<PAGE>
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549

                                   ----------

                                   FORM 10-K/A

               AMENDMENT TO APPLICATION OR REPORT AMENDMENT NO. 1

              [X] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934

                   FOR THE FISCAL YEAR ENDED DECEMBER 31, 2001
                         COMMISSION FILE NUMBER 0-30723

                                   OSCA, INC.
             (Exact name of registrant as specified in its charter)

                DELAWARE                                    72-0868136
     (State or other jurisdiction of                      (IRS Employer
       incorporation or organization)                    Identification No.)

          156 COMMISSION BLVD.
              LAFAYETTE, LA                                   70508
(Address of principal executive offices)                    (Zip Code)

         Registrant's telephone number, including area code 337-837-6047

Securities registered pursuant to Section 12(b) of the Act: None

Securities registered pursuant to Section 12(g) of the Act:

                      CLASS A COMMON STOCK, $0.01 PAR VALUE


                                EXPLANATORY NOTE


The undersigned registrant hereby amends the following items, financial
statements, exhibits or other portions of its Annual Report on Form 10-K as set
forth in the pages attached hereto: PART III: ITEMS 10, 11, 12 AND 13.


<PAGE>



ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF OSCA

         Set forth below is the name, age and position as of April 1, 2002 for
each of the directors and executive officers of OSCA. Pursuant to OSCA's bylaws,
directors are elected to serve for three-year terms until their successors are
elected or their earlier resignation or removal.

<Table>
<Caption>

NAME                      AGE      POSITION
----                      ---      --------
<S>                       <C>      <C>
Mark P. Bulriss            50      Chairman of the Board
Richard A. Pattarozzi      58      Director
Mack G. Nichols            63      Director
John L. Whitmire           61      Director
W. Bernard Pieper          69      Director
Martin M. Hale             61      Director
Richard T. Higgons         59      Director
Robert L. Hollier          59      President, Chief Executive Officer and Director
Richard J. Alario          47      Executive Vice President--Completion Fluids
Jerome F. Borges           43      Vice President--International
Steven J. Brading          50      Vice President, Chief Financial Officer and Corporate Treasurer
J. David Duplantis         51      Vice President--Completion Services
Stephen M. Gray            42      Vice President, General Counsel and Corporate Secretary
Donald H. Michel           50      Senior Vice President--Completion Tools
James H. Tycer             53      Vice President--North American Land
</Table>

         Mark P. Bulriss has been one of OSCA's directors since February 2000
and serves as the chairman of OSCA. Mr. Bulriss has been the Chief Executive
Officer and President of Great Lakes Chemical Corporation, OSCA's majority
stockholder, since April 1998 and became Chairman of the Board of Great Lakes as
of May 4, 2000. Prior to joining Great Lakes Chemical Corporation, Mr. Bulriss
served as President of AlliedSignal Polymers from 1996 to 1998, a $2.1 billion
business unit of AlliedSignal (now Honeywell International), which manufactures
polymers and markets nylon, technical fibers, plastics, films and chemical
intermediates. Before being named president of its polymers unit, Mr. Bulriss
served as President of AlliedSignal's electronic materials business from 1995 to
1996. His 24-year career in chemicals and plastics also includes 16 years with
GE Plastics, a division of the General Electric Corporation. Mr. Bulriss
currently serves as a director of the American Chemistry Council. Mr. Bulriss
received a B. S. degree in Chemical Engineering from Clarkson University.

         Richard A. Pattarozzi has been one of OSCA's directors since April
2000. Mr. Pattarozzi was the President and Chief Executive Officer of Shell
Deepwater Development Co. and Shell Deepwater Production Co. from 1995 to 1999.
From March 1999 until his retirement on January 1, 2000, Mr. Pattarozzi served
as Vice President of Shell Offshore, Inc. He currently serves as a director of
Stone Energy Corporation, an independent oil and gas exploration company,
Transocean Sedco Forex, a worldwide drilling contractor, Tidewater, Inc., a
worldwide boat company and Global Industries, Inc., a worldwide pipeline and
construction company.



                                       1
<PAGE>

         Mack G. Nichols has been one of OSCA's directors since February 2000.
Mr. Nichols, prior to his retirement in 1998, was President and Chief Operating
Officer and a director of Mallinckrodt Inc., a diversified chemical and
healthcare company, from 1995 to 1998. Mr. Nichols served as the President and
Chief Executive Officer of Mallinckrodt Specialty Chemical Company, a
wholly-owned subsidiary of Mallinckrodt Inc., from 1989 to 1995. He is currently
a director of Great Lakes and has served as a director of A. P. Green
Industries, Inc., the National Association of Manufacturers and the Chemical
Manufacturers Association.

         John L. Whitmire has been one of OSCA's directors since April 2000. Mr.
Whitmire was Chairman of the Board and Chief Executive Officer of Union Texas
Petroleum Holdings, Inc. from 1996 until he retired in 1998, when Union Texas
Petroleum Holdings was acquired by Atlantic Richfield Company. Before joining
Union Texas Petroleum Holdings, Mr. Whitmire served in various capacities for
more than 30 years with Phillips Petroleum Company, including Executive Vice
President--exploration and production and as a director from 1994 to 1996. Mr.
Whitmire has served as Chairman of the Board for CONSOL Energy Inc. and CONSOL
Inc. since March 1999. In addition, Mr. Whitmire is a director of the National
Audubon Society and Global Santa Fe Inc.

         W. Bernard Pieper has been one of OSCA's directors since April 2000.
Mr. Pieper served as Vice Chairman and Chief Operating Officer of Halliburton
Company from 1994 until his retirement in 1996. Mr. Pieper has served as a
director of Highlands Insurance Group, Inc., a property and casualty insurance
business, since 1996. Mr. Pieper has also been a director of NCI Building
Systems, Inc. since January 2001.

         Martin M. Hale has been one of OSCA's directors since February 2000.
Since December 2000, Mr. Hale has served as the Executive Vice President of
Hellman, Jordan Management Co., Inc., a registered investment advisor
specializing in asset management, a position he also held from 1983 until
December 1999. Prior to 1983, Mr. Hale was the President and Chief Executive
Officer of Marsh & McLennan Asset Management Company. Mr. Hale also serves as a
director of Great Lakes Chemical Corporation and Octel Corp., a former
subsidiary of Great Lakes, which was spun off in 1998 and as a trustee of the
Museum of Fine Arts, Boston.

         Richard T. Higgons has been one of OSCA's directors since January 2001.
Mr. Higgons is Executive Vice President, Performance Chemicals and Business
Development for Great Lakes, OSCA's majority stockholder. Prior to joining Great
Lakes in 2001, Mr. Higgons was Staff Vice President for corporate development
with Mallinckrodt, Inc., a position he held from 1996 to 2001. From 1991 to
1995, he was Vice President for business development for Mallinckrodt's chemical
business. From 1988 to 1991, Mr. Higgons held several senior management
positions in finance, business development and strategic planning for Imcera
Group, Inc.

         Robert L. Hollier has served as OSCA's President and Chief Executive
Officer since August 1979. He has been one of OSCA's directors since February
2000. He also served as Vice President of Great Lakes from 1991 to 2000. Prior
to founding OSCA, he served as Vice President and Chief Operating Officer of
Gulf Coast Drilling Fluids, Inc. from 1970 to 1979. Prior to his tenure at Gulf
Coast, Mr. Hollier was employed by the Amoco Production Company from 1963 to
1970. He is



                                       2
<PAGE>

also a director of the Louisiana Association of Business Industry and a director
of University of Louisiana at Lafayette's Petroleum Engineering Advisory Counsel
for Excellence.

         Richard J. Alario has been OSCA's Executive Vice President--Completion
Fluids since May 1999. Since joining OSCA in 1981, Mr. Alario has managed
numerous business units and functions, including sales and marketing and
international operations. Prior to joining OSCA, Mr. Alario was employed by
Ashland Chemical Company from 1978 to 1981. Mr. Alario is a director and a
member of the Executive Committee of the National Ocean Industries Association
and a member of the Louisiana State University Petroleum Engineering Department
Industry Advisory Council.

