<PAGE>

                                                                   Exhibit 10.19

                                   INDUSTRIAL LEASE
                                           
    1.    Parties.  This Lease, dated, for reference purposes only August 9,
1990, is made by and between TOBER & AGNEW PROPERTIES, INC., a Delaware
corporation (herein called "Lessor") and STRATEGIC DIAGNOSTICS INCORPORATED, a
Delaware Corporation (herein called "Lessee").

    2.    Promises.  Lessor hereby leases to Lessee and Lessee leases from
Lessor for the Term (as hereinafter defined) at the rental, and upon all of the
conditions set forth herein, all that certain space (the "Premises") which is
the portion of the building erected on Lots 32 and 33, at 128 Sandy Drive,
Newark, Delaware as more fully shown on the plan attached hereto as Exhibit "A",
consisting of Seven Thousand Five Hundred Ten (7,510) square feet, more or less.
The Premises includes all fixtures, improvements, additions and other property 
installed therein at the Commencement Date (as hereinafter defined), or at any
time during the time of this Lease (other than Tenant's movable personal
property and trade fixtures), together with the right to use, in common with
others, any entrances, lobbies, hallways parking lot, walkways, elevators and
other public portions of the building in which the Premises is located (the
"Building").  The Building contains 25,600 square feet.

    3.    Term.   Tenant Improvement Work.

          3.1.   Term.  The term of this Lease and Lessee's obligation to pay 
rent hereunder shall commence upon the date when the Premises is ready for
occupancy and a certificate of occupancy or equivalent certificate has been
issued by the appropriate governmental agency (the "Commencement Date").  The
Premises shall be deemed ready for occupancy when Lessor has substantially
completed the work depicted or described on the plans and specifications listed
in Exhibit "B" attached hereto (the "Tenant Improvement Work").  "Substantial
Completion" shall mean such completion as shall enable Lessee to reasonably and
conveniently use and occupy the Premises for the conduct of its business.  The
term ("Term") of this Lease shall end ten (10) years after the Commencement
Date.  The parties agree to confirm the Commencement Date in writing.  

          3.2    Delay in Possession.  If for any reason Lessor cannot deliver 
possession of the Premises to Lessee on the Commencement Date, Lessee shall not
be obligated to pay rent until possession of the Premises is tendered to Lessee.

          3.3    Lessor's Obligation to Construct Tenant Improvement Work.

                (a)    Lessor hereby covenants and agrees to commence the Tenant
Improvement Work immediately upon execution of the Lease and to complete the
Tenant 
                                       -1-

<PAGE>

Improvement Work in as expeditious a manner as possible in accordance
with all applicable standards of care and diligence.

                (b)    Lessor represents and warrants that it has available to
it the financial resources and personnel and that it possesses the expertise to
commence construction of the Tenant Improvement Work and to complete it in
accordance with the covenants made in subparagraph (a).

                (c)    Any breach of the representations, warranties and
covenants contained in this paragraph 3.3 shall constitute a material breach of
this Lease.  In the event of such breach, Lessee may terminate this Lease.

    4.    Use.

          4.1.  Use.   The Premises shall be used and occupied for the
following: office and laboratory uses and the manufacturing of immunological
reagents and test kits and any uses accessory thereto or any other use which is
reasonably comparable and for no other purpose.

    5.    Base Rent.

                (a)    Lessee shall pay to Lessor as rent for the Premises, 
(the "Base Rent"), in advance, in fixed monthly payments on the first day of
each month of the Term.

                (b)    From the Commencement Date until the first anniversary of
the Commencement Date, the Base Rent shall be an amount to be computed as the
sum of the following components:

                       (i)    $3.45 annually per square foot;

                       (ii)   $3.75 annually per square foot (attributable to
the cost of the Tenant Improvement Work amortized over the entire Term);

                       (iii)  an additional component to be calculated as the
(i) sum of (1) specialty equipment and materials costs plus (2) subcontractor
installation charges, (ii) multiplied by 1.12,  (iii) amortized at the rate of 
11.5% per annum over the first three years of the Term, and (iv) divided by the
number of square feet in the Premises. (All such costs and charges must be
approved by Lessee prior to commencement of work.)

                On the Commencement Date, Lessor and Lessee shall execute an
addendum to this Lease setting forth the amount of the monthly rent to be paid
by Lessee to Lessor and the components thereof.

                                       -2-

<PAGE>

                (c)    Rent for any period during the Term hereof which is for
less than one month shall be a pro rata portion of the monthly installment.

                (d)    Rent shall be payable in lawful money of the United 
States to Lessor at the address stated herein or to such other persons or at 
such other places as Lessor may designate in writing.

                (e)    Commencing on the first anniversary of the Commencement
Date, and on each anniversary of the Commencement Date thereafter through the 
end of the Term and any renewal thereof, the Base Rent shall be computed in 
accordance with the provisions of this subparagraph.  In the event the Consumer
Price Index for Urban Wage Earners and Clerical Workers in the City of 
Philadelphia (1967 = 100) (hereinafter called the "Price Index") or a successor
or substitute index appropriately adjusted, reflects an increase in the cost of
living for the month immediately preceding such anniversary date ("Adjustment 
Month") over and above such cost of living as reflected by the Price Index as it
existed for the month immediately preceding the prior anniversary date
(hereinafter called the "Base Index"), the Base Rent during such lease year
shall equal (i) the number of square feet in the Premises, multiplied by the sum
of the components referenced in subparagraphs 5(b)(ii) and (iii), plus (ii) the
number of square feet in the Premises multiplied by $3.45 (as adjusted in the
prior year in accordance with this subparagraph) plus (iii) the number of square
feet in the Premises, multiplied by the product of (A) $3.45 (as adjusted in the
prior year in accordance with this subparagraph) multiplied by (B) the lesser of
(x) five percent 5% or (y) a fraction, the numerator of which is the Price Index
for the Adjustment Month and the denominator of which is the Base Index (but in
no event shall such increase be less than 4%).  In the event that such 
determination cannot be made until after any anniversary of the Commencement
Date, the increase in the monthly rental payments due for the months prior to
such determination shall be paid to Lessee upon the date the next payment of 
rent is due following such determination.  Commencing on the fourth anniversary
of the Commencement Date, the computation of Base Rent shall no longer include
the component referenced in subparagraph 5(b)(iii), which costs shall have been
reimbursed in full to Landlord by such date.

