follows:

          1.   Sections 1.10 and 1.13 of the Plan are amended by adding the
following sentences to the end thereof:

               "In determining a Participant's Compensation, the family unit of
               a Participant who is a 5% owner or who is both a Highly
               Compensated Employee and one of the ten most highly compensated
               employees will be treated as a single Employee with one
               Compensation. For this purpose, a family unit is the Participant,
               the Participant's spouse, and the Participant's lineal
               descendants who have not attained age 19 on or before the last
               day of the year."

          2.   Section 1.17 of the Plan is amended by adding the following
sentences to the end thereof:

               "For the purposes of Code section 401(k), the fmaily unit of a
               Highly Compensated Employee who is either a 5% owner or one of
               the ten most highly compensated employees will be considered as a
               single Employee. For this purpose, a family unit is the Employee,
               the Employee's spouse, and the lineal ascendants and descendants,
               and spouses of such ascendants and descendants, of any Employee
               or former Employee." 
<PAGE>
 
          3.   Sections 2.1 and 2.3.1 of the Plan are amended by adding the
following sentence to the end thereof:

               "An Employee's election to reduce his/her Compensation may only
               be made with respect to amounts which are not currently available
               to the Employee at the time of the election and which would
               otherwise be payable in cash."

          4.   Section 2.4.3 of the Plan is amended by adding the following
sentences to the end thereof:

               "No amounts shall be recharacterized as described in this Section
               2.4.3 with respect to a Highly Compensated Employee to the extent
               that the recharacterized amount, in combination with Employee
               contributions actually made by the Employee, exceed the maximum
               amount of Employee contributions (determined prior to applying
               Code section 401(m)(2)(A) that the Employee is permitted to make
               under the Plan in the absence of such recharacterization.
               Recharacterized excess contributions shall remain subject to the
               nonforfeitability requirements and distribution limitations that
               apply to elective contributions."

          5.   Section 2.4.6 of the Plan is amended by adding the words "and
excess contributions previously distributed for the Plan Year beginning in such
taxable year" after the words "such Plan Year" in the second sentence of
subsection (ii) thereof, and by adding the following to the end of subparagraph
(ii) thereof:

               "If a Highly Compensated Employee's actual deferral ratio (ADR)
               is determined under the family aggregation rules, the ADR shall
               be reduced in accordance with the "leveling" method described in
               Treasury regulations section 1.401(k)-1(f)(2) and the excess
               contributions shall be allocated among the family members in

                                      -2-
<PAGE>
 
               proportion to the contributions of each family member that have
               been combined."

          6.   Section 2.4.6 is further amended by adding the following sentence
to the end thereof:

               "The income allocable to excess contributions shall be equal to
               the sum of the allocable gain and loss for the Plan Year and the
               allocable gain and loss for the period between the end of the
               Plan Year and the date of distribution."

          7.   Section 2.13 of the Plan is amended by replacing the second
sentence therein with the following sentences:

               "Such contributions shall meet the nondiscriminatory test
               regarding employee and matching contributions set forth in Code
               section 401(m)(2)(A) of the Code. Excess aggregate contributions
               on behalf of Highly Compensated Employees, and income allocable
               to these contributions as determined below, shall be distributed
               in a manner consistent with Code section 401(a) to the Highly
               Compensated Employees on the basis of the respective portions of
               such amounts attributable to each Highly Compensated Employee
               after the close of the Plan Year in which the excess aggregate
               contributions arose and within 2 1/2 months after the close of
               the Plan Year (the distribution may be postponed but not later
               than the Plan Year following the Plan Year to which the excess
               contributions are allocable).

               The amount of excess aggregate contributions for a Highly
               Compensated Employee shall be equal to the total contribution
               taken into account for the actual contribution percentage test
               under Code section 401(m) minus the product of the Employee's
               contribution ratio and the Employee's Compensation. If a Highly
               Compensated Employee's actual contribution ration (ACR) is

                                      -3-
<PAGE>
 
               determined under the family aggregation rules, the ACR shall be
               reduced in accordance with the "leveling" method described in
               Treasury regulations section 1.401(m)-1(e)(2) and the excess
               aggregate contributions shall be allocated among the family
               members in proportion to the contributions of each family member
               that have been combined.

               The amount of excess aggregate contributions for a Plan Year
               shall be determined after determining the excess contributions
               that are treated. as Employee contributions due to
               recharacterization pursuant to Treasury regulation section
               1.401(m)-1(e)(2)(ii).

               For the purposes of this section 2.13, the multiple use of the
               alternative limitation described in Treasury regulation section
               1.401(m)-2(b) shall apply. In the event this Plan exceeds this
               limitation, the actual deferral ratio or the actual contribution
               ratio shall be reduced accordingly for all Highly Compensated
               Employees or for only those Highly Compensated Employees who are
               eligible in both the 401(k) and 401(m) arrangements."

          8.   Section 2.13 of the Plan is further amended by adding the
following sentence to the end thereof:

               "The income allocable to excess aggregate contributions shall be
               equal to the sum of the allocable gain or loss for the Plan Year
               and the allocable gain and loss for the period between the 

                                      -4-
<PAGE>
 
               end of the Plan Year and the date of distribution. Matching
               Contributions attributable to distributed excess aggregate
               contributions shall be forfeited."



                                 MARTIN MARIETTA ENERGY SYSTEMS, INC.


                                 ________________________________________


                                      -5-
 

<PAGE>
                                                                     EXHIBIT 4-N
 
                             FIRST AMENDMENT TO THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                 SAVINGS PLAN FOR SALARIED AND HOURLY EMPLOYEES
                 ----------------------------------------------


          The Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and
Hourly Employees (the "Plan") is amended as follows:

          1.   The Plan is amended by adding a new Article XI to read as
follows:

                                  "ARTICLE XI

               CORRECTION OF EXCESS CONTRIBUTIONS
               ----------------------------------

          11.1 Override of Other Plan Provisions.  To the extent that this
               ---------------------------------                          
               Article XI is inconsistent with any other part of the Plan, this
               Article XI shall apply in lieu of such other part.  This override
               shall take precedence over any contrary language in other parts
               of the Plan, such as language providing that a part of the Plan
               shall apply "notwithstanding any contrary provision of the Plan."

          11.2 Distribution of Excess Accumulations to Terminated Employees.
               ------------------------------------------------------------ 

          (a)  If an individual described in Section 11.2(b) has an Excess
               Accumulation as of December 31, 1992, the following amount shall
               be distributed to or on behalf of such individual as soon as is
               reasonably possible after December 31, 1992 (but no later than
               May 31, 1993):  the sum of (i) the individual's Excess
               Accumulation as of December 31, 1992, plus (ii) earnings
               attributable to such Excess Accumulation from January 1, 1993,
               through the last day of the calendar month immediately preceding
               the month of distribution.  For purposes of this Section 11.2(a),
               all Excess Accumulations shall be deemed to have been invested in
               the Fixed Income Fund.

