<PAGE>   1
                                                                   EXHIBIT 10.18


                                   L E A S E


         THIS LEASE, made as of the 16th day of September, 1988, by and between:

         FLORAL AVENUE ASSOCIATES, L.P.,
         a New Jersey Limited Partnership,
         having an address c/o
         Berger & Bornstein, 237 South Street,
         P.O. Box 2049R, Morristown,
         New Jersey 07960-2049, or its assigns
         (hereinafter referred to as "Landlord")

         and

         RTK CORPORATION, a New Jersey
         corporation, having an address at
         120 Floral Avenue, New Providence,
         New Jersey 07974 (hereinafter
         referred to as "Tenant")


                             W I T N E S S E T H :


         WHEREAS, Landlord owns a building on Floral Avenue, New Providence,
Union County, New Jersey containing approximately THIRTY THOUSAND (30,000)
square feet; and

         WHEREAS, Tenant wishes to lease said building.

         NOW, THEREFORE, in consideration of the mutual covenants hereinafter
set forth, the parties agree as follows:

         1.  Demised Premises.  Landlord has demised and leased, and by these
presents does hereby demise and lease to the Tenant and Tenant has hired and by
these presents does hereby hire from Landlord that certain premises comprising
the land and the office and industrial building on Floral Avenue, New
Providence, New Jersey 07974 (hereinafter "Building"), more particularly shown
on Exhibit A attached hereto and made a part hereof, (the premises being leased
hereunder to Tenant being hereinafter referred to as "premises" or "demised
premises" or "leased premises").

         2.  Term.

             a.  The term of this Lease shall be for a period of ten (10) years
beginning on December 15, 1988, and ending

<PAGE>   2
on December 14, 1998 ("Initial Term"). The words "lease year" shall mean a
period of twelve (12) successive calendar months.

                  b. Landlord shall deliver the demised premises to Tenant in
an "as is" condition, except for Landlord's work as contained on Exhibit B
attached hereto (which work will be done in a good and workmanlike manner) and
except that Landlord shall fulfill all of its obligations contained in
paragraph 11 hereof. Tenant shall be responsible for all leasehold improvements
at its cost and expense, except such as relate to Landlord's work set forth on
Exhibit B. Landlord shall be responsible for all defects of workmanship and
materials on work performed by Landlord contained on Exhibit B from the
Commencement Date ("Commencement Date") to a date two years thereafter.

         3. Rent.

                  a. Payment of rent shall commence on December 15, 1988,
except if (i) Landlord shall not substantially complete its inside work on the
space by said date, rental shall not commence until such date as Landlord
substantially completes its inside work on the space and obtains a Temporary or
Permanent Certificate of Occupancy; or (ii) in the event that Tenant shall take
occupancy and operates its business of any portion of the space prior to said
date, the rental shall commence as of said occupancy date. Landlord agrees to
give Tenant ten (10) days written notice of the commencement of the term of the
Lease. In the event that Landlord shall provide Tenant with a Temporary
Certificate of Occupancy, Landlord will diligently proceed to obtain a
Permanent Certificate of Occupancy. Tenant may begin any work from the date
hereof Tenant may wish to do so long as said work does not unreasonably
interfere with Landlord's work. Landlord agrees that it shall diligently
correct any "punch list" items that are Landlord's responsibility under this
Lease.


                                      -2-
<PAGE>   3
                  Anything contained hereto to the contrary notwithstanding,
the parties acknowledge that any outside work may require site plan approval
from the Township of New Providence and that no outside work may begin until
site plan approval is obtained. Landlord agrees to diligently commence
obtaining such approvals and shall diligently prosecute such applications to
conclusion and thereupon diligently commence all necessary construction. The
parties agree that notwithstanding Landlord's failure to complete said outside
work, Tenant shall take occupancy of the demised premises and commence full
payment of rent as set forth above. If for any reason the outside work as set
forth on Exhibit B shall not be completed by June 30, 1989, rent in the amount
of One Hundred Sixty-Six and 66/100 ($166.66) Dollars per day ("Penalty") shall
abate until such time as Landlord shall complete the outside work. In the event
that Landlord shall be denied governmental approval for the outside work, Tenant
shall have the right, within ten days after receipt of written notice by
Landlord with a copy of the denial of governmental approval to either (i)
cancel this Lease effective not less than sixty (60) days nor more than one
hundred twenty (120) days from the date Tenant notifies Landlord or (ii) reduce
the Penalty above to Fifty ($50.00) Dollars per day. Failure of Landlord to
receive written notice from Tenant within said ten (10) day period shall be
deemed to be an election of Tenant under (ii) above. Time shall be deemed of
the essence.

                  b. In the event that the Commencement Date does not occur by
December 15, 1988, Tenant may elect by written notice to Landlord received by
Landlord no later than December 31, 1988 to postpone the Commencement Date until
February 1, 1989. In such event, notwithstanding the Commencement Date occupancy
prior to February 1, 1989, the Commencement Date shall not deemed to have
occurred until February 1, 1989, unless Tenant shall take occupancy and operates
it business prior to said date. Anything contained herein to the contrary


                                     - 3 -
<PAGE>   4
notwithstanding, Landlord shall in no ????? Tenant in anyway in the event that
the Commencement occurs after December 15, 1988. In all events, if Landlord has
not delivered the premises for Tenant's occupancy, with the interior work
completed, prior to March 1, 1989, Tenant shall have the right, by written
notice to Landlord not later than March 10, 1989, to terminate this Lease. Such
termination shall be Tenant's sole remedy. Time shall be deemed of the essence.

                  c. Tenant covenants and agrees to pay Landlord during the
term of this Lease a fixed annual rental for said demised premises in equal
monthly installments as follows:

<TABLE>
<CAPTION>
                                    FIXED ANNUAL               MONTHLY
             PERIOD                    RENTAL               INSTALLMENTS
             ------                 ------------            ------------
       <S>                          <C>                     <C>
       First Lease Year
       Second Lease Year
       Third Lease Year
       Fourth Lease Year
       Fifth Lease Year
       Sixth Lease Year
       through Seven and
         One-Half
       Seven and One-Half
         through Tenth
</TABLE>

                  d. Except as otherwise provided, all payments of rent shall
be made by the Tenant to the Landlord without notice or demand in equal monthly
installments, in advance, without set-off or deduction of any kind (except in
the case of a judgment obtained by Tenant), and shall be due and payable on the
first day of each and every calendar month of each lease year. In the event
that the Commencement Date shall be other than the first (1st) day of the
month, the rent shall be pro rated on a per diem basis.

                  3. In the event Tenant shall fail to pay within ten (10) days
of the date due any fixed rent rent installment as provided herein, Landlord
may impose a late charge of Five Hundred ($500.00) Dollars for any such late
payment. Said charge to be immediately due and payable with the installment if
the Landlord demands same.

