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                                                                    EXHIBIT 4.15


                       STOCK PLEDGE AND SECURITY AGREEMENT


         THIS STOCK PLEDGE AND SECURITY AGREEMENT (the "Pledge Agreement") is
made and entered into as of July 23, 1999 (the "Closing Date"), by Sterling
Chemicals, Inc., a Delaware corporation (the "Company"), and Sterling Canada,
Inc., a Delaware corporation, each having as its principal place of business c/o
Sterling Chemicals, Inc., 1200 Smith Street, Houston, Texas 77002-4312 (the
Company and each of the foregoing, a "Pledgor," and collectively, the
"Pledgors"), in favor of Harris Trust Company of New York, a New York
corporation, as indenture trustee and collateral agent (the "Collateral Agent")
for the benefit of itself and for the holders (the "Holders") of the Company's
12 3/8% Senior Secured Notes due 2006, and having an office at Wall Street
Plaza, 19th Floor, 88 Pine Street, New York, New York 10005. Capitalized terms
used but not otherwise defined herein shall have the meanings ascribed thereto
in the Indenture (hereinafter defined).

                              W I T N E S S E T H:


         WHEREAS, as of the Closing Date, the Pledgors own and hold the issued
and outstanding shares of capital stock (collectively, the "Pledged Shares") of
the following corporations: (a) Sterling Pulp Chemicals, Ltd., an Ontario
corporation; (b) Sterling NRO Ltd., an Ontario corporation; and (c) Sterling
Chemicals Marketing, Inc., a Barbados corporation ((a) - (c), collectively and
individually, the "Issuer"); and

         WHEREAS, Pledgor and Collateral Agent, as trustee, have entered into
that certain indenture dated as of July 23, 1999 (as amended, amended and
restated, supplemented or otherwise modified from time to time, the
"Indenture"), pursuant to which the Company issued $295 million in the aggregate
principal amount of 12 3/8% Senior Secured Notes due 2006 (together with any
notes issued in replacement thereof or in exchange or substitution therefor, the
"Senior Secured Notes"); and

         WHEREAS, the terms of the Indenture require that the Pledgors (i)
pledge to Collateral Agent for the ratable benefit of the Holders of the Senior
Secured Notes, and grant to Collateral Agent for the ratable benefit of the
Holders of the Senior Secured Notes, a first priority security interest in the
Pledged Collateral (as defined herein) and (ii) execute and deliver this Pledge
Agreement in order to secure the payment and performance by the Pledgors of all
of their obligations under both the Indenture and the Senior Secured Notes
(including all guarantees thereof) (the "Obligations"); and

         WHEREAS, each Pledgor has duly authorized the execution, delivery and
performance of this Pledge Agreement:

         NOW, THEREFORE, in consideration of the premises, and in order to
induce the Holders of the Senior Secured Notes to purchase the Senior Secured
Notes, Pledgor hereby agrees with the Collateral Agent for its benefit and the
ratable benefit of the Holders of the Senior Secured Notes as follows:


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                             ARTICLE I. DEFINITIONS

         SECTION 1.1. Certain Terms. The following terms (whether or not
underscored) shall have the following meanings (such definitions to be equally
applicable to the singular and plural forms thereof) when used in this Pledge
Agreement:

         "Distributions" means any and all stock dividends, liquidating
dividends, Capital Stock resulting from (or in connection with the exercise of)
stock splits, reclassifications, warrants, options, non-cash dividends, mergers
or consolidations, and all other distributions (whether similar or dissimilar to
the foregoing) on or with respect to any Pledged Shares or other Capital Stock
constituting Collateral, but shall not include Dividends.

         "Dividends" means any and all cash dividends and cash distributions
with respect to any Pledged Shares or other Pledged Collateral made in the
ordinary course of business, but shall not include liquidating dividends.

         "Pledge Agreement" is defined in the preamble.

         "Pledged Collateral" means all Pledged Shares, all other pledged
Capital Stock, all other equity securities, all assignments of any amounts due
or to become due with respect thereto, and all other instruments which are now
being delivered by the Pledgor to the Collateral Agent or may from time to time
hereafter be delivered by the Pledgor to the Collateral Agent for the purpose of
pledge under this Pledge Agreement and all proceeds of any of the foregoing.

         "Pledged Shares" means the Capital Stock of any Issuer in the amounts
and percentages listed on Attachment 1 hereto.

         "Satisfaction Date" means the date on which all Obligations under the
Indenture and the Senior Secured Notes have been paid in full or otherwise
satisfied.

         "Securities Act" is defined in clause (a) of Section 6.2.

         SECTION 1.2. Indenture Definitions. Unless otherwise defined herein or
the context otherwise requires, terms used in this Pledge Agreement, including
its preamble and recitals, have the meanings provided in the Indenture.

         SECTION 1.3. U.C.C. Definitions. Unless otherwise defined herein or in
the Indenture or the context otherwise requires, terms for which meanings are
provided in the Uniform Commercial Code from time to time in effect in the State
of New York (the "U.C.C.") are used in this Pledge Agreement, including its
preamble and recitals, with such meanings.

