<PAGE>


                                                                   Exhibit 10.14

                                 EMPLOYMENT AGREEMENT
                                           

    THIS EMPLOYMENT AGREEMENT made as of the 30th day of December 1996, by and 
between ENSYS ENVIRONMENTAL PRODUCTS, INC., a Delaware corporation whose name 
is being changed to STRATEGIC DIAGNOSTICS INC. as of the date hereof (the 
"Company," which is also hereinafter referred to as the "Employer"), and 
RICHARD C. BIRKMEYER (the "Executive").

                                     WITNESSETH:

    WHEREAS, Employer agrees to retain the services of Executive, and 
Executive agrees to work for Employer, all pursuant to the terms and 
conditions hereinafter set forth;

    NOW, THEREFORE, FOR AND IN CONSIDERATION of the premise, the mutual 
promise, covenants and agreements contained herein, and other good and 
valuable consideration, the receipt and sufficiency of which are hereby 
acknowledged, the parties hereto hereby agree as follows:

   1. Employment.  The Employer agrees to employ the Executive and the 
Executive agrees to be employed by the Employer on the terms and conditions 
hereinafter set forth.

   2. Capacity.  The Executive shall serve as the Chief Executive Officer of 
Employer.  The Executive shall render such services to the Company as are 
customary for such position and perform all other services incident thereto.

   3. Effective Date and Term.  Subject to the provisions of Section 6, the 
Executive's employment under this Agreement shall remain in effect for the 
period commencing on the date hereof and terminating on December 31, 1997 
("Initial Term") and shall be automatically extended for periods of one year 
commencing on December 31, 1997 and on each December 31 thereafter, unless 
either the Executive or the Employer gives written notice to the other not 
less than sixty (60) days prior to the date of any such anniversary, of such 
party's election not to extend the term of the Executive's employment 
hereunder.

   4. Compensation and Benefits.  The regular compensation and benefits 
payable to the Executive under this Agreement shall be as follows:

      (a) Salary.  For all services rendered by the Executive under this 
Agreement, the Employer shall pay the Executive a salary at the rate, of 
$164,000 per year, subject to an annual increase of not less than five 
percent (5%) of the then current annual salary, as determined by the Board of 
Directors or the Compensation Committee in accordance with the usual practice 

<PAGE>

of the Employer with respect to review of compensation for its senior 
executives.  The Executive's salary shall be payable in periodic installments 
in accordance with the Employer's usual practice for its senior executives.

      (b) Bonus.  In addition to salary under Section 4(a), the Executive 
shall be entitled to participate in a bonus plan under which he may be 
entitled to receive an annual bonus in an amount, up to 75 % of such salary, 
as shall be determined by the Compensation Committee of the Employer's Board 
of Directors in the beginning of each of the Employer's fiscal years under 
this Agreement commencing with fiscal 1997.  The Compensation Committee and 
the Executive shall establish reasonable performance goals and targets for 
such bonus- Upon completion of each year, the Compensation Committee shall 
review the actual performance against such performance targets and goals and 
notify the Executive of the amount of the award.  Initially, the target 
annual bonus will be 30% of Executive's salary.  The Executive's bonus shall 
be paid to him within ninety (90) days after the end of the fiscal year to 
which it relates, whether he remains an employee of the Employer at the date 
of payment or not.

      (c) Regular Benefits.  The Executive shall also be entitled to 
participate in any and all employee benefit plans, medical insurance plans, 
life insurance plans, disability income plans, retirement plans and other 
benefit plans from time to time in effect for senior executives of the 
Employer.  Such participation shall be subject to (i) the terms of the 
applicable plan documents, (ii) generally applicable policies of the Employer 
and (iii) the discretion of the Board of Directors of the Employer or any 
administrative or other committee provided for in or contemplated by such 
plan, except that all waiting periods for eligibility to participate in 
employee benefit plans shall be waived by the Employer to the extent 
permissible.  The Employer shall also pay the premiums that come due under 
Paul Revere Life insurance Company Disability Income Policies 01024761080 and 
01026933250.

      (d) Perquisites.  The Executive shall be entitled to receive fringe 
benefits ordinarily and customarily provided by the Employer to its senior 
officers during the term of his employment hereunder.  In any event, the 
Employer shall provide the Executive with fringe benefits no less favorable 
to the Executive than those provided by the Employer to any other employee.

      (e) Business Expenses.  The Employer shall promptly reimburse the 
Executive for all travel and other business expenses, including, without 
limitation, cellular phone expenses, incurred by him in the performance of 
his duties and responsibilities, subject to such reasonable requirements with 
respect to substantiation and documentation as may be specified by the 
Employer.

      (f) Equity Award.  The Executive is hereby granted options to purchase 
100,000 shares of the Employer's common stock under the Employer's 1995 Stock 
Incentive Plan at an exercise price of $2.00 per share (the "Option").  The 
Option will be granted pursuant to an Incentive Stock Option Agreement to be 
executed contemporaneously herewith in

                                       2
<PAGE>

substantially the form of Exhibit A attached hereto and incorporated herein 
by this reference.  The grant of options pursuant to this Section 4(e) shall 
be without prejudice to further grants to the Executive in the future under 
any plan adopted by the Employer.