    6.    Operating Expenses.  In addition to the Base Rent, Lessee will pay to 
Lessor as additional rent Lessee's Operating Expense Share of the amount of 
Operating Expenses paid, payable or incurred by Lessor in each year of the Term
and Lessee's Tax Share of the real property taxes payable by Lessor in each year
of the Term, and Lessee's share of the premiums for required insurance payable
by Lessor.  As used in this Lease the following terms shall be defined as 
hereinafter provided: 

                (i)    Lessee's Operating Expense Share shall be twenty-nine 
percent (29%);

                (ii)   "Operating Expenses" shall mean the following:

                                       -3-

<PAGE>

                       (a)   Costs of cleaning, repairing and maintaining the
Common Areas of the Building (including the costs for snow removal).  As used in
this Lease, the term "common areas" means, without limitation, the entrances, 
lobbies, trash facilities, driveways, walkways, landscaping and all other areas
and facilities, including the plumbing, electrical, and sprinkler systems,  
ductwork, roof and exterior wall and windows, in the Building which are provided
for and designated from time to time by Lessor for the general non-exclusive use
and convenience of Lessee and its employees, invitees, licenses or other 
visitors.  Lessor grants Lessee, its employees, invitees, licensees and other
visitors a non-exclusive license for the Term to use the Common Areas; and

                       (b)   The cost of premiums for the insurance required 
under paragraphs 9.1 and 9.3 (provided that Lessee shall pay 100% of any 
increase in or component of any such premiums directly attributable to the 
construction of the Tenant Improvement Work and the specialty equipment 
installed);

                       (c)   Notwithstanding anything else contained in this 
paragraph, "Operating Expenses" shall not include: (i) any capital additions 
made to the Building; (ii) repairs or other work occasioned by fire, windstorm,
or other insured casualty or hazard; (iii) leasing commissions and advertising
expenses incurred in procuring new tenants; (iv) repairs or rebuilding 
necessitated by condemnation to the extent that Lessor has received condemnation
proceeds for such repairs or rebuilding; (v) any depreciation and amortization
of the Building; (vi) principal or interest payments on any indebtedness 
applicable to the Building or the Premises, including any mortgage debt or 
ground rents payable under any ground lease for the Building.

                (iii)   Lessee's Tax Share shall be 29% of the real property 
taxes assessed on the date hereof, plus 100% of any increase in such taxes 
directly attributable to the construction of the Tenant Improvement Work;

                (iv)    As used herein the term "real property tax" shall 
include any form of real estate tax or assessment, general, special, ordinary 
or extraordinary, and any license fee, commercial rental tax, improvement 
bond or bonds, levy or tax (other than inheritance, personal income or estate 
taxes) imposed on the Premises by any authority having the direct or indirect 
power to tax, including any city, state or federal government, or any school, 
agricultural, sanitary, fire, street, drainage or other improvement district 
thereof, as against any legal or equitable interest of Lessor in the Premises 
or in the real property of which the Premises is a part, as against Lessor's 
right to rent or other income therefrom, and as against Lessor's business of 
leasing the Premises.  The term "real property tax" shall also include any 
tax, fee, levy, assessment or charge in substitution of, partially or 
totally, any tax, fee, levy, assessment for charge hereinabove included 
within the definition of "real property tax."

                 All payments of additional rent for operating Expenses payable 
by Lessee shall be paid within ten days of receipt by Lessee of Lessor's 
statement of amounts due, which 

                                       -4-

<PAGE>

statement shall include at Lessee's request copies of relevant invoices and 
receipts.  All payments of additional rent for real property taxes payable by 
Lessee shall be paid within the period prescribed by law for the payment 
thereof without penalty or interest; provided that Lessor has sent to Lessee 
copies of such tax bills when received from the taxing authority.

    7.    Compliance with Law; Environmental Matters.

          7.1    Compliance with Law.  (a) Lessor warrants to Lessee that the 
Premises, in its state existing on the Commencement Date, and the 
above-described uses do not violate any covenants or restrictions of record, 
or any applicable zoning or building code, regulation or ordinance in effect 
on said date.  In the event it is determined that this warranty has been 
violated, then it shall be the obligation of the Lessor to promptly, at 
Lessor's sole cost and expense, rectify any such violation.

                (b)    Except as provided in paragraph 7.2(a), Lessee shall, 
at Lessee's expense, comply promptly with all applicable statutes, 
ordinances, rules, regulations, orders, covenants and restrictions of record, 
and requirements in effect during the Term or any part of the term hereof, 
regulating the use by Lessee of the Premises.

          7.2    Environmental Matters.  Lessor represents and warrants that 
all activities at the Premises since Lessor's acquisition of the Premises 
have been and are being conducted in compliance with all statutes, 
ordinances, regulations, orders, and requirements of common law concerning 
(i) those activities, (ii) repairs or construction of any improvements, (iii) 
handling of any materials, (iv) discharges to the air, soil, surface, or 
groundwater, and (v) storage, treatment, or disposal of any waste at or 
connected with any activity at the Premises ("Environmental Statutes").

          Lessor represents and warrants that no Contamination is present at 
the Premises.  The term "Contamination" means the uncontained presence of 
Hazardous Substances at the Premises, or arising from the Premises which may 
require remediation under any applicable law.  The term "Hazardous 
Substances" means "hazardous substances" as defined pursuant to the 
Comprehensive Environmental Response, Compensation and Liability Act, as 
amended, "regulated substances" within the meaning of Subtitle I of the 
Resource Conservation Recovery Act, as amended, "hazardous wastes". as 
defined pursuant to the Delaware Hazardous Waste Management Act, or 
"regulated substances" as defined pursuant to the Delaware Underground 
Storage Tank Act.

         Lessor represents and warrants that no portion of the Premises 
constitutes any of the following "Environmentally Sensitive Areas":

                       (i)    a wetland or other "water of the United states" 
for purposes of section 404 of the federal Clean Water Act or any similar 
area regulated under any state law;

                                       -5-

<PAGE>

                       (ii)   a portion of the coastal zone for purposes of 
the Federal Coastal Zone Management Act and the Delaware Coastal Zone Act; or

                       (iii)  any other area, including but not limited to a 
floodplain or other flood hazard area, the development of which is specially 
restricted under any applicable law by reason of its physical characteristics 
or prior use.

         Lessor represents and warrants that no tanks for the storage of any 
liquid or gas are present on the Premises except for two underground 500 
gallon liquid propane tanks.

         Lessor represents and warrants that (i) at no point in any structure 
at the Premises will air radiation levels exceed 4 picocuries/liter, (ii) 
Lessor does not know or have reason to know of any investigation of the 
Premises for the presence of radon gas or the presence of the radioactive 
decay products of radon (collectively "Radon") and (iii) Lessor has provided 
to Lessee a report of each investigation relevant to the presence of Radon at 
the Premises of which Lessor has any knowledge.

         The parties hereby agree that if any of the representations or 
warranties contained in this paragraph 7.2 shall prove to be incorrect, or if 
Lessor breaches any covenant contained in this paragraph 7.2, Lessor shall be 
afforded an opportunity to cure such default provided that (i) such breach or 
condition is susceptible of remediation within a reasonable amount of time as 
determined by Lessee; and (ii) Lessor begins promptly after the discovery of 
such breach or condition diligently to remedy same and continues such 
diligent efforts until satisfactory remediation has been achieved.

         Lessor shall indemnify and hold Lessee harmless of, from, and 
against any and all expense, loss or liability suffered by Lessee by reason 
of the Lessor's breach of any provision of this Section including, but not 
limited to, (i) costs to comply with any Environmental Statutes; (ii) costs 
to study or to remedy Contamination of the Premises or arising from the 
Premises; (iii) costs incident to the study or removal of tanks, their 
contents or associated Contamination; (iv) cost to prevent air radiation 
levels in any structure hereafter erected in the Premises from exceeding 4 
picocuries/liter or to reduce air radiation levels in any structure on the 
Premises to 4 picocuries/liter or less; (v) fines, penalties, or other 
sanctions assessed due to Lessor's failure to have complied with 
Environmental Statutes; (vi) loss of value of the Property by reason of a 
failure to comply with Environmental Statutes or the presence on the Property 
of any Hazardous Substance, tank, Environmentally Sensitive Feature or Radon; 
and (vii) legal and professional fees and costs in connection with the 
foregoing.  For purposes of this subparagraph, the term "Lessee" shall mean 
Lessee, its successors and assigns.  Nothing herein shall be construed to 
include (i) any condition or occurrence arising out of Lessee's activities in 
or on the Premises, or (ii) any consequential damages or losses sustained by 
Lessee as a result of interruption of Lessee's business activities or the 
dislocation of Lessee's facilities as a result of a default pursuant to this 
paragraph 7.2.