          (b)  An individual shall be considered described in this Section
               11.2(b) if such individual is not a Regular Employee as of
               December 31, 1992.

          (c)  All amounts distributed to or on behalf of an individual after
               December 31, 1992 under all Defined Contribution Plans of the
               Company or an Affiliate shall be considered to be distributed
               pursuant to Section 11.2(a) until the amount described in Section
               11.2(a) has been distributed to or on behalf of the individual.
<PAGE>
 
          11.3 Distribution of Certain Excess Accumulations to Highly
               ------------------------------------------------------
Compensated Employees.
- --------------------- 

          (a)  If an individual described in Section 11.3(b) (but not in Section
               11.2(b)) made an Excess Contribution in the 1992 Limitation Year,
               the following amount shall be distributed to or on behalf of such
               individual as soon as is reasonably possible after December 31,
               1992 (but no later than May 31, 1993):  the sum of (i) the
               portion of the individual's Excess Accumulation as of December
               31, 1992 that is attributable to the individual's Excess
               Contribution in the 1992 Limitation Year, and (ii) earnings
               attributable to such portion from January 1, 1993 through the
               last day of the calendar month immediately preceding the month of
               distribution.  For purposes of this Section 11.3(a), all Excess
               Accumulations shall be deemed to have been invested in the Fixed
               Income Fund.  In addition, for purposes of this Section 11.3(a),
               whether an individual has an Excess Contribution in the 1992
               Limitation Year shall be determined without regard to any
               Supplemental Deposit deemed to have been made on June 30, 1992
               pursuant to Section 11.6(b)(vi).

          (b)  An individual shall be considered described in this Section
               11.3(b) if such individual is treated as a "highly compensated
               employee" for purposes of Section 2.9 for the 1992 Plan Year.

          (c)  All amounts distributed to or on behalf of an individual after
               December 31, 1992 under all Defined Contribution Plans of the
               Company or an Affiliate shall be considered to be distributed
               pursuant to Section 11.3(a) until the amount described in Section
               11.3(a) has been distributed to or on behalf of the individual.

          11.4 Treatment of All Other Excess Accumulations
               -------------------------------------------

          (a)  This Section 11.4 shall apply to any Excess Accumulation that
               exists as of December 31, 1992 and that is not required to be
               distributed pursuant to Section 11.2(a) or Section 11.3(a),
               provided that Sections 11.4(b) and (c) shall not apply to January
               of 1993.

          (b)  With respect to any calendar month during the 1993 Plan Year in
               which an individual has an Excess Accumulation, such individual
               shall not be entitled to have Basic Deductions or Supplemental
               Deductions made to the Trustee on his/her behalf.  In addition,
               in any calendar month during the 1993 Plan Year in which an
               individual has an Excess Accumulation, such individual shall not
               be entitled to make Supplemental Deposits to the Trustee.  For
               purposes of this Section 11.4(b) and Section 11.4(c), an
               individual shall be deemed to have an

                                      -2-
<PAGE>
 
               Excess Accumulation in a calendar month if such individual has an
               Excess Accumulation as of the last day of the preceding calendar
               month.

          (c)  If an individual has an Excess Accumulation in a calendar month
               during the 1993 Plan Year, such individual shall, for purposes of
               Section 2.6.1, be treated as though a Basic Deduction is paid to
               the Trustee with respect to the individual's Compensation during
               such calendar month.  The Basic Deduction shall be deemed to
               equal 6% of such Compensation.

          (d)  As of September 30, 1993, the Committee shall make reasonable
               projections to identify those individuals who will have an Excess
               Accumulation as of December 31, 1993, and the amount of such
               Excess Accumulation (determined without regard to Section
               11.6(b)(ix)).  During the period from October 1, 1993 to December
               31, 1993, there shall be distributed to or on behalf of each
               identified individual an amount equal to the individual's
               projected Excess Accumulation.

          (e)  All amounts distributed to or on behalf of an individual after
               September 30, 1993 under all Defined Contribution Plans of the
               Company or an Affiliate shall be considered to be distributed
               pursuant to Section 11.4(d) until the amount of the projected
               Excess Accumulation has been distributed to or on behalf of the
               individual.

          11.5 Interaction with Legal Requirements, Other Plan Provisions, and
               ---------------------------------------------------------------
               Other Plans.
               ----------- 

          (a)  For purposes of Sections 2.4 and 2.9 and for all purposes under
               the Code, the deemed Basic Deduction described in Section 11.4(c)
               shall be treated as an actual Basic Deduction, provided that the
               deemed Basic Deduction shall not be treated as an actual Basic
               Deduction for purposes of Section 2.7.5.

          (b)  For purposes of Section 2.9 and for all purposes under the Code,
               an individual shall be treated as having made an actual employee
               contribution for the 1993 Plan Year equal to the sum of the
               amounts described in Section 11.6(b)(viii)(B) for all calendar
               months during 1993 (other than January of 1993), provided that no
               such contribution shall be treated as having been made for
               purposes of Section 2.7.5.

          (c)  For purposes of Section 2.9 and for purposes of Code section
               401(m), any Excess Contribution described in Section 11.3(a)
               (without regard to

                                      -3-
<PAGE>
 
               the phrase "(but not in Section 11.2(b))") shall be deemed not to
               have been made.

          (d)  For purposes of Section 2.9 and for all purposes under the Code,
               an individual shall not fail to be treated as eligible to benefit
               under the Plan solely by reason of not being entitled to have
               Basic Deductions, Supplemental Deductions, or Supplemental
               Deposits made to the Trustee on his/her behalf.

          (e)  A distribution shall not be treated as an "eligible rollover
               distribution" for purposes of the Code to the extent that (i)
               such distribution is treated as made pursuant to this Article XI,
               or (ii) such distribution is described in Section
               11.6(b)(viii)(C) and does not under Section 11.6(b)(viii) reduce
               the Excess Accumulation below zero (taking into account Sections
               11.6(b)(viii)(A), (B), (F), and (G)).

          (f)  For purposes of this Article XI, (i) a transfer of assets with
               respect to an individual from the Plan to another Defined
               Contribution Plan maintained by the Company or an Affiliate shall
               not be treated as a distribution to or on behalf of such
               individual; and (ii) any other transfer of assets from the Plan
               with respect to an individual shall be treated as a distribution
               to or on behalf of such individual.

          (g)  Because of a transfer of assets from the Plan directly or
               indirectly to another Defined Contribution Plan maintained by the
               Company or an Affiliate, there may not be sufficient assets in an
               individual's Personal Investment Account in order to make a
               distribution required by Section 11.2(a), 11.3(a), or 11.4(d).
               In such cases, such other Defined Contribution Plan shall make,
               and this Plan shall accept, a transfer on behalf of the
               individual of the amount necessary to make such a distribution.