                                       4


<PAGE>   5
                  f. Except as otherwise expressly provided herein, the parties
hereto agree that the fixed annual rent payable hereunder shall be totally net
to the Landlord so that this Lease shall yield to Landlord at least the amount
of the fixed annual rent specified herein during each lease year throughout the
term of this Lease.

                  g. Whenever under the terms of this Lease any sum of money is
required to be paid by Tenant in addition to the rent reserved hereunder, said
additional amount shall, at the option of the Landlord, if not paid when due, be
deemed additional rent, and collectible as such with any installment of rent
thereafter falling due hereunder. Nothing contained in this subparagraph shall
be deemed to suspend or delay the obligation of Tenant to pay any and all other
sums as and when due hereunder, nor otherwise limit or circumscribe any other
remedy of Landlord.

         4. Option to Renew.

                  a. So long as Tenant shall not be in default of a monetary
obligation or a material non-monetary obligation under this Lease beyond the
applicable grace periods, Tenant shall have the option to renew this Lease for a
term of Ten (10) years ("Option Period"), with said extended term commencing on
the day after the last day of the Initial Term and terminating Ten (10) years
thereafter upon the same terms and conditions as contained in this Lease except
as otherwise provided.

                  b. The option is exercisable by Tenant, if at all, only in
strict compliance of the aforesaid conditions and by giving Landlord written
notice of its election to extend the Initial Term not later than One Hundred
Eighty (180) days prior to the termination date of the Initial Term. If Landlord
does not receive such notice within said time, Landlord shall notify Tenant of
such fact. Tenant shall have ten (10) days from receipt of said notice from
Landlord to then exercise its option by written notice to Landlord received
within


                                      -5-
<PAGE>   6
said ten (10) day period. Strict compliance with the conditions of the option
and the exercise thereof is deemed material to the parties and time for exercise
is of the essence. Failure to so exercise shall be deemed a waiver of this
option by Tenant, in which event this Lease shall expire on the termination date
for the Initial Term.

                  c.  The fixed annual rental during the first thirty (30)
months of the Option Period shall be equal to the fixed annual rental during
the last thirty months of the Initial Term increased by a fraction, the
numerator of which is the Revised Consumer Price Index for Urban and Clerical
Workers-All Items, N.Y.C., N.Y. - Northeastern New Jersey, ("CPI"), (BASE -
1982-84 = 100) (or any successor or similar index, if subsequently
discontinued), for the last day of the Initial Term, and the denominator is the
CPI for the calendar month of the last day of the ninetieth month of the Initial
Term. However, in no event shall said percentage increase in the fixed annual
rental for this time period exceed eight (8%) percent per annum nor be less than
Four (4%) Percent per annum. Until the CPI calculation can be made, Tenant
shall pay a fixed annual rental equal to the fixed annual rental for the last
year of the Initial Term, with any deficiency paid in the month following
Landlord's notice setting forth the fixed annual rental calculated in
accordance with this paragraph.

                  d.  Tenant covenants and agrees to pay Landlord during the
second thirty (30) months of the Option Period a fixed annual rental equal to
the fixed annual rental for the first thirty (30) months of the Option Period
increased by the percentage increase in the CPI for the period from the first
day of the first thirty (30) months of the Option Period to the last day of the
first thirty (30) months of the Option Period. However, in no event shall said
percentage increase in the fixed annual rental for this time period exceed
eight (8%) Percent per annum nor be less than Four (4%) Percent per annum. Until
the CPI calculation can be made, the same rent


                                     - 6 -
<PAGE>   7
percentage paid shall be paid with any deficiency paid in the month following
Landlord's notice setting forth the fixed annual rental calculated in
accordance with this paragraph.

                  e.  Tenant convenants and agrees to pay Landlord during the
third thirty (30) months of the Option Period a fixed annual rental equal to
the fixed annual rental for the second thirty (30) months of the Option Period
increased by the percentage increase in the CPI for the period from the first
day of the second thirty (30) months of the Option Period to the last day of
the second thirty (30) months of the Option Period. However, in no event shall
said percentage increase in the fixed annual rental for this time period exceed
eight (8%) Percent per annum nor be less than Four (4%) Percent per annum.
Until the CPI calculation can be made, the same rent percentage paid shall be
paid with any deficiency paid in the month following Landlord's notice setting
forth the fixed annual rental calculated in accordance with this paragraph.

                  f.  Tenant covenants and agrees to pay Landlord during the
fourth thirty (30) months of the Option Period a fixed annual rental equal to
the fixed annual rental for the third thirty (30) months of the Option Period
increased by the percentage increase in the CPI for the period from the first
day of the third thirty (30) months of the Option Period to the last day of the
third thirty (30) months of the Option Period. However, in no event shall said
percentage increase in the fixed annual rental for this time period exceed
eight (8%) Percent per annum nor be less than Four (4%) Percent per annum.
Until the CPI calculation can be made, the same rent percentage paid shall be
paid with any deficiency paid in the month following Landlord's notice setting
forth the fixed annual rental calculated in accordance with this paragraph.

         5.       Real Estate Taxes and Assessment.

                  a.  The Tenant agrees during the term of the Lease to pay as
additional rent an amount equal to all the real estate taxes, assessments and
other governmental charges, whether general or special, ordinary and
extraordinary,


                                     - 7 -
<PAGE>   8
unforeseen as well as foreseen, of every kind nature, assessed against the
Building. Tenant shall pay to Landlord said sums on an estimated basis in equal
monthly installments. Tenant shall have the right to institute a proceeding
challenging the amount of the real estate assessment for the Building. Landlord
will cooperate with Tenant and will execute all documents necessary to
challenge any such assessment. Landlord shall not be obligated to bring any
action seeking a reduction in the assessment. Anything herein to the contrary
notwithstanding, Tenant shall, as to special assessments payable in
installments, pay each such installment (assuming the lowest possible
installment under said assessment) payable during the term of this Lease as the
same becomes due. If such sum cannot be paid in installments than one-tenth
(1/10th) of such sum shall be paid in each lease year. Within ninety (90) days
after the expiration of each calendar year, Landlord shall submit a statement
showing the total taxes, assessments and other government charges paid for such
year. If such statement shows that Tenant's monthly payments pursuant to this
paragraph exceeded or are less than actual payments made for the preceding
calendar year, then (i) if said actual payments are less, Tenant shall pay
Landlord such deficiency within thirty (30) days of said billing or (ii) said
actual payments are more, Landlord shall return such sum to Tenant with such
statement. Landlord warrants and represents that there are no special
assessments as of the date hereof.

                  b.  If at any time during the term of this Lease, under the
laws of the State of New Jersey, or any political subdivision thereof, a tax on
rents is assessed against the Landlord or the basic rent, as a substitution in
whole or in part, for a real estate tax, assessment, water rent, rate or
charge, sewer rent, or other governmental imposition or charge with respect to
the premises, Tenant


                                     - 8 -

<PAGE>   9

shall pay its pro rata share of the same, provided such tax is calculated as if
the Building were the only property owned by Landlord. Tenant shall not be
responsible for franchise or income taxes of Landlord.

