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                                                                     EXHIBIT 4.3


                            1993 STOCK OPTION PLAN


     1.  Purpose.  The purpose of this Stock Option Plan ("Plan") is to provide
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additional incentive, in the form of stock options which may be either incentive
stock options or non-qualified stock options, to employees, officers, employee
directors, out-side directors, advisors and consultants (as described in Section
4 hereof) of Enviromatix, Inc., Delaware corporation (the "Corporation"), and
its subsidiaries whose judgment, initiative and efforts contribute significantly
to the successful operation of the corporation's business, and to increase their
proprietary interest in the success of the enterprise to the benefit of the
Corporation and its stockholders.

     2.  Definitions.  When used in this Plan, unless the context otherwise
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requires:

         (a)  "ISO" shall mean a stock option which, at the time such option is
granted, qualifies as an incentive stock option as defined in Section 422 of the
Internal Revenue Code of 1986, as amended, (the "Code").

         (b)  "NQSO" shall mean a stock option which, at the time such option is
granted, does not qualify as an ISO as defined in the Code.

         (c)  "Options" shall mean all ISOs and NQSOs which from time to time
may be granted under this Plan.

         (d)  "Share" shall mean a share of the Common Stock, no par value, of
the Corporation.

         (e)  "Subsidiary" shall mean any corporate subsidiary of the
Corporation, as defined in Section 424(f) of the Code.

     3.  Administration.  The Plan shall be administered by a committee
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("Committee") of the Board of Directors, which shall consist of not less than
two directors of the Corporation, who shall be appointed by, and shall serve at
the pleasure of, the Corporation's Board of Directors ("Board").  Each member of
such Committee, while serving as such, shall be deemed
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to be acting in his capacity as a director of the Corporation. Until the
Committee has been appointed, all of the members of the Board shall constitute
the Committee.

     Subject to the terms of the Plan, the Committee shall have full authority
to select the persons to whom ISOs or NQSOs may be granted under the Plan, to
grant options on behalf of the Corporation, to condition the grant of any such
Options upon the exchange of existing Options held by an Optionee, and to set
the number of Shares to be covered by such Options, the times and dates at which
such Options shall be granted and exercisable and the other terms of such
Options.  The Committee also shall have the authority to establish such rules
and regulations, not inconsistent with the provisions of the Plan, for the
proper administration of the Plan, and to amend, modify or rescind any such
rules and regulations, and to make such determinations and interpretations
under, or in connection with, the Plan, as it deems necessary or advisable.  All
such rules, regulations, determinations and interpretations shall be binding and
conclusive upon the Corporation, its stockholders and all employees, and upon
their respective legal representatives, beneficiaries, successors and assigns
and upon all other persons claiming under or through any of them.

     No member of the Board or the Committee shall be liable for any action or
determination made in good faith with respect to the Plan or any Option granted
under it.  Nothing herein shall be deemed to expand the person liability of a
member of the Board or Committee beyond that which may arise under any
applicable standards set forth in the Corporation's by-laws and Pennsylvania
law, nor shall anything herein limit any rights to indemnification or
advancement of expenses to which any member of the Board or the Committee may be
entitled under any by-law, agreement, vote of the stockholders or directors, or
otherwise.

     4.  Eligibility.  The class of persons who shall be eligible to receive
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ISOs under the Plan shall be the employees (including any directors who also are
employees).  All other directors, ad all advisors and consultants shall be
eligible to receive NQSO's of the

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Corporation or of any Subsidiary who, from time to time, or determined by the
Committee, contribute significantly to the management and growth of the business
of the Corporation or of such Subsidiaries. No consultant or advisor located in
Pennsylvania shall be eligible to receive ISOs or NQSOs under the Plan unless
the Committee receives an opinion of counsel that granting of options under the
Plan would be in compliance with the Pennsylvania Securities Act and the
regulations thereunder. More than one Option may be granted to an employee under
the Plan.

     The Committee may require that the exercise of the Option shall be subject
to the satisfaction of conditions relating to the Optionee's position and duties
with the Corporation and the performance thereof.

     5.  Amount of Stock.  The stock to be offered for purchase pursuant to
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Options granted under this Plan shall be treasury or authorized but unissued
Shares, and the total number of such Shares which may be issued pursuant to
Options under this Plan shall not exceed 3,550,000 Shares, subject to adjustment
as provided in Section 17 hereof.  If any unexercised Options are exchanged for
new Options, lapse or terminate for any reason, the Shares covered thereby may
again be optioned.