          (h)  For purposes of Sections 2.8.3, 4.1, 4.2.3, and any similar
               provisions of this Plan that are in effect at any time on or
               after January 1, 1993, any distribution described in Section
               11.5(e) shall be disregarded, except as provided in the following
               sentence.  Any distribution by this Plan described in Section
               11.5(e) shall, solely for purposes of applying such Plan
               provisions to subsequent distributions, be treated as derived
               from the following sources (in the following order):
               Supplemental Deposits, Supplemental Deductions, Basic Deductions,
               Company Contributions, and earnings attributable to such amounts.
               Each source shall be reduced to zero prior to reduction of a
               source subsequently listed.  In addition, within each source,
               reductions shall be applied in reverse chronological order (i.e.,
                                                                           ---- 
               first to the most recent contributions or earnings).

                                      -4-
<PAGE>
 
          (i) Any distribution described in Section 11.5(e) with respect to an
              individual shall be made from the following Funds within the
              individual's Personal Investment Account in the following order:
              Fixed Income Fund, Equity Investment Fund, Martin Marietta
              Corporation Stock Fund, and Government Bond Fund. A Fund within an
              individual's Personal Investment Account shall be reduced to zero
              prior to any reduction of a Fund subsequently listed.

          (j)  Section 4.4 shall apply to distributions under this Article XI.

          11.6 Definitions.  As used in this Article XI, the following terms
               -----------                                                  
               shall have the designated meaning:

          (a)  "Excess Contribution" shall mean the excess, with respect to an
               ---------------------                                          
               individual for a Limitation Year, of (i) the sum of all Annual
               Additions made with respect to accounts of the individual in all
               Defined Contribution Plans maintained by the Company or an
               Affiliate, over (ii) the applicable limit under Code section
               415(c).  If an individual is considered to have an Excess
               Contribution for a Limitation Year under the preceding sentence,
               such Excess Contribution shall be deemed to consist entirely of
               Supplemental Deposits made by the individual for that Limitation
               Year, determined in reverse chronological order so that the most
               recent Supplemental Deposits made are treated as Excess
               Contributions until the amount so treated equals the total amount
               of the Excess Contributions.

          (b)  "Excess Accumulation" shall mean the total amount of Excess
               ---------------------                                      
               Contributions allocated to an account of an individual with
               respect to the period beginning April l, 1984 and ending December
               31, 1992, adjusted in accordance with the following provisions:

               (i)      With respect to an individual, there shall be determined
                        the first Limitation Year in which the individual had an
                        Excess Contribution ("First Limitation Year").

               (ii)     With respect to such First Limitation Year, there shall
                        be determined the amount of earnings attributable to all
                        Excess Contributions from the first day of the second
                        month following the month of deposit to December 31 of
                        the First Limitation Year.  For purposes of this Section
                        11.6(b)(ii), all Excess Contributions shall be deemed to
                        have been invested in the Fixed Income Fund.

               (iii)    With respect to such First Limitation Year, there shall
                        be determined the amount of all distributions made to or
                        on

                                      -5-
<PAGE>
 
                        behalf of the individual under all Defined Contribution
                        Plans maintained by the Company or an Affiliate.

               (iv)     The individual's Excess Accumulation as of December 31
                        of the First Limitation Year is the sum of the Excess
                        Contribution and the earnings determined under Section
                        11.6(b) (ii), reduced by the distributions described in
                        Section 11.6(b) (iii).

               (v)      With respect to the Excess Accumulation as of December
                        31 of the First Limitation Year, there shall be
                        calculated the amount of earnings attributable to the
                        period from January 1 to June 30 of the Limitation Year
                        immediately following the First Limitation Year ("Second
                        Limitation Year").  For purposes of this Section
                        11.6(b)(v), all Excess Accumulations shall be deemed to
                        have been invested in the Fixed Income Fund.

               (vi)     Solely for purposes of this Article XI, an individual
                        shall be deemed to have made a Supplemental Deposit on
                        June 30 of the Second Limitation Year equal to the sum
                        of the Excess Accumulation as of December 3l of the
                        First Limitation Year plus the earnings calculated
                        pursuant to Section 11.6(b)(v).

               (vii)    A determination shall be made as to whether the
                        individual had an Excess Contribution for the Second
                        Limitation Year taking into account the deemed
                        Supplemental Deposit described in Section 11.6(b)(vi).
                        If there is no such Excess Contribution for the Second
                        Limitation Year, the individual shall have no Excess
                        Accumulation as of December 31 of the Second Limitation
                        Year.  If, however, there is an Excess Contribution in a
                        Limitation Year after the Second Limitation Year,
                        Sections 11.6(b)(i) through (vii) shall apply to such
                        subsequent Limitation Year as if it were the First
                        Limitation Year.

                        If there is an Excess Contribution for the Second
                        Limitation Year (taking into account the deemed
                        Supplemental Deposit described in Section 11.6(b)(vi)),
                        Sections 11.6(b)(i) through (vii) shall be applied to
                        such Second Limitation Year as if it were the First
                        Limitation Year.

                                      -6-
<PAGE>
 
               (viii)   Notwithstanding the preceding provisions of this Section
                        11.6(b), if an individual has an Excess Accumulation as
                        of December 31, 1992, the part of such Excess
                        Accumulation that is not required to be distributed
                        pursuant to Section 11.2(a) or Section 11.3(a) shall be
                        treated in the following manner.  In any calendar month
                        during 1993 ("Current Calendar Month"), the Excess
                        Accumulation as of the last day of the immediately
                        preceding calendar month ("Preceding Calendar Month")
                        shall be reduced by the sum of (A) the deemed Basic
                        Deduction described in Section 11.4(c) for the Current
                        Calendar Month, plus (B) the maximum additional employee
                        contribution that could be made for the Current Calendar
                        Month without creating an Excess Contribution for the
                        Current Calendar Month (determined as if the Current
                        Calendar Month were a short Limitation Year), plus (C)
                        all distributions made to or on behalf of the individual
                        under all Defined Contribution Plans maintained by the
                        Company or an Affiliate.  If that difference is zero (or
                        less), the individual shall not be considered to have an
                        Excess Accumulation as of the last day of the Current
                        Calendar Month and this Section 11.6(b) (viii) shall not
                        apply to any subsequent calendar months.  If that
                        difference is greater than zero, the individual shall be
                        considered to have an Excess Accumulation as of the last
                        day of the Current Calendar Month equal to the sum of:
                        (D) such difference, plus (E) the earnings attributable
                        to such difference for the Current Calendar Month,
                        determined as if the difference had been invested in the
                        Fixed Income Fund.