   5. Extent of Service.  During his employment hereunder, the Executive 
shall, subject to the direction and supervision of the Board of Directors of 
the Employer, devote his full business time, all reasonable efforts and 
business judgment, skill and knowledge to the advancement of the Employer's 
interests and to the discharge of his duties and responsibilities hereunder, 
except for reasonable time spent for service on the boards of directors of 
other corporations, vacations, civic and charitable activities, and 
management of personal investments.

   6. Termination and Termination Benefits.  Notwithstanding the provisions 
of Section 3, the Executive's employment hereunder shall terminate under the 
following circumstances:

      (a) Death.  In the event of the Executive's death during the 
Executive's employment hereunder, the Executive's employment shall terminate 
on the date of his death; provided, however, that the Employer shall continue 
to pay an amount equal to the Executive's salary to the Executive's 
beneficiary designated in writing to the Employer prior to his death (or to 
his estate, if he fails to make such designation or such beneficiary 
predeceases him) for a period of twelve months after the date of the 
Executive's death, at the salary rate in effect on the date of his death, 
without an increase for any portion of such twelve (12) month period, said 
payments to be made on the same periodic dates as salary payments have been 
made to the Executive had he not died.

      (b) Termination by the Employer for Cause.  The Executive's employment 
hereunder may be terminated without further liability on the part of the 
Employer effective immediately by a majority vote of all of the members of 
the Board of Directors of the Employer (excluding the Executive) for cause by 
written notice to the Executive setting forth in reasonable detail the nature 
of such cause.  Only the following shall constitute "cause" for such 
termination:

          (i)     The Executive commits an act constituting fraud or material 
                  misrepresentation with respect to the Employer;

          (ii)    The Executive embezzles funds or assets from the Employer; 

          (iii)   Conviction of the Executive of a felony involving moral 
                  turpitude (excluding motor vehicle violations); or

          (iv)    Gross and willful failure to perform a substantial portion 
                  of his duties and responsibilities hereunder, which failure 
                  continues for more than thirty (30) days after written 
                  notice given to the Executive pursuant to a majority vote of 
                  all of the members of the

                                       3

<PAGE>

                  Board of Directors of the Employer, such vote to set forth 
                  in reasonable detail the nature of such failure.

      (c) Termination by the Executive.  The Executive's employment hereunder 
may be terminated effective immediately by the Executive by written notice to 
the Board of Directors of the Employer, provided that the Executive shall 
receive the benefits specified in Section 6(e) if he terminates his 
employment in the event of the following (any of which being referred to 
herein as "Good Reason"):

          (i)     Failure of such Board of Directors to elect the Executive 
                  to the office of Chief Executive Officer of the Employer or 
                  to continue the Executive in such office;

          (ii)    Failure by the Employer to comply with the provisions of 
                  Section 4(a) or 4(c) or any other material breach by the
                  Employer of any other provision of this Agreement; or

          (iii)   Election by the Employer not to extend the term of the 
                  Executive's employment hereunder in accordance with the
                  provisions of Section 3.

      (d) Termination by the Employer Without Cause.  The Executive's 
employment with the Employer may be terminated without cause by a majority of 
all of the members of the Board of Directors of the Employer (excluding the 
Executive) on written notice to the Executive.

      (e) Certain Termination Benefits.  Unless otherwise specifically 
provided in this Agreement or otherwise required by law or by the terms of 
any employee benefit plan and other compensation plans, programs and 
structures, or fringe benefit programs in which the Executive is a 
participant at the time of the termination of his employment with the 
Company, all compensation and benefits payable to the Executive under this 
Agreement shall terminate on the date of termination of Executive's 
employment hereunder.  Notwithstanding the foregoing, in the event of 
termination by the Executive for Good Reason pursuant to Section 6(c) or by 
the Employer pursuant to Section 6(d), the Executive shall be entitled to the 
following benefits:

          (i)     The Employer shall continue to pay an amount equal to the 
                  Executive's salary to the Executive (or the Executive's
                  beneficiary designated in writing to the Employer prior
                  to his death or to his estate, if he fails to make such 
                  designation or such beneficiary predeceases him) during a 
                  period (the "Severance Period") which shall extend for a 
                  period of twelve (12) months after the date of the Executive's
                  termination, at the salary rate in effect on the date of his
                  termination, said payments to be made on the same periodic 



                                       4

<PAGE>
                  
                  dates as salary payments would have been made to the Executive
                  had his employment not been terminated; provided that in the
                  event that the Employer shall default in the timely payment of
                  any amount due to the Executive under this Section 6(e) or in
                  the performance of any of its other obligations under this 
                  Section 6(e), the Executive, at his option, may accelerate the
                  remaining payments that would become due to him hereunder and 
                  such amounts thereupon shall be due and payable forthwith.
         
