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                                                                   EXHIBIT 10.18

                              IMCO Recycling Inc.
                          Performance Share Unit Plan


                      SECTION 1. ESTABLISHMENT, PURPOSE,
                          AND EFFECTIVE DATE OF PLAN

     1.1  Establishment.  IMCO Recycling Inc., a Delaware corporation, hereby
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establishes the "IMCO RECYCLING INC. Performance Share Unit Plan" for key
employees (the "Plan").  The Plan permits the grant of performance units and
performance share units.

     1.2  Purpose.  The purpose of the Plan is to foster and promote the long-
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term financial success of the Company and its Subsidiaries and materially
increase the value of the Company and its Subsidiaries by (a) encouraging the
long-term commitment of key employees, (b) motivating performance of key
employees by means of long-term performance related incentives, (c) attracting
and retaining outstanding key employees by providing incentive compensation
opportunities, and (d) enabling participation by key employees in the long-term
growth and financial success of the Company and its Subsidiaries.

     1.3  Effective Date.  The Plan shall become effective upon its adoption by
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the Board of Directors of the Company (i.e., December 15, 1999), subject to
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approval by the stockholders of the Company.  Awards may be granted hereunder on
or after the effective date but shall in no event be exercisable by or payable
to a Participant prior to such stockholder approval; and, if such approval of
the stockholders is not obtained within twelve (12) months after the effective
date, such Awards shall be of no force and effect.


                            SECTION 2.  DEFINITIONS

     2.1  Definitions.  In addition to the terms defined elsewhere herein,
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whenever used herein, the following terms shall have their respective meanings
set forth below:

     (a)  "Award" means any Performance Unit or Performance Share Unit granted
          pursuant to the Plan.

     (b)  "Award Agreement" means a written agreement between a Participant and
          the Company which sets forth the terms of the grant of an Award.

     (c)  "Board" means the Board of Directors of the Company.

     (d)  "Cause" means any action by the Participant or inaction by the
          Participant that constitutes: (i) a breach of a written employment
          agreement by that Participant; or (ii) misconduct, dishonesty,
          disloyalty, disobedience or action that might reasonably injure the
          Company or any or its Subsidiaries or their business interests or
          reputation.

     (e)  "Change in Control" shall have the meaning set forth in Section 10.2.
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     (f)  "Code" means the Internal Revenue Code of 1986, as amended.

     (g)  "Committee" means the Compensation Committee of the Board or a
          subcommittee thereof, which shall consist of at least two members.

     (h)  "Company" means IMCO Recycling Inc., a Delaware corporation.

     (i)  "Disability" means any mental or physical illness, condition,
          disability or incapacity that prevents the Participant from reasonably
          discharging the Participant's duties and responsibilities to the
          Company, as determined by the Committee in its sole discretion.

     (j)  "Employee" means a regular salaried employee (including officers and
          directors who are also employees) of the Company or any of its
          Subsidiaries, or any branch or division thereof.  An Award may be
          granted to a potential Employee in connection with hiring, retention
          or otherwise, prior to the date the Employee first performs services
          for the Company or its Subsidiaries, provided that such Award shall
          not become vested to any extent prior to the date the Employee first
          performs such services.

     (k)  "Participant" means any Employee designated by the Committee to
          participate in the Plan.

     (l)  "Performance Goals" shall mean the criteria and objectives determined
          by the Committee pursuant to the Plan, which shall be satisfied or met
          during the applicable Performance Period as a condition precedent to
          the Participant's receipt of payment with respect to any Performance
          Unit Award or Performance Share Unit Award.  Such criteria and
          objectives may include, but are not limited to, earnings before
          interest, taxes, depreciation and amortization; return on assets;
          return on equity; growth in net earnings; growth in earnings per
          share; tangible net asset growth; any combination of the foregoing; or
          any other financial criteria and objectives determined by the
          Committee.

     (m)  "Performance Period" means a period of time determined at date of
          grant by the Committee over which performance is measured for the
          purpose of determining a Participant's right to and the payment value
          of any Performance Unit Award or Performance Share Unit Award.