         6.       Utilities. Tenant shall pay for all charges for electric,
water, sewer and gas attributable to the demised premises directly to the
utility providing same.

         7.       Parking Area and Landscaping (Common Areas). Tenant shall be
responsible to take care of all common areas at Tenant's own cost and expense,
except that in the event that Landlord shall receive a written complaint from
any governmental authority or Landlord's mortgagee concerning the way in which
the outside common areas are maintained, Landlord shall give Tenant notice to
cure the items set forth in the complaint. In the event that Tenant shall not
cure said items within ten (10) days of the date of receipt of said notice by
Tenant, or if Landlord shall receive a second complaint after Tenant shall have
timely cured the items in the first complaint, Landlord thereafter may maintain
said common areas and Tenant shall be responsible for paying to Landlord on an
estimated basis, a sum, in equal monthly installments, to cover the cost of
the common area maintenance for the operation, repair and maintenance of common
areas, including, but not limited to, grounds maintenance, landscaping, snow
and ice removal and driveway areas. In the event that Tenant has overpaid or
underpaid said sum on an annual basis, said underpayment or overpayment shall
be refunded to Tenant or paid by Tenant to Landlord.

         8.       Use and Operation of Premises.

                  a. Throughout the term of this Lease, Tenant covenants to
continuously use the demised premises solely for any lawful use.

                  b. Tenant agrees not to use the premises for any purpose or
use other than that indicated in subparagraph


                                     - 9 -

<PAGE>   10

a. above and Tenant specifically covenants not to permit the premises to be
used for any unlawful purpose, nor commit nor suffer any waste. Tenant may
install a dish at Tenant's own cost and expense so long as Tenant complies with
all applicable governmental regulations.

                  c. Tenant shall not store any material, supplies or products
outside the Building, except in the fenced in area provided by Landlord.

         9. Insurance.

                  a. Tenant agrees to pay for insurance for the Building,
including, but not limited to, all insurance for loss or damage by fire and all
other casualties ordinarily included in extended coverage (not to exceed fair
market value), public liability insurance, and insurance for the payment of
rent and all other insurance of any type, kind or description as in customarily
maintained on properties such as the subject in the State of New Jersey with
such companies and in such amounts as the Landlord shall reasonably deem
advisable to maintain for the Building. Said insurance shall name Landlord and
Tenant as insureds as their interests may appear. Landlord agrees to insure the
Building of its full replacement value above foundations. Said sum shall be
paid to Landlord on an estimated basis in equal monthly installments. In the
event that Tenant has overpaid or underpaid said sum on an annual basis, said
underpayment or overpayment shall be refunded to Tenant or paid by Tenant to
Landlord. All insurance obtained by Landlord and Tenant shall contain
provisions allowing for full waiver of subrogation against the other and each
of Landlord and Tenant hereby respectively release the other from any liability
for damage required to be insured hereunder by Landlord and Tenant,
respectively.

                  b. Landlord shall, during the entire term hereof keep in full
force and effect a policy (blanket or otherwise) of Comprehensive General
Liability Insurance, with


                                     - 10 -
<PAGE>   11
contractual liability endorsement, with respect to the demised premises as to
which the limits of liability shall not be less than ONE MILLION ($1,000,000.00)
DOLLARS per person and THREE MILLION ($3,000,000.00) DOLLARS per accident or
occurrence and in which the property damage liability shall not be less than ONE
HUNDRED THOUSAND ($100,000.00) DOLLARS. The policy shall name the Landlord,
principals of Landlord and Tenant as named insureds, and shall contain clauses
(i) that all provisions thereof, except the limits of liability, shall operate
in the same manner as if that were a separate policy covering each insured, and
(ii) that the insurer will not change, modify or cancel the insurance without
first giving the Tenant ten (10) days' prior written notice. A copy of the
policy or a certificate of insurance shall be delivered to Tenant on or before
the Commencement Date.

                  c. Landlord shall have the right, at its discretion, to
reasonably increase, alter, modify, amend, add to or replace the insurance
requirements for Tenant, but in no event shall the amount of the insurance
purchased exceed replacement cost.

                  d. In the event that Tenant can purchase insurance from
companies of equal quality as maintained by Landlord at a less expensive rate,
Landlord shall either match said cost or purchase said insurance through
Tenant's agents.

         10.      Fire Damage.

                  a. If, after the date hereof, the demised premises or any
part of the Building of which the demised premises are a part, are damaged by
fire, enemy action, or other casualty (such damage being hereafter called "fire
damage"), Landlord shall restore said premises, except that Landlord shall have
the option not to restore if:

                           (i) there shall be remaining less than three (3)
years on Tenant's Lease after exercise of any options exercisable by Tenant; or


                                      -11-
<PAGE>   12
                           (ii)  if Landlord is unable to obtain any necessary
governmental approvals necessary to restore within ninety (90) days of its
application for same, after using reasonable diligence to obtain same during
said ninety (90) day period. Landlord agrees to apply for any necessary
approvals within thirty (30) days of the damage.

                  b.       If Landlord shall, in accordance with subparagraph
a. above, elect not to repair or restore said premises, this Lease shall
terminate on the date of occurrence of the fire damage.

                  c.       If for any reason Landlord shall not restore the
Building within one hundred eighty (180) days from the date that Landlord
obtains its governmental approval, Tenant shall have a right exercisable by
written notice received by Landlord within Fifteen (15) days of the expiration
of said one hundred eighty (180) day period, to terminate this Lease. Time
shall be of the essence.

                  d.       During any time Tenant cannot use all or a portion
of the demised premises, there shall be a proportionate abatement of rent.