     6.  Stock Option Agreement.  Each Option granted under this Plan shall be
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evidenced by an appropriate stock option agreement ("Agreement"), which
Agreement shall expressly specify whether such Option is an ISO or NQSO and
shall be executed by the Corporation and by the person to whom the Option is
granted ("Optionee").  The Agreement shall contain such terms and provisions,
not inconsistent with the Plan, as shall be determined by the Board of
Directors.  Such terms and provisions may vary between Optionees or as to the
same Optionee to whom more than one Option may be granted.

     7.  Option Price.  The exercise price under each Option granted hereunder
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shall be determined by the Board of Directors in its discretion, provided,
however, that the exercise price of an ISO shall in no event be less than an
amount equal to the fair market value of the

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Shares subject to the ISO on the date of grant, as the fair market value may be
determined from time to time by the Board of Directors.

     8.  Ten Percent Stockholders.  If an Optionee owns more than ten percent of
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the total combined voting power of all shares of stock of the Corporation or of
a Parent or Subsidiary at the time an ISO is granted to him, the Option price
for the ISO shall be not less than 110% of the fair market value of the Shares
subject to the ISO on the date the ISO is granted, and such ISO, by its terms,
shall not be exercisable after the expiration of five years from the date the
ISO is granted.  The conditions set forth in this Section 8 shall not apply to
NQSOs.

     9.  Term and Exercise of Option.  Each Option shall expire on such date as
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may be determined by the Committee with respect to such Option, but in no event
shall any Option expire more than ten years from the date it is granted. The
date on which an Option shall be granted shall be the date of the Committee's
authorization of the Option or such later date as may be determined by the
Committee at the time the Option is authorized.

     Options shall be exercisable in such installments and on such dates, and/or
upon the occurrence of such events, as the Committee may specify.  The Committee
may accelerate the exercise date of any outstanding Options, in its discretion,
if it deems such acceleration to be desirable.  In addition, the exercise date
of all outstanding Options shall automatically accelerate, and all such Options
shall become fully vested and exercisable, upon a Change in Control, as defined
in paragraph (b) below.  Except as provided in Section 11, no Option shall be
exercised unless at the time of such exercise the Optionee is then an employee
of the Corporation or any Subsidiary.  Exercisable Options may be exercised, in
whole or in part, from time to time, by giving written notice of exercise to the
Corporation at its principal office, specifying the number of Shares to be
purchased and accompanied by payment in full of the aggregate Option price for
such Shares.  Only full Shares shall be issued under the Plan, and any
fractional Share which might otherwise be issuable upon exercise of an Option
granted hereunder shall be forfeited.

     The Option price shall be payable (a) in cash or its equivalent; (b) in the
discretion of the Committee, in Shares previously acquired by the Optionee,
provided that if

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such Shares were acquired through exercise of an ISO, such Shares have been held
by the Optionee for a period of not less than the holding period described in
Section 422(a)(1) of the Code on the date of exercise, or if such Shares were
acquired through exercise of an NQSO or of an option under a similar plan, such
Shares have been held by the Optionee for a period of more than one year on the
date of exercise, and further provided that the Optionee shall not have tendered
Shares in payment of the exercise price of any other Option under the Plan or
any other stock option plan of the Corporation within six calendar months of the
date of exercise; (c) in the discretion of the Committee, in any combination of
(a) and (b) above. In the event the Option price is paid, in whole or in part,
with Shares, the portion of the Option price so paid shall be equal to the "fair
market value" on the date of tender of the Shares so tendered in payment of such
Option price.

          (b)  For purposes of this Plan, a "Change in Control" with respect to
the Corporation shall mean any of the following events:

               (A)  a merger or consolidation of the Corporation with any other
     corporation, other than a merger or consolidation resulting in the voting
     power of the securities (as described in clause (D) below) of the
     Corporation outstanding immediately prior thereto continuing to represent
     (either by remaining outstanding or by being converted into voting stock of
     the surviving entity) more than a majority of the combined voting power of
     the securities of the Corporation (or such surviving entity) outstanding
     immediately after such merger of consolidation;

               (B)  any sale, lease, exchange, or other transfer (in one
     transaction or in a series of related transactions) of all, or
     substantially all, of the assets of the Corporation;

               (C)  the dissolution and liquidation of the Corporation; or

               (D)  any person or "group" (other than a benefit plan sponsored
     by either the Corporation or a subsidiary of the Corporation and other than
     Technology Leaders LP., Technology Leaders Offshore C.V. and Allied
     Resources Corporation), becoming after December 31, 1996 the "beneficial
     owner," "directly or indirectly, of securities representing a majority of
     the combined voting power of the then outstanding securities of the
     Corporation ordinarily (and apart from the rights accruing under special
     circumstances) having the right to vote in the election of directors
     (calculated as provided in paragraph (d) of Rule 13d-3 in the case of
     rights to acquire such securities). None of the Corporation's shareholders
     at December 31, 1996 shall be deemed to constitute a group for purposes of
     this paragraph (D).