                                       -6-

<PAGE>

          7.3    Condition of Premises.

                (a)  Lessor shall deliver the Premises to Lessee clean and 
free of debris on the Commencement Date and Lessor further warrants to Lessee 
that the Tenant Improvement Work in the Premises shall be in good operating 
condition on the Commencement Date.  In the event that it is determined that 
this warranty has been violated, then it shall be the obligation of Lessor, 
after receipt of written notice from Lessee setting forth with specificity 
the nature of the violation, to promptly, at Lessor's sole cost, rectify such 
violation.

                (b)  Within thirty (30) days after the Commencement Date, 
Lessee shall give Lessor a written list (the "Punch List") of all contended 
defects in Lessor's construction work and of all contained variances in 
Lessor's work as described in Exhibit "HI' attached hereto.  Lessor shall 
correct all items on the Punch List within thirty (30) days after Lessor's 
receipt of the Punch List, unless the nature of the defect or variance is 
such that a longer period of time is required to repair or correct the same, 
in which case Lessor shall exercise due diligence in correcting such defect 
or variance at the earliest possible date and with a minimum of interference 
with Lessee's operations.  Nothing in this subparagraph shall be deemed a 
waiver by Lessee of Lessor's warranty contained in paragraph 7.3(a) for 
violations discovered after delivery of the Punch List.

    8.    Maintenance, Repairs, Alterations and Building Services.

          8.1    Lessor's Obligations

                 (a)   Lessor shall keep in good order, condition and repair 
the Common Areas of the Building, and the heating, ventilation and air 
conditioning system installed for the use of the Premises (the "HVAC").

              (b)  If Lessor fails to perform Lessor's obligations under this 
paragraph 8.1 or under any other paragraph of this Lease, Lessee may at 
Lessee's option and upon 10 days' prior written notice to Lessor (except in 
the case of emergency, in which case no notice shall be required), perform 
such obligations on Lessor's behalf and put the Common Areas and HVAC in good 
order, condition and repair, and the cost thereof shall be offset against the 
installment rent next due.

          8.2    Lessee's Obligations.  Lessee, at its expense, shall 
maintain and keep in good order, condition and repair the plumbing, electric, 
HVAC, lighting, fixtures, interior walls, ceilings, floors, windows, doors 
and plate glass located in, on, or within the Premises or any part thereof, 
and which are for the exclusive use of the Premises or Lessee.  Lessor shall 
procure and maintain at Lessee's expense an HVAC maintenance agreement, which 
shall be in form and substance reasonably satisfactory to Lessee. On the last 
day of the Term hereof, or on any sooner termination, Lessee shall surrender 
the Premises to Lessor in the same condition as received, ordinary wear and 
tear excepted, clean and free of debris.

                                       -7-

<PAGE>


          8.3    Alterations and Additions.

                 (a)   Lessee shall not, without Lessor's prior written 
consent, which consent shall not be unreasonably withheld or delayed, make 
any alterations, improvements, additions, or Utility Installations in, on or 
about the Premises, except for nonstructural alterations not exceeding 
$7,500.  In any event, whether or not in excess of $7,500 in cost, Lessee 
shall make no change or alteration to the exterior of the Premises nor the 
exterior of the Building without Lessor's prior written consent.  As used in 
this paragraph 8.3 the term "Utility Installation" shall mean air lines, 
power panels, electrical distribution systems, lighting fixtures, space 
heaters, air conditioning, plumbing, and fencing.  Should Lessee make any 
alterations, improvements, additions or Utility Installations without the 
prior approval of Lessor, Lessor may require that Lessee remove any or all of 
the same.

                 (b)   Any alterations, improvements, additions or Utility 
Installations in or about the Premises that Lessee shall desire to make and 
which requires the consent of the Lessor shall be presented to Lessor in 
written form, with proposed detailed plans.  If Lessor shall give its 
consent, the consent shall be deemed conditioned upon Lessee acquiring a 
permit to do so from appropriate government agencies, the furnishing of a 
copy thereof to Lessor prior to the commencement of the work and the 
compliance by Lessee of all conditions of said permit in a prompt and 
expeditious manner.

                (c)    Lessee shall pay, when due, all claims for labor or 
materials furnished to or for Lessee at or for use in the Premises, which 
claims are or may be secured by any mechanics' or materialmen's lien against 
the Premises or any interest therein.  Lessee shall give Lessor not less than 
ten (10) days' notice prior to the commencement of any work in the Premises, 
and Lessor shall have the right to post notices of non-responsibility in or 
on the Premises as provided by law.  If Lessee shall, in good faith, contest 
the validity of any such lien, claim or demand, then Lessee shall, at its 
sole expense defend itself and Lessor against the same and shall pay and 
satisfy any such adverse judgment that may be rendered thereon before the 
endorsement thereof against the Lessor or the Premises, upon the condition 
that if Lessor shall require, Lessee shall furnish to Lessor a surety bond 
satisfactory to Lessor in an amount equal to such contested lien claim or 
demand indemnifying Lessor against liability for the same and holding the 
Premises free from the effect of such lien or claim and shall obtain release 
of such lien by substitution of such surety bond as security therefor.  In 
addition, Lessor may require Lessee to pay Lessor's attorneys fees and costs 
in participating in such action if Lessor shall decide it is to its best 
interest to do so.

                (d)   Unless Lessor requires their removal, as set forth in 
paragraph 8.3(a), all alterations, improvements, additions and Utility 
Installations, which may be made on the Premises, shall become the property 
of Lessor and remain upon and be surrendered with the Premises at the 
expiration of the Term.

                                       -8-

<PAGE>

    9.    Insurance; Indemnity.

          9.1    Liability Insurance - Lessor.  Lessor shall obtain and keep 
in force during the Term of this Lease a policy of Combined Single Limit 
Bodily Injury and Property Damage Insurance, insuring Lessor and Lessee 
against any liability arising out of the ownership, use or occupancy 
maintenance of the Premises and all areas appurtenant thereto in an amount 
not less than $500,000 per occurrence.

          9.2    Liability Insurance - Losses.  Lessee shall obtain and keep 
in force during the Term of this Lease a policy of Combined Single Limit 
Bodily Injury and Property Damage Insurance, insuring Lessor and Lessee 
against any liability arising out of the use or occupancy of the Premises and 
all areas appurtenant thereto in an amount not less than $500,000 per 
occurrence.

          9.3    Property Insurance.  Lessor shall obtain and keep in force 
during the Term of this Lease a policy or policies of insurance covering loss 
or damage to the Building, including Lessee's fixtures, equipment or tenant 
improvements in an amount not to exceed the full replacement value thereof as 
the same may exist from time to time, providing protection against all perils 
included within the classification of fire, extended coverage, vandalism, 
malicious mischief, flood (in the event same is required by a lender having a 
lien on the Premises), special extended perils ("all risk", as such term is 
used in the insurance industry).