         11.      Repairs and Alterations.

                  a.       Landlord shall put all electrical, plumbing and HVAC
systems in good working order and have all utilities available on commencement
of the Lease term. Landlord shall maintain the roof and structural elements of
the building during the term of this Lease, and HVAC system for two years from
the date rent commences, so long as any defects are not caused by willful acts
or negligence of Tenant. Except for Landlord's obligations as aforesaid, Tenant
agrees to maintain and repair the demised premises including any equipment
exclusively serving same and loading areas (hereafter collectively referred to
as demised premises). Landlord shall assign to Tenant any warranties that
Landlord may obtain on any installation of equipment exclusively serving the
demised


                                     - 12 -
<PAGE>   13
premises. The Tenant covenants that throughout the term of this Lease it will
take good care of the demised premises, including any alterations, changes and
improvements at any time erected thereon, and to keep same in good order and
repair, and shall promptly make, at its sole cost and expense all repairs to
same, including, but not limited to, all electrical, air-conditioning,
ventilation, heating, plumbing and other mechanical installations therein. At
the end of the term or other termination of this Lease, Tenant shall deliver
the demised premises with all improvements thereon in working order, reasonable
wear and tear only excepted. Tenant shall not be responsible for acts of the
Landlord or its agents.

                  b. Landlord covenants that at the commencement of the term of
this Lease, the premises shall be delivered in a "broom clean" and vacant
condition and shall comply with all "Legal Requirements" (defined below). Tenant
shall, during the term of this Lease, at its sole cost and expense, promptly
comply with and make any repair required by Legal Requirements which shall mean
collectively (i) any statute, ordinance, rule, order, regulation, or requirement
of the federal, state and municipal government and any and all departments,
agencies, bureaus and subdivisions thereof having jurisdiction thereover and
(ii) all rules, ordinances and regulations of the Board of Fire Underwriters.
Anything contained herein to the contrary notwithstanding, Tenant shall not be
responsible for any structural changes as result of a Legal Requirement. Further
in the event of a "Legal Requirement" which does not arise to after the Fifth
Lease Year, Tenant shall only be responsible for a sum equal to the first Ten
Thousand ($10,000.00) Dollars of such costs required by any such "Legal
Requirement" plus a sum equal to one tenth of the cost of such excess each lease
year (including any options exercised by Tenant) payable on the anniversary of
the completion of the work by Landlord. Landlord's costs for said work shall be


                                      -13-
<PAGE>   14
         equal to Landlord's actual out of pocket costs for said work plus any
         interest on any unamortized balance at the rate of 10% per annum.
         Tenant shall pay for the first Ten Thousand ($10,000.00) Dollars of the
         cost of such "Legal Requirement" upon completion of the work by
         Landlord.

                  c. Tenant shall have the right during the term of this Lease
         to make alterations to the building and improvements subject to the
         following conditions: (i) any and all governmental permits and
         authorizations, if any, required therefor shall have been obtained
         prior to the undertaking of said alterations or improvements; (ii) no
         structural alteration or improvement shall be undertaken until detailed
         plans and specifications have first been submitted to and approved in
         writing by the Landlord (which consent will not be unreasonably
         withheld or conditioned); (iii) all alterations and improvements when
         completed shall be of such character as shall not reduce, or otherwise
         adversely affect, the value of the demised premises or building, reduce
         the cubic content of the building, affect the structural soundness of
         the building, nor change the character of the building as to use; (iv)
         all work done in connection with any alterations and improvements shall
         be done promptly and in a good and workmanlike manner and in compliance
         with the building and zoning laws of the place in which the demised
         premises are located, and with all Legal Requirements; (v) said
         alteration or improvement shall be completed free of liens for labor
         and materials supplied or claimed to have been supplied to the demised
         premises; and (vi) Tenant shall, at its sole cost and expense, cause
         adequate builders risk insurance therefor to be maintained, including
         statutory workmen's compensation insurance covering all persons
         employed in connection with the work and with respect to whom death or
         injury claims could be asserted against the Landlord, the Tenant or the
         demised premises; and


                                      -14-
<PAGE>   15
         general liability insurance for the mutual benefit of the Tenant and
         the Landlord with limits of not less than ONE MILLION ($1,000,000.00)
         DOLLARS in the event of injury to one person and of not less than THREE
         MILLION ($3,000,000.00) DOLLARS in the event of injury to any number of
         persons in any one accident, and with limits of not less than ONE
         HUNDRED THOUSAND ($100,000.00) DOLLARS for property damage at times
         when any work is in process in connection with any alteration or
         improvements. Landlord reserves the right to reasonably increase,
         modify or expand the insurance requirements under this paragraph. At
         the completion of any work performed hereunder, Tenant shall supply
         Landlord with an affidavit of Tenant and an affidavit of the actual or
         general contractor supervising the work, certifying that the
         alterations and improvements have been constructed and completed in
         accordance with the approved plans, if the costs of said improvements
         exceed Twenty-Five Thousand ($25,000.00) Dollars. In the event that
         said costs are less than Twenty-Five Thousand ($25,000.00) Dollars,
         Tenant's president shall so certify under oath.

                  d. All salvage shall belong to Tenant, but all alterations and
         improvements which are attached to the building so as to be and become
         part of the realty shall become part of the premises on termination of
         the Lease subject to the terms and conditions of this Lease and shall
         at that time become and remain the property of the Landlord without
         compensation to Tenant therefor. All trade fixtures, equipment and
         furnishings in said demised premises at any time installed by Tenant
         shall remain the property of Tenant and Tenant may remove such property
         from the demised premises whenever Tenant desires to do so it being the
         intention of the parties that all such equipment and furnishings be
         considered as personal property, whether or not attached to any portion
         of the demised premises. At the expiration or sooner termination of


                                      -15-
<PAGE>   16
the term of this Lease, Tenant shall peaceably yield up to Landlord the demised
premises in the condition in which Tenant was required to maintain the same
during the term of this Lease, reasonable wear and tear, and loss or damage due
to fire or the elements excepted. Subject as aforesaid, at the expiration of
the term of this Lease, Tenant may remove from the demised premises its movable
trade fixtures and furnishings belonging to Tenant. Tenant shall repair any
damage caused thereby, but shall not be obligated to redecorate.

                  e.  If Tenant fails to undertake the repairs, maintenance or
replacements in accordance with the provisions of this paragraph or otherwise
to comply with said provisions, and Landlord shall have given Tenant thirty
(30) days written notice (except in the case of an emergency) of the failure,
the Tenant shall be responsible and liable to the Landlord who may, at its
option, proceed to make said repairs and replacements, using such labor and
materials as it shall deem necessary, in its sole discretion, for the purposes
and shall thereupon charge the total of costs, losses or damages incurred, plus
any reasonable attorney fees, plus interest thereon at a variable rate equal to
two (2%) percent above the daily prime interest rate set by Chase Manhattan
Bank, N.Y.C., N.Y. to and against Tenant which shall be due and payable as part
of the next month's rent. The provisions of this subparagraph are in addition
to the rights and remedies of the respective parties as provided in this Lease
or as permitted by law.

         12.  Eminent Domain.

                  a.  If the total demised premises are taken, acquired or
purchased by or through condemnation proceedings or any right of eminent domain
or any other authority of law, or by private purchase in lieu thereof, with or
without the entry of an order in a judiciary proceeding, this Lease shall
terminate as of the date of taking without further liability by the parties
hereto.