         Jerome F. Borges is OSCA's Vice President - International since
November 2001. Prior to joining OSCA, Mr. Borges held numerous senior management
roles in Halliburton Energy Services, including Region Vice President of
Halliburton Energy Services for the Middle East and Asia Pacific. He also was
Global Vice President of Stimulation and Completions for Halliburton Energy
Services from 1996 to 1999 in Houston, Texas. He has experience in marketing,
business development, technology, and front line operations with Halliburton
since 1981.

         Steven J. Brading joined OSCA in May 1999 as OSCA's Vice President,
Chief Financial Officer and Corporate Treasurer. From 1993 to 1999, Mr. Brading
was employed by the Camco Products and Services division of Camco International,
Inc., most recently as Vice President of finance and information systems. Prior
to 1993, Mr. Brading was employed by LTV Corporation as the Controller of its
drilling equipment division.

         J. David Duplantis joined OSCA in May 2001 as OSCA's Vice President -
Business Development. In September 2001 Mr. Duplantis became Vice
President-Completion Services. Prior to joining OSCA, Mr. Duplantis served as
President and Chief Operating Officer of Preeminent Energy Services, Inc. from
1995 to 2001. He also served on that company's Board of Directors. Mr. Duplantis
served as North American Operation Manager for Halliburton Energy Services from
1993 to 1994. Prior to working for Halliburton, Mr. Duplantis worked for Otis
Engineering Corporation in various managerial and technical capacities.

         Stephen M. Gray is OSCA's Vice President, General Counsel and Corporate
Secretary. Mr. Gray joined OSCA in June 2000 in that capacity. From 1996 to
2000, Mr. Gray was employed by Pennzoil Company through its transition to
PennzEnergy Company and merger with Devon Energy Corporation where he most
recently served as Senior Attorney to the offshore business unit. Prior to
joining Pennzoil Company, Mr. Gray was in private practice from 1990 to 1996 and
served the oil and gas industry.

         Donald H. Michel has been OSCA's Senior Vice President--Completion
Tools since September 2001. Mr. Michel rejoined OSCA in April 1999 where he
served as Senior Vice President Completion Tools. Mr. Michel originally joined
OSCA as a Vice President of Business Development in 1986 and served in various
capacities including Sr. Vice President of Sand Control, Pumping and Tools
Division until his departure from OSCA in 1996. From 1996 until 1998, Mr. Michel
was part owner of Wesco Well Screens, a downhole tool manufacturing company.
From



                                       3
<PAGE>

1998 until April 1999, Mr. Michel was president and part owner of Oilfield
Manufacturing, Inc., also a downhole tools manufacturing company.

         James H. Tycer has been OSCA's Vice President--North American Land
since September 2001. Mr.Tycer was Vice President - Completion Services from
March 1998 until September 2001. From 1996 to March 1998, he served as Service
Line Manager for Completion Services of OSCA. Prior to joining OSCA in 1996, Mr.
Tycer held numerous positions with BJ Services from 1981 to 1996, most recently
as Gulf Coast Regional Manager of coiled tubing and nitrogen services for BJ
Services/NOWSCO.

SECTION 16(a)  BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

         Section 16(a) of the Securities Exchange Act of 1934, as amended,
requires OSCA's officers and directors, and persons who beneficially own more
than 10% of a registered class of OSCA's equity securities, to file reports of
ownership and changes in ownership with the Securities and Exchange Commission.
Officers, directors and greater than ten percent stockholders are required by
the regulations promulgated under Section 16(a) to furnish OSCA with copies of
all Section 16(a) forms they file.

         Based solely on OSCA's review of the copies of such reports received by
it, or written representations from certain reporting persons that no such
reports were required for those persons, OSCA believes that, during 2001, all
filing requirements applicable to officers, directors, and greater than ten
percent stockholders were complied with on a timely basis.

ITEM 11. EXECUTIVE COMPENSATION

COMPENSATION OF EXECUTIVE OFFICERS

         The following table sets forth information concerning compensation for
2001, 2000 and 1999 earned by or paid to:

o        OSCA's Chief Executive Officer and

o        OSCA's four highest paid executive officers, other than the CEO, whose
         total annual salary and bonus exceeded $100,000 in 2001 (collectively
         with the CEO, the "Named Executive Officers").



                                       4
<PAGE>

<Table>
<Caption>

                                                                                    Long-Term
                                                                                   Compensation
                                                                                      Awards
                                                                  Other             Securities        All Other
                              Fiscal                              Annual            Underlying      Compensation
    Name and Position          Year     Salary      Bonus      Compensation          Options            (1)
--------------------------    ------    -------    --------    -------------       -------------    -------------
<S>                            <C>     <C>         <C>         <C>                 <C>              <C>
Robert L. Hollier,             2001    $300,131    $     --    $          --              35,000    $      24,760
President and                  2000     289,163     174,600               --             120,000            9,945
Chief Executive Officer        1999     277,440      55,000               --                  --            9,029

Steven J. Brading,             2001     154,102          --               --              15,000           12,543
Vice President, Chief          2000     145,069      60,160               --              25,000            8,575
Financial Officer and          1999      85,673      20,000               --                  --            2,338
and Corporate Treasurer(2)

Richard J. Alario,             2001     161,760          --               --              17,000           13,165
Executive Vice President       2000     153,923      62,400               --              35,000            8,998
Completion Fluids              1999     142,034          --               --                  --           10,616

Donald H. Michel,              2001     160,800          --               --              15,000           12,982
Senior Vice President          2000     153,923      59,280               --              20,000            8,998
Completion Tools(3)            1999     102,692      25,000               --                  --            2,963

Stephen M. Gray,               2001     143,446          --               --               7,500            9,696
Vice President, General        2000      74,308      39,000           30,456(5)            8,000            5,950
Counsel and Corporate
Secretary(4)
</Table>

(1)      These amounts represent (i) employer matching contributions under
         OSCA's Savings Plan and the Great Lakes 401(k) Plan, (ii) employer
         profit sharing contributions by OSCA on behalf of the named executive
         officer to the OSCA Savings Plan and (iii) employer supplemental match
         to Rabbi Trust.

(2)      Mr. Brading joined OSCA in May 1999.

(3)      Mr. Michel rejoined OSCA in April 1999.

(4)      Mr. Gray joined OSCA in June 2000.

(5)      Consists of relocation costs of $29,641 and other benefits of vehicle
         fuel and maintenance costs of $815.

COMPENSATION PURSUANT TO EMPLOYEE BENEFIT PLANS

         OSCA maintains several plans intended to provide incentives to its key
employees. These plans are described below:



                                       5
<PAGE>

Incentive Compensation Plans

         OSCA maintains incentive compensation plans under which certain
employees of OSCA and its subsidiaries may be eligible to receive a cash bonus
following each calendar year based on a comparison of financial performance
against targets established for each plan year.

Stock Compensation Plan

         OSCA has one stock compensation plan that provides for grants of
stock-based awards to key employees and nonemployee directors. Plan provisions
allow grants of incentive and nonqualified stock options, with terms not to
exceed 10 years, at the fair market value of the OSCA Class A Common Stock on
the date of grant, as well as other stock-based awards. The Plan provides for
accelerated vesting of outstanding unvested options as a result of a merger.

Savings Plan

         Eligible employees of OSCA can elect to participate in the OSCA Savings
Plan beginning the first day of hire. Employees may elect to contribute up to
18% of their pay into the plan, subject to certain limits prescribed by Section
402(g) of the Internal Revenue Code. OSCA makes matching contributions, in cash,
equal to 75% of the first 6% of salary contributed by the employee. Employees
determine how their salary deferrals are invested by selecting from several
investment alternatives. OSCA may also elect to make a profit sharing
contribution in an amount at OSCA's discretion, although no profit sharing
contribution is required. All deferrals and contributions are recorded in
individual accounts and held in trust.