          9.4    Insurance Policies.  Insurance required hereunder shall be 
in companies holding a "General Policyholders Rating" of at least B plus, or 
such other rating as may be required by a lender having a lien on the 
Premises, as set forth in the most current issue of "Best Insurance Guide".  
Lessor and Lessee shall deliver to each other copies of policies of all 
insurance required under paragraph 8 or certificates evidencing the existence 
and amounts of such insurance.  No such policy shall be cancellable or 
subject to reduction of coverage or other modification except after thirty 
(30) days' prior written notice to the other.  Each party shall, at least 
thirty (30) days prior to the expiration of such policies, furnish the other 
with renewals thereof.  Lessee shall not do or permit to be done anything 
which shall invalidate the insurance policies referred to in paragraph 9.3.

          9.5    Waiver of Subrogation.  Lessee and Lessor each hereby 
release and relieve the other, and waive their entire right of recovery 
against the other for loss or damage arising out of or incident to the perils 
insured against under paragraph 9.3, which perils occur in, on or about the 
Premises, whether due to the negligence of Lessor or Lessee or their agents, 
employees, contractors and/or invitees.  Lessee and Lessor shall, upon 
obtaining the policies of insurance required hereunder, give notice to the 
insurance carrier or carriers that the foregoing mutual waiver of subrogation 
is contained in this Lease.

          9.6    Indemnity.  Lessee shall indemnify and hold harmless Lessor 
from and against any and all claims arising from Lessee's use of the 
Premises, or from the conduct of 

                                       -9-

<PAGE>

Lessee's business or from any activity, work or things done, permitted or 
suffered by Lessee in or about the Premises or elsewhere and shall further 
indemnify and hold harmless Lessor from and against any and all claims 
arising from any breach or default in the performance of any obligation on 
Lessee's part to be performed under the terms of this Lease, or arising from 
any negligence of the Lessee, or any of Lessee's agents, contractors, or 
employees, and from and against all costs, attorneys' fees, expenses and 
liabilities incurred in the defense of any such claim or any action or 
proceeding brought thereon; and in case any action or proceeding be brought 
against Lessor by reason of any such claim.  Lessee upon notice from Lessor 
shall defend the same at Lessee's expense by counsel satisfactory to Lessor.

          Lessor shall indemnify and hold harmless Lessee from and against 
any and all claims arising from any breach or default in the performance of 
any obligation on Lessor's part to be performed under the terms of this 
Lease, or arising from any negligence of the Lessor, or any of Lessor's 
agents, contractors, or employees, and from and against all costs, attorneys' 
fees, expenses and liabilities incurred in the defense of any such claim or 
any action or proceeding brought thereon; and in case any action or 
proceeding be brought against Lessee by reason of any such claim. Lessor upon 
notice from Lessee shall defend the same at Lessor's expense by counsel 
satisfactory to Lessee.

    10.    Damage or Destruction.

           10.1    Definitions.

                   (a)   "Premises Partial Damage" shall herein mean damage 
or destruction to the Premises to the extent that the cost of repair is less 
than 50% of the fair market value of the Premises immediately prior to such 
damage or destruction. "Premises Building Partial Damage" shall herein mean 
damage or destruction to the Building of which the Premises are a part to the 
extent that the cost of repair is less that 50% of the fair market value of 
the Building as a whole immediately prior to such damage or destruction.

                   (b)   "Premises Total Destruction" shall herein mean 
damage or destruction to the Premises to the extent that the cost of repair 
is 50% or more of the fair market value of the Premises immediately prior to 
such damage or destruction.

                   (c)   "Insured Loss" shall herein mean damage or 
destruction which was caused by an event required to be covered by the 
insurance described in paragraph 10.

           10.2    Partial Damage - Insured Loss.  Subject to the provisions 
of paragraph 10.4, 10.5 and 10.6, if at any time during the Term of this 
Lease there is damage which is an Insured Loss and which falls into the 
classification of Premises Partial Damage or Premises Building Partial 
Damage, then Lessor shall, at Lessor's sole cost, repair such damage, 
including Lessee's fixtures, equipment or tenant improvements as soon as 
reasonably possible and this Lease shall continue in full force and effect.

                                       -10-

<PAGE>

           10.3    Partial Damage - Uninsured Loss.  Subject to the 
provisions of paragraphs 10.4, 10.5 and 10.6, if at any time during the Term 
of this Lease there is damage which is not an Insured Loss and which fails 
within the classification of Premises Partial Damage or Premises Building 
Partial Damage, unless caused by a willful act of Lessee (in which event 
Lessee shall make the repairs at Lessee's expense), Lessor may at Lessor's 
option either (i) repair such damage as soon as reasonably possible at 
Lessor's expense, in which event this Lease shall continue in full force and 
effect, or (ii) give written notice to Lessee within fifteen (15) days after 
the date of the occurrence of such damage of Lessor's intention to cancel and 
terminate this Lease. In the event Lessor shall give such notice of Lessor's 
intention to cancel and terminate this Lease, Lessee shall have the right 
within fifteen (15) days after the receipt of such notice to give written 
notice to Lessor of Lessee's intention to repair such damage at Lessee's 
expense, in which event this Lease shall continue in full force and effect, 
and Lessee shall proceed to make such repairs as soon as reasonably possible. 
 If Lessee does not give such notice within such 15-day period this Lease 
shall be cancelled and terminated and Lessee shall have no further 
obligations or duties thereunder including the payment of rent as of the date 
of the occurrence of such damage.

           10.4     Total Destruction.  If at any time during the term of 
this Lease there is damage, whether or not an Insured Loss, (including 
destruction required by any authorized public authority), which falls into 
the classification of Premises Total Destruction or Premises Building Total 
Destruction, this Lease shall automatically terminate and Lessee shall have 
no further obligations or duties thereunder including the payment of rent as 
of the date of such total destruction.

           10.5    Damage Near End of Term.

                   (a)   If at any time during the last six months of the 
Term of this Lease there is damage, whether or not an Insured Loss, which 
falls within the classification of Premises Partial Damage, Lessor and Lessee 
each has the option to cancel and terminate this Lease as of the date of 
occurrence of such damage by giving written notice to the other of its 
election to do so within 30 days after the date of occurrence of such damage.

                   (b)   Notwithstanding paragraph 10.5(a), in the event that 
Lessee has an option to extend or renew this Lease, and the time within which 
said option may be exercised has not yet expired, Lessee shall exercise such 
option, if it is to be exercised at all, no later that 25 days after the 
occurrence of an Insured Loss falling within the classification of Premises 
Partial Damage during the last six months of the Term of this Lease.  If 
Lessee duly exercises such option during said 25 day period, Lessor shall, at 
Lessor's expense, repair such damage as soon as reasonably possible and this 
Lease shall continue in full force and effect.  If Lessee fails to exercise 
such option during said 25 day period, then Less may at Lessee's option 
terminate and cancel this Lease as of the expiration of said 25 day period by 
giving written notice to Lessee of 

                                       -11-

<PAGE>

Lessor's election to do so within 5 days after the expiration of said 25 day 
period, notwithstanding any term or provision in the grant of option to the 
contrary.