                                     - 16 -

<PAGE>   17
                  b.  Landlord agrees that it will, with all reasonable
dispatch, at its expense, rebuild and restore the remaining portion of the
premises, and all the appurtenances, equipment, utilities, facilities and
installations therein and thereto, to the same condition and tenantability as
existed immediately preceding the taking in such manner that the premises shall
be a complete and integrated structural, architectural and functional unit
similar to, and of equal material and workmanship to, the premises immediately
preceding the taking, with all such appurtenances, equipment, utilities,
facilities and installations in good working order and condition so as to put
the premises in proper order and condition to be used by Tenant for the same
purpose as the premises were being used immediately preceding the taking,
except that Landlord shall have no obligation to replace or rebuild any item
for which Tenant may have been or is compensated for as a result of the taking.
Anything contained herein to the contrary notwithstanding, Landlord shall have
the option not to restore if:

                           (i)  there shall be remaining less than three (3)
years on Tenant's lease after exercise of any options exercisable by Tenant; or

                           (ii)  if Landlord is unable to obtain any necessary
governmental approvals necessary to rebuild within ninety (90) days of its
application for same, after using reasonable diligence to obtain same during
said ninety (90) day period. Landlord agrees to apply for any necessary
approvals within thirty (30) days of the taking.

                  c.  Tenant shall have the right to terminate this Lease if
(i) the number of parking spaces are reduced by more than ten (10); (ii)
Landlord cannot provide Tenant with reasonable substitute access or loading to
the premises if loading or access are taken or (iii) Landlord shall not have
substantially completed any required repairs within one


                                     - 17 -
<PAGE>   18
hundred eighty (180) days of the date Landlord obtains its governmental
approvals. In any of the above events, Tenant shall exercise its right of
termination by written notices to Landlord, received within Thirty (30) days of
expiration of the happening of any of said events. Time shall be deemed of the
essence.

                  d.  The date of any taking shall be the date specified in the
official notice of the condemning authority, or in the absence of such notice,
the vesting of title in said authority. All rent or other charges paid or
payable by Tenant to Landlord shall be adjusted as of the date of said taking
on a proportional basis to reflect the amount of space which shall continue to
be usable by Tenant. Rent and all other charges shall abate during any period
in which Tenant ceases to operate by reason of the taking and restoration. Upon
any termination or cancellation of this Lease, as provided in this section, all
rent or other charges paid in advance for any period after the effective date
thereof shall be refunded to Tenant and all liability of Tenant under this
Lease shall terminate.

                  e.  Landlord reserves to itself alone all rights to damages
or compensation accruing on account of any such taking comprising and included
in the demised premises as aforesaid or by reason of any act of any public or
quasi-public authority for which damages are payable, except that Tenant may
assert any independent claim for its fixtures, moving expenses and leasehold
improvements installed by Tenant.

         13.      Indemnity and Liability for Injury and Loss.

                  a.  Except for negligence or its willful acts, Landlord (i)
shall not be liable to Tenant or any other person on or about the demised
premises for any damage either to person or property; (ii) shall not be
responsible or liable in any way whatsoever for the quality, quantity,
impairment,


                                     - 18 -
<PAGE>   19
interruption, stoppage of or other interference with services involving water,
sewer, heat, gas, electrical current for light and power, telephone or any
other service by any public utility; and (iii) nor be liable for any damage or
injury by water, sewage, steam, electricity, gas, electrical current for light
and power, telephone or any other service by any public utility; and (iv) nor
be liable for any damage or injury by water, sewage, steam, electricity, gas,
rain, ice or snow which may be sustained by said Tenant or other person. Except
that if utilities are interrupted because of Landlord's negligence, Tenant
shall be entitled to a reasonable rent abatement for the time for which said
utilities are interrupted.

                  b. Tenant shall indemnify, defend and save Landlord harmless
from and against all injuries, liability, expense, claim or damage to any
person or property while on the demised premises, arising out of the use or
occupancy of the demised premises by Tenant, except for Landlord's negligence
or willful acts.

         14. Lease Subordination and Non-Disturbance.

                  a. This instrument shall not be a prior lien against the
premises in respect to any mortgages that now or hereafter may be placed
against the Building and that the recording of such mortgage or mortgages shall
have preference and precedence and be superior and prior in lien of this Lease,
irrespective of the date of granting or recording so long as Landlord shall
provide Tenant with a non-disturbance agreement which provides that so long as
Tenant shall not be in default in any of the provisions of this Lease, its
possession will not be disturbed by such mortgagee. Tenant does hereby agree to
accept any mortgagee as the Landlord hereunder and to perform its obligation as
Tenant under this Lease, if any mortgagee acquires title to the Building by
foreclosure or otherwise.

                                     - 19 -
<PAGE>   20

                  b. The term "mortgage" as used in this section includes
mortgages, deeds of trust or any similar instruments and modifications,
extensions, renewals and replacements thereof.

                  c. The provisions of the subordination and attornment
contained in this paragraph shall be self-operative and no further instrument
of subordination shall be required in order to bind Tenant hereunder so long as
any mortgagee of the demised premises shall give Tenant a non-disturbance
agreement. In the event Landlord desires confirmation of such subordination and
attornment, Tenant shall execute and deliver any instrument which may be
required to further evidence the subordination of this Lease to the lien of any
such mortgage or mortgages and the agreement by Tenant to accept the mortgagee
as the Landlord and perform under this Lease if the mortgagee acquires title to
the Building by foreclosure or otherwise, as shall be desired by any aforesaid
mortgagee or proposed mortgagee.

                  d. Tenant shall furnish Landlord (and vice versa), within ten
(10) days of its request, an estoppel certificate relating to the Lease, setting
forth the following: (i) that the Lease is in full force and effect, and if not,
in what respect it is not; (ii) that the Lease has not been modified, or the
extent to which it has been modified; (iii) the amount of monthly rent and date
last paid; and (iv) that to the best of its knowledge, there are no existing
defaults, or if so, specifying the default.

                  e. Tenant does hereby agree to Landlord, now or hereafter,
assigning the rentals under this Lease to a mortgagee, and all extensions,
renewals, modifications and replacements thereof.

                  f. Landlord shall use its best efforts to obtain the
agreement of any mortgagee who has a lien against the demised premises that any
proceeds of insurance or

                                     - 20 -
<PAGE>   21
condemnation can be used by Landlord to restore the demised premises. However,
Landlord's failure to obtain the agreement of any such mortgagee shall not be
deemed a default by Landlord under this Lease nor give rise to any claims by
Tenant under this Lease or otherwise.