Deferred Compensation Plan

         Each year participants may defer up to 100% of base salary and bonus
reduced by the amount of salary and bonus that is deferred by the participant
under OSCA's Savings Plan for such year. The Deferred Compensation Plan is
intended to provide eligible employees with benefits in excess of those that can
be provided under the Savings Plan because of Internal Revenue Code limits.

OPTION GRANTS IN 2001

         The following table provides information related to options granted to
the Named Executive Officers during 2001:



                                       6
<PAGE>


<Table>
<Caption>
                                                                                            POTENTIAL REALIZABLE
                                                                                              VALUE AT ASSUMED
                       NUMBER OF       % OF TOTAL                                              ANNUAL RATE OF
                       SECURITIES        OPTIONS                                                STOCK PRICE
                       UNDERLYING      GRANTED TO      EXERCISE OR                             APPRECIATION
                        OPTIONS         EMPLOYEES       BASE PRICE       EXPIRATION          FOR OPTION TERM(3)
      NAME             GRANTED(1)    IN FISCAL YEAR    ($/SHARE)(2)        DATE             5%               10%
------------------    ------------   --------------    ------------    ------------    ------------    ------------
<S>                   <C>            <C>               <C>             <C>             <C>             <C>
Robert  L. Hollier          35,000            16.0%    $    21.8125           02/11    $    480,122    $  1,216,723
Steven J. Brading           15,000             6.8%         21.8125           02/11         205,766         521,453
Richard J. Alario           17,000             7.7%         21.8125           02/11         233,202         590,980
Donald H. Michel            15,000             6.8%         21.8125           02/11         205,766         521,453
Stephen M. Gray              7,500             3.4%         21.8125           02/11         102,883         260,726
</Table>

(1)  Each option has a term of ten years and is exercisable in cumulative 33%
     installments commencing one year from the date of grant with full vesting
     occurring on the third anniversary of the date of grant.

(2)  The exercise price is the closing price of OSCA Class A Common Stock on the
     day before such stock option grant.

(3)  Amounts reflect assumed rates of 5% and 10% appreciation. Actual gains, if
     any, on stock option exercises depend on the future performance of OSCA
     Class A Common Stock and overall market conditions. At an annual rate of
     appreciation of 5% per year for the option term, the price of OSCA Class A
     Common Stock would be approximately $35.53 per share. At an annual rate of
     appreciation of 10% per year for the option term, the price of OSCA Class A
     Common Stock would be approximately $56.58 per share.

OPTION EXERCISES IN 2001 AND VALUE OF OPTIONS AT DECEMBER 31, 2001

         The following table provides information related to options exercised
by the Named Executive Officers during 2001 and the number and value of options
held at year-end. OSCA does not have any stock appreciation rights outstanding.

<Table>
<Caption>

                                                                 NUMBER OF                         VALUE OF
                        SHARES                                  SECURITIES                       UNEXERCISED
                       ACQUIRED                                 UNDERLYING                       IN-THE-MONEY
                         ON              VALUE              UNEXERCISED OPTIONS                   OPTION AT
                       EXERCISE         REALIZED          AT DECEMBER 31, 2001(#)           DECEMBER 31, 2001 ($)
NAME                     (#)              ($)          EXERCISABLE     UNEXERCISABLE     EXERCISABLE     UNEXERCISABLE
----                  ------------    ------------    -------------    -------------    -------------    -------------
<S>                   <C>             <C>             <C>              <C>              <C>              <C>
Robert  L. Hollier               0               0           40,000          115,000    $     214,000    $     428,000
Steven J. Brading                0               0            8,334           31,666           44,587           89,163
Richard J. Alario                0               0           10,000           37,000           53,500          107,000
Donald H. Michel                 0               0            6,667           28,333           35,668           71,332
Stephen M. Gray                  0               0            2,667           12,833           14,268           28,532
</Table>



                                       7
<PAGE>

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

         The Compensation Committee is composed of Messrs. Bulriss, Nichols,
Pattarozzi and Whitmire. There are no Compensation Committee interlocks between
OSCA and any other entities involving OSCA's executive officers and directors
who serve as executive officers of such entities.

CHANGE-IN-CONTROL AND SEVERANCE AGREEMENTS

         OSCA has entered into change in control agreements with Messrs.
Hollier, Brading, Alario, Michel and Gray. Under these agreements, OSCA or its
successor would make a lump sum severance payment to Messrs. Hollier, Brading,
Alario, Michel and Gray, as applicable, in an amount equal to three times the
individual's annual compensation (which includes among other things base salary,
bonus, deferred bonus, 401(k) contributions matched by OSCA and profit sharing
contributions) in the event that his employment with OSCA is terminated without
cause or he resigns for good reason within one year of a change in control of
OSCA. For purposes of these agreements between OSCA and the Named Executive
Officers, a "change in control" means the following:

         o        any unrelated person is or becomes the "beneficial owner," as
                  defined in Rule 13d-3 under the Exchange Act, directly or
                  indirectly, of OSCA securities representing more than 20% of
                  the combined voting power of its then outstanding securities,
                  other than securities acquired directly from OSCA and Great
                  Lakes holds a beneficial interest representing less than 51%
                  of the combined voting power of OSCA's then outstanding
                  securities;

         o        a merger or consolidation with or into any other corporation,
                  other than

                  (1)      a merger or consolidation which results in OSCA's
                           directors immediately prior to such merger or
                           consolidation continuing to constitute at least a
                           majority of OSCA's board of directors or the board of
                           the surviving entity or its parent, or

                  (2)      a merger or consolidation effected to implement a
                           recapitalization of OSCA or similar transaction in
                           which Great Lakes retains "beneficial ownership" of
                           at least 51% of the voting power of our then
                           outstanding securities, or no unrelated person is or
                           becomes the beneficial owner, directly or indirectly,
                           of OSCA securities representing 20% or more of the
                           combined voting power of OSCA's then outstanding
                           securities, regardless of whether Great Lakes
                           continues to be a "beneficial owner" of any OSCA
                           securities;

         o        OSCA's stockholders approve any plan or proposal for OSCA's
                  liquidation or dissolution or the consummation of a sale or
                  disposition of all or substantially all of OSCA's assets,
                  other than a sale or disposition to a related entity, at least
                  a majority of whose directors were directors of OSCA
                  immediately prior to such sale or disposition; or

         o        if, at the end of any two year period, OSCA's Board does not
                  consist of at least a majority of directors who were either
                  directors at the beginning of that two year period or whose
                  appointment, election or nomination to the board was approved
                  by a vote of at least two-thirds of the directors then in
                  office.



                                       8
<PAGE>

         For purposes of the change in control agreements, where a change in
control results from a series of related transactions, the change in control
will be deemed to have occurred on the date of the consummation of the first
related transaction.

         Notwithstanding any other provision of the change in control
agreements, a change in control will not be deemed to have occurred by virtue of
the consummation of any transaction or series of integrated transactions
immediately following which the record holders of OSCA's common stock
immediately prior to such transaction or series of transactions continue to have
substantially the same proportionate ownership in an entity which owns all or
substantially all of OSCA's assets immediately following this transaction or
series of transactions.

         Mr. Hollier also has a change in control agreement with Great Lakes
Chemical Corporation that shall not be preempted or superseded by the OSCA
change in control agreement. In the event that Mr. Hollier becomes entitled to
receive concurrent severance payments under both the OSCA and Great Lakes
agreements, then the Great Lakes agreement shall supersede the OSCA agreement
and Mr. Hollier shall only be entitled to receive severance payments under the
Great Lakes agreement.

DIRECTORS' COMPENSATION

         In 2001, each nonemployee director was paid an annual retainer of
$24,000 prorated for their time of service. Employees of OSCA or Great Lakes
Chemical Corporation who also serve as directors receive no additional
compensation for serving on the Board or on any Board committee.