          (ii)    During the Severance Period, the Executive shall continue to 
                  receive all benefits described in Sections 4(c) existing on
                  the date of termination (except for any cash bonus plans which
                  shall be prorated through the date of termination).  For 
                  purposes application of such benefits the Executive shall be
                  treated as if he had remained in the employ of the Employer,
                  with a total annual salary at the rate in effect on the date 
                  of termination.
         
          (iii)   In addition to, but not in limitation of, the rights which 
                  the Executive otherwise may have and except as expressly
                  provided in any award subsequent to the grant of the stock 
                  options contemplated by Section 4(f), any restrictions 
                  remaining on any restricted shares issued to the Executive 
                  under the Employer's restricted plans shall immediately lapse,
                  any performance shares issued to the Executive under the 
                  Employer's incentive stock plans shall immediately vest, and 
                  any stock options and stock appreciation rights granted to the
                  Executive shall become exercisable immediately, and the 
                  Executive may exercise all such options or stock appreciation 
                  rights within the later of the remainder of their term or 
                  one year after the expiration of the Severance Period.

          (iv)    If, in spite of the provisions of Section 6(e)(ii) 
                  above, benefits or service credits under any benefit plan 
                  shall not be payable or provided under any such plan to 
                  the Executive, or to the Executive's dependents, 

                                       5
                  
<PAGE>
                  
                  beneficiaries or estate, because the Executive is no 
                  longer deemed to be an employee of the Employer, the 
                  Employer shall pay or provide for payment of such 
                  benefits and service credits for such benefits to the 
                  Executive, or to the Executive's dependents, 
                  beneficiaries or estate; provided, however, that the 
                  Employer shall have no obligations with respect to the 
                  federal or state income tax treatment of the exercise of 
                  any stock options or other stock rights held by the 
                  Executive under any of the Employer's stock incentive 
                  plans.

      (f) No Set-off.  The amounts payable to Executive under Section 6(e) 
shall be treated as damages but as severance compensation to which the 
Executive is entitled by on of termination of his employment, and the 
Employer shall not be entitled to any set-off against, or reduction of, such 
amounts for any reason whatsoever.  Notwithstanding any other provision of 
this Agreement, the Executive shall be under no obligation to seek or accept 
any employment after termination of employment with the Employer for any 
reason.

   7. Disability.  If, due to physical or mental illness, the Executive shall 
be disabled so as to be unable to perform substantially all of his duties and 
responsibilities hereunder, the Employer, acting through its Board of 
Directors, may designate another executive to act in his place during the 
period of such disability.  Notwithstanding any such designation, the 
Executive shall continue to receive his full salary and benefits under 
Section 4 of this Agreement for a minimum of nine (9) months (net of any 
amounts paid to the Executive during such nine (9) month period pursuant to 
Employer's disability income plan, if any), and shall continue to participate 
in the Employer's benefit plans and to receive other benefits as specified in 
Section 4 until the expiration of his term of employment hereunder.  If any 
questions shall arise as to whether during any period the Executive was 
disabled so as to be unable to perform substantially all of his duties and 
responsibilities hereunder due to physical or mental illness, the Executive 
may, and at the request of the Employer will, submit to the Employer a 
certification in reasonable detail by a physician selected by the Executive 
or his guardian to whom the Employer has no reasonable objection as to 
whether the Executive was so disabled and such certification shall for the 
purposes of this Agreement be conclusive of the issue.  If such question 
shall arise and the Executive shall fail to submit such certification, the 
Employer's determination of such issue shall be binding on the Executive.

   8. Withholding.  All payments made by the Employer under this Agreement 
shall be net of any tax or other amounts required to be withheld by the 
Employer under applicable law.

   9. Non-Disclosure, Non-Competition and Non-Solicitation Covenants.

      (a) Definitions.  For purposes of this Section 9, the following terms 
shall have the following respective meanings:

                                       6

<PAGE>

          (i)     "Competitive Position" shall mean (i) the direct or indirect 
                  equity ownership or control of all or any portion
                  of a "Competitor" (as hereinafter defined), or (ii) any 
                  employment, consulting, partnership, advisory, directorship, 
                  agency, promotional or independent contractor arrangement 
                  between Executive and any Competitor whereby Executive is 
                  required to perform services substantially similar to those 
                  that he is to perform for Employer hereunder.

          (ii)    "Competitor" shall refer to any person or entity engaged, 
                  wholly or partly, in the business of distributing, 
                  manufacturing, marketing, selling,servicing, repairing 
                  environmental testing devices.

          (iii)   "Confidential Information" shall mean any and all proprietary
                  and confidential data or information of Employer or any of 
                  its affiliates, other than "Trade Secrets" (as hereinafter 
                  defined), which is of tangible or intangible value to
                  Employer or any of its affiliates and is not public 
                  information or is not generally known or available to 
                  Employer's competitors but is known only to Employer or its
                  affiliates and their employees, independent contractors or 
                  agents to whom it must be confided in order to apply it to 
                  the uses intended.

          (iv)    "Restricted Territory" shall mean the United States of 
                  America.

