<PAGE>   1

                                                                 EXHIBIT 10.99



THE OPTION REPRESENTED BY THIS CERTIFICATE AND THE SHARES OF COMMON STOCK
ISSUABLE UPON THE EXERCISE OF THE OPTION HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR REGISTERED OR QUALIFIED UNDER
THE SECURITIES LAWS OF ANY STATE AND THUS MAY NOT BE OFFERED, SOLD OR OTHERWISE
TRANSFERRED UNLESS REGISTERED UNDER THAT ACT AND REGISTERED OR QUALIFIED UNDER
APPLICABLE SECURITIES LAW OR UNLESS AN EXEMPTION FROM SUCH REGISTRATION OR
QUALIFICATION IS AVAILABLE.



              OPTION TO PURCHASE 55,000 SHARES OF COMMON STOCK OF
                      POLLUTION RESEARCH AND CONTROL CORP.


                              FROM JANUARY 7, 1998
           VOID AFTER 5:00 P.M., LOS ANGELES TIME, ON JANUARY 6, 2002



        This certifies Aubrey Hornsby or registered assigns, is entitled,
subject to the terms set forth below, to purchase from Pollution Research and
Control Corp., a California corporation (the "Company"), the above number of
fully paid and nonassessable shares of Common Stock of the Company ("Common
Stock") at a purchase price of $1.10 per share ("Purchase Price").

        This Option is exercisable from January 7, 1998 to and including 5:00
p.m., Los Angeles time, on January 6, 2002.

Registered Owner:       Aubrey Hornsby

Purchase Price:         $1.10 per share








                                       1
<PAGE>   2



                                OPTION AGREEMENT

         This Option Agreement (the "Agreement") is made and entered into
effective as of May 31, 1996 by and between Pollution Research and Control
Corp., a California corporation ("PRCC") and Aubrey Hornsby ("Optionee").

         WHEREAS, Optionee has been providing valuable services as recognized by
the Company's Board of Directors to PRCC and PRCC is desirous of having Optionee
continue to provide such services to it; and

         WHEREAS, PRCC is willing to grant Optionee an option to purchase up to
an aggregate of 55,000 shares of the no par value common stock of PRCC (the
"Common Stock") under the terms and conditions set forth below.

         NOW, THEREFORE, the parties agree as follows:

         1.      GRANT OF OPTION.  PRCC hereby grants to Optionee, as a matter
of separate agreement and not in lieu of other compensation for services, the
right and option (the "Option") to purchase on the terms and conditions set
forth in this Agreement all or any part of up to an aggregate of 55,000 shares
of Common Stock (the "Option Shares"), for continuous, uninterrupted,
employment service to PRCC or by specific acknowledgement of exception by the
Company's Board of Directors.

         2.      OPTION PRICE.  At any time when shares of Common Stock are to
be purchased pursuant to the Option, the purchase price for each Option share
shall be $1.10 (the ""Option Price"), and for purposes of record, the bid price
of the Company's stock on this date was $.94 cents.

         3.      OPTION PERIOD.  The option period shall commence on January 7,
1998 (the "Date of Grant") and shall terminate four (4) years from the Date of
Grant.

         4.      EXERCISE OF OPTION.  The Option may exercised in whole or in
part at any time after the date hereof by delivering to the Chief Financial
Officer of PRCC (a) a Notice and Agreement of Exercise of Option, substantially
in the form attached hereto as Exhibit "A," specifying the number of Option
Shares with respect to which the Option is exercised, and (b) full payment of
the Option Price for such Shares.





                                       2
<PAGE>   3
         5.      SECURITIES LAWS REQUIREMENTS.  The Option Shares have not been
registered under the Securities Act of 1933, as amended (the "Act"), and no
Shares may be sold, offered for sale, transferred, pledged, hypothecated or
otherwise disposed of except in compliance with the Act and any other
applicable federal and state securities laws.  Additionally, the Option and the
Option Shares have not been qualified under the California Securities Law of
1968, as amended (the "California Law").  PRCC has no obligation to register
the Option shares under the Act or qualify the Option Shares under the
California Law.  Optionee acknowledges that he is aware that Rule 144 of the
General Rules and Regulations under the Act ("Rule 144") affords a limited
exemption from registration for the public resale of registered securities and
under the terms of Rule 144 as currently in effect, the Shares received by
Optionee may be sold to the public without registration only after a period of
two (2) years has elapsed from the exercise date of the Option and then only in
compliance with all other requirements of Rule 144 and the Act.  Optionee
hereby acknowledges, represents, warrants and agrees as follows:

                 (a)      That the Option and the Option Shares are not
registered under the Act or qualified under the California Law, and the Option
Shares shall be, acquired solely for the account of Optionee for investment
purposes only and with no view to their resale or other distribution of any
kind;

                 (b)      Neither the Option nor any Option Share shall be sold
or otherwise distributed in violation of the Act, the California Law or any
other applicable federal or state securities law;

                 (c)      His overall commitment to investments that are not
readily marketable is not disproportionate to his net worth, and his investment
in PRCC will not cause such overall commitment to become excessive;

                 (d)      He has the financial ability to bear the economic
risk of his investment, has adequate means of providing for his current needs
and personal contingencies, and has no need for liquidity in his investment in
PRCC;

                 (e)      He either: (i) has a preexisting personal or business
relationship with PRCC or its officers, directors or controlling persons, or
(ii) has evaluated the business of PRCC and the high risks of investing in
PRCC, the competitive nature of the business in which PRCC is engaged,





                                       3
<PAGE>   4
and has the business or financial experience or has business or financial
advisors who are unaffiliated with, and not compensated by, PRCC and protect
his interests in connection with the transaction;

                 (f)      He has been given the opportunity to review all
books, records and documents of PRCC and to ask questions and receive answers
from PRCC concerning PRCC's business, to obtain additional information
necessary to verify the accuracy of the information he has desired in order to
evaluate his investment, and to consult with such attorneys, accountants and
other advisors as he has desired;

                 (g)      His residence set forth below is his true and correct
residence, and he has no present intention of becoming a resident or
domiciliary of any other state of jurisdiction;

                 (h)      In making the decision to accept the Option and/or
purchase the Option Shares, he has relied solely upon independent
investigations made by or on behalf of him;

                 (i)      No federal or state agency has made any finding or
determination as to the fairness of an investment in PRCC; and

                 (j)      He understands that all the representations and
warranties made by him herein, and all information furnished by him to PRCC,
is true, correct and complete in all respects.