                        Notwithstanding the preceding provisions of this Section
                        11.6(b)(viii), the following provisions shall apply to
                        January of 1993.  The second sentence of Section
                        11.6(b)(viii) shall be applied as if the following
                        amount were substituted for the amounts described in
                        Sections 11.6(b)(viii)(A) and (B):  the excess of (F)
                        the limit under Code section 415(c) applicable to the
                        individual for January of 1993 (determined as if January
                        of 1993 were a short Limitation Year), over (G) the sum
                        of all Annual Additions made for January of 1993 with
                        respect to accounts of the individual in all Defined
                        Contribution Plans maintained by the Company or an
                        Affiliate.

               (ix)     As of December 31, 1993, no individual shall be
                        considered to have an Excess Accumulation.

                                      -7-
<PAGE>
 
          (c)  For purposes of this Article XI, "Affiliate" shall have the
                                                -----------               
               meaning set forth in Section 1.4 except that the phrase "more
               than 50%" shall be substituted for the phrase "at least 80%"
               wherever the phrase "at least 80%" would otherwise be applicable
               under Section 1.4.

          (d)  "Annual Addition" shall have the meaning set forth in Code
               -----------------                                         
               section 415(c)(2) as in effect for the applicable Limitation
               Year, taking into account the effective date prescribed by law
               for changes in Code section 415(c)(2).  Thus, for Limitation
               Years prior to 1992, section 415(c)(2) shall apply without regard
               to the amendments made thereto by section 1106 of the Tax Reform
               Act of 1986.

          (e)  "Defined Contribution Plan" shall mean a defined contribution
               ---------------------------                                  
               plan described in section 401(a) of the Code, which includes a
               trust which is exempt from income tax under section 501(a) of the
               Code; provided that a Participant's contributions under a plan
               which otherwise qualifies as a defined benefit plan shall be
               treated as a defined contribution plan.

          (f)  "Limitation Year" shall mean the twelve-month period starting
               -----------------                                            
               January 1 and ending December 31.

          11.7 Assumptions and Adjustments.
               --------------------------- 

          (a)  For purposes of making the calculations required under this
               Article XI, such as those required under Sections 11.6(a) and
               (b), the Committee shall be authorized to make reasonable
               assumptions and estimations in lieu of making all calculations
               with absolute precision.  For this purpose, an assumption or
               estimation shall be considered reasonable unless such assumption
               or estimation would be expected to systematically understate
               Excess Contributions or Excess Accumulations to a significant
               extent (in comparison to the results that would be obtained if
               all calculations were made with absolute precision).

          (b)  The Committee may determine that even with the use of reasonable
               assumptions and estimations, the calculations required under this
               Article XI are unduly burdensome, i.e., time-consuming or
                                                 -----                  
               expensive.  If such a determination is made, the Committee may
               adopt a reasonable alternative method of calculation.  For this
               purpose, an alternative method shall be considered reasonable
               unless such method would be expected to systematically understate
               Excess Contributions or Excess Accumulations to a significant
               extent (in comparison to the results that would be obtained if
               all calculations were made in accordance with the preceding
               provisions of this Article XI)."

                                      -8-
<PAGE>
 
          2.   This Amendment shall be effective as of January l, 1993 (except
that any provision of this Amendment shall be effective as of such earlier date
or dates as are necessary to carry out the purposes of such provision).

                        MARTIN MARIETTA ENERGY SYSTEMS, INC.


                        By:
                           -------------------------------------------

                                      -9-

<PAGE>
 
                                                                     EXHIBIT 4-O

                            SECOND AMENDMENT TO THE
                          MARTIN MARIETTA SAVINGS PLAN
                       FOR SALARIED AND HOURLY EMPLOYEES


          The Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and
Hourly Employees (the "Plan") is hereby amended as follows:

          1.   Section 1.8 of the Plan is amended by adding the following
sentences to the end thereof:

               A Participant's Compensation in excess of $200,000 shall not be
               taken into account under the Plan for any purpose after December
               31, 1988. Such $200,000 limitation shall be adjusted at the same
               time and in such manner as the limitation set forth in Section
               415(b)(1)(A) of the Code is adjusted under Section 415(d) of the
               Code.

          2.   A new Section 1.9A is added to the Plan to read as follows:

               1.9A  Earnings.  "Earnings" shall mean, for any
                                 --------                                 
               Limitation Year (as defined in Section 5.3), total
               compensation actually paid or made available by
               the Company and its Affiliates for such year,
               including, but not limited to, bonuses, income
               from sources without the United States whether or
               not excludable for Federal income tax purposes,
               amounts related to the value of property
               transferred in connection with the performance of
               services which are includible for Federal income
               tax purposes under Code Section 83(b), amounts
               includible in income under Code Section 132 or any
               successor section thereto, and taxable income
               attributable to employer-provided life insurance.
               Earnings shall not include deferred compensation
               (other than payments under an unfunded plan that
               are currently includible in income), amounts
               realized from the exercise of a non-qualified
               stock option or a stock appreciation right,
               exercise payments under a stock option plan,
               amounts contributed on behalf of a Participant to
               a plan
<PAGE>
 
               which meet the requirements of Code Sections 401(a) and
               401(k), amounts contributed on a pre-tax basis to any plan which
               meets the requirements of Code Section 125, or other
               distributions which receive special tax benefits.  A
               Participant's Earnings in excess of $200,000 shall not be taken
               into account under the Plan for purposes of benefits accruing
               under the Plan after December 31, 1988.  Such $200,000 limitation
               shall be adjusted at the same time and in such manner as the
               limitation set forth in Section 415(b)(1)(A) of the Code is
               adjusted under Section 415(d) of the Code.

          3.   A new Section 1.18A of the Plan is incorporated to read as
follows:

               1.18A  Rollover Deposit means (i) a lump sum distribution
                      ----------------                     
               received by the Plan directly from another plan qualified under
               section 401(a) of the Code; (ii) a sum received by the Plan from
               a Participant who had received such sum as a lump sum
               distribution from a Plan qualified under section 401(a) of the
               Code, either directly from the Participant within 60 days of his
               receipt of the lump sum distribution or through the medium of an
               individual retirement account containing no other assets other
               than those representing employer contributions to a plan
               qualified under section 401(a) of the Code; and (iii) any
               earnings on the sums described in (i) and (ii).

          4.   Section 3.6 of the Plan is amended to read as follows:

               Any such earnings on such short-term investments of monies
               allocated to a Fund shall be allocated monthly to the account
               each Participant having an investment in such Fund in proportion
               to the amount of each Participant's account balance invested in
               such Fund at the end of such month.

          5.   Section 4.2.1 of the Plan is amended by adding the words ",
subject to Section 4.2.8," after the word "then" in the first sentence thereof.

