<PAGE>
           LEASE SUMMARY SHEET

1. LANDLORD:   PENCADER COURTYARD L.P.

2. TENANT:     STRATEGIC DIAGNOSTICS INC.

3. BUILDING:   111 Pencader Drive
               Newark, Delaware, 19702

4. PREMISES:   As set forth on Exhibit A hereto

5. TERM:       TEN (10) years

   Commencement Date:   Upon Substantial Completion of the Premises/Date of
                        Issuance of Certificate of Occupancy

6. RENT:

   (a)   Base Rent: $9.00/square foot, increased by three percent (3%) 
                     annually on a cumulative basis.

NOTE:    This Lease Summary Sheet is for the convenience of Landlord and 
         Tenant and shall not be deemed to be incorporated into or made a 
         part of the attached Lease for any reason.


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                              TABLE OF CONTENTS
                                                                        Page
1.    The Parties..........................................................1

2.    Building, Premises and Common Areas..................................1

3.    Leasing Clause: Quiet Enjoyment......................................2

4.    Use of Premises......................................................2

5.    Term.................................................................2

6.    Rent.................................................................4

7.    Net Lease............................................................4

8.    Subletting Or Assignment.............................................7

9.    Inspection And Repair of Premises....................................8

10.   Damage To Premises...................................................8

11.   Eminent Domain.......................................................9

12.   Tenant's Obligations................................................10

13.   Landlord's Obligations..............................................12

14.   Life Safety.........................................................14

15.   Indemnification.....................................................14

16.   Tenant Default......................................................15

17.   Landlord Default....................................................16

18.   Environmental Compliance............................................17

19.   Mechanics' Liens....................................................19

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20.   Subordination.......................................................19

21.   Estoppel Certificate................................................20

22.   Holding Over........................................................20

23.   Attorney's Fees.....................................................20

24.   Signs...............................................................20

25.   Other Utilities.....................................................21

26.   Broker..............................................................21

27.   Notices.............................................................21

28.   Miscellaneous.......................................................22


                                        -ii-

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                                       LEASE

   This LEASE AGREEMENT (this "Lease") is made and entered into as of this
29th day of October, 1997, between Landlord and Tenant named below.

   1. The Parties

      (a) The name and address of Landlord is:
               
               Pencader Courtyard, L.P.
               1300 Market Street, Suite 300
               Wilmington, DE 19801
               Attn: Keith D. Stoltz

      (b) The name and address of Tenant is:
               
               Strategic Diagnostics Inc.
               128 Sandy Drive
               Newark, DE 19713

   2. Building, Premises and Common Areas

      (a) Landlord, in consideration of the Rent (as hereinafter defined) 
reserved and the terms and conditions herein contained on the part of Tenant 
to be performed, hereby demises and lets unto the Tenant, and Tenant, subject 
to the terms hereof and the performance by the Landlord of its obligations 
hereunder, takes and lets from the Landlord, that certain property located at 
111 Pencader Drive, Newark, Delaware, 19713 within the section of the 
Pencader Corporate Center owned by Landlord (the "Pencader Courtyard 
Property") consisting of 28,653 rentable square feet of manufacturing space, 
warehouse space, office space, and storage space within the Building (the 
"Building") situated thereon and as further described on Exhibit A hereto 
(the "Premises").

      (b) Tenant, its employees, agents, licensees and invitees shall have 
the right to use all areas and equipment, fixtures and furniture within the 
Property (as hereinafter defined) including the Building's entrances, access 
ways, roads, driveways, sidewalks, exterior ramps, parking facilities and 
other similar areas which enable Tenant to obtain full use and enjoyment
of the Premises for all customary purposes (the "Common Areas").
   
      (c) The Building, the Premises, the Common Areas, and the land and other
improvements on the land are hereinafter collectively referred to as the 
"Property."

      (d) Landlord represents and warrants that, immediately after the 
Initial Landlord Improvements are Substantially Completion (as such terms are 
defined in Section 13 hereof) and prior to occupancy by Tenant, the Property 
shall be in compliance with all applicable

<PAGE>
         
laws, rules and regulations, including, without limitation, all Environmental 
Laws (as defined in Section 18 hereof) and the Americans with Disabilities 
Act for 1990, as amended.

      (e) Landlord represents and warrants that it is, as of the date hereof, 
and will continue at all times during the Term (as defined in Section 5 
hereof) to be, in compliance with respect to any and all of its obligations 
and duties, as an "owner" (as defined in the Declaration of Restrictions)  or 
otherwise, provided for in that certain Pencader Corporate Center Declaration 
of Restrictions dated February 13, 1997 by and between Howard P. Wilson (as 
Granter), EHM Pencader I Limited Partnership. New Castle Country Economic 
Development Corporation and Karen Peterson (President of County Council. New 
Castle Country) (the Declaration of Restrictions"). Contemporaneous with the 
execution of this Lease, Landlord shall provide to Tenant a copy of the 
Declaration of Restrictions.

   3. Leasing Clause: Quiet Enjoyment  Landlord represents that (i) it is the 
fee simple owner of the Property, (ii) there are no encumbrances, liens, 
options to purchase and/or mortgage existing with respect to the Property, 
other than that certain First Mortgage and Construction Loan with First Trust 
Bank in effect as of the date of execution of this Lease: and (iii) it has 
full right and authority to make this Lease. Landlord hereby leases the 
Premises to Tenant and Tenant hereby accepts the same from Landlord in 
accordance with the provisions of the Lease. Landlord covenants that, 
provided that Tenant is not in default beyond applicable notice and cure 
periods under this Lease at the time of any exercise of an option. Tenant 
shall have peaceful and quiet enjoyment of the Premises during the Term (as 
defined below) of this Lease.

   4. Use of Premises. Tenant may use and occupy the Premises for 
manufacturing, packaging, production, sales, marketing, research, 
warehousing, general commercial office and storage purposes and uses 
incidental thereto.

   5. Term. The term of this Lease (the "Term") shall begin on the date the 
Initial Landlord Improvements are Substantially Complete or such other time 
as mutually agreed in writing between Landlord and Tenant (the "Commencement 
Date") and shall end on that date which is the last day of the one hundred 
twentieth (120th) month following the first day of the month immediately 
following the Commencement Date (the "Expiration Date"), unless sooner 
terminated in accordance with the terms and conditions contained this lease.

                                       -2-

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   6. Rent.
      (a) Base Rent - The Base Rent (defined below) shall be payable by 
Tenant to Landlord in advance commencing on the Commencement Date, and 
thereafter, on the first day of each month during the Term, in lawful money 
of the United States, payable in monthly installments at an initial rate of 
Nine Dollars ($9.00) per rentable square foot (the "Base Rent"), such rate to 
increase by three percent (3%) annually on a cumulative basis, as set forth 
in this Section 6 (a) below. In the event that the Commencement Date occurs 
on a day other than the first day of a calendar month. Tenant shall pay to 
Landlord a pro rate portion of the monthly installment of Base Rent for such 
partial month, computed at the annual Base Rent of $9.00 per rentable square 
foot. Tenant shall pay Rent promptly when due without abatement, deduction or 
set-off except as specifically stated in this Lease. If Tenant fails to pay 
monthly Rent within ten (10) days after receipt from Landlord of written 
notice that Landlord has not received such monthly Rent as due. Tenant shall 
pay to Landlord a Late Fee (a "Late Fee" equal to five percent (5%) of the 
then applicable Rent in addition to the Rent then due for such month.