          (v)     "Trade Secrets" shall mean all knowledge, data and 
                  information of Employer or any of its affiliates which is 
                  defined as a "trade secret" under applicable law.

          (vi)    "Work Product shall mean all work product, property, data,
                  documentation, "know-how", concepts, plans, inventions, 
                  improvements, techniques,processes or information of any kind,
                  prepared, conceived, discovered, developed or created by 
                  Executive in connection with the performance of his services
                  hereunder.

      (b) Acknowledgments.  Executive hereby acknowledges and agrees that 
during the term of this Agreement (i) Executive will frequently be exposed to 
certain Trade Secrets and Confidential Information; (ii) Executive's 
responsibilities on behalf of Employer will extend to all geographical areas 
of the Restricted Territory; and (iii) any competitive activity on 
Executive's part during the term of this Agreement, or any competitive 
activity on Executive's part in the Restricted Territory for a reasonable 
period thereafter, would necessarily involve Executive's use of Employer's 
Trade Secrets and Confidential Information and would unfairly threaten 
Employer's legitimate business interests, including its substantial 
investment in the proprietary aspects of its business and the goodwill 
associated with its customer base.  Moreover, Executive acknowledges that, in 
the event of the termination of this Agreement, Executive would have 
sufficient skills to find alternative, commensurate work in his field of 
expertise that would not involve a violation of any of the provisions of this 
Section 9. Therefore, Executive acknowledges and agrees that it is reasonable 
for Employer to require Executive to abide by the covenants set forth in this 
Section 9. The parties acknowledge and agree that if the nature of 
Executive's responsibilities for or on behalf of Employer or the geographical 
areas in which Executive must fulfill such responsibilities materially 

                                       7

<PAGE>

change, the parties will execute appropriate amendments to the scope of the 
covenants in this Section 9.

      (c) Nondisclosure: Ownership of Proprietary Property.

          (i)     In recognition of Employer's need to protect its 
                  legitimate business interests, Executive hereby covenants 
                  and agrees that: (A) with regard to each item 
                  constituting a Trade Secret, at all times during which 
                  such item shall constitute a Trade Secret (before or 
                  after termination of this Agreement); and (B) with regard 
                  to any Confidential information, at all times during the 
                  term of this Agreement and for a period of three (3) 
                  years following the expiration or termination of this 
                  Agreement for any reason, Executive shall regard and 
                  treat each item constituting a Trade Secret and all 
                  Confidential Information as strictly confidential and 
                  wholly owned by Employer and will not, for any reason, in 
                  any fashion, either directly or indirectly, use, sell, 
                  lend, lease, distribute, license, give, transfer, assign, 
                  show, disclose, disseminate, reproduce, copy, 
                  misappropriate or otherwise communicate any such item or 
                  information to any third party for any purpose other than 
                  in accordance with this Agreement or as required by 
                  applicable law.
                    
          (ii)    Executive shall immediately notify Employer of any 
                  intended or unintended, unauthorized disclosure or use of 
                  any Trade Secrets or Confidential Information by 
                  Executive or any other person or entity of which 
                  Executive becomes aware.  Executive shall cooperate fully 
                  with Employer in the procurement of any protection of 
                  Employer's rights to or in any of the Trade Secrets or 
                  Confidential Information.
                              
          (iii)   Immediately upon expiration or termination of this Agreement
                  for any reason, or if  notice of termination is required 
                  hereunder, upon receipt of such notice, or at any time after
                  such termination or notice upon the specific request of 
                  Employer, Executive shall return to Employer all written 
                  or descriptive materials of any kind in Executive's 
                  possession or to which Executive has access that 
                  constitute or contain any Confidential information or 
                  Trade Secrets, and the confidentiality obligations 
                  described in this Agreement shall continue until their 
                  expiration under the terms of this Agreement.
                  
          (iv)    To the greatest extent possible, any Work Product 
                  shall be deemed to be "work made for hire" (as defined in 

                                       8
                  
<PAGE>
                  
                  the Copyright Act, 17 U.S.C.A. Section 101 et seq., as 
                  amended) and owned exclusively by Employer.  Executive 
                  hereby unconditionally ad irrevocably transfers and 
                  assigns to Employer all rights, title and interest 
                  Executive currently has or in the future may have, by 
                  operation of law or otherwise, in or to any Work product, 
                  including, without limitation, all patents, copyrights, 
                  trademarks, service marks and other intellectual property 
                  rights.  Executive agrees to execute and deliver to 
                  Employer any transfers, assignments, documents or other 
                  instruments which Employer may deem necessary or 
                  appropriate to vest complete title and ownership of any 
                  Work Product, and all rights therein, exclusively in 
                  Employer.
                  
      (d) Non-competition.  In recognition of Employer's need to protect its 
legitimate business interests, Executive hereby covenants and agrees that 
during the term of this Agreement, Executive will not, either directly or 
indirectly, alone or in conjunction with any other party, accept, enter into 
or take any action in furtherance of a Competitive Position.  Executive 
further agrees that for three (3) years following expiration or termination 
of this Agreement for any reason, Executive will not, either directly or 
indirectly, alone or in conjunction with any other party, accept, enter into 
or take any action in furtherance of a Competitive Position within the 
Restricted Territory (other than action to reject an offer of a Competitive 
Position or to notify Employer of the offer pursuant to the requirements of 
the next sentence of this Section 9(d)).