         6.      Optionee hereby acknowledges that he understands the meaning
and legal consequences of the representations, warranties and covenants
contained herein and that PRCC has relied on the representations made by
Optionee in paragraph 5 hereof in granting this Option, and Optionee agrees to
indemnify and hold harmless PRCC and its officers, directors, controlling
persons, attorneys, agents and employees from and against any and all loss,
damage or liability, together with all costs and expenses (including attorneys'
fees and disbursements) which any of them may incur by reason of any breach and
any representation, warranty, covenant or agreement contained herein.  All
representations, warranties, covenants and agreements, and the indemnification
contained herein shall survive the grant of the Option and the issuance of the
Option Shares by PRCC.

         7.      LEGEND OF CERTIFICATES.  All Option Shares issued pursuant to
this Agreement shall be subject to the provisions of this Agreement and the
certificates representing such Option Shares shall bear the following legend or
language substantially equivalent thereto:





                                       4
<PAGE>   5
                 "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
                 REGISTERED OR QUALIFIED UNDER FEDERAL OR STATE SECURITIES
                 LAWS.  THE SHARES MAY NOT BE OFFERED FOR SALE, SOLD, PLEDGED OR
                 OTHERWISE TRANSFERRED UNLESS SO REGISTERED OR QUALIFIED OR
                 UNLESS AN EXEMPTION EXISTS, THE AVAILABILITY OF WHICH IS TO BE
                 ESTABLISHED TO THE SATISFACTION OF THE COMPANY."



         8.      Transferability of Option.  The Option shall not be
transferable except by the laws of descent and distribution and any attempt to
do so shall void the Option.

         9.      ADJUSTMENT.  The Option Price and the number and kind of
Option Shares shall be subject to corresponding adjustment in the event of any
change in the Common stock by reason of any reclassification, recapitalization,
split-up, combination, exchange of shares, readjustment or stock dividend, in
like manner as if such Option Shares had been issued and outstanding, fully
paid and non-assessable at the time of such occurrence.

         10.     PRIVILEGE OF OWNERSHIP.  Optionee shall not have any of the
rights of a shareholder with respect to the shares covered by the Option except
to the extent that one or more certificates for such Shares shall be delivered
to his upon one (1) or more exercises of the Option.

         11.     NOTICES.  Any notices required or permitted to be given under
this Agreement shall be in writing and they shall be deemed to have been given
upon personal delivery or two (2) business days after mailing the notice by
postage, registered or certified mail.  Such notice shall be addressed to the
party to be notified as shown below:

                 PRCC:                  POLLUTION RESEARCH AND CONTROL CORP.
                                        506 Paula Avenue
                                        Glendale, CA 91201
                                        Attn: President



                 OPTIONEE:              Aubrey Hornsby
                                        3371 Addison Drive
                                        Pensacola, FL 32514



               Any party may change its address for purposes of this Section by
giving the other party written notice of the new address in the manner set
forth above.





                                       5
<PAGE>   6
         12.     GENERAL PROVISIONS.  This Agreement:

                 (a)      Contains the entire agreement between PRCC and
Optionee regarding options of PRCC to Optionee and supersedes all prior
communications, oral or written;

                 (b)      Shall not be construed to give Optionee any rights as
to PRCC or the Common Stock, except as specifically provided herein;

                 (c)      May not be amended nor may any rights hereunder be
waived except signed by an instrument in writing signed by the party sought to
be charged with such amendment or waiver;

                 (d)      Shall be construed in accordance with, and governed
by, the laws of the State of California; and

                 (e)      Shall be binding upon and shall inure to the benefit
of PRCC and Optionee, and their respective successors and assigns, except that
Optionee shall not have the right to assign or otherwise transfer his rights
hereunder to any person.

         IN WITNESS WHEREOF, the parties have executed this Agreement as of the
day and year first above written.

                        PRCC:           POLLUTION RESEARCH AND CONTROL CORP.,
                                        a California corporation



                                        By: /s/ ALBERT E. GOSSELIN, JR.
                                            ---------------------------------
                                            Albert E. Gosselin, Jr.,
                                            President and Chief Executive
                                            Officer

                        OPTIONEE:       /s/ AUBREY HORNSBY
                                        -------------------------------------
                                        Aubrey Hornsby


                                        -------------------------------------


                                       6
<PAGE>   7
                                                                    EXHIBIT A



                    To Pollution Research and Control Corp.



                   NOTICE AND AGREEMENT OF EXERCISE OF OPTION



         I hereby exercise the Option granted to me by POLLUTION RESEARCH AND
CONTROL CORP., a California corporation ("PRCC"), dated as of ____________ as
to ____________ shares of PRCC's no par value Common Stock.

         Enclosed are the documents and payment specified in Paragraph 4 of my
Agreement regarding the Option.




-------------------------                     -------------------------------
(Print Your Name)                             Signature



                                       7