MONTHS
ANNUALIZED RENT
MONTHLY RENT
RATE/SQ. FT

1-12
$257.877
$21,490
$9.00

13-24
$256.613
$22.134
$9.27


25-36
$273.636
$22.805
$9.55

37-48
$281.946
$23,495
$9.84

49-60
$290,541
$24,212
$10.14

61-72
$299,137
$24,928
$10.44

73-84
$308,020
$25,668
$10.75


85-96
$317,189
$26,432
$11.07

97-108
$326.644
$27,221
$11.40

109-120
$336,386
$28,032
$11.74



      (B) Additional Rent - In addition to the Base Rent (and exclusive 
therefore) the sums of money provided for in Section 7 of this Agreement 
(the "Additional Rent") shall be payable by Tenant to Landlord in accordance 
with the term and conditions set forth therin. Whenever under the terns of 
this Lease any sum of money is required to be paid by Tenant in addition to 
the Base Rent herein reserved, and said additional sum is not designated as

                                    -3-


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"Additional Rent", then if not paid when due, said sum shall nevertheless be 
deemed Additional Rent and be collectible as such with any installment of 
Base Rent thereafter falling due hereunder, but nothing herein contained 
shall be deemed to suspend or delay the payment of any such sum at the time 
the same became due and payable hereunder, or limit any other remedy of 
Landlord.

      (c) All payments of Base Rent and Additional Rent shall be paid when 
due, without demand, at Stoltz Management Company, 1303 Delaware Avenue, at
Suite 1505, Wilmington, Delaware 19806, Attn: Accounting Department, or at such
other place as Landlord may from time to time direct by notice to Tenant. All 
checks shall be made payable to the order of Landlord.

   7. Net Lease.
      (a) For the purpose of this Lease:

          (i) Real Estate Taxes shall mean all taxes, assessments, levies and 
other real estate charges (including Delaware lease and use taxes), which are 
assessed, levied or charged upon the Property by the federal, state, county 
or municipality during any calendar year including any which have been 
finally determined by legal proceedings or otherwise to be legally payable, 
less any abatement received by Landlord or any affiliate of Landlord. Real 
Estate Taxes shall not include: (A) any interest or penalties not caused by 
Tenant's actions; or (B) any capital levy, estate, succession, inheritance, 
transfer, sales, use or franchise taxes, or any income, profits, or revenue 
tax, assessment or charge imposed upon the rent received as such by the 
Landlord under this Lease. If at any time during the Term, the method of 
taxation prevailing on the date hereof shall be altered, such additional or 
substitute tax, assessment, levy or imposition shall be deemed to include 
within the term "Real Estate Taxes" for the purposes hereof.

          (ii) Operation and Maintenance Costs shall mean the total accrual 
out-of-pocket costs and expenses to Landlord for the operation and routine 
normal maintenance and repair of the Building and Common Areas which are 
incurred during any calendar year or portion thereof, in accordance with 
generally accepted accounting principles, consistently applied, including 
without limitations, the following items:

            (A) All utilities consumed by the Common Areas and the external 
and/or structural portion of the Building and the servicing and maintenancing 
thereof, including, without limitation, gas, water, sewer, electricity, power 
and lighting;

            (B) All reasonable fees and charges paid to third parties engaged 
in or contracted for the repair (including necessary replacements), 
maintenance, and


                                    -4-


<PAGE>

external security of the Building and Common Areas, including without 
limitation, window cleaning, sprinkler system, snow removal and landscaping;

            (C) Premiums on all fire and extended coverage (with all risk 
coverage) insurance and comprehensive general liability insurance covering 
the Building and the Common Areas and Landlord's personal property and 
fixtures used in connection therewith;

            (D) All repairs (including necessary replacements) and general 
maintenance (including with respect to external security) of the Building and 
the Common Areas performed by Landlord, its employees and/or agents, provided 
that the fees for such repairs and general maintenance shall not exceed the 
fees and charges payable to third parties for similar services in an arms 
length transaction;

            (E) The cost of any reasonably necessary capital improvements to 
the Building and Common Areas made after the Commencement Date, either (i) 
for the primary purpose of reducing Operation and Maintenance Costs or (ii) 
to comply with any requirements mandated by governmental authority under any 
governmental law or regulation that was not applicable to the Building and 
the Common Areas as of the Commencement Date. The costs of all such permitted 
capital improvements shall be amortized over the expected useful life of the 
capital improvement (as reasonably determined by Landlord), together with 
interest on the unamortized balance at the Prime Rate being charged by 
Wilmington Trust Bank, Wilmington, Delaware (or any successor bank); and

            (F) The following shall be excluded from the term "Operation and 
Maintenance Costs" (i) expenses for repairs or other work occasioned by fire, 
windstorm or other insured casualty (excluding any deductible amounts); (ii) 
expenses incurred in leasing or procuring new tenants (e.g., for lease 
commissions, advertising expenses and expenses of renovating space for new or 
existing tenants); (iii) legal expenses in enforcing the terms of any lease; 
(iv) interest and amortization payments on any mortgage or mortgages; (v) the 
cost of any item, whether purchased or leased, that would be considered a 
capital item or improvement under generally accepted accounting principles 
(except to the extent permitted by Section 7(a)(ii)(E) above); (vi) 
depreciation; (vii) Real Estate Taxes; (viii) advertising and promotional 
expenditures; (ix) all items and services for which Tenant reimburses 
Landlord or pays third parties; (x) any costs incurred as a result of 
environmental matters of any kind which are assignable to Landlord under the 
terms and conditions of this Lease; (xi) any costs assigned to Landlord 
under the provisions of Sections 13(a) and (b) of this Lease; and (xii) any 
charge or fee paid entirely by, or for which Landlord is entirely reimbursed 
by, any other tenant occupying the other building within the Pencader 
Courtyard Property;

          (iii) "Tenant's Percentage" shall be 53.89% which is the ratio that 
the rentable square foot area of the Premises (i.e., 28,653 rentable square 
feet) bears to the

                                    -5-



<PAGE>


total rentable square foot area of office space in the two buildings 
(including the Building) located in Pencader Courtyard Property (i.e., 53,168 
rentable square feet).

          (iv) During each calendar year (or part thereof) commencing on the 
Commencement Date, Landlord and Tenant agree that Tenant shall pay monthly, 
in advance, as Additional Rent an amount equal to one-twelfth of Tenant's 
Percentage of the estimated annual Operation and Maintenance Costs and Real 
Estate Taxes for each calendar year. For each calendar year. Landlord shall 
make a reasonable estimate of Tenant's Percentage of the Operation and 
Maintenance Costs and Real Estate Taxes constituting Additional Rent and 
notify Tenant as to such estimate on or about December 15th of the preceding 
calendar year. For each calendar year after the first full calendar year 
during the term of this Lease, the estimate of Tenant's Percentage of the 
Operation and Maintenance Costs and Real Estate Taxes shall not be greater 
than the then current actual Operation and Maintenance Costs for such 
preceding calendar year, increased by five percent (5%) (the "Estimate 
Ceiling"); provided, however, that the Estimate Ceiling shall not apply to 
Landlord's estimate of Operation and Maintenance Costs and Real Estate Taxes 
hereunder until the Lease year commencing January 1, 1999.

          (v) On or about April 1 of each calendar year commencing with 
calendar year 1998, Landlord shall submit to Tenant a reasonably detailed 
statement, certified by Landlord, setting forth the actual Operation and 
Maintenance Costs and Real Estate Taxes for the preceding calendar year and 
Tenant's Percentage thereof. Within thirty (30) days after delivery of such 
statement to Tenant, Landlord or Tenant, as applicable, shall pay to the 
other any difference between Tenant's estimated payments under Section 
7(a)(iv) above and Tenant's Percentage of the actual Operation and 
Maintenance Costs and Real Estate Taxes. Within ninety (90) days after 
receipt of each statement. Tenant shall have the right to audit and contest 
Landlord's determination of Operation and Maintenance Costs and/or Real 
Estate Taxes and to inspect Landlord's records with respect thereto during 
normal hours upon at least ten (10) days advance written notice. If any such 
audit shall reveal a discrepancy in Landlord's determination of the Operation 
and Maintenance Costs and/or Real Estate Taxes, Landlord and Tenant shall 
cooperate in good faith to resolve the discrepancy and mutually agree upon 
the amount of the actual Operation and Maintenance Costs and/or Real Estate 
Taxes. In the event it is determined that Tenant has been charged more than 
its actual Tenants Percentage of Operation and Maintenance Costs and/or Real 
Estate Taxes, Landlord shall refund the excess payment to Tenant and if the 
amount of the excess payment is more than five percent (5%) of Tenant's 
actual Tenant's Percentage of Operation and Maintenance Costs and/or Real 
Estate Taxes. Landlord shall reimburse Tenant for the reasonable cost of 
Tenant's audit up to a maximum amount of $2,000.00 during the first through 
fifth years of the Lease and $2,500.00 during the sixth through tenth years 
of the Lease.