         In addition to the annual retainer, nonemployee directors are paid as
follows:

         o        $1,000 for each Board meeting attended; and

         o        Reimbursement of expenses for travel, lodging and related
                  expenses incurred while attending Board and Board committee
                  meetings.

         o        Nonemployee directors who chair a committee receive an
                  additional $2,000 per year.

         In 2001, each nonemployee director received an option to acquire 1,100
shares of Class A Common Stock at the fair market value of the shares on the
date of the grant. Each option has a term of 10 years and is exercisable in
cumulative 33% installments commencing one year from date of grant.

COMPENSATION COMMITTEE REPORT ON EXECUTIVE COMPENSATION

         The Compensation Committee of the Board of Directors reviews and
approves individual officer salaries, bonuses and stock option grants for
officers other than Mr. Hollier. The Board of Directors determines the
compensation package for Mr. Hollier. The Committee also reviews guidelines for
compensation, bonus and stock option grants for non-officer employees.

         With the approval and assistance of the Compensation Committee, OSCA
has developed and implemented compensation policies which seek to enhance the
profitability of OSCA, and thus




                                       9
<PAGE>

stockholder value, by closely aligning the financial interests of OSCA's senior
managers with those of the stockholders. OSCA has structured its compensation of
senior managers to include an annual bonus and longer-term stock option
incentives to motivate them to perform to the full extent of their abilities.
Neither of these incentives is guaranteed. Both are variable and closely tied to
corporate, business unit and individual performance targets focused on enhancing
OSCA's profitability and increasing stockholder value. The key corporate
performance target is economic value added before taxes. EVA is based on the
comparison of operating income to a cost of capital. The Committee considers the
total compensation of each of the executive officers and other senior managers
in establishing each element of compensation. Eligible persons must be employed
by OSCA at the time bonus compensation is paid.

         The Committee believes that the compensation policies it has
implemented have contributed to focusing senior management on achieving
significant improvements in long-term financial performance.

CHIEF EXECUTIVE COMPENSATION

         Mr. Hollier's base salary was increased in 2001 to $305,900. This was
based on the criteria set forth above. The Committee considered his level and
scope of responsibilities as well. The deterioration of the business environment
in OSCA's industry since July 2001 (including the significant decline in oil
well completion activity in the Gulf of Mexico driven by a weakened economic
environment and decreased oil and natural gas pricing) resulted in OSCA missing
some of the performance targets with respect to the incentive compensation plan
and accordingly Mr. Hollier was not awarded a bonus for 2001.

POSITION ON DEDUCTIBILITY OF COMPENSATION

         Section 162(m) of the Internal Revenue Code imposes a limitation on the
deductibility of nonperformance-based compensation in excess of $1 million paid
to Named Executive Officers. The Committee currently believes that OSCA should
be able to continue to manage its executive compensation program for Named
Executive Officers so as to preserve the related federal income tax deductions.
The Committee intends to monitor the impact of Section 162(m) and consider
structuring executive compensation arrangements so that the deduction limitation
will continue not to apply.

         COMPENSATION COMMITTEE

         Mark P. Bulriss
         Mack G. Nichols
         Richard A. Pattarozzi
         John L. Whitmire

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

         The following table sets forth certain information as of April 1, 2002,
regarding the beneficial ownership of Class A Common Stock by the Named
Executive Officers of OSCA (as required by SEC




                                       10
<PAGE>

rules), and all directors and executive officers as a group. Information
concerning persons known to OSCA to be beneficial owners of more than 5 percent
of its Class A Common Stock is based upon the most recently available reports
furnished by such persons to OSCA on Schedules 13G filed with the Securities and
Exchange Commission.

         In addition, Great Lakes owns 100%, or 7,900,000 shares, of the
outstanding Class B Common Stock of OSCA. Class B Common Stock is convertible
into Class A Common Stock at any time at Great Lakes' option or automatically
upon transfer by Great Lakes other than in a tax-free distribution. Since shares
of Class B Common Stock are entitled to ten votes per share, the shares of Class
B Common Stock owned by Great Lakes represent approximately 92% of the aggregate
voting power of OSCA stock.


<Table>
<Caption>

                                                          AMOUNT AND NATURE OF
                                                          BENEFICIAL OWNERSHIP
NAME AND ADDRESS OF  BENEFICIAL OWNER                     OF CLASS A COMMON(1)       PERCENT OF CLASS
-------------------------------------                     --------------------       ----------------
<S>                                                       <C>                        <C>
Cannell Capital, LLC
   150 California Street, Fifth Floor,
   San Francisco, CA 94111                                          963,400(2)                13.9

Steinberg Priest Capital Management Company, Inc.
   12 East 49th Street
   New York, NY 10017                                               705,000(3)                10.5

Gabelli Asset Management, Inc.
    One Corporate Center
    Rye, NY 10580                                                   589,779(4)                 8.5

The  TCW Group, Inc.
   on behalf of the TCW Business Unit
   865 South Figueroa Street,
   Los Angeles, CA 90017                                            583,300(5)                 8.4

Cramer Rosenthal McGlynn, LLC
   707 Westchester Avenue,
   White Plains, NY 10604                                           456,600(6)                 6.6

DIRECTORS AND NAMED EXECUTIVES:
Mark P. Bulriss                                                       2,000                      *
Martin M. Hale                                                       18,999(7)                   *
Richard T. Higgons                                                       --                      *
Mack G. Nichols                                                       3,199(8)                   *
Richard A. Pattarozzi                                                 5,199(8)                   *
W. Bernard Pieper                                                     2,199(8)                   *
John L. Whitmire                                                      1,199(8)                   *
Robert L. Hollier                                                    91,051(9)                 1.3
Steven J. Brading                                                    16,420(10)                  *
Richard J. Alario                                                    19,526(11)                  *
Don H. Michel                                                        18,466(12)                  *
Stephen M. Gray                                                       6,070(13)                  *
Directors and executive officers as a group (15 persons)            193,494                    2.7
</Table>


                                       11
<PAGE>

----------

*Indicates  less than 1.0%

(1)      Unless otherwise indicated, beneficial ownership is direct, and the
         person indicated has sole voting and investment power.

(2)      Voting and dispositive power over these shares is shared with J. Carlo
         Cannell, the managing member of Cannell Capital, LLC.

(3)      Based upon a Schedule 13G filed jointly by Steinberg Priest Capital
         Management Company, Inc. ("SPCMC"), an investment advisor, and Michael
         A. Steinberg & Co., Inc., a broker-dealer. In the Schedule 13G, SPCMC
         reported that it has sole voting power with respect to 102,000 shares
         and sole dispositive power with respect to 691,500 shares, and
         Steinberg & Co. reported that it has sole dispositive power with
         respect to 13,500 shares.

(4)      As set forth in a Schedule 13D/A filed by Gabelli Funds, LLC ("Gabelli
         Funds"), GAMCO Investors, Inc. ("GAMCO"), Gabelli Associates Limited
         ("GAL"), Gabelli Associates Fund ("GAF"), Gabelli Fund, LDC ("GFL"),
         MJG Associates, Inc. ("MJG"), Gabelli Securities, Inc. ("Gabelli
         Securities"), Gabelli Group Capital Partners, Inc., Gabelli Asset
         Management, Inc., Marc J. Gabelli and Mario J. Gabelli on March 20,
         2002. The Schedule 13D/A reports that these shares represent: (i)
         45,000 shares beneficially owned by Gabelli Funds; (ii) 233,004 shares
         beneficially owned by GAMCO; (iii) 161,300 shares beneficially owned by
         GAL; (iv) 122,475 shares beneficially owned by GAF; (v) 2,000 shares
         beneficially owned by GFL; (vi) 3,000 shares beneficially owned by MJG;
         and (vii) 18,000 shares beneficially owned by Gabelli Securities. The
         Schedule 13D/A reports that each such entity has sole voting and
         dispositive power over the shares reported as beneficially owned by it.

