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                                                                   EXHIBIT 10.4b

                                SECOND AMENDMENT
                                     TO THE
                            STERLING CHEMICALS, INC.
              AMENDED AND RESTATED SALARIED EMPLOYEES' PENSION PLAN


                  WHEREAS, there is reserved to Sterling Chemicals, Inc.
("Chemicals") in Section 15.1 of the Sterling Chemicals, Inc. Amended and
Restated Salaried Employees' Pension Plan (the "Plan") the right to amend the
Plan;

                  NOW, THEREFORE, the Plan is hereby amended by adding thereto a
new Section 9.10A to read as follows:

                  9.10A Canadian Employees Transferred to Salaried Basis. The
         Monthly Retirement Income payable to a participant, who was an employee
         of a Canadian Affiliate Company prior to the date his participation
         under this Plan commenced and who is otherwise entitled to a benefit
         under a defined benefit pension plan maintained by the Canadian
         Affiliate Company (the "Canadian Plan"), with respect to his
         participation in this Plan and his participation in the Canadian Plan
         shall be the greater of:

                  (a) the Monthly Retirement Income or Monthly Vested
         Termination Benefit computed under this Plan as if all benefit service
         accrued under the Canadian Plan and this Plan had been accrued under
         this Plan alone; or

                  (b) the sum of:

                           (i) the Monthly Retirement Income or Monthly Vested
                  Termination Benefit under this Plan computed on the basis of
                  his benefit service solely attributable to his service with
                  the Employers on and after the date his participation in this
                  Plan commenced; and

                           (ii) his non-contributory regular benefits under the
                  Canadian Plan determined on the basis of his benefit service
                  accrued under the Canadian Plan prior to the date his
                  participation in this Plan commenced. Such regular benefits
                  shall be computed on the basis of the provisions of the
                  Canadian Plan as in effect on the date he ceased to be an
                  employee of the Canadian Affiliate Company.

                           There shall be no duplication of benefits for the
         same period of time and if paragraph (a) above is applicable, the
         benefits payable hereunder shall be reduced by the actuarial
         equivalence of the benefits payable under the Canadian Plan. A
         participant subject to this Section 9.10A must retire under both the
         Canadian Plan and this Plan at the same time.

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                  All terms used herein that are defined in the Plan shall have
the same meanings given to such terms in the Plan, except as otherwise expressly
provided herein.

                  Except as amended and modified hereby, the Plan shall continue
in full force and effect and the Plan and this amendment shall be read, taken
and construed as one and the same instrument.

                  This amendment may be executed in several counterparts, each
of which shall be deemed an original, but all of which shall constitute but one
and the same instrument which may be evidenced by any one counterpart.

                  IN WITNESS WHEREOF, Chemicals has executed this instrument to
be effective as of January 1, 1997 upon the receipt of a favorable IRS
determination letter for this amendment.

                                               STERLING CHEMICALS, INC.


                                               By:
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