                               ARTICLE II. PLEDGE

         SECTION 2.1. Grant of Security Interest. Each Pledgor hereby pledges,
hypothecates, assigns, charges, delivers and transfers to the Collateral Agent
for its benefit and for the ratable benefit of the Holders of the Senior Secured
Notes, and hereby grants to the



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Collateral Agent for the ratable benefit of the Holders of the Senior Secured
Notes, a continuing security interest in, all of the following property
(collectively, the "Collateral"):

                  (a) 65% of the issued and outstanding Pledged Shares of each
         Issuer identified on Attachment 1 hereto;

                  (b) 65% of all other Pledged Shares issued from time to time;

                  (c) all other Pledged Collateral, whether now or hereafter
         delivered to the Collateral Agent in connection with this Pledge
         Agreement;

                  (d) all Dividends, Distributions, and other payments and
         rights with respect to any Pledged Collateral; and

                  (e) all proceeds of any of the foregoing.

         Notwithstanding the foregoing, at no time shall the Pledged Shares of
any Issuer constitute in excess of 65% of all issued and outstanding Capital
Stock of such Issuer.

         SECTION 2.2. Security for Obligations. This Pledge Agreement secures
the payment in full and in cash of all Obligations.

         SECTION 2.3. Delivery of Pledged Collateral. All certificates or
instruments representing or evidencing any Collateral, including all Pledged
Shares, shall be delivered to and held by or on behalf of the Collateral Agent
and for the benefit of the Holders of the Senior Secured Notes pursuant hereto,
shall be in suitable form for transfer by delivery and shall be accompanied by
all necessary instruments of transfer or assignment, shall be duly executed in
blank, all in form and substance satisfactory to the Collateral Agent.

         SECTION 2.4. Dividends on Pledged Share. In the event that any Dividend
is to be paid on any Pledged Share at a time when no Event of Default has
occurred and is continuing, such Dividend may be paid directly to the applicable
Pledgor. If any such Event of Default has occurred and is continuing, then any
such Dividend shall be paid directly to the Collateral Agent.

         SECTION 2.5. Continuing Security Interest. This Pledge Agreement shall
create a continuing security interest in the Collateral and shall:

                  (a) remain in full force and effect until all Obligations
         under the Indenture and the Senior Secured Notes are satisfied in full;

                  (b) be binding upon each Pledgor and its successors,
         transferees and assigns; and

                  (c) inure, together with the rights and remedies of the
         Collateral Agent hereunder, to the benefit of the Holders of the Senior
         Secured Notes.

The security interest granted herein shall terminate and all rights to the
Collateral shall revert to each Pledgor on the Satisfaction Date. Upon any such
termination or release of Collateral, the Collateral Agent will, at each
Pledgor's sole expense, deliver to such Pledgor, without any



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representations, warranties or recourse of any kind whatsoever, all certificates
and instruments representing or evidencing all Pledged Shares, together with all
other Collateral held by the Collateral Agent hereunder, and execute and deliver
to such Pledgor such documents as such Pledgor shall reasonably request to
evidence such termination or release.

         SECTION 2.6. Security Interest Absolute. All rights of the Collateral
Agent and the Liens granted to the Collateral Agent hereunder, and all
obligations of each Pledgor hereunder, shall be absolute and unconditional,
irrespective of

                  (a) any lack of validity or enforceability of the Indenture or
         any other agreement or instrument relating thereto;

                  (b) the failure of the Collateral Agent, for its own benefit
         or the benefit of the Holders of the Senior Secured Notes:

                           (i) to assert any claim or demand or to enforce any
                  right or remedy against any Pledgor, any other Guarantor (as
                  such term is defined in the Indenture) or any other Person
                  under the provisions of the Indenture, the Senior Secured
                  Notes and the Security Agreements or otherwise, or

                           (ii) to exercise any right or remedy against any
                  guarantor of, or collateral securing, any Obligations of any
                  Pledgor or any other Guarantor.

                  (c) any change in the time, manner or place of payment of, or
         in any other term of, all or any of the Obligations or any other
         extension, compromise or renewal of any Obligation of any Pledgor or
         any other Guarantor,

                  (d) any reduction, limitation, impairment or termination of
         any Obligation of any Pledgor or any other Guarantor for any reason
         (other than the satisfaction of and repayment in full and in cash of
         all Obligations), including any claim of waiver, release, surrender,
         alteration or compromise, and shall not be subject to (and each Pledgor
         hereby waives any right to or claim of) any defense or set-off,
         counterclaim, recoupment or termination whatsoever by reason of the
         invalidity, illegality, nongenuineness, irregularity, compromise or
         unenforceability of, or any other event or occurrence affecting, any
         Obligation of any Pledgor, any other Guarantor or otherwise,

                  (e) any amendment to, rescission, waiver, or other
         modification of, or any consent to departure from, any of the terms of
         the Indenture, the Senior Secured Notes or the other Security
         Agreements,

                  (f) any addition, exchange, release, surrender or
         non-perfection of any collateral (including the Collateral), or any
         amendment to or waiver or release of or addition to or consent to
         departure from any guaranty, for any of the Obligations, or

                  (g) any other circumstances which might otherwise constitute a
         defense available to, or a legal or equitable discharge of, any
         Pledgor, any other Guarantor, any surety or any guarantor.