(5)      The TCW Group, Inc., on behalf of itself and its direct and indirect
         subsidiaries which collectively constitute the TCW Business Unit, has
         shared voting power and shared dispositive power with respect to these
         shares. According to such amended Schedule 13G, the relevant
         subsidiaries of TCW are TCW Asset Management Company and TCW Investment
         Management Company. Such filing also states that the ultimate parent
         company of TCW is Societe Generale, S.A. ("SG"), a corporation formed
         under the laws of France, that due to the separate management and
         independent operation of its business units SG disclaims beneficial
         ownership of shares of OSCA owned by TCW, and that TCW disclaims
         Beneficial ownership of any shares of OSCA beneficially owned by SG and
         any of SG's other business units.

(6)      Based upon a Schedule 13G filed by Cramer Rosenthal McGlynn, LLC on
         February 14, 2002, Cramer Rosenthal McGlynn, LLC has shared voting and
         investment power with respect to all shares in the table.

(7)      Includes: (1) 1,199 shares that may be purchased within 60 days of
         April 1, 2002 pursuant to the exercise of outstanding options; and (2)
         1,000 shares owned by Mr. Hale's spouse, as to which Mr. Hale disclaims
         beneficial ownership.

(8)      Includes 1,199 shares that may be purchased within 60 days of April 1,
         2002 pursuant to the exercise of outstanding options.



                                       12
<PAGE>

(9)      Includes (1) 51,666 shares that may be purchased within 60 days of
         April 1, 2002 pursuant to the exercise of outstanding options; and (2)
         includes 1,000 shares owned by Mr. Hollier's spouse.

(10)     Includes 13,333 shares that may be purchased within 60 days of April 1,
         2002 pursuant to the exercise of outstanding options.

(11)     Includes 15,666 shares that may be purchased within 60 days of April 1,
         2002 pursuant to the exercise of outstanding options.

(12)     Includes 11,666 shares that may be purchased within 60 days of April 1,
         2002 pursuant to the exercise of outstanding options.

(13)     Includes 5,166 shares that may be purchased within 60 days of April 1,
         2002 pursuant to the exercise of outstanding options.

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

       Great Lakes owns shares representing approximately 53% of the ownership
and 92% of the voting power of OSCA's Common Stock. In addition, one member of
OSCA's Board - Mark P. Bulriss - is an officer and director of Great Lakes, two
members of OSCA's Board - Martin M. Hale and Mack G. Nichols - are directors of
Great Lakes, and a fourth member - Richard T. Higgons - is an officer of Great
Lakes.

ARRANGEMENTS WITH GREAT LAKES

         The terms of OSCA's separation from Great Lakes in June 2000 and many
of the related transactions are governed by a master separation agreement dated
June 20, 2000, which is referred to as the "Separation Agreement," and a number
of additional agreements described below. These other agreements include
agreements relating to the initial public offering and a distribution to Great
Lakes stockholders, the registration of Great Lakes' remaining shares of Class B
common stock, the provision of transitional services by Great Lakes, the supply
of brominated chemicals by Great Lakes and the tax treatment of OSCA's possible
separation from Great Lakes. All of the agreements providing for the separation
from Great Lakes were made in the context of parent-subsidiary relationship and
were negotiated in the overall context of OSCA's separation from Great Lakes.
The terms of these agreements may be more or less favorable than if they had
been negotiated with unaffiliated third parties.

SEPARATION AGREEMENT

         OSCA was historically operated as a wholly owned subsidiary of Great
Lakes. OSCA has directly owned most of its assets, with the exception of some
European subsidiaries that were transferred to OSCA in contemplation of the
separation from Great Lakes in June 2000. The Separation Agreement sets forth
the arrangements with Great Lakes with respect to any additional corporate
transactions that may be required to effect the transfer of any remaining assets
and the assumption of any remaining liabilities necessary to separate OSCA from
Great Lakes.



                                       13
<PAGE>

         OSCA has assumed, and indemnified Great Lakes for, all liabilities and
all claims related to the OSCA business and Great Lakes has retained, and will
indemnify OSCA for, all liabilities and all claims related to its business. In
addition, Great Lakes has agreed to indemnify OSCA for all liabilities related
to the former environmental remediation services business in Mexico and OSCA's
participation in a joint venture formed to provide services associated with
pipeline commissioning and infrastructure support services primarily in the Gulf
of Mexico. In exchange for this indemnity, OSCA has agreed that Great Lakes will
be entitled to all rights and beneficial interests and all tangible and
intangible assets relating to these businesses. OSCA and Great Lakes have agreed
to cooperate with each other in the defense of any and all claims covered by
these provisions of the Separation Agreement.

         The Separation Agreement also contains provisions that govern the
resolution of disputes, controversies or claims that may arise between OSCA and
Great Lakes. The Separation Agreement provides that the parties will use all
commercially reasonable efforts to settle all disputes arising in connection
with the Separation Agreement without resorting to mediation, arbitration or
otherwise. If these efforts are unsuccessful, any party may submit the dispute
for non-binding mediation by delivering notice to the other party of the dispute
and expressly requesting mediation. If, after mediation, the parties disagree
regarding the mediator's recommendation, the dispute will be submitted to
binding arbitration in accordance with the terms of the Separation Agreement.

IPO AND DISTRIBUTION AGREEMENT

         General. OSCA and Great Lakes have entered into an Initial Public
Offering and Distribution Agreement dated June 20, 2000, which is referred to as
the "IPO and Distribution Agreement," with Great Lakes which governs OSCA's
respective rights and duties with respect to its initial public offering in June
2000 and a distribution to Great Lakes stockholders, if any, and contains
covenants designed to facilitate a distribution and to protect its intended
tax-free nature. However, OSCA cannot assure you as to whether or when a
distribution will occur.

         The Distribution. If Great Lakes decides to pursue a distribution to
Great Lakes stockholders, OSCA has agreed that it will cooperate with Great
Lakes in all respects to accomplish a distribution and, at Great Lakes'
direction, promptly take all actions necessary or desirable to effect a
distribution to Great Lakes stockholders, including the registration under the
Securities Act of 1933, as amended, of Great Lakes' shares of OSCA's capital
stock. Great Lakes has the sole discretion to determine whether to proceed with
all or part of a distribution to Great Lakes stockholders and all terms of that
distribution, including the form, structure and terms of any transaction(s)
and/or offering(s) to effect a distribution and the timing of and conditions to
the consummation of a distribution.

         Preservation of the Tax-free Status of a Distribution. If Great Lakes
decides to pursue a distribution to Great Lakes stockholders, Great Lakes would
intend for a distribution to qualify as a tax-free distribution under Section
355 of the tax code to Great Lakes and its stockholders. OSCA has agreed to
covenants in the IPO and Distribution Agreement that are intended to preserve
the tax-free status of a distribution to Great Lakes stockholders. OSCA may take
any action otherwise prohibited by these covenants only if Great Lakes has
determined, in its sole and absolute discretion, that the action would not
jeopardize the tax-free status of a distribution. See "--Cooperation on Tax
Matters." Some of these covenants are described in greater detail below:



                                       14
<PAGE>

         o        Stock Issuance. Prior to the completion of a distribution to
                  Great Lakes stockholders, OSCA has agreed not to issue or
                  agree to issue shares of OSCA's capital stock in an amount
                  that would result in Great Lakes ceasing to own an amount of
                  OSCA's capital stock which constitutes "control" for purposes
                  of Section 368(c) of the tax code or any successor statute or
                  provision, as such definition may be amended from time to
                  time. This covenant will not prohibit OSCA from issuing stock
                  options and restricted stock awards to OSCA's employees so
                  long as it repurchases sufficient shares of OSCA's capital
                  stock prior to the date when such options and awards become
                  exercisable to ensure that Great Lakes' continues to have
                  control of it and Great Lakes approves of OSCA's procedures in
                  connection with these repurchases.