           10.6    Abatement of Rent; Lessee's Remedies.

                   (a)   In the event of damage described in paragraphs 10.2 
or 10.3 and Lessor or Lessee repairs or restores the Premises pursuant to the 
provisions of this paragraph 10, the rent payable hereunder for the period 
during which such damage, repair or restoration continues shall be abated in 
proportion to the degree to which Lessee's use of the Premises is impaired.  
Except for abatement of rent Lessee shall have no claim against Lessor for 
any damage suffered by reason of any such damage, destruction, repair or 
restoration.

                   (b)   If Lessor shall be obligated to repair or restore 
the Premises under the provisions of this paragraph 10 and shall not commence 
meaningful repair or restoration within 30 days after such obligations shall 
accrue, Lessee may at Lessee's option cancel and terminate his Lease by 
giving Lessor written notice of Lessee's election to do so at any time prior 
to Lessor's meaningful commencement of such repair or restoration.  In such 
event this Lease shall terminate as of the date of such notice and Lessee 
shall have no further obligations or duties thereunder, including the payment 
of rent, as of the date of the occurrence of the damage.

           10.7    Termination - Advance Payments.  Upon termination of this 
Lease pursuant to this paragraph 10, an equitable adjustment shall be made 
concerning any advance rent and any advance payments made by Lessee to Lessor.

           10.8    Waiver.  Lessor and Lessee waive the provisions of any 
statutes which relate to termination of leases when leased property is 
destroyed and agree that such event shall be governed by the terms of this 
Lease.

    11.    Utilities.  Lessee shall pay for all water, gas, heat, light, 
power, telephone and other utilities and services supplied to the Premises, 
together with any taxes thereon.  Such services are to be separately metered 
to Lessee.

    12.    Assignment and Subletting.

           12.1    Lessor's Consent Required.  Lessee shall not voluntarily 
or by operation of law assign, transfer, mortgage, sublet, or otherwise 
transfer or encumber all of any part of Lessee's interest in this Lease or in 
the Premises, without Lessor's prior written consent, which Lessor shall not 
unreasonably withhold or delay.  Lessor shall respond in writing to Lessee's 
request for consent hereunder in a timely manner and any attempted 
assignment, transfer, mortgage, encumbrance or subletting without such 
consent shall be void and shall constitute a breach of this Lease.

                                       -12-

<PAGE>

           12.2    Lessee Affiliate.  Notwithstanding the provisions of 
paragraph 12.1 hereof, Lessee may assign or sublet the Premises, or any 
portion thereof, without Lessor's consent, to any corporation which controls, 
is controlled by or is under common control with Lessee, or to any 
corporation resulting from the merger or consolidation with Lessee, or to any 
person or entity, which acquires all or substantially all of the assets of 
Lessee as a going concern of the business that is being conducted on the 
Premises, provided that said assignee assumes, in full, the obligations of 
Lessee under this Lease.  Any such assignment shall not, in any way, affect 
or limit the liability of Lessee under the terms of this Lease even if after 
such assignment or subletting the terms of this Lease are changed or altered, 
provided, however, that any material change to the terms of this Lease 
(including, but not limited to, the Term or Rent) after such an assignment or 
subletting, shall require the prior consent of Lessor and any such change 
made without Lessor's prior consent shall not be binding on Lessor.

           12.3    No Release of Losses.  Regardless of Lessor's consent, no 
subletting or assignment shall release Lessee of Lessee's obligation or alter 
the primary liability of Lessee to pay the Rent and to perform all other 
obligations to be performed by Lessee hereunder.  The acceptance of Rent by 
Lessor from any other person shall not be deemed to be a waiver by Lessor of 
any provision hereof.  Consent to one assignment or subletting shall not be 
deemed consent to any subsequent assignment or subletting. In the event of 
default by any assignee of Lessee or any successor of Lessee, in the 
performance of any of the terms thereof, Lessor may proceed directly against 
Lessee without the necessity of exhausting remedies against said assignee.  
Lessor may consent to subsequent assignments or subletting of this Lease or 
amendments or modifications to this Lease with assignees of Lessee or any 
successor of Lessee, and without obtaining its or their consent thereto and 
such action shall not relieve Lessee of liability under this Lease.

           12.4    Assignment Fees.  In the event Lessee shall assign or 
sublet the Premises then Lessee shall an assignment processing fee equal to 
$200.00 for each such request.

    13.    Defaults; Remedies.

           13.1    Defaults.  The occurrence of any one or more of the 
following events shall constitute a material default and breach of this Lease 
by Lessee:

                   (a)   The failure by Lessee to make any payment of rent as 
and when due, where such failure shall continue for a period of five days 
after Lessee's receipt of written notice from Lessor.  In the event that 
Lessor serves Lessee with a Notice to Pay Rent or Quit pursuant to applicable 
Unlawful Detainer statutes, such Notice to Pay Rent or Quit shall also 
constitute the notice required by this subparagraph;

                   (b)   The failure by Lessee to observe or perform any of 
the covenants, conditions or provisions of this Lease to be observed or 
performed by Lessee, other than described in paragraph (a) above, where such 
failure shall continue for a period of 30 days after written notice hereof 
from Lessor to Lessee; provided, however, that if the nature of Lessee's 

                                       -13-

<PAGE>

default is such that more than 30 days are reasonably required for its cure, 
then Lessee shall not be deemed to be in default if Lessee commenced such 
cure within said 30-day period and thereafter diligently prosecutes such cure 
to completion;

                   (c)   (i) The making by Lessee of any general arrangement 
or assignment for the benefit of creditors; (ii) Lessee becomes a "debtor" as 
defined in 11 U.S.C. Section 101 or any successor statute thereto (unless, in 
the case of a petition field against Lessee, the same is dismissed within 60 
days); (iii) the appointment of a trustee or receiver to take possession of 
substantially all of Lessee's assets located at the Premises or of Lessee's 
interest in this Lease, where possession is not restored to Lessee within 30 
days; or (iv) the attachment, execution or other judicial seizure of 
substantially all of Lessee's assets located at the Premises or of Lessee's 
interest in this Lease, where such seizure is not discharged within 30 days.  
Provided, however, in the event that any provision of this paragraph 13.1(c) 
is contrary to any applicable law, such provision shall be of no force or 
effect;

                   (d)   The discovery by Lessor that any financial statement 
given to Lessor by Lessee, any assignee of Lessee, any subtenant of Lessee, 
any successor in interest of Lessee or any guarantor of Lessee's obligation 
hereunder, and any of them, was materially false.

           13.2    Remedies.  In the event of any such material default or 
breach by Lessee, Lessor may at any time after providing Lessee with written 
notice, but without limiting Lessor in the exercise of any right or remedy 
which Lessor may have by reason of such default or breach:

                   (a)   Terminate Lessee's right to possession of the 
Premises by any lawful means, in which case this Lease shall terminate and 
Lessee shall immediately surrender possession of the Premises to Lessor.  In 
such event Lessor shall be entitled to recover from Lessee all damages 
incurred by Lessor by reason of Lessee's default including, but not limited 
to, the cost of recovering possession of the Premises; expenses of reletting, 
including necessary renovation and alteration of the premises, reasonable 
attorneys' fees, and any real estate commission actually paid; the worth at 
the time of award by the court having jurisdiction thereof of the amount by 
which the unpaid rent for the balance of the term after the time of such 
award exceeds the amount of such rental loss for the same period that Lessee 
proves could be reasonably avoided.

