Exhibit 10.21

                              ARCH CHEMICALS, INC.
                              ANNUAL INCENTIVE PLAN
                     (As amended effective December 9, 1999)


            1.    ADOPTION AND PURPOSE. The Company hereby adopts this Plan
providing for the award of annual incentive compensation to selected employees
of the Company and its Subsidiaries if specified Performance Goals are achieved.
The general purpose of the Plan is to promote the interests of the Company and
its Subsidiaries by providing to their employees incentives to continue and
increase their efforts with respect to, and remain in the employ of, the Company
and its Subsidiaries.

            2.    ADMINISTRATION. The Plan will be administered by the
Administrator.

                  Subject to the express provisions of the Plan, the
Administrator shall have plenary authority, in its discretion, to administer the
Plan and to exercise all powers and authority either specifically granted to it
under the Plan or necessary and advisable in the administration of the Plan,
including without limitation the authority to interpret the Plan; to prescribe,
amend and rescind rules and regulations relating to the Plan; to grant Awards,
to determine the terms, provisions and conditions of all Awards granted under
the Plan (which need not be identical), the individuals to whom and the time or
times when Awards shall be granted, and to make all other necessary or advisable
determinations with respect to the Plan. The determination of the Administrator
on such matters shall be conclusive.

            3.    PARTICIPANTS. The Administrator shall from time to time select
the officers and key employees of the Company and its Subsidiaries to whom
Awards are to be granted, and who will, upon such grant, become participants in
the Plan.

            4.    PERFORMANCE AWARDS. (a) The Performance Goals and Performance
Period applicable to an Award shall be determined by the Administrator no later
than 90 days after the commencement of the Performance Period and shall be
communicated to the Participant; provided for the 1999 Performance Period, not
later than August 1, 1999. For those employees of the Company or any
Subsidiaries who become Participants after January 1 of a given year, such
determination shall be made for the Performance Period as soon as practicable by
the Administrator. The Administrator shall have the discretion to later revise
the Performance Goals.

                  (b)   In making an Award, the Administrator may take into
account an employee's responsibility level, performance, cash compensation
level,
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incentive compensation awards and such other considerations as it deems
appropriate. Each Award shall be established in dollars and shall be based on
the Company's Performance Goals for the Performance Period.

            5.    EMPLOYMENT. Except as provided in the next sentence, and
unless the Administrator otherwise decides following termination, an Award shall
terminate for all purposes if the Participant is not an employee in good
standing with the Company or any subsidiary on the last day of the Performance
Period. The Participant (or in the event of the Participant's death, his or her
beneficiaries or estate) whose employment was terminated prior to such last day
because of death, disability or Retirement will be considered as the
Administrator determines in its sole discretion for pro rata portion of the
payment of his or her Award based upon the portion of the Performance Period
during which he or she was so employed so long as the Performance Goals are
subsequently achieved.

            6.    VESTING AND PAYMENT OF AWARDS. Awards shall not vest in a
Participant until actually paid; provided however, that if all or a portion of
an Award for a Performance Period is based on a Performance Goal that is a
financial goal (including the payout of any bonus bank amount), such portion of
an Award shall vest on the last day of such Performance Period in those
Participants who are employees of the Company or its subsidiaries on such last
day to the extent earned as a result of the achievement of such financial
Performance Goal. The vested Award for the Participants who were employed on
such last day but were not so employed continuously throughout such Performance
Period shall be prorated to reflect the period during which they were employed
by the Company or its subsidiary during the Performance Period. Payment with
respect to an Award will be distributed in a lump sum wholly in cash as soon as
practicable following the determination of actual performance and approval by
the Administrator that the Performance Goals with respect to an Award has been
met. Required withholding taxes shall be withheld from the payment of any Award.

            7.    DEFERRAL. Participants may defer the payment of Awards subject
to and as provided in the Employee Deferral Plan (or its successor).

            8.    NONEXCLUSIVE PLAN. The adoption of the Plan by the Company
shall not be construed as creating any limitation on the power of the
Administrator to adopt such other incentive arrangements as it may deem
desirable and such arrangements may be either generally applicable or applicable
only in specific cases.

            9.    NONASSIGNABILITY. No Awards may be transferred, alienated,
pledged or assigned other than by will or by the laws of descent and
distribution.


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            10.   AMENDMENT OR DISCONTINUANCE. The Plan may be amended,
terminated or discontinued by the Administrator at any time as the Administrator
determines. Upon termination of the Plan, unvested Awards shall terminate and
participants shall have no rights to unvested Awards.

            11.   EFFECT OF PLAN. Neither the adoption of the Plan nor any
action of the Administrator shall be deemed to give any officer or employee any
right to continued employment or any other rights.

            12.   PLAN REMAINS UNFUNDED. Nothing contained in this Plan shall be
deemed to create a trust or fund of any kind or create any fiduciary
relationship whether or not the Company elects to fund the Plan through a "rabbi
trust". Nothing contained herein shall be deemed to give any Participant any
ownership or other proprietary, security or other rights in any funds, stock or
assets owned or possessed by the Company, whether or not earmarked for the
Company's own purposes as a reserve or fund to be utilized by the Company for
the discharge of its obligations hereunder. To the extent that any person
acquires a right to receive payments or distributions from the Company under
this Plan, such right shall be no greater than the right of any unsecured
creditor of the Company.

            13.   EFFECTIVE DATE OF PLAN. The Plan shall take effect as of
January 1, 1999.

            14.   GOVERNING LAW. This Plan shall be governed by the laws of the
State of Connecticut without giving effect to its conflicts of law.

            15.   DEFINITIONS. For the purpose of this Plan, unless the context
requires otherwise, the following terms shall have the meanings indicated:

                  (a)   "Administrator" means (1) for Participants who report
      directly to the Chief Executive Officer or Chief Operating Officer and who
      are subject to Section 16 of the Securities Exchange Act of 1934, as
      amended, the Committee and (2) for all other Participants, the Chief
      Executive Officer of the Company (or his or her designees).

                  (b)   "Award" means an incentive award made pursuant to the
      Plan, the payment of which is contingent upon attainment of Performance
      Goals.

                  (c)   "Board" means the board of directors of the Company.

                  (d)   "Committee" means the Compensation Committee of the
      Board (or its successor committee).


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                  (e)   "Company" means Arch Chemicals, Inc., a Virginia
      corporation.

                  (f)   "Participant" means an individual selected by the
      Administrator to participate in the plan for a fiscal year.

                  (g)   "Performance Goals" means performance goal (or goals)
      and formulae as may be established by the Administrator which shall be
      based on the one or more financial or nonfinancial performance factors as
      the Administrator selects with respect to the Performance Period.

                  (h)   "Performance Period" means the fiscal year of the
      Company or such other period of time as is designated by the Administrator
      during which the Performance Goals are measured.

                  (i)   "Plan" means this Arch Chemicals, Inc. Annual Incentive
      Plan as amended from time to time.

                  (j)   "Retirement" means, with respect to any participant, the
      participant's retirement as an employee of the Company on or after
      reaching age 55 with at least ten years of service.

                  (k)   "Subsidiary" means any corporation in an unbroken chain
      of corporations beginning with the Company if, at the time of the granting
      of the Award, each of the corporations other than the last corporation in
      the unbroken chain owns stock possessing 50% or more of the total combined
      voting power of all classes of stock in one of the other corporations in
      the chain. The "Subsidiaries" means more than one of any such
      corporations.