                                      -2-
<PAGE>
 
          6.   Section 4.2.2 of the Plan is amended by adding the words "or to
have an eligible rollover distribution transferred from the Plan to an eligible
retirement plan pursuant to Section 4.2.8" after the words "and such Participant
does not consent in writing to receive the entire value of such account," in the
first sentence thereof, and by amending the fifth sentence thereof to read as
follows:

               The entire value of a Participant's Personal Investment
               Account shall be distributed to such Participant in a single-sum
               payment not later than April 1 of the calendar year following the
               calendar year in which such Participant attains age seventy and
               one-half (70- 1/2) or such earlier date as selected by the
               Participant as provided above.

          7.   A new Section 4.2.8 is added to the Plan to read as follows:

               4.2.8. This section applies to distributions made on or after
               January 1, 1993. Notwithstanding any provision of the Plan to the
               contrary that would otherwise limit a Participant's election
               under this Section 4.2.8, a Participant may elect, at the time
               and in the manner prescribed by the Committee and subject to the
               following sentence, to have all or any portion of an eligible
               rollover distribution paid in a direct rollover directly to an
               eligible retirement plan specified by the Participant. The
               Participant's right to make such an election shall be limited by
               the following rules: (i) a Participant with an eligible rollover
               distribution amounting to less than $200 shall not have the right
               to elect a direct rollover pursuant to this Section 4.2.8; (ii) a
               Participant may elect a direct rollover for a portion of an
               eligible rollover distribution only if such portion equals or
               exceeds $500; and (iii) a Participant may only elect one direct
               rollover for each eligible rollover distribution.

               An "eligible rollover distribution" is any distribution of all or
               any portion of the balance to

                                      -3-
<PAGE>
 
               the credit of the Participant, except that an eligible rollover
               distribution does not include:   (i) any distribution that is one
               of a series of substantially equal periodic payments (not less
               frequently than annually) made for the life (or life expectancy)
               of the Participant or the joint lives (or joint life
               expectancies) of the Participant and the Participant's designated
               beneficiary, or for a specified period of ten years or more; (ii)
               any distribution to the extent such distribution is required
               under Code section 401(a)(9); (iii) the portion of any
               distribution that is not includible in gross income (determined
               without regard to the exclusion for net unrealized appreciation
               with respect to employer securities); and (iv) other items
               designated not to be eligible rollover distributions by
               regulation, revenue ruling, notice, or other guidance issued by
               the Department of Treasury.

               An "eligible retirement plan" is an individual retirement account
               described in Code section 408(a), an individual retirement
               annuity described in Code section 408(b), an annuity plan
               described in Code section 403(a), or a qualified trust described
               in Code section 401(a), that accepts the Participant's eligible
               rollover distribution. However, in the case of an eligible
               rollover distribution to a surviving spouse, an eligible
               retirement plan is an individual retirement account or individual
               retirement annuity. The Participant's surviving spouse and the
               Participant's spouse or former spouse who is the alternate payee
               under a qualified domestic relations order, as defined in Code
               section 414(p), are considered Participants with regard to the
               interest of the spouse or former spouse.

          8.   Section 4.3 of the Plan is amended by adding the following
sentence to the end thereof:

               Such payment shall be made within five years after the
               Participant's death, or, where the distribution of payments to
               the Participant had

                                      -4-
<PAGE>
 
               commenced before the Participant's death, at least as rapidly as
               the method of distribution used as of the date of the
               Participant's death.

          9.   Section 5.12.2 of the Plan is amended by adding the words "If
permitted by law" at the beginning of the existing sentence therein and by
inserting the following sentence before this existing sentence:

               If, notwithstanding subparagraphs (a) through (i) of
               Section 5.12.1, a Basic Deduction, Supplemental Deduction, or
               Supplemental Deposit is made on behalf of a Participant which
               results in the limitations set forth in Section 5.7 of this
               Article V being exceeded, then such excess and any earnings
               thereon may be returned to the Participant.

          10.  Section 5.12.2 of the Plan is further amended by adding the
following sentences at the end thereof:

               If such a return is not permitted under the law, then
               these amounts (including forfeitures) shall be used to reduce
               Company Contributions for the following Limitation Year (and
               succeeding Limitation Years, if necessary) for the Participant if
               that Participant is covered by the Plan as of the end of the
               Limitation Year.  If the Participant is not covered by the Plan
               as of the end of the Limitation Year, such excess Company
               Contributions shall be held unallocated in a suspense account for
               the Limitation Year.  The amounts in such suspense account shall
               be used to reduce Company Contributions on behalf of each
               Participant to whom such amounts are allocated or reallocated,
               for the Limitation Year in which such amounts are allocated or
               reallocated, and shall be allocated and reallocated in the
               following manner:

                                      -5-
<PAGE>
 
                         (i) The amounts in such suspense account shall be
               allocated and reallocated in the following Limitation Year to the
               accounts of the remaining Participants in the Plan.

                         (ii)  If the allocation or reallocation of the amounts
               in such suspense account causes the limitations set forth in
               Article V to be exceeded with respect to all Participants'
               accounts for that Limitation Year, then the amounts which may not
               be allocated as the result of such limitations shall be held
               unallocated in the suspense account.  All amounts so remaining in
               the suspense account must be allocated and reallocated among the
               accounts of the remaining Participants (subject to the
               limitations set forth in this Article V) in the following
               Limitation Year, and succeeding Limitation Years, if necessary.

          11.  Section 6.1 of the Plan is amended by inserting the words
"(hereinafter referred to as the Determination Date)" after the first reference
to "Plan Year" therein and by adding the following to the end thereof:

               If the Plan is part of a required aggregation group of
               plans, the Plan shall be deemed to be top-heavy, and the
               provisions of Article VI shall apply for the following Plan Year,
               if the sum of the present value of the cumulative accrued
               benefits for Key Employees under all defined benefit plans
               included in the required aggregation group and the aggregate of
               the accounts of Key Employees under all defined contribution
               plans included in the required aggregate group exceeds 60 percent
               of a similar sum determined for all employees.  The term
               "required aggregation group" shall mean (1) each plan of an
               Employer or an Affiliate which qualifies under Code section
               401(a) in which at least one Key Employee is a Participant, and
               (2) any other plan which enables a plan described in the
               preceding subsection (1) to meet the requirements of Code
               sections 401(a) (4) or 410.

                                      -6-
<PAGE>
 
          12.  Section 6.4 of the Plan is amended by changing "415(c)(1)(A)" to
"415(b)(1)(A)" in subsection (a) thereof and by adding the words "both more than
a one-half (1/2) percent interest and" before the words "the largest interests"
in subsection (b) thereof.