                   (b)   Maintain Lessee's right to possession in which case 
this Lease shall continue in effect whether or not Lessee shall have 
abandoned the Premises.  In such event Lessor shall be entitled to enforce 
all of Lessor's rights and remedies under this Lease, including the right to 
recover the rent as it becomes due hereunder;

                   (c)   Pursue any other remedy now or hereafter available 
to Lessor under the laws or judicial decisions of the State of Delaware.  
Unpaid installments of rent and other unpaid monetary obligations of Lessee 
under the terms of this Lease shall bear interest from the date due at the 
maximum rate then allowable by law.

                                       -14-

<PAGE>

           13.3    Default by Lessor.  Lessor shall not be in default unless 
Lessor fails to perform obligations required of Lessor within a reasonable 
time, but in no event later than ten (10) days after written notice by Lessee 
to Lessor and to the holder of any first mortgage or deed of trust covering 
the Premises whose name and address shall have theretofore been furnished to 
Lessee in writing, specifying wherein Lessor has failed to perform such 
obligation; provided, however, that if the nature of Lessor's obligation is 
such that more than ten (10) days are required for performance then Lessor 
shall not be in default if Lessor commences meaningful performance within 
such lo-day period and thereafter diligently prosecutes the same to 
completion.

           13.4    Late Charges.  Lessee hereby acknowledges that late 
payment by Lessee to Lessor of rent and other sums due hereunder will cause 
Lessor to incur costs not contemplated by this Lease, the exact amount of 
which will be extremely difficult to ascertain. Such costs include, but are 
not limited to, processing and accounting charges, and late charges which may 
be imposed on Lessor by the terms of any mortgage or trust deed covering the 
Premises.  Accordingly, if any installment of rent shall not be received by 
Lessor or Lessor's designee within fifteen (15) days after such amount shall 
be due, then, without any requirement for notice to Lessee, Lessee shall pay 
to Lessor a late charge equal to 3% of such overdue amount.  The parties 
hereby agree that such late charge represents a fair and reasonable estimate 
of costs Lessor will incur by reason of late payment by Lessee.  Acceptance 
of such late charge by Lessor shall in no event constitute a waiver of 
Lessee's default with respect to such overdue amount, nor prevent Lessor from 
exercising any of the other rights and remedies granted hereunder.

    14.    Condemnation.  If the Premises or any portion thereof are taken 
under the power of eminent domain, or sold under the threat of the exercise 
of said power (all of which are herein called "condemnation"), this Lease 
shall terminate as to the part so taken as of the date the condemning 
authority takes title or possession, whichever first occurs.  If more than 
10% of the floor area of the Building, or more than 25% of the area of the 
Premises is taken by condemnation, Lessee may, at Lessee's option, to be 
exercised in writing within fifteen (15) days after Lessor shall have given 
Lessee written notice of such taking (or in the absence of such notice, 
within fifteen (15) days after the condemning authority shall have taken 
possession) terminate this Lease as of the date the condemning authority 
takes such possession.  If Lessee opts to terminate this Lease as described 
in the foregoing, Lessee's obligations and duties under this Lease shall 
cease as of the date of condemning authority take such possession.  If Lessee 
does not terminate this Lease in accordance with the foregoing, this Lease 
shall remain in full force and effect as to the portion of the Premises 
remaining, except that the rent shall be reduced in the proportion that the 
floor area of the Building taken bears to the total floor area of the 
Building situated on the Premises.  No reduction of rent shall occur if the 
only area taken is that which does not have a building located thereon.  Any 
award for the taking of all or any part of the Premises under the power of 
eminent domain or any payment made under threat of the exercise of such power 
shall be the property of Lessor, whether such award shall be made as 
compensation for diminution in value of the leasehold or for the taking of 
the fee, or as severance damages; provided, however, that Lessee shall be 
entitled to any award for loss of or damage to Lessee's equipment, trade 
fixtures and removable personal property.  In the event that this Lease 

                                       -15-

<PAGE>

is not terminated by reason of such condemnation, Lessor shall to the extent 
of severance damages received by Lessor in connection with such condemnation, 
repair any damage to the Premises caused by such condemnation except to the 
extent that Lessee has been reimbursed therefor by the condemning authority.

    15.    Brokers' Fees.

           Lessor shall be responsible for all brokers, commissions or 
finder's fees charged by Stoltz Realty and Dunn Associates, and warrants to 
Lessee that no brokers' commissions, finders' fees or similar payments shall 
be claimed through Lessee in connection with the execution of this Lease, and 
agrees to indemnify and hold Lessee harmless from any liability that may 
arise from such claims, including reasonable attorney's fees.

    16.    Estoppel Certificate.

           (a)   Lessee shall at any time upon not less than 10 days I prior 
written notice from Lessor execute, acknowledge and deliver to Lessor a 
statement in writing (i) certifying that this Lease is unmodified and in full 
force and effect (or, if modified, stating the nature of such modification 
and certifying that this Lease, as so modified, is in full force and effect) 
and the date to which the rent is paid and (ii) acknowledging that there are 
not, to Lessee's knowledge, any uncured defaults, or events which with the 
passage of time would be defaults, on the part of Lessor hereunder, or 
specifying such defaults if any are claimed.  Any such statement may be 
conclusively relied upon by any prospective purchaser or encumbrancer of the 
Premises.

           (b)   At Lessor's option, Lessee's failure to deliver such 
statement within such time shall be a material breach of this Lease or shall 
be conclusive upon Lessee (i) that this Lease is in full force and effect, 
without modification except as may be represented by Lessor, (ii) that there 
are no uncured defaults in Lessor's performance, and (iii) that not more than 
one month's rent has been paid in advance or such failure may be considered 
by Lessor as a default by Lessee under this Lease.

           (c)   If Lessor desires to finance, refinance, or sell the 
Premises, or any part thereof, Lessee hereby agrees to deliver to any lender 
or purchaser designated by Lessor such financial statements of Lessee as may 
be reasonably required by such lender or purchaser.  Such statements shall 
include to the extent available the past three years' financial statements of 
Lessee.  All such financial statements shall be received by Lessor and such 
lender or purchaser in confidence and shall be used only for the purposes 
herein set forth.

    17.    Lessor's Liability.  The term "Lessor" as used herein shall mean 
only the owner or owners at the time in question of the fee title or a 
lessee's interest in a ground lease of the Premises.  In the event of any 
transfer of such title or interest, Lessor herein named (and in case of any 
subsequent transfers then the grantor) shall be relieved from and after the 
date of such transfer of all liability as respects Lessor's obligations 
thereafter to be performed, provided that 

                                       -16-

<PAGE>

any funds in the hands of Lessor or the then grantor at the time of such 
transfer, in which Lessee has an interest, shall be delivered to the grantee. 
 The obligations contained in this Lease to be performed by Lessor shall, 
subject as aforesaid, be binding on Lessor's successors and assigns, only 
during their respective periods of ownership.

    18.    Severability.  The invalidity of any provisions of this Lease as 
determined by a court of competent jurisdiction, shall in no way affect the 
validity of any other provision hereof.