         15. Defaults, Remedies and Bankruptcy.

                  a. The following shall constitute events of default under
this Lease:

                           (1) failure to pay when due any installment of rent
or additional rent reserved herein, or any part of either which failure shall
continue for more than ten (10) days after written notice thereof to Tenant;

                           (2) failure in the performance of or compliance with
any of the other covenants, conditions and/or terms of this Lease, which failure
shall continue for more than thirty (30) days after written notice thereof to
Tenant or Landlord, as the case may be except if said performance or compliance
cannot be reasonably completed within said thirty (30) days period, Tenant shall
have such time as is reasonable so long as Tenant immediately commences
performance or compliance and diligently continues to completion;

                           (3) abandonment, vacation or desertion of the
premises or suspension of business at the demised premises for more than thirty
(30) days;

                           (4) if this Lease shall be assigned, sublet, pass to
or devolve upon one other than the Tenant, except as herein provided;

                           (5) the filing by or against Tenant of any petition
with respect to its own financial condition under any bankruptcy law or any
amendment thereto (including, without limitation, a petition for reorganization,
arrangement or extension), or under any other insolvency law or laws providing
for the relief of debtors (which petition, if filed against Tenant shall not be
dismissed within ninety (90)


                                     - 21 -
<PAGE>   22

days); the appointment of a receiver, trustee, custodian, conservator or
liquidator for Tenant on all or substantially all of Tenant's assets, and
the underlying proceeding is not dismissed within ninety (90) days after the
commencement thereof; making of a general assignment for the benefit of
creditors.

                  b. Upon the occurrence of an event of default, Landlord, in
addition to any and all rights and remedies it may have at law and equity, may
exercise any one or more of the following remedies:

                           (1) Landlord may give Tenant a notice (the
Termination Notice) of its intention to terminate this Lease specifying a date
not less than three (3) days thereafter, upon which date this Lease (unless
cured in said three (3) days), the term and estate hereby granted and all rights
of Tenant hereunder shall expire and terminate. Notwithstanding the foregoing:
(i) Tenant shall remain liable for damages as hereinafter set forth, and
(ii) Landlord may institute dispossess proceedings for non-payment of rent, or
other proceedings to enforce the payment of rent without giving the Termination
Notice. Upon any such termination or expiration of this Lease, Tenant shall
peaceably quit and surrender the premises to Landlord, and Landlord may without
further notice enter upon, re-enter, possess and repossess itself thereof, by
force, summary proceedings, ejectment or otherwise and may have, hold and enjoy
the premises and the right to receive all rental and other income of and from
the same as heretofore provided;

                           (2) Landlord may, at Landlord's sole option (without
imposing any duty upon Landlord to do so), and Tenant hereby authorizes and
empowers Landlord to: (i) re-enter the premises as Tenant's agent or for any
occupant of the premises under Tenant, or for its own account or otherwise,
(ii) relet the same for any term, (iii) remodel the same


                                     - 22 -


<PAGE>   23
if reasonably necessary or desirable for such reletting purposes and (iv)
receive and apply the rent so received to pay all fees and expenses incurred by
Landlord, directly or indirectly, as a result of Tenant's default, including,
without limitation, any legal fees and expenses arising therefrom, the cost of
re-entry, repair, remodeling and reletting and the payment of the rent and other
charges due hereunder. No entry, re-entry or reletting by Landlord, whether by
summary proceedings, termination or otherwise, shall discharge Tenant from any
of its liability to Landlord as set forth in this Lease, except to the extent
Landlord receives rent therefor and applies the same to Tenant's obligations as
aforesaid;

                           (3) Regardless of whether Landlord relets the
premises, or enters or re-enters the same, whether by summary proceedings,
termination or otherwise, Tenant will pay Landlord, and be liable to Landlord
for, the full amount of all fixed annual rent, additional rent, and other
charges then due or thereafter to become due to Landlord hereunder less any sums
collected by Landlord during the remaining term of this Lease. Said amount shall
be paid by Tenant to Landlord on the days originally fixed herein for payment
thereof;

                           (4) If the Landlord or Tenant shall fail to pay any
taxes or make any other payment required to be made under this Lease, or shall
default in the performance of any covenant, agreement, term, provision or
condition herein contained, Landlord may after notice to Tenant (or Tenant may
after reasonable notice to Landlord), without being under any obligation to do
so and without thereby waiving such default, make such payment and/or remedy
such default for the account and at the sole expense of the other. Tenant shall
pay to Landlord (or vice versa), on demand, the amount of all sums so paid and
all expenses so incurred by Landlord (or Tenant), together with interest, at the
rate set forth in subparagraph


                                     - 23 -
<PAGE>   24
15(b)(5) below, on such sums and expenses from the date incurred until payment
in full;

                           (5)  Interest on any sums due to Landlord from
Tenant (or vice versa) under this Lease shall accrue from the date such sums
became due and payable, at a variable rate equal to two (2%) percent above
prime interest rate as set daily by Chase Manhattan Bank, N.Y.C., N.Y.;

                           (6)  Tenant, for itself and on behalf of any and all
persons claiming through or under it, including without limitation, creditors
of every kind, hereby waives and surrenders all rights and privileges which it
or any of them may have under or by reason of any present or future law to
redeem the premises, or to have a continuance of this Lease for the remainder
of the term, after being dispossessed or ejected therefrom by process of law or
after the termination of this Lease as herein provided.

                  c.  The failure on the part of Landlord to re-enter or
repossess the premises, or to execute any of its rights as provided in this
section upon any default, shall not be deemed a waiver of any of the terms and
conditions of this Lease and shall not preclude said Landlord from exercising
any such rights upon any subsequent occurring default or defaults. All of
Landlord's rights shall be cumulative and shall not preclude the Landlord from
exercising any other rights which it may have under law.

                  d.  Landlord shall have no duty to mitigate damages which
might be the obligation of Tenant under this Lease.

         16.  Assignment and Subletting.  Tenant shall have the right to assign
this Lease or sublet the premises or any part thereof so long as Tenant shall
remain primarily liable hereunder; and further provided that said use complies
with all governmental requirements. If Tenant shall desire to sublet or assign
this Lease, Tenant shall notify Landlord in


                                     - 24 -

<PAGE>   25
writing. In the event Tenant notifies Landlord of its intention to assign or
sublet this Lease, Landlord shall have the option exercisable within thirty (30)
days of the receipt of said notice to cancel this Lease on sixty (60) days
notice to Tenant; except that Landlord shall have no such right to cancel if any
such assignment or subletting is to a company which has and maintains common
ownership with Tenant equal to at least ten (10%) percent nor in the event of a
sale of One Hundred (100%) percent of Tenant's stock so long as such successive
ownership continues to operate the business of Tenant in substantially the form
operated by Tenant. Further, Landlord shall have no right to cancel this Lease
under this provision if there is a subletting of less than fifty (50%) percent
of the demised premises (in square footage) for a term of less than five (5)
years. In the event that Landlord shall elect to cancel this Lease as is
provided for herein, Landlord shall pay to Tenant the remaining unamortized
costs of Tenant's leasehold improvements as shown on Tenant's most recent
federal income tax return so long as Tenant supplies Landlord with copies of
Tenant's tax return showing leasehold improvements in detail together with
Tenant's request for assignment of rights itemizing said amounts and detailing
what each amount was spent for giving receipts for payment, and setting forth
the period over which said expenditures are being amortized for period from the
commencement of this Lease. Tenant shall further notify Landlord within thirty
(30) days of receipt of any notice of adjustment from any taxing authority if
any such amounts or amortization periods are changed at the request of such
taxing authority. Time shall be deemed of the essence.