          13.  Section 6.7 of the Plan is deleted.

          14.  Section 8.12 of the Plan is amended by replacing the second
sentence in subsection (a) thereof with the following:

               An "hour of service" is (i) each hour for which an Employee
               is paid, or entitled to payment, for the performance of duties
               for the Employer; (ii) each hour for which the Employee is paid,
               or is entitled to payment, by the Employer on account of a period
               of time during which no duties are performed due to vacation,
               holiday, illness, incapacity (including Disability), layoff, jury
               duty, military duty or leave of absence (no more than 501 hours
               of service will be credited under this subsection for any single
               continuous period); and (iii) each hour for which back pay is
               either awarded or agreed to by the employer.  The hours of
               service credited under (i) or (ii) will not be credited under
               (iii) above.

          15.  Section 8.12 of the Plan is further amended by adding the words
"for a Participant who does not have a nonforfeitable right to any of his or her
Accrued Benefit derived from Company Contributions" before the words "only when"
in subsection (d) thereof.

          16.  The title of Section 10.3.1 of the Plan is amended to read
"Definitions."

          17.  Section 10.3.1 of the Plan is amended by deleting the word
"qualified" therein, by adding the word "and" after the word "Participant" in
subsection (a) therein, by deleting " ; and " from subsection (b) therein and by
deleting subsection (c) in its entirety.

                                      -7-
<PAGE>
 
          18.  Section 10.3.1 of the Plan is further amending by adding the
following paragraph to read as follows:

               The term "qualified domestic relations order" means a
               domestic relations order which meets the requirements of Section
               10.3.2.

          19.  Section 10.3.6 is amended by deleting the word "qualified"
therein.



                    MARTIN MARIETTA ENERGY SYSTEMS, INC.


                    By: ____________________________________

                                      -8-

<PAGE>
                                                                     EXHIBIT 4-P
 
                             THIRD AMENDMENT TO THE
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                 SAVINGS PLAN FOR SALARIED AND HOURLY EMPLOYEES
                 ----------------------------------------------


          The Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and
Hourly Employees (the "Plan") is amended as follows:

1.  The following new definition is added to Article I:

          "1.23  "Employer" shall mean (a) the Company, and (b) any Affiliate
                  --------                                                   
          who adopts the Plan pursuant to Section 9.7.  With respect to any
          Participants employed by an Employer, references in this Plan to
          employment with the Company or Compensation received from the Company
          shall mean employment with, or Compensation received from, the
          Employer.  In addition, any references in the Plan to its adoption by
          the Company, or to contributions and expenses paid by the Company,
          shall mean the adoption by, and contributions and expenses paid by, an
          Employer, as applicable."


2.  New Sections 9.7 and 9.8 are added to the Plan to read as follows:

     "9.7.   Adoption of Plan by Employers.
             ----------------------------- 

          9.7.1  With the consent of the Company, any Affiliate may adopt the
                 Plan and the Trust Agreement for any of its divisions or
                 locations as it may specify by delivering to the Committee and
                 the Trustee:

                 9.7.1.1  A written instrument, duly executed and acknowledged:

                          (a)  adopting and assuming, jointly and severally, the
                          obligations of the Company under the Plan and Trust
                          Agreement;

                          (b) appointing the Company and the Committee as its
                          agents and attorneys-in-fact for all purposes with
                          respect to the Plan and Trust Agreement, including
                          amending or terminating the Plan and Trust Agreement
                          and giving or receiving notices, instructions,
                          directions and other communications to the Trustee;
                          and

                          (c) specifying the divisions or locations for which it
                          is adopting the Plan and Trust Agreement.

                                       1
<PAGE>
 
                 9.7.1.2  A duly certified copy of resolutions of the board of
                          directors of the adopting corporation, or a similar
                          document from the person or persons having the power
                          to bind the partnership or other entity, authorizing
                          the adoption of the Plan and the Trust Agreement and
                          approving and authorizing the execution,
                          acknowledgement and delivery of the written instrument
                          described in Section 9.7.1.1; and

                 9.7.1.3  A copy of a document evidencing the Company's consent
                          to the adoption of the Plan and the Trust Agreement by
                          such Affiliate.

          9.7.2  The Company's consent to any adoption of this Plan and Trust
                 Agreement shall be evidenced by:

                 9.7.2.1  written approval and consent to such adoption by the
                          Committee if such adoption would add fewer than 100
                          eligible employees, or

                 9.7.2.2  a resolution of the Company's Board of Directors
                          approving and consenting to such adoption if such
                          adoption would add 100 or more eligible employees on
                          its effective date.

          9.7.3    In giving its consent to any adoption of the Plan and Trust
                   Agreement under Section 9.7.2, the Company or the Committee
                   may make its consent subject to such terms and conditions as
                   it may prescribe.

     9.8  Discontinuance of Participation.  An Employer's discontinuance of its
          -------------------------------                                      
participation under the Plan may be voluntary or involuntary, partial or
complete, as described below:

          9.8.1    Any Employer may, with the approval of the Committee, elect,
                   at any time, to discontinue its participation hereunder in
                   whole or in part with respect to any of its divisions or
                   locations by filing written notice thereof with the Committee
                   and specifying the group or groups of Participants affected
                   by such election.

          9.8.2    The Plan shall discontinue as to all Participants of any
                   Employer which shall be declared bankrupt or which makes any
                   general assignment for the benefit of creditors.

                                       2
<PAGE>
 
          9.8.3    The Plan shall discontinue as to Participants of any Employer
                   in the event of the dissolution, merger, consolidation, or
                   sale or other disposition of the business and assets or stock
                   of such Employer, unless provision is made for the
                   continuance of the Plan by a successor. In the event the Plan
                   is discontinued pursuant to this Section 9.8.3, the Committee
                   shall make such current or deferred distribution to the
                   Participants affected by such discontinuance as it shall deem
                   appropriate and in accordance with section 9.5 and the other
                   provisions of the Plan; provided, however, if provision is
                   made for the continuance of the Plan by a successor, the
                   Board of Directors of the Company or, if such disposition of
                   the business is either approved by the Board of Directors of
                   the Company or is a disposition for which no approval by the
                   Board of Directors is required, the Committee may, if they so
                   determine, direct that the portion of the Trust Fund
                   allocable to such Participants be transferred to a successor
                   qualified plan or funding medium covering such Participants.
                   The Committee, in its sole discretion, may permit the value
                   of such Participants' Personal Investment Accounts to remain
                   in the Plan pending the completion of the dissolution,
                   merger, consolidation or sale or other disposition of the
                   business and assets or stock of such Participants' Employer,
                   as the case may be, for such a period of time as shall be
                   designated by the Committee."


                                MARTIN MARIETTA ENERGY SYSTEMS, INC.