          (vi) All sums due under this Section 7 shall be appropriately 
apportioned and prorated for any portion of a Lease year, so that Tenant 
shall not be obligated to pay any Operation and Maintenance Costs or Real 
Estate Taxes that accrue either prior to the

                                    -6-


<PAGE>

Commencement Date or following the Expiration Date. In the event that this 
Lease shall expire at any time other that at the end of a calendar year, 
then within thirty (30) days after statements reflecting the actual Operation 
and Maintenance Costs and Real Estate Taxes for the year in which such 
expiration occurs are submitted by Landlord to Tenant (pro-rated on the basis 
of the number of calendar year days included within such partial Lease year 
divided by 365 days), either Landlord or Tenant shall pay to the other party 
the adjustment sum due. The provisions of this paragraph shall survive the 
expiration of this Lease.

          (b) All sums, liabilities, obligations and other amounts which 
Tenant is required to pay or discharge pursuant to Section 7 of this Lease in 
addition to Base Rent, together with any interest, penalty or other sum which 
may be added for late payment thereof shall constitute Additional Rent 
hereunder. Base Rent and Additional Rent may be referred to collectively as 
"Rent". Tenant shall not be entitled to any abatement or reduction (except 
as other-wise expressly provided in Section 10 hereof) set-off or deduction 
with respect to its obligations to pay Rent hereunder. In the event of any 
failure on the part of Tenant to pay or discharge any additional Rent, 
Landlord shall have all rights, powers and remedies provided for herein or by 
law or equity or otherwise in the case of nonpayment of Base Rent.
   
      8. Subletting or Assignment.

          (a) Tenant shall be permitted to (i) assign or otherwise transfer 
this Lease, or the Term and estate hereby granted or (ii) sublet the Premises 
or any part thereof, or offer or advertise to do so or allow the same to be 
used or occupied by anyone other than Tenant only upon receiving the prior 
written-consent of Landlord, which consent shall not be unreasonably if 
withheld, delayed or conditioned. Tenant specifically acknowledges that by 
way of example and without limitation. Landlord may withhold its consent if; 
(x) the reputation or financial responsibility of a proposed assignee or 
subtenant is unsatisfactory to Landlord in its reasonable discretion; (y) 
Landlord determines in its reasonable discretion that the business of the 
proposed assignee or subtenant is not consistent with the nature of the 
Premises; or (z) Tenant is renting or subletting the Premises or any part 
thereof for a rent which exceeds Tenants Base Rent hereunder, unless Tenant 
agrees to deliver such excess rent to Landlord as Additional Rend hereunder. 
Any violation of the provisions hereinabove set forth shall constitute a 
default hereunder and Landlord, after notice and an opportunity to cure 
pursuant to Section 16, shall have option to cancel the same and proceed in 
accordance with the provisions set forth in this Lease. Any consent by 
Landlord to a particular assignment or sublease, shall not constitute consent 
or approval of any subsequent assignment or sublease and Landlords written 
approval shall be required in all instances. In the event that Landlord 
consents to any assignment or sublease, Landlord shall not be deemed to have 
released Tenant from its obligation hereunder unless so stated in a separate 
agreement between Landlord and Tenant.

      (i) Landlord shall have fifteen (15) days from the date on which Tenant 
has submitted to Landlord the information set forth in this Section 8, to 
notify


                              -7-

<PAGE>

Tenant in writing of Landlord's rejection or consent to the proposed 
subtenant or assignee, Landlord shall specify the reasons for rejection in 
any notice of rejection.  In the even Landlord reasonably claims that any of 
the above information is incomplete, Landlord shall immediately notify 
Tenant, in writing, of such claim, and the fifteen (15) day period shall be 
extended by the number of days of Tenant's delay in delivering reasonably 
complete information to Landlord in accordance with this Section 8.  
Landlord's consent shall be conclusively deemed given after the fifteen (150 
day period, unless refused or delayed as described above.

          (ii) Notwithstanding the provisions of this Section 8, Tenant shall 
have the right to assign or transfer any interest in this Lease to a 
subsidiary, parent or an affiliate of Tenant or a successor to Tenant, 
including, without limitation, by way of merger, consolidation, corporate 
reorganization or the purchaser of all or substantially all of Tenant's 
assets (so long as the surviving entity after such purchase has a financial 
net worth greater than or equal to that of Tenant), each without Landlord's 
consent.

         (iii) Notwithstanding anything to the contrary in this Section 8, 
any transfer, sale, pledge or other disposition and/or power to vote the 
outstanding shares of corporate stock of Tenant shall not be deemed an 
assignment.

        (b) Upon written notice delivered to Landlord by Tenant of Tenant's 
desire to sublet the Premises Landlord agrees to use all reasonable best 
efforts to assist Tenant in obtaining a sublettor suitable to Landlord in 
accordance with this Section 8.

        (c) Estoppels and Landlord Waivers.  Landlord shall, at Tenant's 
reasonable request:  (i) provide Tenant with an estoppel certificate stating 
whether Landlord knows of any defaults under this Lease at the time of any 
proposed subletting or assignment; and (ii) provide to any lender to Tenant 
an agreement in recordable form stating that Landlord waives any and all 
rights to Tenant's fixtures, inventory, equipment, furniture or other 
personal property located at the Property.

     9. Inspection and Repair of Premises.  Landlord may inspect and repair 
the Premises at reasonable times and after reasonable prior notice to Tenant 
(except prior notice shall not be required in emergencies).  In making any 
inspection or performing maintenance or repairs to, or construction in, or 
around the Premises, Landlord shall use all commercially reasonable efforts 
to protect Tenant's property and personnel from loss and injury and to avoid 
interfering with the conduct of Tenant's business.

                                  -8-
              

<PAGE>

   10. Damage to Premises.

       (a) If the Property or any portion of the Property to which Landlord 
is required to make repairs, maintenance or replacements pursuant to the 
terms hereof is damaged by fire or other casualty, then, except as provided 
below, the damage shall be promptly repaired by and at the expense of 
Landlord.  Until such repairs and restoration are completed, the Base Rent, 
Real Estate Taxes and Maintenance and Operating Expenses shall be equitably 
abated to the extent that damage to the Premises and/or other portions of the 
Property materially adversely interferes with the conduct of Tenant's 
business.  If such damage to the Property or any portion thereof, for which 
Landlord is required to make repairs, maintenance or replacements, shall 
materially adversely interfere with the conduct of Tenant's business and the 
parties agree that such damage shall not be susceptible of complete repair 
and restoration within one hundred twenty (120) days after the occurrence of 
such casualty, then Landlord or Tenant may, by written notice to the other, 
terminate this Lease as of the date of occurrence of such damage, provided 
such notice is given within forty-five (45) days after the date of such 
casualty.  If such damage shall be the responsibility of Landlord and can be 
repaired within one hundred twenty days (120) days and Landlord fails to 
repair or restore such damage within such period, then Tenant may terminate 
this Lease by thirty (30) days' prior written notice to Landlord, in addition 
to all other remedies Tenant may have under this Lease at law or in equity.  
The parties agree to cooperate with each other to process the release of the 
Insurance proceeds for the aforementioned repair purposes.  In the event of 
the termination of this Lease pursuant to this Section 10, Base Rent, Real 
Estate Taxes and Maintenance and Operating Expenses shall be prorated as of 
the date of such termination. 