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         SECTION 2.7. Postponement of Subrogation, etc. No Pledgor will exercise
any rights which it may acquire by reason of any payment made hereunder, whether
by way of subrogation, reimbursement or otherwise, until the Satisfaction Date.
Any amount paid to any Pledgor on account of any payment made hereunder shall be
held in trust for the benefit of the Holders of the Senior Secured Notes and
shall immediately be paid to the Collateral Agent, for the ratable benefit of
the Holders of the Senior Secured Notes, and credited and applied against the
Obligations, whether matured or unmatured, in accordance with the terms of the
Indenture, provided, however, that if

                  (a) any Pledgor has made payment to the Collateral Agent for
         the ratable benefit of the Holders of the Senior Secured Notes of all
         or any part of the Obligations, and

                  (b) the Satisfaction Date has occurred,

the Collateral Agent, on behalf of the Holders of the Senior Secured Notes,
agrees that, at such Pledgor's request, the Collateral Agent, on behalf of the
Holders of the Senior Secured Notes, will execute and deliver to such Pledgor
appropriate documents (without recourse and without representation or warranty
necessary to evidence the transfer by subrogation to such Pledgor of an interest
in the Obligations resulting from such payment by such Pledgor. In furtherance
of the foregoing, prior to the Satisfaction Date, each Pledgor shall refrain
from taking any action or commencing any proceeding against any other Guarantor
(or its successors or assigns, whether in connection with a bankruptcy
proceeding or otherwise) to recover any amounts in respect of payments made
under this Pledge Agreement to the Collateral Agent or the Holders of the Senior
Secured Notes.

                  ARTICLE III. REPRESENTATIONS AND WARRANTIES

         SECTION 3.1. Warranties, etc. Each Pledgor represents and warrants unto
the Collateral Agent and the Holders of the Senior Secured Notes, as at the date
of each pledge and delivery hereunder (including each pledge and delivery of
Pledged Shares) by such Pledgor to the Collateral Agent of any Collateral as set
forth in this Article.

         SECTION 3.2. Ownership, No Liens, etc. Each Pledgor is the legal and
beneficial owner of, and has good and valid title to (and has full right and
authority to pledge and assign) the Collateral, free and clear of all Liens,
except any Lien granted pursuant hereto in favor of the Collateral Agent or any
Permitted Lien.

         SECTION 3.3. Valid Security Interest. The execution and delivery of
this Pledge Agreement creates a valid first-priority security interest in the
Collateral and (a) in the case of the Pledged Shares, upon the delivery of such
Collateral to the Collateral Agent or a person described in Section 8-301(a)(2)
of the U.C.C. such security interest will be a valid first-priority, perfected
security interest, and (b) in the case of all other Collateral, upon the filing
of the U.C.C. financing statements (Form U.C.C.-1) delivered by the Pledgors to
the Collateral Agent with respect to such Collateral, such security interest
will be a valid first-priority, perfected security interest. Each Pledgor has
filed all U.C.C. financing statements (Form U.C.C.-1) referred to above in the
appropriate offices therefor (or has provided the Collateral Agent with copies



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thereof suitable for filing in such offices) and has taken all of the other
actions referred to above necessary to create perfected and first-priority
security interests in the applicable Collateral.

         SECTION 3.4. INTENTIONALLY OMITTED.

         SECTION 3.5. As to Pledged Shares. In the case of any Pledged Shares
constituting Collateral, all such Pledged Shares are duly authorized and validly
issued, fully paid and non-assessable, and constitute sixty-five percent (65%)
of the issued and outstanding Capital Stock of each Issuer. No Pledgor has any
Subsidiaries incorporated outside of the United States of which it directly owns
any Capital Stock other than the Issuers and the Unrestricted Subsidiaries. All
Pledged Shares are certificated, have been delivered to the Collateral Agent or
a person described in Section 8-301(a)(2) of the U.C.C., with stock powers,
accompanied by undated instruments of transfer duly executed in blank and the
Collateral Agent has "control" (as defined in the U.C.C.) of such Pledged
Shares.

         SECTION 3.6. Authorization, Approval, etc. No authorization, approval
or other action by, and no notice to or filing with, any Governmental Authority,
regulatory body or other Person (other than those that have been, or on the
Closing Date will be, duly obtained or made and which are, or on the Closing
Date will be, in full force and effect) is required either

                  (a) for the pledge by such Pledgor of any Collateral pursuant
         to this Pledge Agreement or for the execution, delivery and performance
         of this Pledge Agreement by such Pledgor, or

                  (b) for the exercise by the Collateral Agent of the voting or
         other rights provided for in this Pledge Agreement, or, except with
         respect to any Pledged Shares as may be required in connection with a
         disposition of such Pledged Shares by laws affecting the offering and
         sale of securities generally, the remedies in respect of the Collateral
         pursuant to this Pledge Agreement,

provided, however, that in order to exercise the voting and certain other rights
provided for in this Pledge Agreement, the Pledged Shares must be transferred
into the name of the Collateral Agent on the books and records of the Issuer
prior to the exercise of such voting or other rights.

         SECTION 3.7. Compliance with Laws. Each Pledgor is in compliance with
the requirements of all applicable laws (including, the provisions of the Fair
Labor Standards Act), rules, regulations and orders of every Governmental
Authority, the non-compliance with which could have a material adverse effect on
the business, prospects, financial condition or results of operations of the
Pledgor and its Subsidiaries (as defined in the Indenture), taken as a whole, or
draw into question the validity of this Pledge Agreement or the other documents
contemplated by the Indenture or adversely affect the value of the Pledged
Shares.