      (e) Non-solicitation of Customers.  Executive hereby covenants and agrees 
that (i) during the term of this Agreement, Executive will not, either 
directly or indirectly, alone or in conjunction with any other party, 
solicit, divert or appropriate or attempt to solicit, divert or appropriate 
any customer or actively sought prospective customer of Employer for the 
purpose of providing such customer or actively sought prospective customer 
with services or products competitive with those offered by Employer during 
the term of this Agreement; and (ii) for a period of three (3) years 
following expiration or termination of the term of this Agreement for any 
reason, Executive will not, either directly or indirectly, alone or in 
conjunction with any other party, solicit, divert or appropriate, or attempt 
to solicit, divert or appropriate any customer or actively sought prospective 
customer of Employer for the purpose of providing such customer or actively 
sought prospective customer with services or products competitive with those 
offered by Employer during the term of this Agreement.

      (f) Nonsolicitation of Employer Personnel.  Executive hereby agrees that 
during the term of this Agreement, except to the extent that he is required 
to do so in connection with his responsibilities hereunder, Executive will 
not, either directly or indirectly, alone or in conjunction with any other 
party, solicit or attempt to solicit any employee, consultant, contractor or 
other personnel of Employer to terminate, alter or lessen such party's 
affiliation with Employer or to violate the terms of any agreement or 
understanding between such party and Employer.  Executive further agrees that 

                                       9

<PAGE>

during the three (3) year period following expiration or termination of this 
Agreement for any reason, Executive will not, either directly or indirectly, 
alone or in conjunction with any other party, solicit or attempt to solicit 
any "key" (as that term is hereinafter defined) employee, consultant, 
contractor or other personnel of Employer to terminate, alter or lessen that 
party's affiliation with Employer or to violate the terms of any agreement or 
understanding between such party and Employer.  For purposes of the preceding 
sentence "key" employees, consultants, contractors or other personnel of 
Employer are those with knowledge of or access to Employer's Trade Secrets or 
Confidential Information.

      (g) Remedies.  Executive agrees that damages at law for Executive's 
violation of any of the covenants in this Section 9 would not be an adequate 
or proper remedy and that, should Executive violate or threaten to violate 
any of the provisions of such covenants, Employer or its successors or 
assigns shall be entitled to seek a temporary or permanent injunction against 
Executive in any court having jurisdiction prohibiting any further violation 
of any such covenants, in addition to any award or damages (compensatory, 
exemplary or otherwise) for such violation.  The Executive agrees not to 
raise as a defense to such action that Employer has an adequate remedy at law.

      (h) Partial Enforcement.  Employer has attempted to limit the rights of 
Executive to compete only to the extent necessary to protect Employer from 
unfair competition. Employer, however, agrees that, if the scope of 
enforceability of any of these restrictive covenants is in any way disputed 
at any time, a court or other trier of fact may modify and enforce such 
covenant to the extent that it believes to be reasonable under the 
circumstances existing at the time.

      (i) Survival.  Notwithstanding any expiration or termination of this 
Agreement, the provisions of this Section 9 shall survive and remain in full 
force and effect, as shall any other provision hereof that, by its terms or 
reasonable interpretation thereof, sets forth obligations that extend beyond 
the termination of this Agreement.

   10. Assignment; Successors and Assigns, etc.  Neither the Employer nor the 
Executive may make any assignment of this Agreement or any interest herein, 
by operation of law or otherwise, without the prior written consent or the 
other party and without such consent any attempted transfer or assignment 
shall be null and of no effect; provided, however, that the Employer may 
assign its rights under this Agreement without the consent of the Executive 
in the event the Employer shall hereafter effect a reorganization, 
consolidate with or merge into any other Person, or transfer all or 
substantially all of its properties or assets to any other Person.  This 
Agreement shall inure to the benefit of and be binding upon the Employer and 
the Executive, their respective successors, executors, administrators, heirs 
and permitted assigns. In the event of the Executive's death prior to the 
completion by the Employer of all payments due him under this Agreement, the 
Employer shall continue such payments to the Executive's beneficiary 
designated in writing to the Employer prior to his death (or to his estate, 
if he fails to make such designation or such beneficiary predeceases him).

                                       10

<PAGE>

   11. Payments to the Executive.  The Employer shall pay the reasonable 
attorneys' fees and disbursements incurred by the Executive in connection 
with the preparation and negotiation of this Agreement.  If litigation shall 
be instituted to enforce or interpret any provision hereof and the Executive 
shall prevail, the Employer will reimburse the Executive for his reasonable 
attorneys' fees and disbursements incurred in such proceeding and will pay 
prejudgment interest at the legal rate then in effect on any money judgment 
or award obtained by the Executive in such proceeding.