       (b) Landlord and Tenant to each hereby release and discharge the other 
party and any officer, agent, employee or representative of such party from 
any claim, suit, action, and liability for any and all loss of, or damage 
to, any of its property located within or upon or constituting a part of the 
Premises (including the Building) or the Property, to the extent that such 
loss or damage is recovered or should have been recovered under an insurance 
policy or policies required by the terms of this Lease.  Each party agrees to 
require its insurers to issue policies containing such provisions and a 
waiver of the right subrogation.  Landlord and Tenant shall provide notice to 
the other party to the extent either of their respective policies do not 
contain such a required waiver of claims and right of subrogation.

    11. Eminent Domain. If the property or any portion thereof shall be taken 
under the power of eminent domain or conveyed in lieu thereof, and the taking 
of which materially adversely interferes with the conduct of Tenant's 
business, then Tenant shall have the right to terminate this Lease as of the 
date of vesting of title of such taking, an in which event Base Rent, Real 
Estate Taxes and Maintenance and Operating Expenses shall be pro-rated as of 
such date.  If Tenant does not terminate this Lease, Landlord shall proceed 
with due diligence to make all repairs necessary to restore the Property to 
as near its former condition as circumstances

                                     -9-


<PAGE>

will permit and the Lease shall remain in full force and effect, except that, 
effective on the date of taking or conveyance, the Premises shall be reduced 
by the portion of the Premises so taken or conveyed, and the Base Rent, Real 
Estate Taxes and Maintenance and Operating Expenses shall be proportionately 
reduced by the portion of the Premises taken or conveyed.

    12. Tenant's Obligations.

        (a) Tenant shall maintain, at its sole cost and expense, with an 
insurer(s) reasonably acceptable to Landlord and rated "A" or better by 
Best's Insurance Guide:

            (i) Standard Commercial General Liability Insurance.  The limits 
of liability of such insurance shall be an amount which is not less than One 
Million Dollars ($1,000,000) per occurrence an account of bodily injuries to 
or death of one person and One million Dollars ($1,000,000) per occurrence 
for property damage liability or Two Million Dollars ($2,000,000) combined 
single limit for personal injury and property damage.  Such insurance shall 
cover Tenant against any claim directly out of liability for bodily injury and 
death and personal injury and property damage occurring in an about the 
Premises and otherwise resulting from any acts and operations of Tenant, its 
agents and employees.  The total amount of a deductible or otherwise 
self-insured retention with respect to such coverage shall not be more than 
$10,000 per occurrence.  Such insurance shall include inter alia: (i) 
"occurrence" rather than "claims made" policy forms unless such "occurrence" 
policy forms are not available; (ii) any and all liability assumed by the 
Tenant under the terms of this Lease, to the extent such as insurance is 
available; (iii) the Landlord, as an additional insured, with respect to (A) 
the Premises, and (B) all operations of the Tenant, and (C) any property and 
areas and facilities of the Landlord used by the Tenant, its employees, 
invitees, customers and guests; and (iv) severability of insured and cross 
liability so the protection of such insurance shall be afforded to the 
Landlord in the same manner as if a separate policy had been issued to each 
of the insured parties; and

            (ii) Excess Liability Insurance in Umbrella Form, the limits of 
which shall be an amount which is not less than Three Million Dollars 
($3,000,000) per occurrence or in the aggregate; and

            (iii) "all risk" property insurance on Tenant's personal 
property, including inventory, trade fixtures, floor coverings, furniture or 
other property.  This insurance shall include fire and extended coverage 
perils.

        (b) Tenant shall be responsible, as its sole cost, for the provision, 
maintenance, and repair (including replacement if reasonably necessary) of 
the following:

            (i) Utilities, including without limitation, electricity, sewage 
and water, with respect to the interior of the Building.  Such Tenant 
responsibilities expressly do

                                      -10-

<PAGE>

not include maintenance and repair with respect to the structural electrical, 
plumbing and sewage systems of the Premises:

            (ii) Janitorial and cleaning services with respect to the 
interior of the Building:

            (iii) General maintenance and repair to the interior of the 
Building, including, without limitation, light fixtures, interior walls, 
ceilings, floors, doors, and windows.  Such Tenant responsibilities expressly 
do not include maintenance and repair with respect to the structural aspects 
of the Building, any external loading docks and any elevators; and

            (iv) Heating, ventilation and air conditioning ("HVAC") units and 
compressors.

        (c) Tenant shall comply with all laws pertaining to Tenant's specific 
use of the Premises, provided Tenant shall not be required to make any 
alterations or improvements of a capital nature to the Premises or the 
Building unless due to its specific use thereof.  Tenant shall, at its own 
expense, observe and comply with all applicable Environmental Laws (hereafter 
defined) and all regulations or standards as are promulgated thereunder with 
respect to its particular use of the Premises and Tenant shall correct any 
violation thereof arising from its specific use of the Premises from and 
after the Commencement Date through the Expiration Date.  This provision 
shall survive the expiration or termination of this Lease. 

        (d)  During the Term, Tenant may make improvements, alterations or 
additions to the interior of the Premises (including the interior of the 
Building) provided such work is done in a workmanlike manner with materials 
and finishes at least comparable to those then existing in the Premises, and 
provided that any improvements, alterations and additions effecting the 
external structure of the Building, including without limitation, the roof, 
exterior walls, bearing walls, support beams, foundation, columns and lateral 
support, shall be made only with the prior written consent of Landlord, which 
consent shall not be unreasonable withheld, conditioned or delayed. Any of 
the foregoing Tenant improvements shall remain the sole property of Tenant 
notwithstanding that such improvements may be affixed to the Building and 
Tenant shall remove such improvements at the expiration of the Term hereof 
and shall, at Tenant's cost, repair any damage such removal causes, and 
restore the Premises without restoration of pre-existing equipment, to the 
condition which existed prior to the installation of Tenant's alterations, 
improvements, or additions.  If Tenant makes any improvements, alterations 
or additions, Tenant agrees to comply with all insurance requirements and all 
laws, ordinances, rules and regulations of all governmental authorities, 
provided that Landlord shall cooperate with Tenant in securing any necessary 
permits, the cost for such permits to be borne by Tenant.

                                      -11-

<PAGE>

        (e) Tenant may install and maintain its own security system for the 
Premises, which may include establishing limited access areas within the 
Premises that are reasonably acceptable to Landlord.  At its sole option, 
Tenant may remove any security, telephone or computer system or any portion 
thereof (the "Systems") installed on behalf of Tenant, provided Tenant 
repairs any damage caused by such removal.  In no event, however, shall 
Tenant be required to remove any portion of the Systems (including without 
limitations, cabling) installed in any wall, floor, partition, ceiling or 
under any floor covering.

        (f) At or before the expiration or earlier termination of this Lease. 
Tenant shall surrender the Premises in substantially as good condition as 
when entered, except for loss or damages resulting from casualty, 
condemnation, acts of God, ordinary wear and tear and any improvements, 
alterations or additions made to the Premises. 

            (i) Tenant at is expense, shall remove from the Premises all of 
Tenant's property (except with respect to the "interior block walls" as 
described in Section 12(f)(ii)below and such items as Landlord and Tenant 
shall have expressly agreed, in writing, to remain, which property shall 
become the property of the Landlord), and Tenant shall repair any damage to 
the Premises resulting from any installation and/or removal of Tenant's 
property.  Any other items of Tenant's property (except with respect to the 
"interior block walls" as described in Section 12(f)(ii) below) that shall 
remain in the Premises after the expiration of the Lease, or following any 
earlier termination date, may, at the option of Landlord, be deemed to have 
been abandoned, and in such case, such items may be retained by Landlord as 
its property or be disposed of by Landlord, without accountability, in such 
manner as Landlord shall determine at Tenant's expense. 