     (n)  "Performance Unit Award" or "Performance Share Unit Award" means an
          Award representing a contingent right to receive cash at the end of a
          Performance Period based upon the achievement of certain Performance
          Goals pursuant to Section 6 of the Plan.

     (o)  "Plan" means the IMCO Recycling Inc. Performance Share Unit Plan as
          set forth herein and any amendments hereto.

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     (p)  "Resigns for Good Reason" means a Participant's resignation caused by,
          and within ninety (90) days after the occurrence of, any one of the
          following: (i) an action is taken by the Company which results in a
          material diminution in the position or status of the Participant with
          the Company immediately prior to said action, except in connection
          with a termination of the Participant's employment as a result of the
          Participant's Disability or for Cause; (ii) a transfer or proposed
          transfer of the Participant to a location outside of the Participant's
          city of residence immediately prior to such transfer, without the
          Participant's prior written consent; or (iii) the Company reduces the
          annual base salary of the Participant, unless such decrease is the
          result of a general reduction affecting the annual base salaries of
          sixty percent (60%) or more of the then similarly situated employees
          of the Company; provided that the Company has failed to rescind or
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          remedy the action or occurrence prompting such resignation within five
          (5) days (or if it requires a longer period, a reasonable period of
          time) after the Participant has given the Company written notice
          identifying such action or occurrence.

     (q)  "Retirement" means termination of employment due to retirement from
          the Company and its Subsidiaries in accordance with standard
          retirement policies of the Company and its Subsidiaries then in
          effect, or permitted early retirement as determined by the Board in
          its sole discretion.

     (r)  "Subsidiary" means any corporation or entity of which more than 50% of
          the outstanding securities or ownership interests having ordinary
          voting power to elect a majority of the members of the Board of
          Directors or persons in a similar capacity of such corporation or
          entity, is, directly or indirectly, owned by the Company.

     2.2  Definitional Terms; Gender and Number.  All terms defined in this Plan
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shall have the meanings set forth herein when used in any Award Agreement or
other document made or delivered pursuant to the Plan, except where the context
thereof shall otherwise require.  Except when otherwise indicated by the
context, words in the masculine gender when used in the Plan shall include the
feminine gender, the singular shall include the plural, and the plural shall
include the singular.  The words "hereof," "herein," "hereunder," and similar
terms when used in this Plan shall refer to this Plan as a whole and not to any
particular provision of the Plan.


                   SECTION 3.  ELIGIBILITY AND PARTICIPATION

     3.1  Eligibility and Participation.  Participants in the Plan shall be
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selected by the Committee from among those Employees who in the opinion of the
Committee, are key employees in a position to contribute materially to the
Company's continued growth and development and to its long-term financial
success.  The Committee, upon its own action, may grant, but shall not be
required to grant, an Award to any eligible Employee of the Company or any
Subsidiary.  The Committee shall determine the amounts, terms and conditions of
each Award granted hereunder.  Awards may be granted by the Committee at any
time and from time

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to time to new Participants, or to already-participating Participants, or to a
greater or lesser number of Participants, and may include or exclude previous
Participants, as the Committee shall determine. The grant of an Award shall be
evidenced by an Award Agreement setting forth such terms, provisions,
limitations and performance criteria as are approved by the Committee, but not
inconsistent with the Plan.

     Except as required by this Plan, Awards granted at different times need not
contain similar provisions.  The Committee's determinations under the Plan
(including without limitation determinations of which Employees are to receive
Awards, the form, amount and timing of such Awards, the terms and provisions of
such Awards and the Award Agreements evidencing same) need not be uniform and
may be made by the Committee selectively among Participants who receive, or are
eligible to receive, Awards under the Plan.

     Notwithstanding any other provision contained in this Plan to the contrary,
the Committee may delegate to the Chief Executive Officer of the Company from
time to time the authority to grant up to a certain number (to be designated by
the Committee from time to time) of Performance Units and/or Performance Share
Units to be awarded to eligible Employees to be chosen by the Chief Executive
Officer in his sole discretion, so long as those Employees are not at the date
of grant an officer of the Company and are not and are not likely to be a
"covered employee" (as that term is defined under Section 162(m) of the Code and
the Treasury Regulations promulgated thereunder).