         SECTION 3.8. Power to Enter Into Agreement. Each Pledgor has full
corporate power and authority to enter into this Pledge Agreement.

         SECTION 3.9. Due Execution. This Pledge Agreement has been duly
executed and delivered by Pledgor and constitutes a legal, valid and binding
obligation of each Pledgor, enforceable against each Pledgor in accordance with
its terms, except as the enforceability hereof



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may be limited by bankruptcy, insolvency or similar laws affecting creditors'
rights generally and equitable principles of general applicability.

         SECTION 3.10. No Litigation. No litigation, investigation or proceeding
of or before any arbitrator or governmental authority is pending or, to the best
knowledge of any Pledgor, threatened by or against Pledgor or against any of its
properties or revenues with respect to this Pledge Agreement or any of the
transactions contemplated hereby.

         SECTION 3.11. Legal Pledge. The pledge of the Collateral pursuant to
this Pledge Agreement is not prohibited by any applicable law or governmental
regulation, release, interpretation or opinion of the Board of Governors of the
Federal Reserve System or other regulatory agency (including, without
limitation, Regulations T, U and X of the Board of Governors of the Federal
Reserve System).


                             ARTICLE IV. COVENANTS

         SECTION 4.1. Protect Collateral, Further Assurances, etc. No Pledgor
has or will sell, assign, transfer, pledge, or encumber in any other manner the
Collateral (except in favor of the Collateral Agent hereunder and as
specifically provided by the Indenture). Each Pledgor will warrant and defend
the right and title herein granted unto the Collateral Agent in and to the
Collateral (and all right, title and interest represented by the Collateral)
against the claims and demands of all Persons whomsoever. Each Pledgor agrees
that at any time, and from time to time, at the expense of such Pledgor, such
Pledgor will promptly execute and deliver all further instruments, and take all
further action, that may be necessary or desirable, or that the Collateral Agent
may reasonably request, in order to perfect and protect any security interest
granted or purported to be granted hereby or to enable the Collateral Agent to
exercise and enforce its rights and remedies hereunder with respect to any
Collateral. No Pledgor will permit any Issuer to issue any Capital Stock unless
the same are immediately pledged to the Collateral Agent hereunder and the
additional Capital Stock is pledged to Collateral Agent at the pro-rata levels
outlined in Section 2.1 hereof and delivered to the Collateral Agreement or a
person described in Section 8.301(a)(2) of the U.C.C.

         SECTION 4.2. Stock Powers, etc. Each Pledgor agrees that all Pledged
Shares (and all other Capital Stock constituting Collateral) delivered by such
Pledgor pursuant to this Pledge Agreement will be accompanied by duly executed,
undated stock powers or other equivalent instruments of transfer reasonably
acceptable to the Collateral Agent. Each Pledgor will, from time to time upon
the reasonable request of the Collateral Agent, promptly deliver to the
Collateral Agent such stock powers, instruments and similar documents,
reasonably satisfactory in form and substance to the Collateral Agent, with
respect to the Collateral as the Collateral Agent may reasonably request and
will, from time to time upon the request of the Collateral Agent after the
occurrence of any Event of Default, promptly cause each Issuer to transfer any
Pledged Shares or other Capital Stock constituting Collateral into the name of
any nominee designated by the Collateral Agent.

         SECTION 4.3. Continuous Pledge. Subject to Section 2.4 hereof, each
Pledgor will, at all times, keep pledged to the Collateral Agent pursuant hereto
all Pledged Shares and all other



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Capital Stock constituting Collateral, all Dividends and Distributions with
respect thereto, and all other Collateral and other Capital Stock, instruments,
proceeds and rights from time to time received by or distributable to such
Pledgor in respect of any Collateral. Any Distributions on Pledged Shares
consisting of Capital Stock will be certificated.

         SECTION 4.4. Voting Rights, Dividends, etc. Each Pledgor agrees:

                  (a) if an Event of Default shall have occurred and be
         continuing, promptly upon receipt thereof by such Pledgor and without
         any request therefore by the Collateral Agent, to deliver (properly
         endorsed where required hereby or requested by the Collateral Agent) to
         the Collateral Agent all Dividends, Distributions and all proceeds of
         the Collateral, all of which shall be held by the Collateral Agent as
         additional Collateral for use in accordance with Section 6.4 hereof;
         and

                  (b) if an Event of Default shall have occurred and be
         continuing and the Collateral Agent shall have notified such Pledgor of
         the Collateral Agent's intention to exercise its voting power under
         this Section:

                           (i) the Collateral Agent may exercise (to the
                  exclusion of such Pledgor) the voting power and all other
                  incidental rights of ownership with respect to any Pledged
                  Shares or other Capital Stock constituting Collateral, and
                  such Pledgor hereby grants the Collateral Agent an irrevocable
                  proxy, exercisable under such circumstances, to vote the
                  Pledged Shares and such other Collateral; and

                           (ii) promptly to deliver to the Collateral Agent such
                  additional proxies and other documents as may be necessary to
                  allow the Collateral Agent to exercise such voting power.