            (ii) With respect to the "interior block walls" constructed as 
part of the Initial Landlord Improvements (as defined in Section 13(a)), 
Tenant shall not remove such interior block walls, unless, within thirty (30) 
days after the expiration or earlier termination of this Lease, Landlord 
requests, in writing, that Tenant remove the interior block walls from the 
Premises, such removal (and repair of any damage caused thereby) to be 
completed at the sole cost and expense of Tenant.

    13. Landlord's Obligations

        (a) Landlord shall have sixty (60) days from the date of execution of 
this Lease (the "Substantial Completion Period"), at Landlord's sole cost and 
expense, to substantially complete all construction work and improvements 
specified on the design and construction plans (as approved by Tenant), 
including, without limitation, improvements with respect to the interior 
structure (including the interior block walls), systems, and facilities within 
the Building as set forth on Exhibit A hereto (the "Initial Landlord 
Improvements").  For the purposes of this Lease, the Premises shall be 
"Substantially Complete" as of the date when (x) the Initial Landlord 
Improvements have been substantially completed in conformity with the 

                                      -12-

<PAGE>

specifications outlined therein in all aspects necessary to permit Tenant to 
occupy and utilize the Premises for the uses permitted by this Lease, subject 
to minor punch list items and (y) Landlord is able to obtain from the 
appropriate governmental office in the County of New Castle, State of 
Delaware, a Certificate of Occupancy with respect to the Premises (and a copy 
of such Certificate of Occupancy is furnished to Tenant), or if Landlord is 
unable to obtain such a Certificate of Occupancy (but New Castle County has 
not refused to issue the same) due to the County's administrative delay in 
its final inspection and issuance process.  Landlord's architect certifies to 
Tenant that the Premises has been completed in accordance with the applicable 
laws and that Landlord is entitled to the issuance of a Certificate of 
Occupancy regarding the Premises and that such Certificate of Occupancy 
should be issued in due course.  In the event that Landlord does not 
Substantially Complete the Premises within the Substantial Completion Period. 
Tenant's obligation hereunder with respect to the payment to Landlord of 
Rent when due shall be abated for one (1) calendar day for every one (1) 
calendar day beyond the Substantial Completion Period for which Landlord 
fails to Substantially Complete the Premises, up to a maximum of sixty (60) 
days beyond the Substantial Completion Period (i.e. one hundred twenty (120) 
calendar days from the date of execution of this Lease).  In the event that 
Landlord doe not Substantially Complete the Premises within one hundred 
twenty (120) calendar days of the date of execution of this Lease, Tenant 
shall have the right to terminate this Lease.  For the avoidance of doubt, 
Landlord's obligations under this Section 13(a) shall not be subject to Force 
Majeure provisions set forth in Section 17(b) hereunder.

        (b) During the term of this Lease, Landlord, without cost to Tenant, 
shall maintain, repair and replace, as necessary, and keep in good order and 
in safe and operational condition, all structural portions of the Property, 
and all service systems for the same, including, without limitation:

            (i) the structural plumbing, Building electrical and mechanical 
lines and equipment associated therewith, all of which either are located in 
or serve the Building, the Premises or Common Areas:

            (ii) the exterior structure of the Building including the roof, 
exterior walls, bearing walls, support beams, foundation, columns, and 
lateral support; and

        (c) Without limiting subsections (a) and (b) above, Landlord shall 
provide the following services and facilities, such cost to be borne by Tenant 
as Additional Rent in accordance with the terms of this Lease:

            (i) All utilities necessary for the Common Areas and external 
structural portion of the Building, including, without limitation, gas, 
water, sewer, electricity, power and lighting;

                                      -13-

<PAGE>

            (ii) General cleaning and maintenance of the external portion of 
the Building and the Common Areas, including, without limitation, parking 
facilities, snow removal services, landscaping and garbage/trash removal 
(except any environmentally sensitive or hazardous medical garbage/trash); and

            (iii) the exterior capital improvements to the Common Areas, 
including curbs, driveways, parking areas, sidewalks, lighting, and ditches.

        (d) Tenants Premises and leasehold interests hereunder shall include, 
for the benefit of Tenant, its employees and agents, a total of seventy (70) 
parking spaces within the Property, such parking spaces to be located in 
reasonably close proximity to the Building.  Upon Tenant's reasonable 
request, Landlord shall designate ten (10) of such parking spaces (to be 
located in the ten spaces closest to the main entrance of the Building, 
notwithstanding any parking spaces which under applicable law must be 
reserved for handicapped drivers, emergency, fire or other similar safety 
purposes), by way of appropriate and conspicuous signs or markings, for the 
benefit of Tenant, for the use of Tenant's invitees, licenses and/or visitors 
(the "Visitors' Parking Spaces"). Tenant understands and acknowledges that, 
after the designation of the Visitors Parking Spaces.  Tenant solely shall be 
responsible for any necessary policing or enforcement with respect thereto. 

    14. Life Safety.  Landlord, without cost to Tenant, shall install and 
maintain within the Property any required sprinkler systems, fire alarms, 
emergency lighting, and other related life safety equipment, and exits from 
the Premises to comply with all requirements of federal, state, county and 
city governments and all other governmental authorities having or claiming 
jurisdiction with respect to the occupancy of the Premises.

    15. Indemnification.

        (a) Tenant shall defend and indemnify Landlord and hold Landlord 
harmless from and against any and all losses, claims, liability, expenses and 
damages which, either directly or indirectly, in whole or in part, arise out 
of or result from: (i) the negligence or willful misconduct of Tenant, its 
agents, contractors or employees; (ii) judgements, citations, fines or other 
penalties rendered or assessed against Landlord as a result of Tenant's 
failure to comply with all federal, state and local laws, safety and health 
regulations relating to Tenant's specific use of the Premises, provided that 
Landlord agrees to give Tenant prompt notice of any such violation asserted 
by any government agency; and (iii) the breach of any provision of this lease 
by Tenant, its agents, contractors or employees.

        (b) Landlord shall defend and indemnify Tenant and hold Tenant 
harmless from and against any and all losses, claims, liability, expenses and 
damages which, either directly or indirectly, in whole or in part, arise out 
of or result from (i) the negligence or willful misconduct of Landlord, its 
agents, contractors or employees; (ii) judgements, citations,

                                      -14-

<PAGE>

fines or other penalties rendered or assessed against Tenant as a result of 
Landlord's failure to comply with all federal, state and local laws, safety 
and health regulations relating to any portion of the Building or the Common 
Areas which Landlord has assumed the duty to maintain pursuant to this Lease, 
provided that Tenant agrees to give Landlord prompt notice of any such 
violation asserted by any government agency; (iii) judgements, citations, 
fines or other penalties rendered or assessed against Tenant, as well as any 
liability imposed upon Tenant, as a result of: (A) the presence of any 
Hazardous Materials (as defined herein)on, in or beneath the Premises at or 
before the Commencement Date including, but not limited to polychlorinated 
biphenyls ("PCBs"), asbestos and any material currently or formerly contained 
in an underground storage tank ("UST"); (B) the subsequent placement of 
Hazardous Materials on, in or beneath the Premises by Landlord; (C) the 
presence of any USTs at the Premises; (D) the (past or future) violation of, 
or noncompliance with any Environmental Law (as defined herein) by Landlord; 
or (E) any other environmental condition with respect to the Premises not 
caused by Tenant; and (iv) the breach of any provision of this Lease by 
Landlord, its agents, contractors or employees.

        (c) Nothing in this Section 15 is intended to require indemnification 
for any property claim for which insurance is required to be maintained under 
the terms of this Lease.  The rights and obligations of Landlord and Tenant 
under this Section 15 shall survive the expiration or earlier termination of 
this Lease. 