                           SECTION 4.  ADMINISTRATION

     4.1  Administration.  The Committee shall be responsible for the
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administration of the Plan.  Any member of the Committee may be removed at any
time, with or without cause, by resolution of the Board in its sole discretion.
Any vacancy occurring in the membership of the Committee may be filled by
appointment by the Board.

     Plan administrative costs and expenses shall be paid by the Company.  The
Committee is authorized to interpret the Plan, to prescribe, amend, and rescind
rules and regulations relating to the Plan, to provide for conditions and
assurances deemed necessary or advisable to protect the interests of the
Company, to correct any errors or inconsistencies in and make adjustments for
mistakes or errors made in the administration of the Plan, and to make all other
determinations necessary or advisable for the administration and application of
the Plan, including but not limited to the eligibility and participation
determinations as set forth in Section 3. Notwithstanding any provision
contained herein to the contrary, the Committee may, at any time and from time
to time, in its absolute discretion (i) accelerate the date on which any Award
granted under the Plan vests, (ii) extend the date on which any Award granted
under the Plan terminates, or (iii) remove, suspend or alter the restrictions
imposed with respect to any Award granted under the Plan.  Except as otherwise
provided herein, determinations, interpretations, or other actions made or taken
by the Committee pursuant to the provisions of the Plan shall be final and
binding and conclusive for all purposes and upon all persons whomsoever,
including the Company and all Participants.

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     To the extent that the Committee determines that the restrictions imposed
by the Plan preclude the achievement of the material purposes of the Awards in
jurisdictions outside the United States, the Committee will have the authority
and discretion to modify those restrictions as the Committee determines to be
necessary or appropriate to conform to applicable requirements or practices of
jurisdictions outside of the United States.


                          SECTION 5.  DURATION OF PLAN

     5.1  Duration of Plan.  The Plan shall remain in effect, subject to the
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Board's right to earlier terminate the Plan pursuant to Section 11 hereof, until
December 15, 2009.  Notwithstanding the foregoing, all Awards granted prior to
the date specified in the preceding sentence will continue to be effective in
accordance with their terms and conditions.


      SECTION 6.  PERFORMANCE UNIT AWARDS AND PERFORMANCE SHARE UNIT AWARDS

     6.1  Grant of Performance Unit  or Performance Share Unit Awards.  Subject
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to the provisions of this Section 6, Performance Unit Awards or Performance
Share Unit Awards may be granted to Participants at any time and from time to
time as shall be determined by the Committee.  The Committee shall have complete
discretion in determining the number of Performance Units or Performance Share
Units to be awarded to any Participant.  Any Award shall be subject to such
conditions, restrictions and contingencies (including such Performance Goals) as
the Committee shall determine.  The Performance Period shall also be determined
by the Committee and set forth in the Award Agreement.

     6.2  Performance Goals.  At the beginning of each Performance Period, the
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Committee shall (i) establish for each Performance Period the specific
Performance Goals as the Committee believes are relevant to the Company's
overall business objectives; (ii) determine the value of a Performance Unit or a
Performance Share Unit relative to the Performance Goals; and (iii) instruct
senior management to notify each Participant in writing of the established
Performance Goals and the minimum, target, and maximum Performance Unit or
Performance Share Unit value for such Performance Period.

     6.3  Adjustments.  The Committee will make appropriate adjustments to
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exclude the effect of extraordinary corporate transactions, such as
acquisitions, divestitures, recapitalizations and reorganizations, and will not
take into account extraordinary or non-recurring accounting charges and items,
insofar as they would otherwise affect the results under the applicable
Performance Goals.