          (c)  Notwithstanding anything to the contrary contained in paragraph
(b) above, the completion of an initial public offering by the Corporation in
which the Corporation registers shares of its Capital Stock pursuant to the
Securities Act of 1933, as amended, shall not result in a "Change in Control"
for purposes of this Plan.

          (d)  For purposes hereof, the terms "group" and "beneficial owner"
shall have the meanings given to them in Rule 3d-3; and Rule 13d-3 shall mean
Rule 13d-3 of the Securities and Exchange Commission promulgated under the
Securities Exchange Act of 1934."

     10.  Maximum Value of ISOs.  The aggregate fair market value of the Shares,
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determined as of the date of grant, with respect to which ISOs first become
exercisable during any calendar year by an Optionee (under this Plan and any
other plan of the Corporation or any parent or Subsidiary) shall not exceed
$100,000.

     11.  Termination of Employment.
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          (a)  Except as set forth below, in the event of termination by the
Corporation of an employee Optionee's employment with the Corporation or in the
event that a non-employee director's membership on the Board of Directors, any
unexercised Option shall be exercisable by the Optionee not later than 90 days
after the date of such termination but only to the extent such option was
exercisable on the date of such termination. In ho event shall such unexercised
Option be exercisable after the expiration of its term.

          (b)  If, however, the termination of employment or Board membership is
due to the disability of the Optionee (to an extent and in a manner as shall be
determined in each case by the Committee in its sole discretion), the Optionee
shall have the privilege of exercising the unexercised Option to the extent such
option was exercisable on the date of such

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termination, not later than one year of such date, but in no event shall any
Option be exercisable after the expiration of its term.

          (c)  If, however, the termination of employment or Board membership is
due to death of the Optionee while in the employ of the Corporation or a
Subsidiary, the estate of the holder or the person or persons who acquired the
right to exercise such Option by bequest or inheritance, shall have the
privilege of exercising the unexpired Option, to the extent such option was
exercisable on the date of such termination due to death, not later than one
year of such date, but in no event shall any Option be exercisable after the
expiration of its term.

          (d)  If, however, after full consideration of the facts presented on
behalf of both the Corporation and the Optionee, that the Optionee has been
discharged from employment or service with the Corporation for Cause, such
Option shall terminate immediately. For the purpose of this paragraph, "Cause"
shall have the mean: (A) a pattern of gross negligence or an act of willful
misconduct by Optionee in the performance of his duties to the Corporation which
has a material adverse effect on the Corporation's reputation, business,
properties or business relationships; or (B) Optionee's conviction of a felony
or of misappropriation of funds of the Corporation; or (C) Optionee's
appropriation to himself of a corporate opportunity of the Corporation which
Optionee fails to make available to the Corporation within 30 days after notice
thereof to Optionee from the Corporation; or (D) the material breach by Optionee
of his obligations under any provision of his employment agreement or service
contract with the Corporation, and the failure by Optionee to remedy such breach
within thirty (30) days after notice thereof to Optionee. In the event of a
finding that the Optionee has been discharged for Cause, then in addition to
immediate termination of the Option, the Optionee shall automatically forfeit
all Option Shares for which the Corporation has not yet delivered the share
certificates upon refund of the Option price; or (E) such conduct or the
occurrence of such thing as shall entitle the Corporation to discharge the

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Optionee under an employment agreement (if any) which he has entered into with
the Corporation and which provides for a discharge "for cause".

          (e)  Notwithstanding the provisions of subparagraphs 11(a), 11(b) and
11(c) above, the Committee may determine with respect to any Option granted
under the Plan, that the Option shall terminate at a time prior to the
expiration of such time periods. With respect to Options granted under the Plan
that are not intended to qualify under Section 422 of the Code, the Committee
may determine that such Options shall terminate at a time later than the
expiration of such time periods, as set forth in an executed Stock Option
Agreement.

     12.  Withholding and Use of Shares to Satisfy Tax Obligations.  The
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obligation of the Corporation to deliver Shares upon the exercise of any Option
shall be subject to applicable federal, state and local tax withholding
requirements.