    19.    Time of Essence.  Time is of the essence.

    20.    Incorporation of Prior Agreements; Amendments.  This Lease 
contains all agreements of the parties with respect to any matter mentioned 
herein.  No prior agreement or understanding pertaining to any such matter 
shall be effective.  This Lease may be modified in writing only, signed by 
the parties in interest at the time of the modification.  Except as otherwise 
stated in this Lease, Lessee hereby acknowledges that neither the real estate 
brokers listed in paragraph 15 hereof nor any cooperating broker on this 
transaction nor the Lessor or any employees or agents of any of said persons 
has made any oral or written warranties or representations to Lessee relative 
to the condition or use by Lessee of said Premises and Lessee acknowledges 
that Lessee assumes all responsibility regarding the Occupational Safety 
Health Act, the legal use and adaptability of the Premises and the compliance 
thereof with all applicable laws and regulations in effect during the term of 
this Lease except as otherwise specifically stated in this Lease.

    21.    Notices.  Any notice required or permitted to be given hereunder 
shall be in writing and may be given by personal delivery or by certified 
mail, and if given personally or by mail, shall be deemed sufficiently given 
if addressed to Lessee or to Lessor at the address noted below the signature 
of the respective parties, as the case may be. Each such notice shall be 
deemed given upon personal delivery or, if by certified mail, upon mailing.  
Either party may by notice to the other specify a different address for 
notice purposes except that upon Lessee's taking possession of the Premises, 
the Premises shall constitute Lessee's address for notice purposes.  A copy 
of all notices required or permitted to be given to Lessor hereunder shall be 
concurrently transmitted to such party or parties at such addresses as Lessor 
may from time to time hereafter designate by notice to Lessee.

    22.    Waivers.  No waiver by Lessor or any provision hereof shall be 
deemed a waiver of any other provision hereof or of any subsequent breach by 
Lessee of the same or any other provision.  Lessor's consent to, or approval 
of any act, shall not be deemed to render unnecessary the obtaining of 
Lessor's consent to or approval of any subsequent act by Lessee.  The 
acceptance of rent hereunder by Lessor shall not be a waiver of any preceding 
breach by Lessee of any provision hereof, other than the failure of Lessee to 
pay the particular rent so accepted, regardless of Lessor's knowledge of such 
preceding breach at the time of acceptance of such rent.

                                       -17-

<PAGE>

    23.    Recording.  Either Lessor or Lessee shall, upon request of the 
other, execute, acknowledge and deliver to the other a "short form" 
memorandum of this Lease for recording purposes.

    24.    Holding Over.  If Lessee, with Lessor's consent, remains in 
possession of the Premises or any part thereof after the expiration of the 
term hereof, such occupancy shall be a tenancy from month to month upon all 
the provisions of this Lease pertaining to the obligations of Lessee, but all 
options and rights of first refusal, if any, granted under the terms of this 
Lease shall be deemed terminated and be of no further effect during said 
month to month tenancy.

    25.    Cumulative Remedies.  No remedy or election hereunder shall be 
deemed exclusive but shall, wherever possible, be cumulative with all other 
remedies at law or in equity.

    26.    Covenants and Conditions.  Each provision of this Lease 
performable by Lessee shall be deemed both a covenant and a condition.

    27.    Binding Effect; Choice of Law.  Subject to any provisions hereof 
restricting assignment or subletting by Lessee, this Lease shall bind the 
parties, their personal representatives, successors and assigns.  This Lease 
shall be governed by the laws of the State of Delaware.

    28.    Subordination.

                 (a)   This Lease, at Lessor's option, shall be subordinate 
to any ground lease, mortgage, deed of trust, or any other hypothecation or 
security now or hereafter placed upon the real property of which the Premises 
are a part and to any and all advances made on the security thereof and to 
all renewals, modifications, consolidations, replacements and extensions 
thereof.  Notwithstanding such subordination, Lessee's right to quiet 
possession of the Premises shall not be disturbed if Lessee is not in default 
and so long as Lessee shall pay the Rent and observe and perform all of the 
provisions of this Lease, unless this Lease is otherwise terminated pursuant 
to its terms.  If any mortgagee, trustee or ground lessor shall elect to have 
this Lease prior to the lien of its mortgage, deed of trust or ground lease, 
and shall give written notice thereof to Lessee, this Lease shall be deemed 
prior to such mortgage, deed of trust, or ground lease, whether this Lease is 
dated prior or subsequent to the date of said mortgage, deed of trust or 
ground lease or the date of recording thereof.

                 (b)   Lessee agrees to execute any documents required to 
effectuate an attornment, a subordination or to make this Lease prior to the 
lien of any mortgage, deed of trust or ground lease, as the case may be.  If 
Lessee fails to execute such documents within 10 days after written demand, 
Lessor may execute such documents on behalf of Lessee as Lessee's 
attorney-in-fact.  Lessee does hereby make, constitute and irrevocably 
appoint Lessor as Lessee's attorney-in-fact and in Lessee's name, place and 
stead, to execute such documents in accordance with this paragraph 28(b).

                                       -18-

<PAGE>

    29.    Intentionally Omitted

    30.    Lessor's Access.  Lessor and Lessor's agents, upon prior written 
notice to Lessee, shall have the right to enter the Premises at reasonable 
times for the purpose of inspecting the same, showing the same to prospective 
purchasers, lenders, or lessees, and making such alterations, repairs, 
improvements or additions to the Premises or to the Building of which they 
are a part as Lessor may deem necessary or desirable; provided, however that 
upon such entry Lessor and/or Lessor's agents (except in the case of 
emergency) shall be required to be accompanied by a representative of Lessee 
for purposes of protecting and preserving the confidentiality of Lessee's 
work on the Premises.  Lessor may not at any time place on or about the 
Premises any ordinary "For Sale" signs.  Lessor may at any time during the 
last 120 days of the Term hereof place on or about the Premises on the 
Building any ordinary "For Lease" signs, all without rebate of rent or 
liability to Lessee; provided that Lessor shall not permitted to place "For 
Lease" signs on or about the Premises until any options or rights available 
to Lessee to extend the term of this Lease or to renew this Lease or any 
options or rights of first refusal to lease the Premises or rights of first 
offer to purchase the Premises have lapsed.

    31.    Signs.  Lessee shall not place any sign upon the Premises without 
Lessor's prior written consent, which shall not be unreasonably withheld, 
except that Lessee shall have the right, without the prior permission of 
Lessor, to place ordinary and usual for rent or sublet signs thereon.

    32.    Merger.  The voluntary or other surrender of this Lease by Lessee, 
or a mutual cancellation thereof, or a termination by Lessor, shall not work 
a merger, and shall, at the option of Lessor, terminate all or any existing 
subtenancies or may, at the option of Lessor, operate as an assignment to 
lessor of any or all of such subtenancies.

    33.    Consents.  Wherever in this Lease the consent of one party is 
required to an act of the other party, such consent shall not be unreasonably 
withheld.

    34.    Quiet Possession.  Upon Lessee paying the rent for the Premises 
and observing and performing all of the covenants, conditions and provisions 
on Lessee's part to be observed and performed hereunder, Lessee shall have 
quiet possession of the Premises for the entire Term hereof subject to all of 
the provisions of this Lease.  The individuals executing this Lease on behalf 
of Lessor represent and warrant to Lessee that they are fully authorized and 
legally capable of executing this Lease on behalf of Lessor and that such 
execution is binding upon all parties holding an ownership interest in the 
Premises.