     6.4  Payment.  Upon completion of the Performance Period, the Committee
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shall certify the level of the Performance Goals attained and the amount of the
Award payable as a result thereof.  The basis for payment of each Performance
Unit or Performance Share Unit for a given Performance Period shall be the
achievement of those Performance Goals determined by the Committee at the
beginning of the Performance Period.  If minimum performance is not

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achieved for a Performance Period, no payment shall be made, the Performance
Unit Award or Performance Share Unit Award will terminate and all contingent
rights thereunder shall cease. If minimum performance is achieved or exceeded,
the value of a Performance Unit or Performance Share Unit shall be based on the
degree to which actual performance met or exceeded the pre-established minimum
performance standards, as determined by the Committee. The amount of payment
shall be determined by multiplying the number of Performance Units or
Performance Share Units granted at the beginning of the Performance Period times
the final Performance Unit or Performance Share Unit value. Payments shall be
made in cash following the close of the applicable Performance Period.

     6.5  Deferral.  If the terms of the particular Award granted by the
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Committee so provide, the Participant may be provided an option to defer payment
of the Participant's vested Performance Unit Award or Performance Share Unit
Award.

     6.6  Termination of Employment Due To Death, Disability or Retirement.  In
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the case of death, Disability, or Retirement, the holder of a Performance Unit
or Performance Share Unit (or his beneficiary, as the case may be) shall be
entitled to receive following the end of the particular Performance Period, a
pro rata payment based on the number of months' service during the Performance
Period, and the level of achievement of Performance Goals during the Performance
Period, to be determined by the Committee following the end of the Performance
Period.

     6.7  Termination of Employment Other Than Death, Disability or Retirement.
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Except in circumstances in which a Change in Control is involved pursuant to
Section 9 hereof, in the event that a Participant terminates employment with the
Company for any reason other than death, Disability or Retirement, all
Performance Unit Awards and Performance Share Unit Awards shall be forfeited.

     6.8  Funding.  No provision of the Plan shall require the Company, for the
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purpose of satisfying any obligations under the Plan, to purchase assets or
place any assets in a trust or other entity to which contributions are made or
otherwise to segregate any assets in a manner that would provide any Participant
any rights that are greater than those of a general creditor of the Company, nor
shall the Company maintain separate bank accounts, books, records or other
evidence of the existence of a segregated or separately maintained or
administered fund if such action would provide any Participant with any rights
that are greater than those of a general creditor of the Company.  Participants
shall have no rights under the Plan other than as unsecured general creditors of
the Company.  However, the Company may establish a "Rabbi Trust" for purposes of
securing the payment pursuant to a Change in Control.

     6.9  Nontransferability.  Performance Units or Performance Share Units
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granted under the Plan may not be sold, transferred, pledged, assigned, or
otherwise alienated or hypothecated, other than by will or by the laws of
descent and distribution until the termination of the applicable Performance
Period.  All rights with respect to Performance Unit Awards and Performance
Share Unit Awards granted to a Participant under the Plan shall be exercisable
during his lifetime only by such Participant.

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<PAGE>

     6.10 Restrictions on Awards.  It is intended that the Plan will provide
          ----------------------
Participants with opportunities for long-term incentive compensation which is
not subject to the deduction limitation rules prescribed under Section 162(m) of
the Code, and that the Plan be construed to the degree possible as providing for
remumeration which is "performance-based compensation" within  the meaning of
Section 162(m) of the Code and the Treasury Regulations promulgated thereunder.
Notwithstanding the foregoing, the Committee may grant Awards to non-officers
and individuals who are not and are likely not to be "covered employees" as that
term is defined under Section 162(m) and the Treasury Regulations, which Awards
may thereby not meet the requirements of being "performance-based compensation."
In order for Awards to be "performance-based compensation," the grant of the
Awards and the establishment of the Performance Goals shall be made during the
period required under Section 162(m) of the Code.

     6.11 Maximum Amount.  No Participant may receive during any fiscal year of
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the Company, payment of Awards covering an aggregate of more than 300% of the
target amount designated in the Participant's Award Agreement, which amount must
be based on maximum achievement of Performance Goals and certified by the
Committee.  In addition, and in any event, no Participant may receive during any
fiscal year payment of Awards totaling in excess of $4,500,000.