     If the exercise of any Option is subject to the withholding requirements of
applicable federal tax laws, the Committee, in its discretion (and subject to
such withholding rules ("Withholding Rules") as shall be adopted by the
Committee), may permit the Optionee to satisfy the federal withholding tax, in
whole or in part, by electing to have the Corporation withhold (or by returning
to the Corporation) Shares, which Shares shall be valued, for this purpose, at
their fair market value on the date the amount of tax required to be withheld is
determined (the "Determination Date").  Such election must be made in compliance
with and subject to the Withholding Rules, and the Committee may not withhold
Shares in excess of the number necessary to satisfy the minimum federal income
tax withholding requirements.  In the event Shares acquired under the exercise
of an ISO are used to satisfy such withholding requirement, such Shares must
have been held by the Optionee for a period of not less than the holding period
described in Section 422(a)(1) of the code on the Determination Date.  In the
event Shares acquired through exercise of an NQSO or of an option under a
similar plan are used to satisfy such withholding requirement, such Shares must
have been held by the Optionee for a period of more than one year on the
Determination Date.

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     13.  Non-Assignability.  Each Option granted under the Plan shall be non-
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transferable by the Optionee except by will or the laws of descent and
distribution, and each Option shall be exercisable during the Optionee's
lifetime only by him.

     14.  Restrictions on Transfer.
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          (a)  The Corporation shall have the right of first refusal to re-
purchase any Shares offered for sale or transfer by the Optionee, his executor,
administrator, or beneficiaries, which Shares were issued to the Optionee
pursuant to one or more Options granted to the Optionee under this Plan. Such
offer shall be communicated to the Corporation by written notice, stipulating
the terms and conditions of such offer therein, forwarded by registered or
certified mail. The Corporation shall exercise its right to repurchase (or to
designate a third party to repurchase) by giving written notice thereof by
registered or certified mail to the Optionee, his executor, administrator or
beneficiaries no later than 30 days after the date of the receipt of the offer.
Within 30 days after receipt of such notice, the Optionee, his executor,
administrator or beneficiaries shall deliver a certificate or certificates for
the Shares being sold, together with appropriate duly signed stock powers
transferring such Shares to the Corporation, and the Corporation shall deliver
to the Optionee, his executor, administrator or beneficiaries the Corporation's
check in the amount of the purchase price for the Shares being sold.

     In the event that such offer shall not be accepted by the Corporation
in the manner set forth above, the Optionee, his executor, administrator or
beneficiaries may dispose of the Shares offered to any other person, firm or
corporation, without restriction (subject to the requirements of applicable
securities laws) except that the transfer of such Shares to any such purchaser
shall not be on terms more favorable than the terms upon which the Shares were
originally offered to the Corporation. If, within 60 days after the expiration
of the 30 day period of any offer made hereunder, the Optionee, his executor,
administrator, or beneficiaries offering to sell any Shares issued hereunder,
shall fail to consummate a sale thereof to any

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other purchaser, then no sale of such Shares may be made thereafter without
again reoffering the same to the Corporation in accordance with the provisions
of this subparagraph.

          (b)  In the event of the Optionee's termination of employment, the
Corporation shall have the right to repurchase all Shares issued or to be issued
to the Optionee under this Plan at their fair market value, which, in the
absence of an agreement between the Corporation and the Optionee shall be the
net book value per share as hereinafter defined, but not less than Optionee's
cost.

     The net book value of the Corporation's Common Stock shall be determined as
of the end of the Corporation's fiscal quarter immediately preceding the date of
termination hereof. Net book value of the Corporation's Common Stock shall be
that amount computed by deducting the sum of total liabilities and the
liquidation value of any Preferred Stock from total assets, as determined in
accordance with generally accepted accounting principles consistently applied,
and as shows on the financial statements of the Corporation as of the end of the
applicable fiscal quarter. The net book value per share of the Corporation's
Common Stock shall be determined by dividing the remainder by the number of
Shares of the Corporation's Common Stock issued and outstanding as of such date.

          (c)  The right of first refusal and buy-back rights shall terminate
when the Corporation has made a public offering of its Common Stock pursuant to
the Securities Act of 1933, as amended.

          (d)  The right of first refusal and buy-back rights granted to the
Corporation pursuant to subparagraphs 14(a) and 14(b) above are separate and
independent obligations of the Optionee and shall survive any termination of
employment. Furthermore, such rights shall not be construed as an absolute
obligation on the part of the Corporation to repurchase any Shares tendered.

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          (e)  Each certificate for Shares issued by the Corporation to the
Optionee shall bear an appropriate legend that the transfer of such Shares is
restricted by the provisions of this Plan.