All Dividends, Distributions and proceeds which may at any time and from time to
time be held by Pledgor but which Pledgor is then obligated to deliver to the
Collateral Agent, shall, until delivery to the Collateral Agent, be held by such
Pledgor separate and apart from its other property in trust for the Collateral
Agent. The Collateral Agent agrees that unless an Event of Default shall have
occurred and be continuing and the Collateral Agent shall have given the notice
referred to in this Section, each Pledgor have the exclusive power to exercise
all voting and other consensual rights with respect to any Capital Stock
(including any of the Pledged Shares) constituting Collateral and the Collateral
Agent shall, upon the written request of such Pledgor, promptly deliver such
proxies and other documents, if any, as shall be reasonably requested by such
Pledgor, and which are necessary to allow such Pledgor to exercise such powers
with respect to any such share of Capital Stock (including any of the Pledged
Shares) constituting Collateral; provided, however, that no vote shall be cast,
or consent, waiver or ratification given, or action taken by any Pledgor that
would materially impair the value of any Collateral or be inconsistent with or
violate any provision of the Indenture, the Senior Secured Notes or this Pledge
Agreement.



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                        ARTICLE V. THE COLLATERAL AGENT

         SECTION 5.1. Collateral Agent Appointed Attorney-in-Fact. Each Pledgor
hereby irrevocably appoints the Collateral Agent as such Pledgor's
attorney-in-fact, with full authority and in the name, place and stead of the
Pledgor or in its own name, from time to time in the Collateral Agent's
discretion, to take, upon the occurrence and during the continuance of an Event
of Default, any action and to execute any instrument which the Collateral Agent
may deem necessary or advisable to accomplish the purposes of this Pledge
Agreement, including without limitation:

                  (a) to ask, demand, collect, sue for, recover, compromise and
         receive and give acquittance and receipts for moneys due and to become
         due under or in respect of any of the Collateral,

                  (b) to receive, endorse and collect any drafts or other
         instruments, documents and chattel paper, in connection with clause (a)
         above; and

                  (c) to file any claims or take any action or institute any
         proceedings which the Collateral Agent may deem necessary or desirable
         for the collection of any of the Collateral or otherwise to enforce the
         rights of the Collateral Agent with respect to any of the Collateral.

         SECTION 5.2. Authority of Collateral Agent.

                  (a) The Collateral Agent shall have and be entitled to
         exercise all powers hereunder that are specifically granted to the
         Collateral Agent by the terms hereof, together with such powers as are
         reasonably incidental thereto. The Collateral Agent may perform any of
         its duties hereunder or in connection with the Pledged Collateral by or
         through agents or employees and shall be entitled to retain counsel and
         to act in reliance upon the advice of counsel concerning all such
         matters. Neither the Collateral Agent nor any director, officer,
         employee, attorney or agent of the Collateral Agent shall be
         responsible for the validity, effectiveness or sufficiency hereof or of
         any document or security furnished pursuant hereto. The Collateral
         Agent and its directors, officers, employees, attorneys and agents
         shall be entitled to rely on any communication, instrument or document
         reasonably believed by it or them to be genuine and correct and to have
         been signed or sent by the proper person or persons.

                  (b) Each Pledgor acknowledges that the rights and
         responsibilities of the Collateral Agent under this Pledge Agreement
         with respect to any action taken by the Collateral Agent or the
         exercise or non-exercise by the Collateral Agent of any option, right,
         request, judgment or other right or remedy provided for herein or
         resulting or arising out of this Pledge Agreement shall, as between the
         Collateral Agent and the Holders of the Senior Secured Notes, be
         governed by the Indenture and by such other agreements with respect
         thereto as may exist from time to time among them, but, as between the
         Collateral Agent and each and any Pledgor, the Collateral Agent shall
         be conclusively presumed to be acting as agent for the Holders of the
         Senior Secured Notes



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         with full and valid authority so to act or refrain from acting, and
         each Pledgor shall not be obligated or entitled to make any inquiry
         respecting such authority.

         SECTION 5.3. Resignation or Removal of the Collateral Agent. Until such
time as the Obligations shall have been paid in full, the Collateral Agent may
at any time, by giving written notice to Pledgor, the Trustee (as defined in the
Indenture) and the Holders of the Senior Secured Notes, resign and be discharged
of the responsibilities hereby created, such resignation to become effective
upon (i) the appointment of a successor Collateral Agent and (ii) the acceptance
of such appointment by such successor Collateral Agent. As promptly as
practicable after the giving of any such notice, the Trustee (if the Trustee is
not then acting as the Collateral Agent hereunder), or if the Trustee and the
Collateral Agent are the same person or entity, the Holders of the Senior
Secured Notes shall appoint a successor Collateral Agent, which successor
Collateral Agent shall be reasonably acceptable to the Pledgors. If no successor
Collateral Agent shall be appointed and shall have accepted such appointment
within 90 days after the Collateral Agent gives the aforesaid notice of
resignation, the Collateral Agent may apply to any court of competent
jurisdiction to appoint a successor Collateral Agent to act until such time, if
any, as a successor shall have been appointed as provided in this Section. Any
successor so appointed by such court shall immediately and without further act
be superseded by any successor Collateral Agent appointed by the Holders of the
Senior Secured Notes, as provided in this Section. Simultaneously with its
replacement as Collateral Agent hereunder, the Collateral Agent so replaced
shall deliver to its successor all documents, instruments, certificates and
other items of whatever kind (including, without limitation, the certificates
and instruments evidencing the Collateral and all instruments of transfer or
assignment) held by it pursuant to the terms hereof. Any Collateral Agent that
has resigned shall be entitled to fees, costs and expenses to the extent
incurred or arising, or relating to events occurring, before its resignation or
removal.