                      SECTION 7.  BENEFICIARY DESIGNATION

     7.1  Beneficiary Designation.  Each Participant under the Plan may name,
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from time to time, any beneficiary or beneficiaries (who may be named
contingently or successively) to whom any benefit under the Plan is to be paid
in the event of such Participant's death before such Participant receives any or
all of such benefit.  Each designation will revoke all prior designations by the
same Participant, shall be in a form prescribed by the Committee, and will be
effective only when filed by the Participant in writing with the Committee
during his lifetime.  In the absence of any such designation, benefits remaining
unpaid at the Participant's death shall be paid to his estate.


                        SECTION 8.  RIGHTS OF EMPLOYEES

     8.1  Employment.  Nothing in the Plan shall interfere with or limit in any
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way the right of the Company to terminate any Participant's employment at any
time or confer upon any Participant any right to continue in the employ of the
Company.

     8.2  Participation.  No Employee shall have a right to be selected as a
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Participant or, having been so selected, to be selected again as a Participant.

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<PAGE>

                         SECTION 9.  CHANGE IN CONTROL

     9.1  In General.
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     (a)  Notwithstanding any other provision contained herein, in the event of
          a Change in Control, as defined in Section 9.2 below, affecting the
          Company in which the outstanding Awards granted by the Company prior
          to such Change in Control (and the Company's obligations in connection
          therewith) are not fully assumed by the Company after the Change in
          Control or the corporation or entity resulting from the Change in
          Control, or replaced by fully equivalent substitute Awards, then all
          outstanding Awards shall automatically be accelerated and become fully
          vested, whereupon all Performance Unit Awards and Performance Share
          Unit Awards shall be paid based upon the extent to which Performance
          Goals during the Performance Period have been met up to the date of
          the Change in Control, but in any event, not less than the target
          Award amount as set forth in each Participant's Award Agreement.

     (b)  If there is a Change in Control of the Company in which the
          outstanding Awards granted by the Company prior to such Change in
          Control (and the Company's obligations in connection therewith) are
          fully assumed by the Company after the Change in Control or the
          corporation or other legal entity resulting from the Change in
          Control, or replaced by fully equivalent substitute Awards, then,
          except as otherwise provided in this Section 9, no acceleration of
          vesting of any unmatured installments of outstanding Awards granted by
          the Company shall occur.

     (c)  In addition, notwithstanding any other provision contained in this
          Plan, in the event that a Participant's employment is terminated by
          the Company, within that period commencing on the date which is ninety
          (90) days prior to and continuing during the 24-month period following
          the effective date of a Change in Control (i.e., with such period
          ending on the same day of the 24th month following the effective date
          of the Change in Control), for any reason (other than such
          Participant's (i) voluntary resignation (which does not constitute a
          Resign for Good Reason resignation), (ii) termination as a result of
          death,  Disability or Retirement, or (iii) termination by the Company
          for Cause), or such Participant Resigns for Good Reason within such
          period, then to the extent the Awards granted to such Participant have
          not already become fully vested pursuant to this Section 9, all
          outstanding Awards granted by the Company to such Participant shall,
          without further action by any person, immediately become fully vested
          in full, effective as of the date of such termination of employment,
          whereupon all Performance Unit Awards and Performance Share Unit
          Awards shall be paid out based upon the higher of the targeted
          Performance Goals or the extent to which the Performance Goals during
          the Performance Period have been met up to the date of the Change in
          Control or the date of termination (whichever date results in the
          then-higher value of the particular Award).