    36.    Options; Right of First Refusal.

           36.1    Definition.  As used in this paragraph the word "Options" 
has the following meaning: (1) the right or option to extend the term of this 
Lease or to renew this Lease; (2) the option or right of first refusal to 
lease any space contiguous to the Premises.

                                       -19-

<PAGE>

           36.2    Options Personal.  Each Option granted to Lessee in this 
Lease is personal to Lessee and may not be exercised or be assigned, 
voluntarily or involuntarily, by or to any person or entity other than 
Lessee, provided, however, the Option may be exercised by or assigned to any 
Lessee Affiliate as defined in paragraph 12 of this Lease.  The Options 
herein granted to Lessee are not assignable separate and apart from this 
Lease.

           36.3    Effect of Default on Options.

                   (a)   Lessee shall have no right to exercise an option, 
notwithstanding any provision in the grant of Option to the contrary, (i) 
during the time commencing from the date Lessor gives to Lessee a notice of 
default pursuant to paragraph 13.1(a) or 13.1(b) and continuing until the 
default alleged in said notice of default is cured, or (ii) at any time after 
an event of default described in paragraphs 13.1(c) or 13.1(d) (without any 
necessity of Lessor to give notice of such default to Lessee).

                   (b)   The period of time within which an option may be 
exercised shall not be extended or enlarged by reason of Lessee's inability 
to exercise an option because of the provisions of paragraph 36.3.

           36.4    Option to Renew.  Lessee shall have the right, at its sole 
option, to renew this Lease for an additional period of three (3) years 
following the term hereof, upon the same terms and conditions in effect at 
the expiration of the prior term (including provision for the escalation of 
rent and including this option to renew); provided Lessee shall have given 
Lessor no more than six and no less than three months written notice in 
advance at the end of the prior term.

           36.5    Option to Extend Promises.  Lessor hereby grants to Lessee 
the right at any time and from time to time to lease any or all of the 
unleased space adjacent to the Premises for a term concurrent with the 
remaining Term of this Lease, at a Base Rent (prior to the inclusion of 
reimbursement for Lessor's "tenant finish work" in such space) of $3.95 per 
square foot (as escalated beginning on the first anniversary of the 
Commencement Date to reflect any increase in the Price Index between the date 
of this Lease and the date of the exercise of this option), on all the other 
terms and conditions set forth in this Lease.  For purposes of this paragraph 
36.5, "tenant finish work" shall mean improvements to such space made by 
Lessor comparable in quality and type to the Tenant Improvement Work 
described in Exhibit C, for which Lessor shall be reimbursed an amount equal 
to $30.15 per square foot (as escalated beginning on the first anniversary of 
the Commencement Date to reflect any increase in the Price Index between the 
date of this Lease and the date of the exercise of this option) plus interest 
thereon calculated at 1 1/2% over the prime rate then in effect at Wilmington 
Trust Company.

           36.6    Right of First Refusal.  If, at any time during the term 
of this Lease or any extension thereof, Lessor or its successors or assigns 
shall receive a bona fide offer from any 

                                       -20-

<PAGE>

third party to lease all or any portion of the space adjacent to the 
Premises, Lessor shall offer such space to Lessee upon same financial terms 
as set forth in such offer.  Lessor's offer to Lessee shall be in writing, 
and Lessee shall have a period of fourteen days within which Lessee may 
elect, by written notice to Lessor, to rent such space on the same terms as 
set forth in such offer.  If Lessee shall refuse any such offer and if Lessor 
shall nevertheless fail to complete the leasing of such space under the terms 
of such offer, Lessor shall not thereafter lease such space except by 
preceding in accordance of the terms of this paragraph as though any 
subsequent offer were a new offer made under the terms hereof.

    37.    Multiple Tenant Building.  Lessee agrees that it will abide by, 
keep and observe all reasonable rules and regulations which Lessor may make 
from time to time for the management, safety, care, and cleanliness of the 
Building and grounds, the parking of vehicles and the preservation of good 
order therein as well as for the convenience of other occupants and tenants 
of the Building.  The violations of any such rules and regulations shall be 
deemed a material breach of this Lease by Lessee.

    38.    Security Measures.  Lessee hereby acknowledges that the rent 
payable to Lessor hereunder does not include the cost of guard service or 
other security measures, and that Lessor shall have no obligation whatsoever 
to provide same.  Lessee assumes all responsibility for the protection of 
Lessee, its agents and invitees from acts of third parties.

    39.    Easements.  Lessor reserves to itself the right, from time to 
time, to grant such easements, rights and dedications that Lessor deems 
necessary or desirable, and to cause the recordation of Parcel Maps and 
restrictions, so long as such easements, rights, dedications, Maps and 
restrictions do not interfere with the use of the Premises by Lessee.  Lessee 
shall sign any of the aforementioned documents upon request of Lessor and 
failure to do so shall constitute a material breach of this Lease.

    40.    Performance Under Protest.  If at any time a dispute shall arise 
as to any amount or sum of money to be paid by one party to the other under 
the provisions hereof, the party against whom the obligation to pay the money 
is asserted shall have the right to make payment "under protest" and such 
payment shall not be regarded as a voluntary payment, and there shall survive 
the right on the part of said party to institute suit for recovery of such 
sum.  If it shall be adjudged that there was no legal obligation on the part 
of said party to pay such sum or any part thereof, said party shall be 
entitled to recover such sum or so much thereof as it was not legally 
required to pay under the provisions of this Lease.

    41.    Authority.  If either Lessor or Lessee is a corporation, trust, or 
general or limited partnership, each individual executing this Lease on 
behalf of such entity represents and warrants that he or she is duly 
authorized to execute and deliver this Lease on behalf of said entity.

                                       -21-

<PAGE>

LESSOR AND LESSEE HAVE CAREFULLY READ AND REVIEWED THIS LEASE AND EACH TERM 
AND PROVISION CONTAINED HEREIN AND, BY EXECUTION OF THIS LEASE, SHOW THEIR 
INFORMED AND VOLUNTARY CONSENT THERETO, THE PARTIES HEREBY AGREE THAT, AT THE 
TIME THIS LEASE IS EXECUTED, THE TERMS OF THIS LEASE ARE COMMERCIALLY 
REASONABLE AND EFFECTUATE THE INTENT AND PURPOSE OF LESSOR AND LESSEE WITH 
RESPECT TO THE PREMISES.

The parties hereto have executed this Lease at the place and on the dates 
specified immediately adjacent to their respective signatures.

Executed at Strategic Diagnostics Industries, Inc., 128 Sandy Drive, Newark, DE 
19713 on Oct. 26, 1993.

                        LESSOR: TOBER & AGNEW PROPERTIES, INC. 

                        By:    /s/ ROBERT C. TOBER              
                           -------------------------------------
                                   (Seal)

                        Title:      PRES. 
                              ----------------------------------


Executed at Strategic Diagnostics Industries, Inc., 128 Sandy Drive, Newark, DE
19713 on Oct. 26, 1993.

                        LESSEE: STRATEGIC DIAGNOSTICS INDUSTRIES               
                                INCORPORATED 

                        By:  /s/ ANNE CAVANAUGH                  
                           -------------------------------------
                                 (Seal)

                        Title:      VICE PRES.
                              ----------------------------------



                                       -22-