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                                                                   Exhibit 10(d)

                         MINE SAFETY APPLIANCES COMPANY
                            SUPPLEMENTAL PENSION PLAN
                                   MAY 5, 1998

                                    SECTION I
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                                     PURPOSE
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          I.1   Purpose. The purpose of the Mine Safety Appliances Company
Supplemental Pension Plan, as originally adopted on April 24, 1984, is to
provide certain employees of Mine Safety Appliances Company with additional
retirement income by supplementing the pension benefit provided to such
employees under the Non-Contributory Pension Plan for Employees of Mine Safety
Appliances Company (the "Pension Plan") to the extent benefits payable
thereunder are limited by Section 415 of the Internal Revenue Code of 1986, as
amended from time to time (the "Code"). The purposes of this plan instrument are
(i) to memorialize in writing the existing supplemental pension plan of Mine
Safety Appliances Company, (ii) to provide an additional supplement to pension
benefits under the Pension Plan to the extent that they are limited by Section
401(a)(17) of the Code, and (iii) to provide certain Change-in-Control
protection of the supplemental benefits provided hereunder.

                                   SECTION II
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                                   DEFINITIONS
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          II.1  Definitions. The following definitions shall apply for purposes
of the Plan, unless a different meaning is plainly indicated by the context:

                (a) Beneficial Owner shall have the meaning set forth in Rule
13d-3 under the Exchange Act.

                (b) Board shall mean the Board of Directors of the Company, as
constituted from time to time.

                (c) Change in Control shall be deemed to have occurred if the
event set forth in any one of the following paragraphs shall have occurred:

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                    (I)   any Person is or becomes the Beneficial Owner,
          directly or indirectly, of securities of the Company (not including in
          the securities beneficially owned by such Person any securities
          acquired directly from the Company or its Affiliates (which term shall
          have the meaning set forth in Rule 12b-2 promulgated under Section 12
          of the Exchange Act)) representing thirty percent (30%) or more of the
          combined voting power of the Company's then outstanding securities,
          excluding any Person who becomes such a Beneficial Owner in connection
          with a transaction described in clause (i) of paragraph (III) below;
          or

                    (II)  the following individuals cease for any reason to
          constitute a majority of the number of directors then serving:
          individuals who, on May 5, 1998, constitute the Board and any new
          director (other than a director whose initial assumption of office is
          in connection with an actual or threatened election contest, including
          but not limited to a consent solicitation, relating to the election of
          directors of the Company) whose appointment or election by the Board
          or nomination for election by the Company's shareholders was approved
          or recommended by a vote of at least two-thirds (2/3) of the directors
          then still in office who either were directors on May 5, 1998 or whose
          appointment, election or nomination for election was previously so
          approved or recommended; or

                    (III) there is consummated a merger or consolidation of the
          Company or any direct or indirect subsidiary of the Company with any
          other corporation, other than (i) a merger or consolidation which
          would result in the voting securities of the Company outstanding
          immediately prior to such merger or consolidation continuing to
          represent (either by remaining outstanding or by being con-

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          verted into voting securities of the surviving entity or any parent
          thereof), in combination with the ownership of any trustee or other
          fiduciary holding securities under an employee benefit plan of the
          Company or any subsidiary of the Company, at least fifty-one percent
          (51%) of the combined voting power of the securities of the Company or
          such surviving entity or any parent thereof outstanding immediately
          after such merger or consolidation, or (ii) a merger or consolidation
          effected to implement a recapitalization of the Company (or similar
          transaction) in which no Person is or becomes the Beneficial Owner,
          directly or indirectly, of securities of the Company representing
          thirty percent (30%) or more of the combined voting power of the
          Company's then outstanding securities; or

                    (IV)  the shareholders of the Company approve a plan of
          complete liquidation or dissolution of the Company or there is
          consummated an agreement for the sale or disposition by the Company of
          all or substantially all of the Company's assets, other than a sale or
          disposition by the Company of all or substantially all of the
          Company's assets to an entity, at least fifty-one percent (51%) of the
          combined voting power of the voting securities of which are owned by
          shareholders of the Company in substantially the same proportions as
          their ownership of the Company immediately prior to such sale.

Notwithstanding the foregoing, a Change in Control shall not be deemed to have
occurred by virtue of the consummation of any transaction or series of
integrated transactions immediately following which the record holders of the
common stock of the Company immediately prior to such transaction or series of
transactions continue to have substantially the same proportionate ownership in
an entity which owns all or substantially all of the assets of the Company
immediately following such transaction or series of transactions.

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                (d) Code shall mean the Internal Revenue Code of 1986, as
amended from time to time.

                (e) Committee shall mean the Compensation Committee of the
Board.

                (f) Company shall mean Mine Safety Appliances Company and
(except as used in the definitions of Change in Control and Person in this
Section II) any successor to all or a major portion of its assets or business,
which successor assumes the obligations of the Company under this Plan by
operation of law or otherwise.