   12. Enforceability.  The unenforceability or invalidity of any provision 
of this Agreement shall not affect the validity or enforceability of the 
remaining provisions hereof, but such remaining provisions shall be construed 
and interpreted in such a manner as to carry out fully the intent of the 
parties hereto; provided, however, that should any judicial body interpreting 
this Agreement deem any provision hereof to be unreasonably broad in time, 
territory, scope or otherwise, it is the intent and desire of the parties 
hereto that such judicial body, to the greatest extent possible, reduce the 
breadth of such provision to the maximum legally allowable parameters rather 
than deeming such provision totally unenforceable or invalid.

   13. Waiver.  No waiver, termination or discharge of this Agreement, or any 
of the terms or provisions hereof, shall be binding upon either party hereto 
unless confirmed in writing.  No waiver by either party hereto of any term or 
provision of this Agreement or of any default hereunder shall affect such 
party's right thereafter to enforce such term or provision or to exercise any 
right or remedy in the event of any other default, whether or not similar.

   14. Notices.

      (a) All notices, consents, requests and other communications hereunder 
shall be in writing and shall be sent by hand delivery, by certified or 
registered mail (return-receipt requested), by facsimile or by a recognized 
national overnight courier service as set forth below.

        If to Employer:    Strategic Diagnostics Inc.
                           128 Sandy Drive
                           Newark, Delaware 19713-1147
                           Attn:     Chairman of the Board

        with a copy to:    William B. Marianes, Esq.
                           Troutman Sanders LLP
                           600 Peachtree Street, N.E.
                           Suite 5200
                           Atlanta, Georgia 30308-2216

        If to Executive:   Richard C. Birkmeyer
                           c/o Strategic Diagnostics Inc.
                           128 Sandy Drive  
                           Newark, Delaware 19713-1147

                                       11

<PAGE>

      (b) Notices delivered pursuant to this Section 14 hereof shall be 
deemed given: at the time delivered, if personally delivered, three (3) 
business days after being deposited in the mail, if mailed; and one (1) 
business day after timely delivery to the courier, if by overnight courier 
service. 

      (c) Either party hereto may change the address to which notice is to be 
sent by written notice to the other party hereto in accordance with this 
Section 14.

   15. Headings.  The titles, captions and headings contained in this 
Agreement are inserted by convenience of reference only and are not intended 
to be part of or to affect in any way the meaning or interpretation of this 
Agreement.

   16. Counterparts.  This Agreement may be executed in one or more 
counterparts, each of which shall be deemed to be an original but all of 
which together will constitute one and the same instrument.

   17. Amendment.  This Agreement may be amended or modified only by a 
written instrument signed by the Executive and by a duly authorized 
representative of the Employer.

   18. Governing Law.  This is a Delaware contract and shall be construed 
under and be governed in all respects by the laws of the State of Delaware.

    IN WITNESS WHEREOF, the parties hereto have executed this Agreement to be 
effective as of the date first written above.

                             "Employer"

ATTEST:                      ENSYS ENVIRONMENTAL PRODUCTS, INC.


/s/ DAN DAMSTRA              By:       /s/ GROVER C. WRENN     
----------------------                 -----------------------
              
                             Title:    PRESIDENT & CEO                        
                                       -----------------------  

                             "Executive"

WITNESS:                     RICHARD C. BIRKMEYER
----------------------       ---------------------------------  


                                       12
                                                                              
<PAGE>

    IN WITNESS WHEREOF, the parties hereto have executed this Agreement to be
effective as of the date first written above.

                             "Employer"

ATTEST:                      ENSYS ENVIRONMENTAL PRODUCTS, INC.


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



                             "Executive"

WITNESS:                     RICHARD C. BIRKMEYER


 /s/ ANNE CAVANAUGH          /s/ RICHARD C. BIRKMEYER        
----------------------       --------------------------------  

                                       13

<PAGE>


                                      Exhibit A
                       Form of Incentive Stock Option Agreement
  
                                 AMENDED AND RESTATED
                          ENSYS ENVIRONMENTAL PRODUCTS, INC.
                              1995 STOCK INCENTIVE PLAN
                           INCENTIVE STOCK OPTION AGREEMENT

100,000                                          December 30, 1996 
No. of Shares                                    Date of Grant


    Pursuant to the Amended and Restated EnSys Environmental Products, Inc. 
1995 Stock Incentive Plan (the "Plan"), EnSys Environmental Products, Inc. 
(the "Company") hereby grants to Richard C. Birkmeyer (the "Optionee") an 
option (the "Option") to purchase on or prior to December 30 , 2006 (the 
"Expiration Date') all or any part of One Hundred Thousand (100,000) shares 
(the "Option Shares") of "Stock" (as defined in Section 2 of the Plan) at a 
price of $ per share of Stock in accordance with the schedule set forth in 
Section 1 hereof and subject to the terms and conditions set forth 
hereinafter and in the Plan.  This Option shall be construed in a manner to 
qualify it as an incentive stock option under Section 422 of the Internal 
Revenue Code of 1986, as amended (the "Code"), to the maximum extent 
permitted.