         SECTION 5.4. Release; Termination of Agreement.

                  (a) This Pledge Agreement shall terminate upon the earlier to
         occur of: (i) full and final payment and performance of the Obligations
         (and upon receipt by the Collateral Agent of the Pledgors' written
         certification that all such Obligations have been satisfied) and
         payment in full of all fees and expenses owing by the Pledgors to the
         Collateral Agent, (ii) the day of the Legal Defeasance of all of the
         Obligations pursuant to Section 8.02 of the Indenture (other than those
         surviving Obligations specified therein) or (iii) such other
         termination date as is provided by the Indenture. At such time, the
         Collateral Agent shall, at the request of any Pledgor, reassign and
         redeliver to such Pledgor all of the Collateral hereunder that has not
         been sold, disposed of, retained or applied by the Collateral Agent in
         accordance with the terms hereof. Such reassignment and redelivery
         shall be without warranty by or recourse to the Collateral Agent,
         except as to the absence of any prior assignments by the Collateral
         Agent of its interest in the Collateral, and shall be at the expense of
         such Pledgor.

                  (b) Each Pledgor agrees that it will not, except as permitted
         by the Indenture, sell or dispose of, or grant any option or warrant
         with respect to, any of the Collateral; provided, however, that if any
         Pledgor shall sell any of the Collateral in accordance with the terms
         of the Indenture, the Collateral Agent shall, at the request of such
         Pledgor and



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         subject to requirements of Section 10.03 of the Indenture, release the
         Collateral subject to such sale free and clear of the Lien under this
         Pledge Agreement.

         SECTION 5.5. Collateral Agent May Perform. If any Pledgor falls to
perform any agreement contained herein, the Collateral Agent may itself perform,
or cause performance of, such agreement, and the expenses of the Collateral
Agent incurred in connection therewith shall be payable by such Pledgor pursuant
to Section 6.5 hereof.

         SECTION 5.6. Collateral Agent Has No Duty. The powers conferred on the
Collateral Agent hereunder are solely to protect its interest (on behalf of the
Holders of the Senior Secured Notes) in the Collateral and shall not impose any
duty on it to exercise any such powers. Except for the reasonable care of any
Collateral in its possession and the accounting for moneys actually received by
it hereunder, the Collateral Agent shall have no duty as to any Collateral or
responsibility for

                  (a) ascertaining or taking action with respect to calls,
         conversions, exchanges, maturities, tenders or other matters relative
         to any Collateral, whether or not the Collateral Agent has or is deemed
         to have knowledge of such matters, or

                  (b) taking any necessary steps to preserve rights against
         prior parties or any other rights pertaining to any Collateral.

         SECTION 5.7. Reasonable Care. The Collateral Agent is required to
exercise reasonable care in the custody and preservation of any of the
Collateral in its possession, provided, however, the Collateral Agent shall be
deemed to have exercised reasonable care in the custody and preservation of any
of the Collateral, if it takes such action for that purpose as the relevant
Pledgor reasonably requests in writing from time to time, but failure of the
Collateral Agent to comply with any such request at any time shall not in itself
be deemed a failure to exercise reasonable care. If an Event or Event of Default
has occurred and is continuing, the Collateral Agent shall not be required to
comply with any request of any Pledgor with respect to the matters described in
this Section.

                              ARTICLE VI. REMEDIES

         SECTION 6.1. Certain Remedies. If an Event of Default shall have
occurred and be continuing:


                  (a) The Collateral Agent may exercise in respect of the
         Collateral, in addition to other rights and remedies provided for
         herein or otherwise available to it, all the rights and remedies of a
         secured party on default under the U.C.C. (whether or not the U.C.C.
         applies to the affected Collateral) and also may, without notice except
         as specified below, sell the Collateral or any part thereof in one or
         more parcels at public or private sale, at any of the Collateral
         Agent's offices or elsewhere, for cash, on credit or for future
         delivery, and upon such other terms as the Collateral Agent may deem
         commercially reasonable. Each Pledgor agrees that, to the extent notice
         of sale shall be required by law, at least ten day's prior notice to
         such Pledgor of the time and place of any public sale or the time after
         which any private sale is to be made shall constitute reasonable



                                      -11-
<PAGE>   12

         notification. The Collateral Agent shall not be obligated to make any
         sale of Collateral regardless of notice of sale having been given. The
         Collateral Agent may adjourn any public or private sale from time to
         time by announcement at the time and place fixed therefore, and such
         sale may, without further notice, be made at the time and place to
         which it was so adjourned.