         17. Signs. The Tenant may display any sign, picture, advertisement,
awning, merchandise, or notice on the outside of the building of which the
demised premises are a



                                     - 25 -
<PAGE>   26
part, which shall be in conformance with all governmental regulations.

         18. Miscellaneous.

                  a. Notices. All notices and demands which are required to or
are permitted by the terms of this Lease shall be given in writing, whether
herein specified or not, and shall be sent by United States registered or
certified mail, return receipt requested, postage prepaid, addressed to the
parties as follows:

                  To or for Landlord:

                  United States Land Resources, L.P.
                  c/o Berger & Bornstein
                  237 South Street
                  P.O. Box 2049R
                  Morristown, New Jersey 07960-2049

                  To or for Tenant:

                  RTK Corporation
                  120 Floral Avenue
                  New Providence, New Jersey 07974

                  With a copy to:

                  Rand Agins, Esq.
                  Lasser, Hochman, Marcus
                    Guryan & Kuskin
                  75 Eisenhower Parkway
                  Roseland, New Jersey 07068

         Said addresses and the names of the parties to whom notices are to be
sent may be changed from time to time by either party or by an assignee or
successor of either of them by the giving of written notice to the other sent
as above provided. Said notice shall be deemed given two (2) business days
after mailing.
                  b. Definition of "Landlord". The term "Landlord" as used in
this Lease means only the owner for the time being of the land and building of
which the demised premises form a part so that in the event of any sale of said
land and building the Landlord making said sale shall be thereafter freed and
relieved of all covenants and obligations of Landlord hereunder (except with
respect to obligations and covenants relating to the period prior to said sale)
provided,


                                     - 26 -
<PAGE>   27
however, that the purchaser at any such sale agrees to carry out any and all
covenants and obligations of Landlord hereunder.

                  c.       Abandonment of Fixtures.  If, after the default in
payment of rent or violation of any other provision of this Lease or at any
time during the term hereof or upon expiration of this Lease, Tenant moves out
or is dispossessed and fails to remove any trade fixtures or any other property
within thirty (30) days after said moving or dispossession then, in that event,
the said fixtures and property shall be deemed abandoned by the Tenant and
shall become property of the Landlord.

                  d.       Waiver of Performance.  The failure of either party
to insist upon strict performance of any of the covenants or conditions of this
Lease or to exercise any option herein conferred in any one or more instance
shall not be construed as a waiver or relinquishment for the future of any such
covenants, conditions or options but the same shall be and remain in full force
and effect.

                  e.       Landlord's Right of Entry.  Landlord or its duly
authorized agents or representatives shall have the right to enter upon said
premises on all reasonable hours for the purpose of examining the same upon
reasonable prior notice or, in the event of emergency, in order that repairs and
alterations may be made for the safety and preservation thereof, provided,
however, that Landlord's right to enter upon said premises shall be subject to
the exercise of ordinary care and caution in doing so and with minor
inconvenience with Tenant's business. Landlord or Landlord's duly authorized
agents or representatives shall also have the right to show the premises to
persons wishing to purchase the same or during the six (6) months next prior to
the expiration of the term of the Lease, lease the same.

                                     - 27 -
<PAGE>   28

                  f. Elimination of Liens by Tenant. Tenant shall not suffer or
permit or cause any liens of any action to be filed against the demised
premises by reason of any cause of Tenant or Tenant's agents or employees. In
the event that any such lien is filed, Tenant shall have the same discharged of
record by bonding or otherwise, within thirty (30) days after notice thereof.
Nothing in this Lease contained shall be deemed to be a consent on the part of
the Landlord to subject the demised premises to lien or claim under a
mechanic's lien law of New Jersey by reason of labor or material furnished to
Tenant in connection with the demised premises.

                  g. Captions. The captions and headings throughout this Lease
are for convenience and reference only and the words contained therein shall in
no way be held or deemed to define, limit, describe, explain, modify, amplify
or add to the interpretation, construction or the meaning of any provisions of,
or the scope or intent of this Lease, nor in any way affect this Lease.

                  h. Successors and Assigns. This Lease shall be binding upon
and shall inure to the benefit of the parties hereto, their respective heirs,
representatives, successors and, to the extent this Lease is assignable by the
terms hereof, the assigns of such parties.

                  i. Real Estate. Tenant will look solely to the estate and
property of Landlord in the Building (or the proceeds of sale of the same or
proceeds of insurance or condemnation) for the collection of any judgment (or
other judicial process) requiring the payment of money or any other obligation
of or by Landlord in the event of any default or breach by Landlord with
respect to any of the terms, covenants and conditions of this Lease to be
observed and/or performed by Landlord and in any way relating to this Lease or
to the land and improvements of which the demised premises are a



                                     - 28 -

<PAGE>   29
part, and no other assets of Landlord or any holder of an interest in the
Landlord of the said property shall be subject to levy, execution or other
procedure for the satisfaction of Tenant's remedies.

                  j.  Brokerage Commission.  Landlord recognizes Douglas
Elliman and David T. Houston Company as the brokers who were the procuring
cause of this Lease transaction. Landlord agrees to pay said brokers a
commission by a separate agreement.

         19.  Quiet Enjoyment.  So long as Tenant shall not be in default in
any of the terms of this Lease, Tenant shall peaceably and quietly have, hold
and enjoy the demised premises for the term and any extensions.

         20.  Additional Space.  Prior to the third (3rd) anniversary of this
Lease (unless Tenant properly exercises its option to renew hereunder in which
event prior to the sixth (6th) anniversary date of this Lease), Tenant shall be
entitled to have Landlord construct one (1) addition to the demised premises so
long as Tenant shall not have been in monetary default of this Lease (beyond
applicable grace periods) or in material non-monetary default (beyond
applicable grace periods) of this Lease. In the event, that Tenant shall
request in writing that Tenant is desirous of Landlord building an addition
(the additional space to be ten thousand (10,000) square feet of contiguous
space) on the plan attached hereto, Landlord shall immediately commence to
obtain approvals to do so, so long as:

                  (1)  Landlord and Tenant can agree upon the rental for said
addition. Landlord and Tenant hereby agree that they shall both act reasonably
and with due diligence in attempting to arrive at an agreement. The parties
agree that if the parties failure to agree to the contrary within thirty (30)
days of the date of Tenant's exercise of its option, rental for the additional
space shall be the sum of Ten


                                     - 29 -

<PAGE>   30
($10.00) Dollars per square foot per year increased during the Initial Term or
Option Period based upon the CPI increase as is provided herein for the Option
Period from the date hereof to the date Tenant takes occupancy of said
additional space and increase every thirty (30) months thereafter in the Initial
Term and Option Period as is provided for in the Option Period of this Lease;
and

                  (2) Landlord's obligation hereunder shall be subject to
obtaining all necessary governmental approvals for the construction of said
addition. Landlord shall diligently pursue said approvals and diligently
commence the construction of said addition upon the receipt of said approvals.