         o        Acquisition Transactions. Until two years after the completion
                  of a distribution to Great Lakes stockholders, or, if Great
                  Lakes determines not to complete a distribution, the last date
                  on which Great Lakes distributed any OSCA common stock in
                  connection with a distribution, OSCA has agreed not to enter
                  into or permit any transaction or series of transactions which
                  would result in a person or persons acquiring or having the
                  right to acquire shares of OSCA's capital stock that would
                  comprise 50% or more of either the value of all outstanding
                  shares of OSCA's capital stock or the total combined voting
                  power of OSCA's outstanding voting stock.

         o        Continuation of Active Trade or Business. Until two years
                  after the completion of a distribution to Great Lakes
                  stockholders, or, if Great Lakes determines not to complete a
                  distribution, the last date on which Great Lakes distributed
                  any OSCA common stock in connection with a distribution, OSCA
                  has agreed to continue to conduct the active trade or
                  business, within the meaning of Section 355 of the tax code,
                  of OSCA as it was conducted immediately prior to the
                  completion of a distribution. During such time, OSCA has
                  agreed not to:

                  o        liquidate, dispose of or otherwise discontinue any
                           portion of OSCA's active trade or business with a
                           value in excess of $25 million; or

                  o        dispose of any business or assets that would cause it
                           to be operated in a manner inconsistent in any
                           material respect with the business purposes for a
                           distribution as described to the IRS or tax counsel.
                           Also, until two years after the completion of a
                           distribution, OSCA has agreed not to liquidate,
                           dispose of, or otherwise discontinue the conduct of
                           any portion of OSCA's active trade or business if
                           such liquidation, disposition or discontinuance would
                           breach the covenant described below regarding OSCA's
                           continuity of business.

         o        Continuity of Business. Until two years after the completion
                  of a distribution to Great Lakes stockholders, or, if Great
                  Lakes determines not to complete a distribution, the last date
                  on which Great Lakes distributed any OSCA common stock in
                  connection with a distribution, OSCA has agreed that:



                                       15
<PAGE>

         o        it will not voluntarily dissolve or liquidate; and

         o        except in the ordinary course of business, neither OSCA nor
                  any of its direct or indirect subsidiaries will sell,
                  transfer, or otherwise dispose of or agree to dispose of
                  assets, including any shares of capital stock of OSCA's
                  subsidiaries, that, in the aggregate, constitute more than:

                  (x)      60% of OSCA's gross assets; or

                  (y)      60% of OSCA's consolidated gross assets and those of
                           OSCA's subsidiaries.

                  For this purpose, OSCA is not deemed to directly or indirectly
                  control a subsidiary unless it owns, directly or indirectly,
                  shares constituting control for tax purposes.

         o        Discharge of Intracompany Debt. Prior to the first date on
                  which Great Lakes distributes any of OSCA's common stock in
                  connection with a distribution, OSCA has agreed to fully
                  discharge and satisfy all debt that it owes Great Lakes. For
                  this purpose, debt does not include payables arising in the
                  ordinary course of business. Until two years after the
                  completion of a distribution, or, if Great Lakes determines
                  not to complete a distribution, the last date on which Great
                  Lakes distributed any OSCA common stock in connection with a
                  distribution, OSCA will not be able to have any indebtedness
                  payable to Great Lakes.

         In the event that Great Lakes notifies OSCA that it no longer intends
to proceed with or complete a distribution to Great Lakes stockholders and Great
Lakes has not yet distributed any of its OSCA common stock, these covenants to
preserve the tax-free status of a distribution will terminate.

         Cooperation on Tax Matters. OSCA and Great Lakes have agreed to
procedures with respect to the tax-related covenants in the IPO and Distribution
Agreement. OSCA is required to notify Great Lakes if it desires to take any
action prohibited by the tax-related covenants described above. Upon this
notification, if Great Lakes determines that the proposed action might
jeopardize the tax-free status of a distribution to Great Lakes stockholders,
Great Lakes has agreed to elect either to:

         o        use all commercially reasonable efforts to obtain a private
                  letter ruling from the IRS or a tax opinion that would permit
                  OSCA to take the desired action, and OSCA has agreed to
                  cooperate in connection with such efforts; or

         o        provide all reasonable cooperation to OSCA in connection with
                  OSCA's obtaining an IRS ruling or tax opinion.

In either case, Great Lakes has agreed to bear its reasonable costs and expenses
of obtaining an IRS ruling or tax opinion.

         In addition, in the event that Great Lakes, at any time prior to a
distribution, ceases to own OSCA's common stock constituting control for tax
purposes, OSCA has agreed to cooperate and



                                       16
<PAGE>

take (or refrain from taking) all actions reasonably requested by Great Lakes or
necessary so as to permit Great Lakes to regain ownership of OSCA's common stock
which constitutes control for tax purposes in a manner that would not jeopardize
the tax-free status of the distribution.

         Indemnification for Tax Liabilities. OSCA has generally agreed to
indemnify Great Lakes and its affiliates against any and all tax-related losses
incurred by Great Lakes in connection with any proposed tax assessment or tax
controversy with respect to a distribution to Great Lakes stockholders to the
extent caused by any breach by OSCA of any of its representations, warranties or
covenants made in the IPO and Distribution Agreement. This indemnification does
not apply to actions which Great Lakes permits OSCA to take as a result of a
determination under the tax-related covenants described above.

         Other OSCA Covenants. Great Lakes currently owns a significant portion
of OSCA's common stock. As a result, Great Lakes will continue to include OSCA
as a "subsidiary" for various financial reporting, accounting and other
purposes. Accordingly, OSCA has agreed to additional covenants in the IPO and
Distribution Agreement. Some of these covenants are described below:

         o        Covenants Regarding the Incurrence of Debt. For so long as
                  Great Lakes continues to own at least 50% of OSCA's
                  outstanding common stock, the amount of OSCA's indebtedness
                  for borrowed money will affect Great Lakes' financial
                  position. Thus, OSCA has agreed to the following limitations
                  on OSCA's ability to incur debt during that time:

                  o        it will not, without Great Lakes' consent, incur
                           indebtedness in excess of an aggregate $40.0 million
                           outstanding at any time;

                  o        it may, however, incur indebtedness in connection
                           with an acquisition so long as the entity OSCA is
                           acquiring meets certain capital requirements and
                           OSCA's indebtedness after giving effect to the
                           transaction would not exceed $50.0 million; and

                  o        it may not, without Great Lakes' consent, consummate
                           or agree to consummate any acquisition that does not
                           meet OSCA's debt thresholds.

         o        Other Covenants. For so long as Great Lakes continues to own
                  at least 50% of OSCA's outstanding common stock, OSCA has
                  agreed that:

                  o        it will not, without Great Lakes' prior written
                           consent, which it may withhold in its sole and
                           absolute discretion, take any action which has the
                           effect of limiting Great Lakes' ability to freely
                           sell, pledge or otherwise dispose of shares of OSCA's
                           common stock or limiting the legal rights of or
                           denying any benefit to Great Lakes as an OSCA
                           stockholder in a manner not applicable to OSCA's
                           stockholders generally;

                  o        it will not, without Great Lakes' prior written
                           consent, which it may withhold in its sole and
                           absolute discretion, issue any shares of common stock
                           or any



                                       17
<PAGE>

                           rights, warrants or options to acquire OSCA's common
                           stock, if after giving effect to such issuance, Great
                           Lakes would own less than 50% of the then outstanding
                           shares of OSCA's common stock; and

                  o        to the extent that Great Lakes is a party to, or
                           enters into, any agreements that provide that actions
                           of its subsidiaries may result in its being in breach
                           or default under any agreement, and OSCA has been
                           advised of the existence of these agreements, it will
                           not take any actions that may result in Great Lakes
                           being in breach or default.

         o        Financial Information. OSCA has agreed that, for so long as
                  Great Lakes is required to consolidate OSCA's results of
                  operations and financial position or account for its
                  investment in OSCA's company, it will provide Great Lakes with
                  certain financial information regarding OSCA and OSCA's
                  subsidiaries. This covenant is subject to provisions intended
                  to protect the confidentiality commitments OSCA has made to
                  OSCA's customers.