                  (b) The Collateral Agent may

                           (i) transfer all or any part of the Collateral into
                  the name of the Collateral Agent or its nominee, with or
                  without disclosing that such Collateral is subject to the Lien
                  hereunder,

                           (ii) notify the parties obligated on any of the
                  Collateral to make payment to the Collateral Agent of any
                  amount due or to become due thereunder,

                           (iii) enforce collection of any of the Collateral by
                  suit or otherwise, and surrender, release or exchange all or
                  any part thereof, or compromise or extend or renew for any
                  period (whether or not longer than the original period) any
                  obligations of any nature of any party with respect thereto,

                           (iv) endorse any checks, drafts or other writings in
                  any Pledgor's name to allow collection of the Collateral,

                           (v) take control of any proceeds of the Collateral
                  and

                           (vi) execute (in the name, place and stead of any
                  Pledgor) endorsements, assignments, stock powers and other
                  instruments of conveyance or transfer with respect to all or
                  any of the Collateral.

         SECTION 6.2. Securities Laws. If the Collateral Agent shall determine
to exercise its right to sell all or any of the Collateral pursuant to Section
6.1, each Pledgor agrees that, upon request of the Collateral Agent, such
Pledgor will use commercially reasonable efforts to, at its own expense:

                  (a) execute and deliver, and cause each issuer of the
         Collateral contemplated to be sold and the directors and officers
         thereof to execute and deliver, all such instruments and documents, and
         do or cause to be done all such other acts and things, as may be
         necessary or, in the opinion of the Collateral Agent, advisable to
         register such Collateral under the provisions of the Securities Act of
         1933, as from time to time amended (the "Securities Act"), and to cause
         the registration statement relating thereto to become effective and to
         remain effective for such period as prospectuses are required by law to
         be furnished, and to make all amendments and supplements thereto and to
         the related prospectus which, in the opinion of the Collateral Agent,
         are necessary or advisable. all in conformity with the requirements of
         the Securities Act and the rules and regulations of the Securities and
         Exchange Commission applicable thereto;



                                      -12-
<PAGE>   13

                  (b) use its best efforts to qualify the Collateral under the
         state securities or "Blue Sky" laws and to obtain all necessary
         governmental approvals for the sale of the Collateral, as requested by
         the Collateral Agent;

                  (c) cause each such issuer to make available to its security
         holders, as soon as practicable, an earnings statement that will
         satisfy the provisions of Section 11(a) of the Securities Act; and

                  (d) do or cause to be done all such other acts and things as
         may be necessary to make such sale of the Collateral or any part
         thereof valid and binding and in compliance with applicable law.

Each Pledgor further acknowledges the impossibility of ascertaining the amount
of damages that would be suffered by the Collateral Agent or the Holders of the
Senior Secured Notes by reason of the failure by such Pledgor to perform any of
the covenants contained in this Section and, consequently, agrees that, if such
Pledgor shall fall to perform any of such covenants, it shall pay, as liquidated
damages and not as a penalty, an amount equal to the value (as determined by the
Collateral Agent) of the Collateral on the date the Collateral Agent shall
demand compliance with this Section.

         SECTION 6.3. Compliance with Restrictions. Each Pledgor agrees that in
any sale of any of the Collateral whenever an Event of Default shall have
occurred and be continuing, the Collateral Agent is hereby authorized to comply
with any limitation or restriction in connection with such sale as it may be
advised by counsel is necessary in order to avoid any violation of applicable
law (including compliance with such procedures as may restrict the number of
prospective bidders and purchasers, require that such prospective bidders and
purchasers have certain qualifications and restrict such prospective bidders and
purchasers to persons who will represent and agree that they are purchasing for
their own account for investment and not with a view to the distribution or
resale of such Collateral), or in order to obtain any required approval of the
sale or of the purchaser by any Governmental Authority, and each Pledgor further
agrees that such compliance shall not result in such sale being considered or
deemed not to have been made in a commercially reasonable manner, nor shall the
Collateral Agent be liable nor accountable to any Pledgor for any discount
allowed by reason of the fact that such Collateral is sold in compliance with
any such limitation or restriction.

         SECTION 6.4. Application of Proceeds. All cash proceeds received by the
Collateral Agent in respect of any sale of, collection from or other realization
upon, all or any part of the Collateral may, in the discretion of the Collateral
Agent, be held by the Collateral Agent as additional collateral security for, or
then or at any time thereafter be applied (after payment of any amounts payable
to the Collateral Agent pursuant to Section 7.07 of the Indenture and, Section
6.5 below) in whole or in part by the Collateral Agent against, all or any part
of the Obligations in such order as the Collateral Agent shall elect. Any
surplus of such cash or other proceeds held by the Collateral Agent and
remaining after the Satisfaction Date, shall be paid over to the applicable
Pledgor or to whomsoever may be lawfully entitled to receive such surplus. The
Pledgors shall remain liable on a joint and several basis for any deficiency.



                                      -13-
<PAGE>   14

         SECTION 6.5. Indemnity and Expenses. Each Pledgor hereby jointly and
severally indemnifies and holds harmless the Collateral Agent from and against
any and all claims, losses and liabilities arising out of or resulting from this
Pledge Agreement (including enforcement of this Pledge Agreement), except
claims, losses or liabilities resulting from the Collateral Agent's gross
negligence or wilful misconduct, and each Pledgor will pay to the Collateral
Agent the amount of any and all reasonable expenses, including the reasonable
fees and disbursements of its counsel and of any experts and agents, which the
Collateral Agent may incur, in each case, in connection with:

                  (a) the administration of this Pledge Agreement,

                  (b) the custody, preservation, use or operation of, or the
         sale of, collection from or other realization upon, any of the
         Collateral,

                  (c) the exercise or enforcement of any of the rights of the
         Collateral Agent hereunder, or

                  (d) the failure by any Pledgor to perform or observe any of
         the provisions hereof.