    16. Tenant Default.

        (a) Event of Default. Tenant shall not be deemed to be in default 
hereunder unless an "Event of Default," as hereinafter specified, has 
occurred.  The following shall constitute Events of Default by Tenant 
hereunder:

            (i) Failure to pay the Base Rent or Additional Rent within ten 
(10) days after receipt of Landlord's written notice of such deficiency (a 
"Financial Default"); provided, however, that Landlord shall not avail itself 
of any of the remedies set forth in Section 16(b) (below) on account of 
Financial Default for at least twenty (20) days from the date of such 
Financial Default (i.e. thirty (30) days from Tenant's receipt of written 
notice from Landlord that Tenant has failed to timely pay the applicable Base 
Rent or Additional Rent);

            (ii) Failure to comply with or perform any of the other material 
terms, covenants, conditions or agreements to be complied with or performed 
by Tenant and continuance of such failure for thirty (30) days after written 
notice from Landlord to Tenant, or, if the failure is of such a character as 
cannot reasonably be cured within thirty (30) days, failure to initiate 
within said thirty (30) day period such action as reasonably can be taken 
toward curing the same and/or failure to prosecute such action as promptly as 
is reasonably practicable after said action is initiated;

                                      -15-

<PAGE>

            (iii) Tenant is adjudicated a bankrupt in a proceeding against it 
or a receiver for Tenant or for all or a substantial part of its property is 
appointed, or a court order is entered approving a petition seeking 
reorganization or an arrangement under the Bankruptcy Code, and any such 
adjudication, appointment or order is not vacated, set aside or otherwise 
terminated to stayed within sixty (60) days from the date of its entry.

        (b) Landlord's Remedies.  If an Event of Default shall have occurred 
and shall have continued after any applicable cure period provided herein, 
then or at any time thereafter, Landlord may at its option; (1) terminate this 
Lease by notice to Tenant, recover possession of the Premises, and recover 
from Tenant the present value of the difference, if any, between the Base 
Rent and Additional Rent owed by Tenant for the remaining portion of the Term 
and the fair rental value of the Premises for the period; provided, however, 
that if such Event of Default was a result of a Financial Default, Landlord 
may terminate this Lease by notice to Tenant, recover possession of the 
Premises, and recover from Tenant the present value of the Base Rent and 
Additional Rent owed by Tenant for the remaining portion of the Term (such 
present value calculation to exclude any Late Fees); or (2) without 
terminating this Lease, recover possession of the Premises and relet the 
Premises or any part of the Premises, as the agent of the Tenant, and Tenant 
shall pay the Landlord the present value of the difference, if any, between 
the Base Rent and Additional Rent owed by Tenant for the remaining portion of 
the Lease term and the amount received or to be received under such reletting 
for such period.  Landlord shall use best efforts to mitigate its damages as 
a result of an Event of Default by Tenant. 

    17. Landlord Default

        (a) If Landlord shall:

            (i) file or have filed against it a petition or case under any 
section or chapter of the United States Bankruptcy Code, as amended, or under 
any similar law or statute of the United States or any state and such 
petition or case is not discharged within sixty (60) days; or

            (ii) fail to fulfill any covenant or provision of this Lease on 
its part to be performed and fail to remedy such failure within thirty (30) 
days after Tenant shall have given Landlord written notice of such failure, 
then the same shall be an event of default and Tenant shall have all rights, 
powers and remedies available at law or equity; provided, however that if 
Landlord continues to fail to fulfill a covenant or provision of this Lease  
on its part to be performed without remedy for a period of ninety (90) days 
and such failure materially adversely affects Tenant's business, Tenant may 
terminate this Lease. 

                                      -16-
<PAGE>

        (b) Force Majeure.  The obligations of Tenant hereunder shall not be 
affected, impaired or excused and Landlord shall have no liability whatsoever 
to Tenant, with respect to any act, event or circumstances arising out of:

            (i) Landlord's failure to fulfill or delay in fulfilling any of 
its obligations under this Lease by reason of strike or other labor trouble 
(with respect to Landlord only), governmental preemption of properties or 
other controls in connection with a national or other public emergency or 
shortages of fuel, supplies, labor or materials, beyond Landlord's reasonable 
control, acts of God, governmental delays or delays caused by Tenant 
(collectively, "Force Majuere"); provided, however, that Section 17(b) shall 
not apply to or relieve Landlord of Landlord's obligation to Substantially 
Complete the Initial Landlord Improvements within the Substantial Completion 
Period as set forth in Section 13(a) of this Lease; or

            (ii) Any failure or defect in the supply, quantity or character 
of service furnished to the Premises, or by reason of any requirement, act 
or omission of any public utility or others serving the Premises, beyond the 
Landlord's reasonable control.

    18. Environmental Compliance.

        (a) Landlord represents that, to the best of Landlord's knowledge 
and belief, the Property and its existing uses comply with, and Landlord has 
not received any notice or communication of any violation or non-compliance 
with, is not in violation of, and has not violated, in connection with he 
ownership, use, maintenance or operation of the Property and the conduct of 
the business related thereto, any applicable federal, state, county, regional 
or local statutes, laws, regulations, rules, ordinances, codes, standards, 
orders, licenses, permits and authorizations of any governmental authorities 
relating to environmental, health or safety matters (including, without 
limitation, Hazardous Materials, as defined in Section 18(b) below) 
(collectively, "Environmental Laws").  Landlord shall, at its own expense, 
promptly observe and comply with all present and future Environmental Laws, 
as amended from time to time, and all regulations or standards as are or may 
be promulgated thereunder. 

        (b) Without limited the generality of Section 18(a), Landlord 
represents that, to the best of Landlord's knowledge and belief, Landlord, 
its agents, contractors and employees (i) have operated the Property and have 
at all times received, handled, used, stored, treated, transported and 
disposed of any chemical, material or substance, exposure to which (by humans 
or the environment) is prohibited, limited or regulated by an Environmental 
Law or federal, state, county, regional or local authority or which even if 
not so prohibited, limited or regulated, poses a hazard to the health and 
safety of the occupants of the Property or the occupants of the area near the 
Property (collectively, "Hazardous Materials") in strict compliance with all 
Environmental Laws, and (ii) have removed (or will remove prior to the 
Commencement Date) from the Property all Hazardous Materials.

                                      -17-
<PAGE>

        (c) Landlord represents that, to the best of Landlord's knowledge and 
belief, there is no fact pertaining to the physical condition of the Property 
or the area surrounding the Property which (i) materially and adversely 
affects or materially and adversely will affect the Property, or the use, 
enjoyment or value thereof, or Landlord's ability to perform the obligations 
contained in this Lease, and (ii) which Landlord has not disclosed to Tenant 
in writing prior to the date of this Lease.

        (d) Landlord represents that, to the best of Landlord's knowledge and 
belief, it has received no notices of any violation or claimed violation of 
any of the matters referred to in Sections 14, 19(a) and 19(b) or of any 
pending or contemplated investigation, lawsuit or other action relating 
thereto, nor are there any unresolved or outstanding investigations, 
lawsuits, enforcement actions, administrative orders, or other actions.

        (e) Landlord shall provide Tenant with copies of all communications, 
permits or agreements with any governmental authority or agency (federal, 
state or local) or any private entity relating in any way to the presence, 
release, threat of release, placement on or in the Premises or any portion 
thereof, or the generation, transportation, storage, treatment, or disposal 
at the Premises of any Hazardous Materials.

        (f) If Tenant generates, transports, stores, or disposes of any 
Hazardous Materials, or in any portion of the Property or Building:

             (i) Tenant shall, at its own expense, observe and comply in all 
material respects with applicable Environmental Laws, and all regulations or 
standards as are or may be promulgated thereunder with respect to Tenant's 
activities on the Property;

            (ii) Tenant shall provide Landlord with copies of all 
communications, permits or agreements with any governmental authority or 
agency (federal, state or local) or any private entity relating in any way to 
the presence, release, threat of release, placement on or in the Premises or 
any portion thereof, or the generation, transportation, storage, treatment, 
or disposal at the Premises of any Hazardous Materials; and

           (iii) Landlord shall have the right, when accompanied by Tenant's 
representative (except in cases of emergency), to enter the Premises and/or 
conduct appropriate tests, at Landlord's own expense, for the purposes of 
ascertaining that Tenant complies with all applicable laws, rules or permits 
relating in any way to the presence of Hazardous Materials on the Land, the 
Premises, or any portion thereof.  Landlord shall provide to Tenant a copy of 
the results of any such tests or investigations.