         o        Auditors and Audits; Annual Statements and Accounting. OSCA
                  has agreed that, for so long as Great Lakes is required to
                  consolidate OSCA's results of operations and financial
                  position or account for its investment in OSCA under the
                  equity method of accounting (in accordance with generally
                  accepted accounting principles), it will:

                  o        not change OSCA's auditors without Great Lakes' prior
                           written consent, which will not be unreasonably
                           withheld;

                  o        use OSCA's best efforts to enable OSCA's auditors to
                           complete their audit of OSCA's financial statements
                           such that they will date their opinion the same date
                           that they date their opinion on Great Lakes'
                           financial statements;

                  o        provide to Great Lakes and its auditors all
                           information required for Great Lakes to meet its
                           schedule for the filing and distribution of its
                           financial statements;

                  o        make available to Great Lakes and its auditors work
                           papers related to the annual audit of OSCA as well as
                           access to the personnel who perform the annual audit
                           and OSCA's and OSCA's subsidiaries' books and records
                           so that Great Lakes and its auditors may conduct
                           reasonable audits relating to OSCA's financial
                           statements;

                  o        adhere to generally accepted accounting principles,
                           applied in a manner consistent with Great Lakes;

                  o        notify and consult with Great Lakes regarding any
                           changes to OSCA's accounting principles; and

                  o        make any changes to OSCA's accounting estimates and
                           principles requested by Great Lakes.



                                       18
<PAGE>

         OSCA has generally agreed to indemnify Great Lakes and its affiliates
against all liabilities arising out of any incorrect, inaccurate or incomplete
financial or other information it provides to Great Lakes pursuant to the terms
of the IPO and Distribution Agreement.

         Indemnification Relating to the Initial Public Offering and a
Distribution. OSCA has generally agreed to indemnify Great Lakes and its
affiliates against all liabilities arising out of any material untrue statements
and omissions in any and all registration statements, including the initial
public offering prospectus, information statements and/or other documents filed
with the SEC in connection with a distribution. However, OSCA's indemnification
obligations to Great Lakes do not apply to information relating to Great Lakes,
excluding information relating to OSCA. Great Lakes has agreed to indemnify OSCA
for this information.

         Expenses. In general, unless otherwise provided for in the IPO and
Distribution Agreement or any other agreement, OSCA and Great Lakes will pay
their own respective costs and expenses incurred in connection with the offering
and a distribution to Great Lakes stockholders.

         o        Expenses Relating to a Distribution. Great Lakes will
                  generally be responsible for the payment of all costs, fees
                  and expenses relating to a distribution to Great Lakes
                  stockholders; provided that OSCA will be responsible for the
                  payment of (a) the costs, fees and expenses of all of OSCA's
                  financial, legal, accounting and other advisors incurred in
                  connection with a distribution and (b) any internal fees,
                  costs and expenses incurred by OSCA or any of OSCA's
                  affiliates in connection with a distribution.

REGISTRATION RIGHTS AGREEMENT

         In the event that Great Lakes does not divest itself of all of its
shares of OSCA's common stock in a distribution, Great Lakes could not freely
sell all of its shares without registration under the Securities Act.
Accordingly, OSCA has entered into a Registration Rights Agreement with Great
Lakes dated June 20, 2000 to provide it with registration rights relating to the
shares of OSCA's common stock which it holds.

         Shares Covered. The Registration Rights Agreement covers those shares
of OSCA's common stock that are held by Great Lakes immediately following OSCA's
initial public offering and any other shares of OSCA's common stock that Great
Lakes acquires thereafter.

         Demand Registrations. Great Lakes may request registration, which is
referred to as a "demand registration," under the Securities Act of all or any
portion of OSCA's shares that it owns covered by the Registration Rights
Agreement and OSCA will be obligated to register such shares as requested by
Great Lakes.

         o        Terms of Each Offering. Subject to certain limitations, Great
                  Lakes will designate the terms of each offering effected
                  pursuant to a demand registration.

         o        Timing of Demand Registrations. OSCA is not required to
                  undertake a demand registration within 90 days of the
                  effective date of a previous demand registration, other than a
                  demand registration that was effected as a shelf registration.
                  Also,




                                       19
<PAGE>

                  OSCA has the right to postpone the filing or effectiveness of
                  any demand registration for up to 90 days if in the reasonable
                  judgment of OSCA's legal counsel that the demand registration
                  would reasonably be expected to have a material adverse effect
                  on any existing proposal or plans by OSCA to engage in
                  material transactions; provided, however, that OSCA may
                  exercise this right only once in any 12-month period.

         o        Priority on Demand Registrations. Other parties, including
                  OSCA, can participate in any demand registration only if all
                  of the securities Great Lakes proposes to include in such
                  registration are so included.

         o        Selection of Professionals. Great Lakes will select the
                  investment banker(s) and manager(s), subject to OSCA's
                  reasonable objection in some circumstances, as well as any
                  financial printer, solicitation and/or exchange agent and
                  counsel for the offering. OSCA will select its own outside
                  counsel and independent auditors.

         Piggyback Registrations. The Registration Rights Agreement also
provides for "piggyback" registration rights for Great Lakes. Whenever OSCA
proposes to register any of OSCA's securities under the Securities Act for
itself or others, subject to customary exceptions, it must provide prompt notice
to Great Lakes and include in such registration all shares of OSCA's stock which
Great Lakes requests to be included, each of which is referred to as a
"piggyback registration."

         o        Priority on Piggyback Registrations. If a piggyback
                  registration is being made on OSCA's behalf and the
                  underwriters advise it that cutbacks are necessary, OSCA must
                  include in such registration:

                  o        first, the securities it proposes to offer;

                  o        second, the securities requested to be included by
                           Great Lakes; and

                  o        third, any other securities requested to be included
                           in such registration.

         If a piggyback registration is being made on behalf of other holders of
         OSCA's securities and the underwriters advise OSCA that cutbacks are
         necessary, it must include in such registration:

                  o        first, the securities requested to be included by the
                           holders requesting such registration and the
                           securities requested to be included by Great Lakes,
                           pro rata among these holders and Great Lakes on the
                           basis of the number of securities owned by each
                           applicable holder; and

                  o        second, any other securities requested to be included
                           in such registration.

         Selection of Underwriters. In many circumstances, Great Lakes has the
right to reasonably object to OSCA's selection of any investment banker(s) and
manager(s) in connection with a piggyback registration.



                                       20
<PAGE>

         Holdbacks. The Registration Rights Agreement contains customary
holdback provisions, including covenants by OSCA not to effect a public sale or
distribution of OSCA's securities during periods prior to and following the date
of any registration statement filed in connection with a demand registration or
a piggyback registration.

         Registration Procedures and Expenses. The Registration Rights Agreement
sets forth customary registration procedures, including a covenant by OSCA to
make available its senior management for road show presentations. OSCA will be
obligated to pay all registration expenses incurred in connection with the
Registration Rights Agreement, including all filing fees, fees and expenses of
compliance with securities and/or blue sky laws, financial printing expenses,
fees and disbursements of custodians, transfer agents, exchange agents and/or
information agents, as well as fees and disbursements of counsel for OSCA and
the fees of all independent certified public accountants, underwriters,
excluding discounts and commissions, and other persons retained by OSCA. In
addition, OSCA must reimburse Great Lakes for the fees and disbursements of its
outside counsel as well as out-of-pocket expenses incurred in connection with
any such registration.

         Indemnification. The Registration Rights Agreement contains customary
indemnification and contribution provisions by OSCA for the benefit of Great
Lakes and any underwriters. Great Lakes has agreed to indemnify OSCA and any
underwriter solely with respect to information provided by Great Lakes.

         Transfer. Great Lakes may transfer shares covered by the Registration
Rights Agreement and the holders of such transferred shares will be entitled to
the benefits of the Registration Rights Agreement; provided that each such
transferee agrees to be bound by the terms of the Registration Rights Agreement.
These transferees will be entitled to the rights available to Great Lakes
described above; provided, however, that the holder or holders of a majority of
the shares covered by the Registration Rights Agreement will be entitled to
exercise these rights. Any successor entities to OSCA will be bound by the terms
of the Registration Rights Agreement.