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<PAGE>

     9.2  Definition.  For purposes of the Plan, a "Change in Control" shall
          ----------
mean the occurrence of any of the following events:  (i) there shall be
consummated any merger or consolidation pursuant to which shares of the
Company's Stock would be converted into or exchanged for cash, securities or
other property, or any sale, lease, exchange or other disposition (excluding
disposition by way of mortgage, pledge or hypothecation), in one transaction or
a series of related transactions, of all or substantially all of the assets of
the Company (a "Business Combination"), in each case unless, following such
Business Combination, all or substantially all of the holders of the outstanding
Stock immediately prior to such Business Combination beneficially own, directly
or indirectly, more than 50.1% of the outstanding common stock or equivalent
equity interests of the corporation or entity resulting from such Business
Combination (including, without limitation, a corporation which as a result of
such transaction owns the Company or all or substantially all of the Company's
assets either directly or through one or more Subsidiaries) in substantially the
same proportions as their ownership, immediately prior to such Business
Combination, of the outstanding Stock, (ii) the stockholders of the Company
approve any plan or proposal for the complete liquidation or dissolution of the
Company, (iii) any "person" (as such term is defined in Section 3(a)(9) or
Section 13(d)(3) under the 1934 Act) or any "group" (as such term is used in
Rule 13d-5 promulgated under the 1934 Act), other than the Company or any
successor of the Company or any Subsidiary of the Company or any employee
benefit plan of the Company or any Subsidiary (including such plan's trustee),
becomes a beneficial owner for purposes of Rule 13d-3 promulgated under the 1934
Act, directly or indirectly, of securities of the Company representing 50.1% or
more of the Company's then outstanding securities having the right to vote in
the election of directors, or (iv) during any period of two consecutive years,
individuals who, at the beginning of such period constituted the entire Board,
cease for any reason (other than death) to constitute a majority of the
directors, unless the election, or the nomination for election, by the Company's
stockholders, of each new director was approved by a vote of at least a majority
of the directors then still in office who were directors at the beginning of the
period.


          SECTION 10.  AMENDMENT, MODIFICATION,AND TERMINATION OF PLAN

     10.1 Amendment, Modification, and Termination of Plan.  The Board at any
          ------------------------------------------------
time may terminate, and from time to time may amend or modify the Plan,
provided, however, that unless required by law, no action contemplated or
permitted by this Section 11.1 shall reduce the amount of any Award theretofore
granted under the Plan without the consent of the affected Participant.


                         SECTION 11.  TAX WITHHOLDING

     11.1 Tax Withholding.  The Company shall have the power and the right to
          ---------------
deduct or withhold, or require a Participant to remit to the Company, an amount
sufficient to satisfy Federal, state, and local taxes, domestic or foreign,
required by law or regulation to be withheld with respect to any taxable event
arising as a result of the Plan.

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                          SECTION 12.  INDEMNIFICATION

     12.1 Indemnification.  Each Person who is or shall have been a member of
          ---------------
the Committee or of the Board, or who acts on behalf of or at the direction of
the Committee or Board with respect to this Plan, shall be indemnified and held
harmless by the Company against and from any loss, cost, liability, or expense
that may be imposed upon or reasonably incurred by him in connection with or
resulting from any claim, action, suit, or proceeding to which he may be a party
or in which he may be involved by reason of any action taken or failure to act
under the Plan and against and from any and all amounts paid by him in
settlement thereof, with the Company's approval, or paid by him in satisfaction
of any judgment in any such action, suit, or proceeding against him, provided he
shall give the Company an opportunity, at its own expense, to handle and defend
the same before he undertakes to handle and defend it on his own behalf.  The
foregoing right of indemnification shall not be exclusive of any other rights of
indemnification to which such persons may be entitled under the Company's
Certificate of Incorporation or Bylaws, as a matter of law, or otherwise, or any
power that the Company may have to indemnify them or hold them harmless.


                           SECTION 13.  MISCELLANEOUS

     13.1 Requirements of Law.  The granting of Awards shall be subject to all
          -------------------
applicable laws, rules, and regulations, and to such approvals by any
governmental agencies or national securities exchanges as may be required.

     13.2 Governing Law.  The Plan, and all agreements hereunder, shall be
          -------------
construed in accordance with and governed by the laws of the State of Delaware.

     13.3 Substitute Awards.  Awards may be granted under the Plan from time to
          -----------------
time in substitution for similar instruments held by employees or directors of a
corporation, partnership, or limited liability company who become or are about
to become Employees of the Company or any Subsidiary as a result of a merger or
consolidation of the employing corporation with the Company, the acquisition by
the Company of equity of the employing entity, or any other similar transaction
pursuant to which the Company becomes the successor employer.  The terms and
conditions of the substitute Awards so granted may vary from the terms and
conditions set forth in this Plan to such extent as the Committee or Board at
the time of grant may deem appropriate to conform, in whole or in part, to the
provisions of the incentives  in substitution for which they are granted.

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