   1. Vesting of Option.  Subject to the provisions of Sections 4 and 5 hereof
and the discretion of the "Board" (as defined in Section 1 of the Plan) to 
accelerate the vesting schedule hereunder, this Option shall become vested 
and exercisable with respect to the following number of Option Shares 
according to the timetable set forth below:

                   Number of Shares of Stock   Cumulative Number of
                     Vested and Becoming      Shares of Stock Available
   Date             Available for Exercise         for Exercise
   ----             ----------------------         ------------

December 30, 1996           25,000                    25,000

December 30, 1996           25,000                    50,000

December 30, 1996           25,000                    75,000

December 30, 1996           25,000                   100,000


   2. Manner of -Exercise.  The Optionee may exercise this Option only in the 
following manner: from time to time on or prior to the Expiration Date of 
this Option, the Optionee may give written notice to the Board of his 
election to purchase some or all of the vested Option Shares purchasable at 
the time of such notice as determined in accordance with the cumulative 
number of shares of Stock available for exercise specified in the third 
column of the schedule set forth in Section 1 hereof.  Said notice shall 
specify the number of shares of Stock to be purchased. 

      (a) Payment of the purchase price for the Option Shares may be made by 

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one or more of the following methods: (i) in cash, by certified or bank check 
or other instrument acceptable to the Board; or (ii) in the form of shares of 
Stock that are not then subject to restrictions under any Company plan 
(subject to the Board's discretion); or (iii) by the Optionee delivering to 
the Company a properly executed exercise notice together with irrevocable 
instructions to a broker to promptly deliver to the Company cash or a check 
payable and acceptable to the Company to pay the option purchase price; 
provided that in the event the Optionee chooses to pay the option purchase 
price as so provided, the Optionee and the broker shall comply with such 
procedures and enter into such agreements of indemnity and other agreements 
as the Board shall prescribe as a condition of such payment procedure.  
Payment instruments will be received subject to collection.

      (b) The delivery of certificates representing the Option Shares will be 
contingent upon the Company's receipt from the Optionee of full payment 
therefor, as set forth above, and any agreement, statement or other evidence 
as the Company may require to satisfy itself that the issuance of Option 
Shares to be purchased pursuant to the exercise of Options under this 
Agreement and any subsequent resale of the shares of Stock will be in 
compliance with applicable laws and regulations.

      (c) If requested upon the exercise of this Option, certificates for 
shares may be issued in the name of the Optionee jointly with another person 
or in the name of the executor or administrator of the Optionee's estate.

      (d) Notwithstanding any other provision hereof or of the Plan, no 
portion of this Option shall be exercisable after the Expiration Date hereof.

   3. Non-transferability of Option.  This Option shall not be transferable 
by the Optionee otherwise than by will or by the laws of descent and 
distribution and this Option shall be exercisable, during the Optionee's 
lifetime, only by the Optionee or his legal representative.

   4. Termination of Employment.  If the Optionee's employment by the Company 
or a Subsidiary (as defined in Section 1 of the Plan) is terminated, the 
period within which to exercise the Option shall be subject to the provisions 
set forth below.  For this purpose, an approved leave of absence or a 
transfer of employment from the Company to a Subsidiary, from a Subsidiary to 
the Company or from a Subsidiary to another Subsidiary shall not be deemed a 
"termination of Optionee's employment.'

      (a) Termination Due to Death.  If the Optionee's employment terminates 
by reason of death, any Option held by the Optionee may be exercised, to the 
extent exercisable at the date of death, by the Optionee's legal 
representative or legatee for a period of 180 days from the date of death or 
until the Expiration Date, if earlier.

      (b) Termination Due to Disability.  If the Optionee's employment 
terminates by reason of Disability (as defined in Section 1 of the Plan), any 

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Option held by the optionee may be exercised, to the extent exercisable on 
the date of termination, for a period of twelve months from the date of 
termination or until the Expiration Date, if earlier.

      (c) Termination for Cause.  If the Optionee's employment terminates for 
Cause (as defined in Section 1 of the Plan), any Option held by the Optionee 
shall terminate immediately and be of no further force and effect.

      (d) Other Termination.  If the Optionee's employment terminates for any 
reason other than death, Disability or Cause, and unless otherwise determined 
by the Board, any Option held by the Optionee may be exercised, to the extent 
exercisable on the date of termination for a period of one year from the date 
of termination or until the Expiration Date, if earlier.

      (e) Termination without Cause or for Good Reason.  Notwithstanding 
anything herein to the contrary, in the event the Company terminates 
Optionee's employment without Cause or Optionee terminates his employment for 
Good Reason' (as hereinafter defined), all of the Options granted pursuant 
to Section 1 hereof shall immediately become vested and exercisable in 
accordance with the terms hereof.  For purposes of this Agreement, each of 
the following events shall constitute  Good Reason' for Optionee to terminate 
his employment with the Company:

          (i)     Failure of the Board to elect Optionee to the 
                  office of Chief Executive Officer of the Company or to 
                  continue the Optionee in such office;

          (ii)    Any material breach by the Company of any provision of 
                  any Employment Agreement then in effect with Optionee; or

          (iii)   Election by the Company not to extend the term of 
                  Optionee's employment under any Employment Agreement then 
                  in effect with Optionee.