         Duration. The registration rights under the Registration Rights
Agreement will remain in effect with respect to any shares of OSCA's common
stock until:

                  o        the applicable shares have been sold pursuant to an
                           effective registration statement under the Securities
                           Act;

                  o        the applicable shares have been sold to the public
                           pursuant to Rule 144 under the Securities Act, or any
                           successor provision;

                  o        the applicable shares have been otherwise
                           transferred, new certificates for them not bearing a
                           legend restricting further transfer shall have been
                           delivered by the company and subsequent public
                           distribution of them shall not require registration
                           of them under the Securities Act or any similar state
                           law;

                  o        the applicable shares have ceased to be outstanding;
                           or



                                       21
<PAGE>

                  o        in the case of shares held by a transferee of Great
                           Lakes, when those shares become eligible for sale
                           pursuant to Rule 144(k) under the Securities Act, or
                           any successor provision.

BROMINATED PRODUCTS SUPPLY AGREEMENT

         OSCA and Great Lakes have entered into the "Brominated Products Supply
Agreement" dated June 20, 2000 which governs the arrangements by which Great
Lakes supplies OSCA with brominated products. The Brominated Products Supply
Agreement has an initial term that expires on December 31, 2004, and is
renewable for successive one year periods unless either party gives notice of
its desire to terminate the agreement at least twelve months prior to any
successive renewal term. Under this agreement, OSCA is obligated to purchase
from Great Lakes, and Great Lakes is obligated to supply OSCA with, at least 80%
of OSCA's annual requirements for these products, subject to a maximum amount
which will vary depending upon OSCA's average purchases over the preceding three
year period.

         The contract price for brominated products will be determined based on
Great Lakes' cost plus a margin.

         Beginning in the third year of the agreement, if OSCA receives a bona
fide written offer for the same or similar products on the same or similar terms
and conditions for a net price lower than the price under the agreement, Great
Lakes is required to match this offer or release OSCA from its obligations to
purchase a maximum portion of OSCA's requirements as set forth below:

                  o        For contract year three: 40% of OSCA's annual
                           requirements.

                  o        For contract year four: 60% of OSCA's annual
                           requirements.

                  o        For contract year five and for all years thereafter:
                           100% of OSCA's annual requirements.

         Unless the release provisions described above apply, OSCA is required
to buy a minimum volume, regardless of its actual requirements.

         In 2001, OSCA paid Great Lakes $17.9 million for brominated products
purchased under the agreement.

TAX DISAFFILIATION AGREEMENT

         OSCA and Great Lakes have entered into a "Tax Disaffiliation Agreement"
dated June 20, 2000 which governs the allocation of federal, state, local and
foreign tax liabilities and contains agreements with respect to other tax
matters. The Tax Disaffiliation Agreement sets forth the procedures for
preparing and filing tax returns, paying tax liabilities, amending returns, tax
audits and contests and record retention.

         Under the Tax Disaffiliation Agreement, until OSCA ceases to be a
member of the Great Lakes consolidated group for federal, state, local or
foreign tax purposes, Great Lakes generally will be responsible for preparing
and filing, including any amendments thereto, the Great Lakes



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<PAGE>

consolidated tax group's federal income tax return and consolidated or combined
state and local tax returns, and Great Lakes will pay the taxes due with respect
to such tax returns. For tax periods during which OSCA is a member of the Great
Lakes consolidated tax group, it will calculate OSCA's tax liability as if it
was a separate affiliated group of corporations filing a consolidated return,
but OSCA will pay its calculated taxes to Great Lakes, which will then file the
consolidated or combined return with the appropriate tax authorities. In
connection with any applicable tax return, Great Lakes will have the exclusive
right, in its sole discretion, to determine the manner in which that tax return
will be prepared and filed, including the manner in which any item of gain,
loss, deduction, credit or other attribute shall be reported, whether any
extensions may be requested, the tax elections that will be made by OSCA and its
subsidiaries, whether any claims for refunds will be filed, and whether any
refunds shall be used as credits against other taxes. There may be some U.S.
state or local jurisdictions in which OSCA will file a separate tax return for
tax periods before tax deconsolidation. In that circumstance, it would file the
income tax return with the appropriate tax authorities, and pay the tax directly
to the tax authority.

         OSCA will prepare and file all tax returns and pay all taxes due with
respect to all tax returns required to be filed by it for all tax periods after
it ceases to be a member of the Great Lakes consolidated tax group and for
state, local and foreign jurisdictions in which OSCA's return is not combined or
consolidated with Great Lakes' return. Without the prior written consent of
Great Lakes, OSCA may not amend any tax return for a period in which it was a
member of the Great Lakes consolidated tax group. Some specified net operating
losses, net capital losses, unused tax credits and other deductible or
creditable tax attributes of OSCA's or any of OSCA's subsidiaries, which are
referred to as "tax attributes," may be relinquished by OSCA under the Tax
Disaffiliation Agreement. Other than those tax attributes required to be
allocated to OSCA under the appropriate federal, state, local, or foreign tax
law, no tax attributes will be allocated to OSCA on a carry-forward basis after
the deconsolidation nor will any carryback attributes of OSCA's be allowed to be
utilized for a consolidated tax return period.

         Great Lakes has the sole right to represent the interests of the Great
Lakes consolidated tax group, including OSCA, in any tax audits, litigation or
appeals that involve, directly or indirectly, periods prior to the time that
OSCA ceases to be a member of the Great Lakes consolidated tax group, unless it
is solely liable for the taxes at issue and any redetermination of taxes would
not result in any additional tax liability or detriment to any member of the
Great Lakes consolidated tax group. In addition, OSCA and Great Lakes have
agreed to provide each other with the cooperation and information reasonably
requested by the other in connection with tax planning, the preparation or
filing of any tax return, the determination and payment of estimated tax and in
the conduct any tax audits, litigation or appeals.

         OSCA and Great Lakes have agreed to indemnify each other for tax or
other liabilities resulting from the failure to pay any taxes required to be
paid under the Tax Disaffiliation Agreement, tax or other liabilities resulting
from negligence in supplying inaccurate or incomplete information or the failure
to cooperate with the preparation of any tax return or the conduct of any tax
audits, litigation or appeals. The Tax Disaffiliation Agreement requires OSCA to
retain records, documents and other information necessary for the preparation of
tax returns or for the audit thereof and to provide reasonable access to Great
Lakes with respect to such records, documents and information.



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<PAGE>

SERVICES AGREEMENT

         OSCA and Great Lakes have entered into a "Services Agreement" dated
June 20, 2000 pursuant to which Great Lakes will furnish OSCA with a number of
transitional services. These services will generally be provided to OSCA for an
amount that is reasonably related to Great Lakes' costs and will include, among
other things:

                  o        treasury and cash management;

                  o        risk management;

                  o        human resources and benefits administration support;

                  o        purchasing; and

                  o        legal assistance on an as-needed basis.

         The Services Agreement will remain in force until the first to occur
of:

                  o        a distribution of OSCA's common stock to Great Lakes
                           stockholders;

                  o        a divestiture of OSCA's common stock by Great Lakes;

                  o        the date on which OSCA's credit facility is no longer
                           outstanding;

                  o        OSCA's termination of all of the transitional
                           services; or

                  o        the termination of the Services Agreement by either
                           OSCA or Great Lakes because of an uncured default by
                           either party, declaration of the agreements
                           invalidity under applicable law or force majeure.



                                   SIGNATURES

         Pursuant to the requirements of the Securities Exchange Act of 1934,
OSCA has duly caused this amendment to be signed on its behalf by the
undersigned, who has been duly authorized.


                                      OSCA, Inc.

                                      /s/ Steven J. Brading
                                      ------------------------------------------
                                      Steven J. Brading
                                      Vice President and Chief Financial Officer

Dated: April 23, 2002



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