                                By:________________________________________

                                       3

<PAGE>
                                                                     EXHIBIT 4-Q
 
                      FOURTH AMENDMENT OF THE SAVINGS PLAN
                      FOR SALARIED AND HOURLY EMPLOYEES OF
                      MARTIN MARIETTA ENERGY SYSTEMS, INC.
                      ------------------------------------


          The Savings Plan for Salaried and Hourly Employees of Martin Marietta
Energy Systems, Inc. ("Plan") is hereby amended as follows:

          1.   Section 2.1 of Article II of the Plan is amended and restated in
its entirety to read as follows:

               "Any regular employee of the Company shall be eligible
               to become a Participant in this Plan effective as of the date he
               commences employment with the Company."

          2.   Section 2.4 of Article II of the Plan is amended by adding the
following sentence at the end thereof:

               "Effective January 1, 1994, a Participant will no
               longer be permitted to make Supplemental Deposits to the Plan
               pursuant to this Section 2.4."

          3.   Section 2.6.1 of Article II of the Plan is amended and restated
in its entirety to read as follows:

                   "At the time a Participant's Basic Deduction is paid to
               the Trustee, the Company shall pay to the Trustee out of
               accumulated earnings and profits an amount equal to 50% of the
               Basic Deduction paid to the Trustee on behalf of such
               Participant."
<PAGE>
 
          4.   The provisions of this Fourth Amendment shall be effective as of
January 1, 1994.
                         Signed this ____ day of _______________, 1993

                         MARTIN MARIETTA ENERGY
                         SYSTEMS, INC.


                         By:______________________________________________


                                      -2-

<PAGE>
                                                                     EXHIBIT 4-R
 
                             FIFTH AMENDMENT TO THE

                      MARTIN MARIETTA ENERGY SYSTEMS, INC.

                 SAVINGS PLAN FOR SALARIED AND HOURLY EMPLOYEES
           _________________________________________________________

          The Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and
Hourly Employees (the "Plan") is hereby amended as follows:

          1.   Sections 1.8 and 1.9A are amended by adding the following
sentences to the end thereof:

               "In determining a Participant's Compensation, the family unit of
               a Participant who is a 5% owner or who is both a Highly
               Compensated Employee and one of the ten most highly compensated
               employees will be treated as a single Employee with one
               Compensation. For this purpose, a family unit is the Participant,
               the Participant's spouse, and the Participant's lineal
               descendants who have not attained age 19 on or before the last
               day of the year."

          2.   A new Section 1.12A is added to the Plan to read as follows:

               1.12A "Highly Compensated Employee" means an Employee
                      ---------------------------                   
               who performs service during the Determination Year and (i) is a
               5% owner, as defined in Code section 416(i)(l)(A)(iii), at any
               time during the Determination Year or the Look-Back Year; (ii)
               receives Compensation in excess of $75,000 (indexed in accordance
               with Code section 415(d)) during the Look-Back Year and is a
               member of the top-paid group for the Look-Back Year; (iii)
               receives Compensation in excess of $50,000 (indexed in accordance
               with Code section 415(d)) during the Look-Back Year and is a
               member of the top-paid group for the Look-
<PAGE>
 
               Back Year; (iv) is an officer, within the meaning of Code section
               416(i), during the Look-Back Year who receives Compensation
               greater than 50% of the dollar limitation in effect under Code
               section 415(b)(1)(A) for the calendar year in which the Look-Back
               Year begins; (v) would be both described in (ii), (iii) or (iv)
               above, if the Determination Year were substituted for the Look-
               Back Year, and is one of the 100 Employees who receive the most
               Compensation from the Company during the Determination Year.

               For purposes of this definition, the "Determination Year" is the
               Plan Year for which the determination of who is highly
               compensated is being made. The "Look-Back Year" is the 12-month
               period immediately preceding the Determination Year, or the
               calendar year ending with or within the Determination Year.

               The "Top-Paid Group" consists of the top 20% of Employees ranked
               on the basis of Compensation received during the year. For the
               purpose of determining the number of Employees in the Top-Paid
               Group, the Employees described in Code section 414(q)(8) and
               Treasury Regulations section 1.414(q) - IT, Q+A9(b), shall be
               excluded.

               In determining which employees are officers, the number
               of officers shall be limited to 50, or, if lesser, the greater of
               3 Employees or 10 percent of Employees, excluding those Employees
               who may be excluded in determining the Top-Paid Group.  If no
               officer has Compensation in excess of 50% of the Code section
               415(b)(1)(A) limit, the highest paid officer shall be treated as
               highly compensated.

               "Compensation" for the purposes of this definition shall be
               compensation within the meaning of Code section 415(c)(3),
               including elective or salary

                                      -2-
<PAGE>
 
               reduction contributions to a cafeteria plan, cash or deferred
               arrangement or tax-sheltered annuity.

               For the purposes of this definition, all employers aggregated
               with the Company under Code sections 414(b), (c), (m) and (o)
               shall be treated as a single employer.

               A Highly Compensated Employee who is a 5% owner or one
               of the most highly compensated employees, the Highly Compensated
               Employee's spouse and lineal descendants shall be treated as a
               single Employee receiving an amount of Compensation and a plan
               contribution or benefit that is based on the Compensation,
               contributions and benefits of such family member and the Highly
               Compensated Employee.

          3.   Section 2.8.3 of the Plan is amended by replacing "two-year" with
"five-year" in subparagraph (i) therein.

          4.   Section 2.9 of the Plan is amended by replacing the second
sentence therein with the following sentences:

               "Such contributions shall meet the nondiscriminatory test
               regarding employee and matching contributions set forth in Code
               section 401(m)(2)(A). Excess aggregate contributions on behalf of
               Highly Compensated Employees, and income allocable to these
               contributions (as determined below), shall be distributed in a
               manner consistent with Code section 401(a) to the Highly
               Compensated Employees on the basis of the respective portions of
               such amounts attributable to each Highly Compensated Employee
               after the close of the Plan Year in which the excess aggregate
               contributions arose and within 2 1/2 months after the close of
               the Plan Year (this distribution may be postponed but not later
               than the close of the Plan Year following the Plan Year to which
               the excess aggregate contributions relate).

                                      -3-
<PAGE>
 
               The income allocable to excess aggregate contributions shall be
               the sum of the allocable gain and loss for the Plan Year and the
               allocable gain and loss for the period between the end of the
               Plan Year and the date of distribution.

               The amount of excess aggregate contributions for a Highly
               Compensated Employee shall be equal to the total contribution
               taken into account for the actual contribution percentage test
               under Code section 401(m) minus the product of the Employee's
               contribution ratio and the Employee's Compensation. If a Highly
               Compensated Employee's actual contribution ratio (ACR) is
               determined under the family aggregate rules, the ACR shall be
               reduced in accordance with the "leveling" method described in
               Treasury regulations section 1.401(m)-1(e)(2) and the excess
               aggregate contributions shall be allocated among the family
               members in proportion to the contributions of each family member
               that have been combined.

               The amount of excess aggregate contributions for a Plan
               Year shall be determined after determining the excess
               contributions that are treated as Employee contributions due to
               recharacterization pursuant to Treasury regulation section
               1.401(m)-1(e)(2)(ii).