                (g) ERISA shall mean the Employee Retirement Income Security Act
of 1974, as from time to time amended.

                (h) Exchange Act shall mean the Securities Exchange Act of 1934,
as amended from time to time.

                (i) Participant shall mean an employee of the Company or a
Participating Affiliate (i) who is designated by the Board for participation
herein, and (ii) who participates in the Pension Plan and whose hypothetical
benefits under the Pension Plan determined on the basis of the provisions of the
Pension Plan without regard to the limitations of Sections 401(a)(17)and 415 of
the Code would exceed the actual benefits payable under the Pension Plan taking
into account such limitations.

                (j) Participating Affiliate shall have the meaning given such
term in the Pension Plan.

                (k) Pension Plan shall mean the Non-Contributory Pension Plan
for Employees of Mine Safety Appliances Company, as it may be amended from time
to time.

                (l) Person shall have the meaning given in Section 3(a)(9) of
the Exchange Act, as modified and used in Sections 13(d) and 14(d) thereof,
except that such term shall not include (i) the Company or any of its
subsidiaries, (ii) a trustee or other fiduciary holding

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securities under an employee benefit plan of the Company or any of its
Affiliates, (iii) an underwriter temporarily holding securities pursuant to an
offering of such securities, or (iv) a corporation owned, directly or
indirectly, by the shareholders of the Company in substantially the same
proportions as their ownership of stock of the Company, or (v) any individual or
entity [including the trustees (in such capacity) of any such entity which is a
trust] which is, directly or indirectly, the Beneficial Owner of securities of
the Company representing five percent (5%) or more of the combined voting power
of the Company's then outstanding securities immediately before the date hereof
or any Affiliate of any such individual or entity, including, for purposes of
this Plan, any of the following: (A) any trust (including the trustees thereof
in such capacity) established by or for the benefit of any such individual; (B)
any charitable foundation (whether a trust or a corporation, including the
trustees or directors thereof in such capacity) established by any such
individual; (C) any spouse of any such individual; (D) the ancestors (and
spouses) and lineal descendants (and spouses) of such individual and such
spouse; (E) the brothers and sisters (whether by the whole or half blood or by
adoption) of either such individual or such spouse; or (F) the lineal
descendants (and their spouses) of such brothers and sisters.

                (m) Plan shall mean The Mine Safety Appliances Company
Supplemental Pension Plan, as set forth in this plan instrument, as it may be
amended from time to time.

                (n) Supplemental Retirement Benefit shall have the meaning set
forth in Section 3.1 hereof.

                                   SECTION III
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                                    BENEFITS
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          III.1 Supplemental Retirement Benefit. Each Participant (or his or her
joint annuitant or designated survivor or beneficiary) shall be entitled under
this

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Plan to receive a Supplemental Retirement Benefit equal to the difference
between (i) the benefits (if any) that would have been payable to such
individual under the Pension Plan if the limitations on benefits imposed on the
Pension Plan by Section 415 of the Code (and by Section 401(a)(17) of the Code
as to any such individual who is an employee of the Company or a Participating
Affiliate on May 5, 1998 or becomes such an employee at any time after May 5,
1998) were not imposed, and (ii) the benefits (if any) actually payable to such
individual under the Pension Plan.

                Subject to Section 3.3 hereof, the benefits under this Plan
shall be payable at the same time or times and in the same manner as such
benefits are payable under the Pension Plan, and any election of an optional
form of payment, or designation of a survivor or beneficiary that is effective
under the Pension Plan shall also apply to the benefits payable under this Plan.

          III.2 Vesting. A Participant shall be vested in his or her
Supplemental Retirement Benefit only if vested in his or her benefit under the
Pension Plan.

          III.3 Effect of Change in Control. Notwithstanding any other provision
of this Plan, if a Participant is vested in his or her Supplemental Retirement
Benefit on the date of the Participant's termination of employment and that
termination date occurs on, or within the three-year period immediately
following, a Change in Control, then, not later than the fifth (5/th/) business
day following such termination date, the Company shall pay the Participant a
lump sum amount equal to the actuarial equivalent of the Participant's
Supplemental Retirement Benefit (in lieu of making payment of such Supplemental
Retirement Benefit in accordance with Section 3.1 hereof). For purposes of this
Section 3.3, "actuarial equivalent" shall be determined using the same
assumptions utilized under the Pension Plan immediately prior to the
Participant's termination date, or, if more favorable to the Participant,
immediately prior to the Change in Control.

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                                   SECTION IV
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                                 ADMINISTRATION
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          IV.1  Administration. The Plan shall be administered by the Committee.

          IV.2  Duties. The Committee shall perform the duties required, and
shall have the powers necessary, to administer the Plan and carry out the
provisions thereof.

          IV.3  Powers. The powers of the Committee shall be as follows:

                    (a)  To determine any question arising in connection with
                the Plan (and its decision or action in respect thereof shall be
                final, conclusive and binding upon the Company and the
                Participants and any other individual interested herein);

                    (b)  To engage the services of counsel or attorney (who may
                be counsel or attorney for the Company) and an actuary, if it
                deems necessary, and such other agents or assistants as it deems
                advisable for the proper administration of the Plan; and

                    (c)  To receive from the Company and from Participants such
                information as shall be necessary for the proper administration
                of the Plan.