   5. Change of Control.  In the event of a "Change of Control" (as defined 
in Section 12 of the Plan), each Option will automatically become exercisable 
to the extent provided in Section 12 of the Plan, as in effect on the date of 
grant of this Option.

   6. Option Shares.  The Option Shares are shares of Stock of the Company as 
constituted on the date of this Option, which are subject to adjustment as 
provided in Section 3(b) of the Plan.

   7. No Special Employment Rights.  This Option will not confer upon the 
Optionee any right with respect to continuance of employment by the Company 
or a Subsidiary, nor will it interfere in any way with right of the 
Optionee's employer to terminate the Optionee's employment at any time.

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   8. Rights as a Shareholder.  The Optionee shall have no rights as a 
shareholder with respect to any shares of Stock which may be purchased by 
exercise of this Option unless and until a certificate or certificates 
representing such shares are duly issued and delivered to the Optionee.  
Except as otherwise expressly provided in the Plan, no adjustment shall be 
made for dividends or other rights for which the record date is prior to the 
date such stock certificate is issued.

   9. Qualification under Section 422.  It is understood and intended that 
the option granted hereunder shall qualify as an "incentive stock option" as 
defined in Section 422 of the Code to the maximum extent permitted by law.  
Accordingly, the Employee understands that the loss of the benefits of an 
incentive stock option under Section 422 of the Code may result from a sale 
or other disposition of any shares of Stock acquired upon exercise of the 
Option within the one-year period beginning on the day after the day of the 
transfer of such shares of Stock to him, nor within the two-year period 
beginning on the day after the grant of the Option.  If the Employee intends 
to dispose or does dispose (whether by sale, gift, transfer or otherwise) of 
any such shares of Stock within said periods, he will notify the Company 
within thirty (30) days after such disposition.  In addition, no more than 
$100,000 of the aggregate fair market value (as defined in the Plan) of Stock 
Options (as defined in Section 1 of the Plan) granted under the Plan may 
become exercisable for the first time by the Optionee during any calendar 
year and be treated as incentive stock options under Section 422 of the Code.

  10. Tax Withholding.  No later than the date as of which part or all of the 
value of any of the Option Shares first becomes includable in the Optionee's 
gross income for Federal tax purposes, the Optionee shall make arrangements 
with the Company in accordance with Section 8 of the Plan regarding the 
payment of any federal, state or local taxes required to be withheld with 
respect to the income.

  11. The Plan.  In the event of any discrepancy or inconsistency between 
this Agreement and the Plan, the terms and conditions of the Plan shall 
control, provided that, it is understood and acknowledged that in the event 
of any termination of Optionee's employment other than due to death, 
disability or for cause, the provisions of Sections 4(d) and 4(e) of this 
Agreement shall control.

  12. Counterparts.  This Agreement may be executed in one or more 
counterparts, each of which shall be deemed to be an original but all of 
which together constitute one and the same instrument.

  13. Miscellaneous.  Notices hereunder shall be mailed or delivered to the 
Company at its principal place of business and shall be mailed or delivered 
to Optionee at the address set forth below or, in either case, at such other 
address as one party may subsequently furnish to the other party in writing.

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                        ENSYS ENVIRONMENTAL PRODUCTS, INC.


                        By:       /s/ ROBERT E. FINNIGAN               
                           ------------------------------------------
                           Member of the Compensation Committee of the Board of
                           Directors of EnSys Environmental Products, Inc.


    Receipt of the foregoing Option is acknowledged and its terms and 
conditions are hereby agreed to:

                                                                     
                           ------------------------------------------
                           Richard C. Birkmeyer (Optionee)

Date:------------------    Address:----------------------------------
                              
                           ------------------------------------------

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  12. Counterparts.  This Agreement may be executed in one or more 
counterparts, each of which shall be deemed to be an original but all of 
which together constitute one and the same instrument.

  13. Miscellaneous.  Notices hereunder shall-be mailed or delivered to the 
Company at its principal place of business and shall be mailed or delivered 
to optioned at the address set forth below or, in either case, at such other 
address as one party may subsequently furnish to the other party in writing.

                        ENSYS ENVIRONMENTAL PRODUCTS, INC.


                        By: ------------------------------------------
                            Member of the Compensation Committee of 
                            the Board of Directors of EnSys Environmental
                            Products, Inc.


    Receipt of the foregoing Option is acknowledged and its terms and 
conditions are hereby agreed to:

                                    /s/  RICHARD C. BIRKMEYER               
                             ------------------------------------------
                             Richard C. Birkmeyer (Optionee)

Date:   December 30, 1996    Address:      10 Stage Rd.                    
       ------------------             ----------------------------     
                                           Newark, DE  19711                  
                             -------------------------------------   

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