               Matching Contributions attributable to distributed excess
               aggregate contributions shall be forfeited.

               For the purposes of this section 2.10.2, the multiple
               use of the alternative limitation described in Treasury
               regulation section 1.401(m)-2(b) shall apply.  In the event this
               Plan exceeds this limitation, the actual deferral ratio or the
               actual contribution ratio shall be reduced accordingly for all
               Highly Compensated Employees or for only those Highly Compensated
               Employees who are eligible in both the 401(k) and 401(m)
               arrangements."

                                      -4-
<PAGE>
 
                                 MARTIN MARIETTA ENERGY
                                 SYSTEMS, INC.


                                 _______________________________

                                      -5-

<PAGE>
                                                                       EXHIBIT 5

           [LETTERHEAD OF LOCKHEED MARTIN CORPORATION APPEARS HERE]



                                March 15, 1995


Lockheed Martin Corporation
6801 Rockledge Drive
Bethesda, Maryland 20817

          Re:  Martin Marietta Energy Systems, Inc. 401(k) Savings
               Plan for Hourly Employees, Martin Marietta Energy
               Systems, Inc. 401(k) Savings Plan for Salaried
               Employees, Martin Marietta Energy Systems, Inc.
               Savings Plan for Salaried and Hourly Employees
               (collectively, the "Plans")

Ladies and Gentlemen:

      I submit this opinion to you in connection with the filing with the 
Securities and Exchange Commission of a registration statement on Form S-8 (the 
"Registration Statement") on the date hereof. The Registration Statement 
registers shares of common stock ("Common Stock") of Lockheed Martin Corporation
(the "Corporation") for use in connection with the Plans. The Plans contemplate 
that Common Stock may be treasury or authorized but unissued shares or may be 
acquired in the open market. As Assistant General Counsel of the Corporation, I 
have examined such corporate records, certificates and other documents and have 
reviewed such questions of law as I deemed necessary or appropriate for the 
purpose of this opinion.

      Based upon that examination and review, I advise you that in my opinion:

      (i)  the Corporation has been duly incorporated and is validly existing 
           under the laws of the State of Maryland; and

      (ii) to the extent that the operation of the Plans results in the issuance
           of Common Stock, such shares of Common Stock have been duly and
           validly authorized and, when issued in accordance with the terms set
           forth in the Registration Statement, will be legally issued, fully
           paid and nonassessable.

      I hereby consent to the filing of this opinion as an exhibit to the 
Registration Statement and to the reference to my opinion in the Registration 
Statement.

                                           Very truly yours,

                                           /s/ Stephen M. Piper

                                           Stephen M. Piper
                                           Assistant General Counsel
                                           Lockheed Martin Corporation


<PAGE>
 
                                                                    EXHIBIT 23-A

              CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS


          We consent to the incorporation by reference in Lockheed Martin
Corporation's Registration Statement (Form S-8) pertaining to the Martin
Marietta Energy Systems, Inc. 401(k) Savings Plan for Salaried Employees, Martin
Marietta Energy Systems, Inc. 401(k) Savings Plan for Hourly Employees, and
Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and Hourly
Employees of: (a) our report dated January 20, 1995, with respect to the
consolidated financial statements of Martin Marietta Corporation and
subsidiaries for the year ended December 31, 1994, included in its Current
Report (Form 8-K), dated February 17, 1995; (b) our report dated November 1,
1994, with respect to the consolidated balance sheet of Lockheed Martin
Corporation as of October 31, 1994, included in its Registration Statement 
(Form S-4 No. 33-57645), dated February 9, 1995; (c) our report dated May 20,
1994, with respect to the financial statements of Martin Marietta Energy
Systems, Inc. 401(k) Savings Plan for Salaried Employees included in the Plan's
Annual Report (Form 11-K) for the year ended December 31, 1993; (d) our report
dated May 20, 1994, with respect to the financial statements of Martin Marietta
Energy Systems, Inc. 401(k) Savings Plan for Hourly Employees included in the
Plan's Annual Report (Form 11-K) for the year ended December 31, 1993; and (e)
our report dated May 20, 1994, with respect to the financial statements of
Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and Hourly
Employees included in the Plan's Annual Report (Form 11-K) for the year ended
December 31, 1993; all filed with the Securities and Exchange Commission.


                                                 ERNST & YOUNG LLP


Washington, D.C.
March 13, 1995


<PAGE>
 
                                                                    EXHIBIT 23-B


              CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

     We consent to the incorporation by reference in Lockheed Martin
Corporation's Registration Statement (Form S-8) pertaining to the Martin
Marietta Energy Systems, Inc. 401(k) Savings Plan for Salaried Employees, Martin
Marietta Energy Systems, Inc. 401(k) Savings Plan for Hourly Employees, and
Martin Marietta Energy Systems, Inc. Savings Plan for Salaried and Hourly
Employees of our report dated January 31, 1995, with respect to the consolidated
financial statements of Lockheed Corporation for the year ended December 25,
1994, included in its Current Report (Form 8-K), dated February 21, 1995, filed
with the Securities and Exchange Commission.

                                                               ERNST & YOUNG LLP

Los Angeles, California
March 13, 1995


<PAGE>
 
                                                                    EXHIBIT 23-C

             CONSENT OF KPMG PEAT MARWICK LLP INDEPENDENT AUDITORS


The Board of Directors
General Electric Company:
The Board of Directors
Martin Marietta Corporation:

       We consent to the incorporation by reference in this Registration 
Statement on Form S-8 of Lockheed Martin Corporation of our report, dated 
February 3, 1993, relating to the consolidated financial statements of GE 
Aerospace Businesses as of December 31, 1992 and 1991 and for each of the years 
in the two-year period ended December 31, 1992, which report is incorporated by 
reference in the December 31, 1993 annual report on Form 10-K of Martin Marietta
Corporation, which is incorporated herein by reference.


Harrisburg, Pennsylvania
March 13, 1995


<PAGE>
 

                                                                    EXHIBIT 23-D
 
                        CONSENT OF ARTHUR ANDERSEN LLP
                        INDEPENDENT PUBLIC ACCOUNTANTS

As independent public accountants, we hereby consent to the incorporation by 
reference in this registration statement on Form S-8 of our report dated January
20, 1994 on our audits of the combined financial statements of the General 
Dynamics Space Systems Group as of December 31, 1993 and 1992 and for each of 
the three years in the period ended December 31, 1993 included in the Martin 
Marietta Corporation's Form 8-K dated May 13, 1994, which is incorporated by 
reference into the Lockheed Martin Corporation registration statement on Form 
S-4 dated February 9, 1995.


                                                 ARTHUR ANDERSEN LLP


San Diego, California
March 13, 1995




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