     15.  Issuance of Shares and Compliance with Securities Acts.  Within a
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reasonable time after exercise of an Option, the Corporation shall cause to be
delivered to the Optionee a certificate for the Shares purchased pursuant to the
exercise of the Option.  At the time of any exercise of any Option, the
Corporation may, if it shall deem it necessary and desirable for any reason
connected with any law or regulation of any governmental authority relative to
the regulation of securities, require the Optionee to represent in writing to
the Corporation that it is his then intention to acquire the Common Stock for
investment and not with a view to distribution thereof and that such Optionee
will not dispose of such Shares in any manner that would involve a violation of
applicable securities laws  In such event, no Shares shall be issued to such
holder unless and until the Corporation is satisfied with such representation.
Certificates for Shares issued pursuant to the exercise of Options may bear an
appropriate securities law legend.

     16.  Rights as a Stockholder.  An Optionee shall have no rights as a
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stockholder with respect to Shares covered by his Option until the date of the
issuance or transfer of the Shares to him and only after such Shares are fully
paid. No adjustment shall be made for dividends or other rights for which the
record date is prior to the date of such issuance or transfer.

     17.  Stock Adjustments.  In the event of a reorganization,
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recapitalization, change of shares, stock split, or spinoff, stock dividend,
reclassification, subdivision or combination of shares, merger, consolidation,
rights offering, or any other change in the corporate structure or shares of the
Corporation, the Committee shall make such adjustment as it, in its sole
discretion, deems appropriate in the number and kind of shares authorized by the
Plan, in the number and kind of shares covered by grants made under the Plan or
in the purchase prices of outstanding Options, and such adjustments shall be
effective and binding on the Optionee and

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the Corporation for all purposes of the Plan, provided, however, that no such
adjustments shall be made to any ISO without the Optionee's consent if such
adjustment would cause such ISO to fail to qualify as such under Section 422 of
the Code.

     In the event of a corporate transaction (as that term is described in
Section 424(a) of the Code and the Treasury Regulations issued thereunder as,
for example, a merger, consolidation, acquisition of property or stock,
separation, reorganization, or liquidation), each outstanding Option shall be
assumed b the surviving or successor corporation, provided, however, that in the
event of a proposed corporate transaction, the Committee may terminate all or a
portion of the outstanding Options if it determines that such termination is in
the vest interests of the Corporation.  If the Committee decides to terminate
outstanding Options, the Committee shall give each Optionee holding an Option to
be terminated not less than seven days' notice prior to any such termination by
reason of such a corporate transaction, and any such outstanding Option which is
to be so terminated may be exercised (if and only to the extent that it is then
exercisable) up to and including the date immediately preceding such
termination.  Notwithstanding the preceding sentence, as provided in Section 9
hereof, the Committee, in its discretion, may accelerate, in whole or in part,
the date on which any or all Options become exercisable.

     18.  Adoption by Board and Approval by Stockholders.  This Plan becomes
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effective upon adoption by the Board of Directors and approval by the
stockholders of the Corporation.

     19.  Termination and Amendment of the Plan.  Subject to the right of the
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Board to terminate the Plan prior thereto, the Plan shall terminate on and no
Options shall be granted hereunder after January 15, 2003. The Board shall have
power at any time, in its discretion, to amend, abandon or terminate the Plan,
in whole or in part, provided that no such action shall affect any Options
theretofore granted and then outstanding under the Plan. Nothing contained in
this Section 19, however shall terminate or affect the continued existence of
rights

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created under Options issued hereunder and outstanding on January 15, 2003,
which by their terms extend beyond such date.

     Any Plan amendment which (1) materially reduces the price at which Options
may be granted, (2) materially increases the number of Shares which may be
issued under the Plan, except pursuant to paragraph 17 above, (3) materially
modifies the requirement as to persons eligible to receive Options, or (4)
materially increases the benefits accruing to participants under the Plan shall
not be effective unless approved by the stockholders of the Corporation at any
meeting called for such purpose or by the consent of the stockholders.

     20.  Interpretation.  A determination of the Committee as to any question
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which may arise with respect to the interpretation of the provisions of this
Plan or any Options shall be final and conclusive and nothing in this Plan, or
in any regulation hereunder, shall be deemed to give any Optionee, his legal
representatives, assigns or any other person any right to participate therein
except to such extent, if any, as the Committee may have determined or approved
pursuant to this Plan. The Committee may consult with legal counsel who may be
counsel to the Corporation and shall not incur any liability for any action
taken in good faith in reliance upon the advice of such counsel.

    21.  Governing Law.  With respect to any ISOs granted pursuant to the Plan
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and the Agreements thereunder, the Plan, such Agreements and any ISOs granted
pursuant thereto shall be governed by the applicable Code provisions to the
maximum extent possible. Otherwise, the laws of the Commonwealth of Pennsylvania
shall govern the operation of, and the rights of Optionees under, the Plan, the
Agreements and any Options granted thereunder.

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