        (g) If the presence, release, threat of release, placement on or in 
the land, the Premises or any portion thereof, or the generation, 
transportation, storage, treatment or


                         -18-

<PAGE>

disposal at the land, the Building, or any portion thereof of any Hazardous 
Materials solely due to Tenant's actions:

            (i) gives rise to liability under RCRA, CERCLA, other 
Environmental Laws or any common law theory based on nuisance or strict 
liability.

           (ii) impacts or causes an effect to public health which is 
prohibited by or in violation of Environmental Laws.

Tenant shall promptly take, at Tenant's sole cost and expense, any and all 
remedial and removal action required by applicable Environmental Laws.  
Tenant's obligations under this Section 18(g)(ii) shall survive the 
termination of the Lease for any reason.

        (h) The representations contained in this Section 19 shall survive 
the expiration or earlier termination of this Lease.

    19. Mechanics Liens.  Prior to Tenant performing any construction or 
other work in or about the Premises for which a lien could be filed against 
the Premises or the Building (a 'Mechanics' Lien'), Tenant shall have its 
contractor execute a waiver of such Mechanics' Lien, satisfactory to 
Landlord, and provide Landlord with the original copy thereof.  
Notwithstanding the foregoing, if any Mechanics' Lien or other lien shall be 
filed against the Premises or the Building purporting to be for labor or 
materials furnished or to be furnished at the request of Tenant, then at its 
expense.  Tenant shall cause such Mechanics' Lien or other lien to be removed 
of record by payment, bond or otherwise, within thirty (30) days after the 
filing thereof. If Tenant shall fail to cause such Mechanics' Lien or other 
lien to be removed of record within such thirty (30) day period, Landlord may 
cause such Mechanics' Lien or other lien to be removed of record by payment, 
bond or otherwise, without investigation as to the validity thereof or as to 
any offsets or defenses thereto, in which event Tenant shall reimburse 
Landlord in the amount paid by Landlord, including expenses, within ten (10) 
days after Landlord's billing therefor.  Tenant shall indemnify and hold 
Landlord harmless from and against any and all claims, costs, damages, 
liabilities and expenses (including attorney fees) which may be brought or 
imposed against or incurred by Landlord by reason of any such Mechanics' Lien 
or other lien or removal of record.

    20. Subordination

        (a) Subject to the provisions of paragraph (b) below, this Lease shall 
be subject and subordinate at all times to the lien of any mortgages now 
placed on the Premises or the Building without necessity of any further 
instrument or act on the part of the Tenant to effectuate such subordination.


                         -19- 

<PAGE>

        (b) Landlord covenants and agrees to use its best efforts to obtain 
and furnish to Tenant, within six (6) months of Tenant's execution of this 
Lease, an agreement ("Non-Disturbance Agreement') executed and acknowledged 
from the holder(s) of any mortgage now encumbering the Building or the 
Premises ("Existing Holder"), whereby each Existing Holder agrees to not 
disturb Tenant in its rights, use and possession of the Premises and Building 
under this Lease or to terminate this Lease, except to the extent permitted 
to Landlord by the terms of this Lease, notwithstanding the foreclosure or 
the enforcement of the mortgage or termination or other enforcement of an 
underlying lease or installment purchase agreement.  Tenant covenants and 
agrees to execute and deliver upon demand the Non-Disturbance Agreement(s).

        (c) Tenant further agrees that this Lease shall be subject and 
subordinate to the lien of any mortgages hereafter placed upon the Premises 
or the Building, provided that the Landlord shall have used its best efforts 
to cause the holder thereof to have entered into a Non-Disturbance Agreement 
with Tenant as described in paragraph (b) above.

    21. Estoppel Certificate.  At any time and from time to time and within 
ten (10) days after written request by Landlord or Tenant, Landlord or 
Tenant, as the case may be, shall execute, acknowledge and deliver to the 
other a statement in writing duly executed by Landlord or Tenant, as the case 
may be, certifying (i) that this Lease is in full force and effect, without 
modification or amendment (or, if there have been any modifications or 
amendments, that this Lease is in full force and effect as modified and 
amended and setting forth the date of the modifications and amendments), (ii) 
that the dates to which annual Base Rent and Additional Rent have been paid, 
(iii) that to the knowledge of the certifying party, no default exists under 
this Lease or specifying each such default and (iv) as to any other 
reasonable and customary request for certification of factual information 
concerning this Lease; it being the intention and agreement of Landlord and 
Tenant that any such statement by Tenant may be relied upon by a prospective 
purchaser or a prospective mortgagee of the Building, or by a prospective 
assignee or subtenant of Tenant, or by others, in any matter affecting the 
Premises.

    22. Holding Over.  If Tenant shall hold over after the expiration of the 
Term, its tenancy shall be on a month-to-month basis and Tenant shall pay to 
Landlord an amount equal to 125% of the then current Base Rent required to be 
paid by Tenant under this Lease, applied to the first thirty (30) days Tenant 
shall remain in possession after the expiration or sooner termination of this 
Lease, and 150% of the then current Base Rent required to be paid by Tenant 
under this Lease, applied to the holdover period from and after the 31st day 
Tenant shall remain in possession after the expiration or sooner termination 
of this Lease.  Payments made by Tenant to Landlord under this Section 22 
shall not be exclusive of any other rights or remedies afforded to Landlord 
in law or equity.

    23. Attorney's Fees.  In the event of litigation of any dispute or 
controversy arising from, in, under or concerning this Lease or any amendment 
hereof, including, without


                         -20-


<PAGE>

limiting the generality of the foregoing, any claimed breach or default 
hereof or thereof, the prevailing party in such action shall be entitled to 
recover from the other party in such action, such sum as the court shall fix 
as reasonable attorney's fees incurred by such prevailing party.

    24. Signs.  Tenant shall not install or affix any signs to the exterior 
of the Building or any exterior part of the Property without the prior 
written consent of Landlord, which consent shall not unreasonably be 
withheld.  Tenant acknowledges that, by way of example and without 
limitation, Landlord may withhold its consent with respect to a proposed 
installation of a sign by Tenant if: (i) such sign or subsequent removal 
thereof would cause in Landlord's reasonable determination material damage to 
the exterior of the Building or the exterior of the Property; (ii) such sign 
violates local zoning or land use laws; or (iii) the color, size, location or 
aesthetic character of such sign is significantly inconsistent with that of 
the Property.

    25. Other Utilities.  At Tenant's sole cost and expense, Tenant shall 
have the right to introduce into the Premises such other utilities as Tenant 
might require and Tenant shall pay the cost of such other utilities directly 
to the applicable utility companies.  Tenant shall, at its sole cost and 
expense, remove all such utilities and restore the Premises to substantially 
the same condition as when this Lease was executed, ordinary wear and tear, 
condemnation, casualty and Act of God excluded, and shall repair any damage 
caused by such removal.

    26. Broker.  Neither Landlord nor Tenant had any conversations with any 
broker concerning the leasing of the Premises.  Each party agrees to and 
hereby does defend, indemnify and hold the other harmless against and from 
any brokerage commissions, or finders' fees or claims therefor by a party 
claiming to have dealt with the indemnified party and all costs, expenses and 
liabilities in connection therewith, including, without limitation, 
reasonable attorneys' fees and expenses for any breach of the foregoing. The 
foregoing indemnification shall survive the termination of this Lease for any 
reason.