                  The parties acknowledge that the additional space shall be
constituted of substantially the same quality and character as Tenant's existing
office space, including finishes originally provided by Landlord under this
Lease. Upon completion of said improvements, Landlord shall construct a parking
area for the total number of cars required by law. Landlord hereby warrants
that, as of this date, Landlord has no knowledge of any reason why the demised
premises cannot be expanded to the maximum permissible size under existing
zoning ordinances.

                  IN WITNESS WHEREOF, the parties hereto have hereunto set
their hands and seals the day and year first above written.


                                       LANDLORD:

                                       FLORAL AVENUE ASSOCIATES, L.P.
                                       BY: UNITED STATES LAND RESOURCES,
                                            L.P., General Partner
                                            BY: UNITED STATES REALTY
                                                 RESOURCES, INC.,
                                                 General Partner

ATTEST:



/s/ Robert A. Bornstein                        By: /s/ Lawrence S. Berger
------------------------------                    ------------------------
ROBERT A. BORNSTEIN, Assistant                    LAWRENCE S. BERGER,
                     Secretary                     President


                                      -30-
<PAGE>   31
                                       TENANT:

ATTEST:                                RTK CORPORATION



                                       By: /s/ ROY D. TARTAGLIA
-------------------------------            ------------------------------------



         The obligations of Tenant under this Lease are hereby personally
guaranteed. However, the undersigned's liability under this paragraph shall
terminate upon the conclusion of the Fifth Lease Year if Tenant shall not be in
monetary default (beyond the applicable grace periods) of this Lease during the
first five (5) lease years or be in material non-monetary default (beyond the
applicable grace periods) under this Lease during the first five (5) lease
years.


                                       /s/ ROY D. TARTAGLIA
                                       ------------------------------------
                                       ROY D. TARTAGLIA


                                       /s/ RICHARD A. THOMAS
                                       ------------------------------------
                                       RICHARD A. THOMAS


LSB-001
DISP. 229


                                     - 31 -

<PAGE>   32

                          EXHIBIT B - LANDLORD'S WORK


         1. Landlord shall finish the space in accordance with plans and
specifications of Vatche Simonian, dated the 21st day of August, 1988,
including handwritten notes.

         2. Landlord shall complete the work shown on the site plan of Kinzler
and Ritter/Land Planning, dated June, 1988.


LSB-001
DISP. 229

<PAGE>   33
                            FIRST AMENDMENT TO LEASE

         THIS FIRST AMENDMENT TO LEASE (this "First Amendment") is made as of
the 10th day of March, 1999 by and between:

                  FLORAL AVENUE ASSOCIATES, L.P.
                  a New Jersey limited partnership
                  c/o Berger & Bornstein, P.A.
                  237 South Street, P.O. Box 2049
                  Morristown, New Jersey 07962-2049
                  (hereinafter referred to as "Landlord")

                  and

                  RTK CORPORATION
                  a New Jersey Corporation
                  having an address at
                  120 Floral Avenue
                  New Providence, New Jersey
                  (hereinafter referred to as "Tenant");

                                   WITNESSETH

         WHEREAS, Landlord, as landlord, and Tenant, as tenant, entered into a
Lease (the "Lease") dated September 16, 1988, pursuant to which Landlord leased
to Tenant an approximate 30,000 square foot building located at 120 Floral
Avenue, New Providence, Union County, New Jersey; and

         WHEREAS, the Lease, by its terms, shall expire on May 31, 1999, and
Landlord and Tenant have agreed to extend the term of the Lease in accordance
with the provisions of this First Amendment.

         NOW, THEREFORE, Landlord and Tenant agree as follows:

         1.       TERM.  Paragraph 2 of the Lease is hereby amended to reflect
that the term of the Lease is extended for five (5) years from June 1, 1999
through May 31, 2004 (the "Extension Period").

         2.       RENT.

                  Paragraph 3 of the Lease is amended to reflect that the fixed
annual rent for the Demised Premises for the Extension Period shall be Two
Hundred Forty Thousand ($240,000) Dollars payable in equal monthly installments
of $20,000.00.

                                       1
<PAGE>   34

         3. OPTION TO RENEW.

                  (a) Paragraph 4(a) of the Lease is hereby modified to reflect
that the "Option Period" shall be for a term of five (5) years commencing on
June 1, 2004.

                  (b) Paragraph 4(b) of the Lease is hereby modified to reflect
that Tenant's written notice to extend shall be delivered to Landlord not later
than December 1, 2003.

                  (c) Paragraphs 4(c), 4(d), 4(e) and 4(f) of the Lease are
hereby deleted and replaced by the following:

                  The fixed annual rent for the Option Period shall be equal to
$330,000.00 and shall be payable in equal monthly installments of $27,500.00.

         4.       GUARANTY TERMINATION. The guaranty set forth on page 31 of the
Lease is hereby terminated.

         5.       LANDLORD'S WORK. Landlord shall complete the following
work on or before August 20, 1999:

                  a. Install new standard commercial grade carpeting in
Tenant's office space, as selected by Tenant from Landlord's samples.

                  b. Repair loose floor tiles in tiled areas.

                  c. Extend HVAC system into back "file room" located in east
corner of building.

                  d. Repair where needed outside spaulding concrete and paint
the repaired area.

         6.       HVAC SYSTEM. During the Extension Period, Landlord will
maintain the HVAC System in working order.

         7.       MISCELLANEOUS. Paragraph 20 of the Lease is hereby deleted in
its entirety. All capitalized terms used in this First Amendment shall, unless
otherwise defined herein, have the respective meanings ascribed to said terms
in the Lease. All


                                       2



<PAGE>   35

provisions of the Lease, except as expressly modified pursuant to this First
Amendment, shall remain unchanged and in full force and effect.




                                    LANDLORD:
                                    FLORAL AVENUE ASSOCIATES, L.P.
                                    By: Floral Avenue GP, L.L.C.
                                    By: United States Land Resources, L.P.
                                    By: United States Realty Resources, Inc.



                                    By:
                                       ----------------------------------------
                                        LAWRENCE S. BERGER, PRESIDENT


                                    TENANT
                                    RTK CORPORATION


                                    By: /s/ ROY D. TARTAGLIA
                                       ----------------------------------------
                                        ROY TARTAGLIA, CEO


                                    By: /s/                            7/13/99
                                       ----------------------------------------
                                                         CONTROLLER


                                       3