                     ARTICLE VII. MISCELLANEOUS PROVISIONS

         SECTION 7.1. Security Agreement. This Pledge Agreement is a Security
Agreement executed pursuant to the Indenture and shall (unless otherwise
expressly indicated herein) be construed, administered and applied in accordance
with the terms and provisions thereof.

         SECTION 7.2. Amendments, etc. No amendment to or waiver of any
provision of this Pledge Agreement nor consent to any departure by any Pledgor
herefrom shall in any event be effective unless the same shall be in writing and
signed by the Collateral Agent (on behalf of the Holders of the Senior Secured
Notes) and each Pledgor, and then such waiver or consent shall be effective only
in the specific instance and for the specific purpose for which it is given.

         SECTION 7.3. Protection of Collateral. The Collateral Agent may from
time to time, at its option, and at the expense of the Pledgors, perform any act
which any Pledgor agrees hereunder to perform and which such Pledgor shall fall
to perform after being requested in writing so to perform (it being understood
that no such request need be given after the occurrence and during the
continuance of an Event of Default) and the Collateral Agent may from time to
time take any other action which the Collateral Agent reasonably deems necessary
for the maintenance, preservation or protection of any of the Collateral or of
its security interest therein.

         SECTION 7.4. Addresses for Notices. All notices and other
communications provided for hereunder shall be in writing and addressed,
delivered or transmitted, if to any Pledgor, at the address or facsimile number
of the Company provided for in the Indenture, and, if to the Collateral Agent,
at Harris Trust Company of New York, Wall Street Plaza, 19th Floor, 88 Pine
Street, New York, NY 10005, Telecopier No.: (212) 701-7664, Attn: Peter Morse,
or as to any such party at such other address or facsimile number as shall be
designated by such party in a written notice to each other party complying as to
delivery with the terms of this Section. Any



                                      -14-
<PAGE>   15

notice, (a)(i) if mailed and properly addressed with postage prepaid or (ii) if
properly addressed and sent by pre-paid courier service, shall be deemed given
when such notice has been received or (b) if transmitted by facsimile, shall be
deemed given when transmitted (and telephonic confirmation of receipt thereof
has been received).

         SECTION 7.5. Heading. The various headings of this Pledge Agreement are
inserted for convenience only, and shall not affect the meaning or
interpretation of this Pledge Agreement or any provisions hereof.

         SECTION 7.6. Severability. Any provision of this Pledge Agreement which
is prohibited or unenforceable in any jurisdiction shall, as to such provision
and such jurisdiction, be ineffective to the extent of such prohibition or
unenforceability, without invalidating the remaining provisions of this Pledge
Agreement or affecting the validity or enforceability of such provision in any
other jurisdiction.

         SECTION 7.7. Governing Law. THIS PLEDGE AGREEMENT SHALL BE DEEMED TO BE
A CONTRACT MADE UNDER AND GOVERNED BY THE INTERNAL LAWS OF THE STATE OF NEW
YORK, EXCLUDING THE LAW OF CONFLICTS.

         SECTION 7.8. Counterparts. This Pledge Agreement may be executed by the
parties hereto in several counterparts, each of which shall be deemed to be an
original (whether such counterpart is originally executed or an electronic copy
of an original) and all of which shall constitute together but one and the same
agreement. This Pledge Agreement shall become effective and binding upon any
Pledgor when a counterpart hereof executed on behalf of such Pledgor shall have
been received by the Collateral Agent.

                   [Signatures commence on the following page]




                                      -15-
<PAGE>   16



         IN WITNESS WHEREOF, the parties hereto have caused this Pledge
Agreement to be duly executed and delivered by their respective officers
thereunto duly authorized as of the day and year first above written.

                                     PLEDGORS:

                                     STERLING CHEMICALS, INC.


                                     By
                                        ----------------------------------------
                                         Title:


                                     STERLING CANADA, INC.


                                     By
                                        ----------------------------------------
                                         Title:


                                     COLLATERAL AGENT:


                                     HARRIS TRUST COMPANY OF NEW YORK,
                                     a New York corporation, as Collateral Agent


                                     By
                                        ----------------------------------------
                                         Title:


                                      -16-
<PAGE>   17



                                  ATTACHMENT 1
                                       to
                                Pledge Agreement



<TABLE>
<CAPTION>

NAME OF PLEDGOR

              Pledged Shares
              --------------

                  Issuer                                                        Capital Stock
                  ------                         --------------------------------------------------------------------------


                                                 Authorized           % of Shares         Outstanding            Number of
                                                   Shares               Pledged              Shares               Shares
                                                 ----------           -----------         -----------           -----------
<S>                                              <C>                  <C>                 <C>                   <C>
Sterling Pulp Chemicals, Ltd.
    o    Class A Special                                 --            43,685.127                  65%           28,395.333

Sterling NRO Ltd.
    o    Class A Special                                 --            73,714.994                  65%           47,914.714
    o    Common                                        1000                  1000                  65%                  650

Sterling Chemicals Marketing, Inc.                     1000                  1000                  65%                  650
</TABLE>


                                      -17-