    27. Notices.  Any notice or other communication required to be given 
either party (i) shall be in writing and either hand delivered, delivered by 
courier, transmitted by telecopier or mailed by registered or certified mail, 
return receipt requested, postage prepaid, (ii) shall be effective on the 
date of actual receipt, and (iii) shall be sent to the parties at the 
following addresses or at such other addresses as either party may from time 
to time notify the other

        If to Tenant, to:

               Strategic Diagnostics Inc.
               128 Sandy Drive
               Newark, DE  19713
               Fax: (302) 456-6793
               Attention:  Richard Birkmeyer

                         -21-

<PAGE>

        With a required copy to:

               Pepper, Hamilton & Scheetz LLP
               1235 Westlakes Drive
               Suite 400
               Berwyn, PA  19312
               Fax: (610) 640-7835
               Attention:  William A. Scari, Jr., Esquire

        If to the Landlord, to:

               Pencader Courtyard, L.P.
               1300 Market Street, Suite 300
               Wilmington, DE  19801
               Fax: (302) 655-3854
               Attention:  Randy M. Stoltz

        With a required copy to:

               Pencader Courtyard, L.P.
               1300 Market Street, Suite 300
               Wilmington, DE  19801
               Fax: (302) 655-3854
               Attention:  Keith D. Stoltz

    28. Miscellaneous

        (a) Landlord Transfer.  Within ten (10) days following any transfer 
by Landlord of its ownership interest in the Property, Landlord shall provide 
Tenant with written notice of such transfer of the Property and the name and 
address of the successor Landlord to whom Tenant should send future rent 
payments and notices (the "Transfer Notice").  In the event that a 
predecessor Landlord fails to provide the Transfer Notice; (a) Tenant shall 
not be liable to any successor Landlord for any rent payments paid to a 
predecessor Landlord; and (b) any successor Landlord shall be bound by any 
notice sent to a predecessor Landlord.

        (b) Captions.  The captions appearing within the body of this Lease 
have been inserted as a matter of convenience and for reference only and in 
no way define, limit or enlarge the scope of meaning of this Lease or any 
provision of this Lease.

        (c) Counterparts.  This Lease may be executed in several 
counterparts, all of which constitute one and the same instrument.


                         -22-


<PAGE>

        (d) Governing Law.  This Lease shall be governed by and construed in 
accordance with the laws of the State of Delaware.

        (e) Construction.  The language of this Lease shall be construed 
according to its normal and usual meaning and not strictly for or against 
either Landlord or Tenant.  The rule of construction which allows a court to 
construe a document more strictly against its author shall not govern the 
interpretation of this Lease.

        (f) Remedies.  No right or remedy herein conferred upon or reserved 
to either party is intended to be exclusive of any other right or remedy, and 
every right and remedy shall be cumulative and in addition to any other right 
or remedy given by this Lease or now or hereafter existing at law or in 
equity.  The failure of either party to insist upon the strict performance of 
any obligation shall not be deemed a waiver thereof.

        (g) Severability.  If any provision of this Lease shall be invalid or 
unenforceable to any extent, the remainder of this Lease shall not be 
affected thereby, and every provision of this Lease shall be valid and 
enforceable to the fullest extent permitted by law.

        (h) Entire Agreement.  This Lease constitutes the entire agreement 
between the parties with respect to the lease of the Property, superseding 
any other oral or written agreements between the parties with respect to the 
lease of the Property that may exist at the time of the execution of this 
Lease, including, without limitation, that certain Letter Agreement dated 
September 17, 1997 between Landlord and Tenant, and may be amended only by 
written agreement of the parties.  No representations, inducements, promises 
or agreements, oral or otherwise, between Landlord and Tenant regarding the 
Property not embodied herein.

        (i) Successors and Assigns.  This Lease shall be binding upon and 
shall inure to the benefit of the parties hereto, their heirs, executors, 
administrators, successors and permitted assigns.

        (j) Time is of the Essence.  Landlord and Tenant agree that in 
fulfilling all terms and conditions of this Lease, time is of the essence.

            [SIGNATURE PAGE FOLLOWS]


                         -23-

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      IN WITNESS WHEREOF, Landlord and Tenant, intending to be legally bound 
hereby, have signed this Lease as of the day and year first above written.

                                          LANDLORD,

                                          PENCADER COURTYARD, L.P.


                                          /s/ Randy M. Stoltz
                                          ----------------------------------
                                          By: Randy M. Stoltz
                                          Its: (illegible)
                                              


                                          TENANT

                                          STRATEGIC DIAGNOSTICS INC.


                                          /s/ Richard C. Birkmeyer
                                          ----------------------------------
                                          By: Richard C. Birkmeyer
                                          Its: President







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STRATEGIC DIAGNOSTIC

Scope of Work

Walls
Standard Interior Partitions:  3 5/8" Metal Studs 25 ga. 10' High with 1/2" 
Drywall and 3 1/2" insulation in office and conference rooms.

Bathroom Partitions: 6" Track with staggered 3 5/8" Metal Studs 25 ga. 10' 
High with 1/2" Drywall and 3 1/2" insulation.

Exterior Partitions:  Exterior Metal Studs are existing and will be insulated 
with 3" insulation and sheathed with 1/2" drywall in the office area.

Masonry Partitions in Manufacturing, Quality Control, Wet Lab and Lab as 
shown on plan:  6" CMU 0" High
Masonry Partitions in Shipping and Inventory: 6" CMU 12' High

Ceilings
Office Manufacturing/Labs/Bathrooms: 2'x 2' Grid System with 2' x 2' 
Armstrong Cortrga Tegular tile or equal with R11 insulation laid on top.
Shipping & Inventory:  2' x 4' Grid System with 2' x 4' Fissured 
Non-Directional Flay Lay-in Tile.
Ceiling Height:  Office Areas: 9'10"
                 Open Offices  9'10"
                 Shipping & Inventory 11'5"
                 Break Room 9'10"
                 Hallways & Other Areas 9'10"
                 Manufacturing/Labs  9'10"

Doors: (Office & Bathrooms) 3'0" x 7'0" Solid Core Birch Veneer with half
       glass
       (All Others Except Existing Exterior) 3'0" x 7'0" Hollow Metal
       (Overhead Door) 10'0" x 9'0" Sectional Overhead Door
Hardware:  (Bathroom) Push/Pull Sets with kick plates and closers, hinges and 
           door stop.
           (All other Doors) Passage Sets, hinges and door stop.

Plumbing:  Toilets and Urinals and Sinks as shown on plan.  Stainless Steel 
           sink in Break Room.
           Rough plumbing (deionized) in Wet Lab, Quality Control, and Lab.
           (2) 80 Gallon Hot Water Heaters

Cabinets:  6' Base Cabinet in Break Room and Counter Top

Paint:  (Drywall) Acrylic Eggshell Enamel (2) coats
        (Interior Block) Semi-gloss Enamel
        (Metal Doors and Frames) Oil Base Semi-gloss
        (Wood Doors) Clear Urethane Stain

Flooring:  (Carpet) Queen Moriah #738 Slate or equal with carpet cove base
           (VCT) Armstrong Excellon with Vinyl Cove Base



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Page two
Strategic Diagnostic
Scope of Work

Mechanical:  (Office/Manufacturing/Labs/Bathrooms/Roof Top Units to provide 
Heating and Cooling.

             (Shipping and Inventory Gas Fired Unit Heaters to maintain 70 
degrees at 20 degrees outside.

Electrical:  Outlets as shown on plans including (10) 208 Volt Outlets  3 of 
             which are 3 phase Switches for lights
             2' x 4' Lay-in fixtures with prismatic lenses
             Electrical wiring and hook up for 3 cold rooms:
Sprinklers:  Per Code

Toilet Partitions:  As shown on plan in standard color of grey or tan

Loading Area:  Black top Driveway, Dock Height 4', drainage to not hold water

Blinds:  Existing in building


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