          IV.4  Claims Procedure. Subject to the provisions of this Plan, the
Committee shall make all determinations as to the right of any individual to a
benefit. Any denial by the Committee of the claim for benefits under the Plan by
a Participant or any other individual interested herein shall be stated in
writing by the Committee and delivered or mailed to the Participant or such
individual. Such notice shall set forth the specific reasons for the denial,
written to the best of the Committee's ability in a manner that may be
understood without legal or actuarial counsel. In addi-

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tion, the Committee shall afford to any Participant (or his or her joint
annuitant, designated survivor or beneficiary) whose claim for benefits has been
denied a reasonable opportunity for a review of the decision denying the claim.

                                    SECTION V
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                            NONALIENATION OF BENEFITS
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          Neither the Participant nor any other individual shall have any right
to assign or otherwise to alienate the right to receive payments under the Plan,
in whole or in part. The immediately preceding sentence shall not apply to any
benefit payable pursuant to a "qualified domestic relations order," as defined
in Section 414(p) of the Code, which the Committee determines is applicable to
any benefit hereunder.

                                   SECTION VI
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                            AMENDMENT AND TERMINATION
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          The Company reserves the right at any time by action of the Board to
terminate the Plan or to amend its provisions in any way. Notwithstanding the
foregoing, no termination or amendment of the Plan may (i) reduce the benefits
payable under the Plan to the Participant (or his or her joint annuitant or
designated survivor or beneficiary) if the Participant's termination of
employment with the Company (and Participating Affiliates, if applicable) has
occurred prior to such termination of the Plan or amendment of its provisions,
or (ii) reduce the benefit to be paid with respect to the Participant on the
date of such termination of the Plan or amendment of its provisions below the
amount that would have been paid with respect to the Participant if his or her
employment had terminated on the day before such termination or amendment.

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                                   SECTION VII
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                                  MISCELLANEOUS
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          VII.1 No Right to Employment. This Plan shall not be construed as
providing any Participant with the right to be retained in the Company's employ
(or the employ of any Participating Affiliate) or to receive any benefit not
specifically provided hereunder.

          VII.2 No Effect on Other Compensation and Benefits. Nothing contained
herein shall exclude or in any manner modify or otherwise affect any existing or
future rights of any Participant to participate in and receive the benefits of
any compensation, bonus, pension, life insurance, medical and hospitalization
insurance or other employee benefit plan or program to which he or she otherwise
might be or become entitled as an officer or employee of the Company (or any
Participating Affiliate).

          VII.3 No Amendment to Pension Plan. This Plan shall not be deemed to
constitute an amendment to, or a part of, the Pension Plan. All references
hereunder to the Pension Plan shall include any amended or successor plan or
plans maintained by the Company, the terms of which may be applicable at any
time to a Participant's defined benefit retirement benefit. If, however, the
Pension Plan terminates, merges with, or is replaced by a successor plan, and as
a result thereof the amount of the Supplemental Retirement Benefit to be paid to
any Participant hereunder would be reduced or calculated on a different basis,
or commence at a later date or dates, such Supplemental Retirement Benefit shall
not be less than an amount calculated pursuant to the provisions of this Plan
and in accordance with the terms of the Pension Plan, as in effect immediately
prior to such termination, merger or replacement.

          VII.4 Governing Law. This Plan shall be construed in accordance with
and governed by the laws of the Commonwealth of Pennsylvania, without regard to
its conflicts of law principles.

          VII.5 Status. This Plan is not intended to

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satisfy the requirements for qualification under Section 401(a) of the Code. It
is intended to be a nonqualified plan that is not subject to ERISA. The Plan
shall be construed and administered so as to effectuate this intent.

          VII.6 Expenses. All expenses of establishing and administering the
Plan shall be paid by the Company. No individual interested herein shall have
any interest in any specific assets of the Company by reason of the individual's
interest under the Plan, and such individuals shall have only the status of
unsecured creditors of the Company with respect to any benefits that become
payable under this Plan.

          VII.7 Successors. The Company shall require any successor (whether
direct or indirect, by purchase, merger, consolidation or otherwise) to all or
substantially all of the business and/or assets of the Company to expressly
assume the Company's obligations hereunder in the same manner and to the same
extent that the Company would be required to perform if no such succession had
taken place.

          VII.8 Withholding Requirements. Payment of benefits under this Plan
shall be subject to applicable withholding requirements.

          IN WITNESS WHEREOF, Mine Safety Appliances Company has caused this
plan to be executed by its duly authorized officers this 5th day of May, 1998.

ATTEST:                                 MINE SAFETY APPLIANCES COMPANY

                                        By:
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             Secretary                               Chairman and Chief
                                                     Executive Officer

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