Document:

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                                                                  Exhibit 10.1.2

                                 March 13, 2002
BY FEDERAL EXPRESS
------------------

Mr. Gary Nadeau
20791 N. Swansway
Deer Park, IL  60010-3768

Dear Gary:

This letter is a revision and replacement of my letter dated March 8, 2002 to
reflect certain considerations that have been raised with respect to the
severance arrangements being offered to you as a result of the termination of
your employment with Mykrolis Corporation (the "Company") effective as of March
8, 2002 (the "Separation Date"). The purpose of this letter is to confirm the
agreement between you and the Company concerning your severance arrangements, as
follows:

     1.   FINAL SALARY AND VACATION PAY. You will receive pay for all work you
have performed for the Company during the current payroll period through the
Separation Date, to the extent not previously paid, as well as pay, at your
current base rate of pay, for any vacation days you had earned, but not used, as
of the Separation Date in accordance with Company policy.

     2.   SEVERANCE BENEFITS. In consideration of your acceptance of this
Agreement and subject to your meeting in full your obligations under it, the
Company will provide you the following severance pay and benefits:

     (A)  The Company will pay you salary continuation payments for a period of
          eighteen (18) months following the Separation Date (the "Severance Pay
          Period") as follows: (i) from the Separation Date until December 31,
          2002, you will be paid at your current (i.e. post reduction) base
          salary, at the rate of One Hundred and Seventy Thousand and 00/100
          Dollars ($170,000.00) per year; (ii) thereafter from January 1, 2003
          until the expiration of the Severance Pay Period, you will be paid
          your prior 2001 (i.e. pre-reduction) base salary, at the rate of Two
          Hundred and 00/100 Dollars ($200,000.00) per year. Payments will made
          in the form of salary continuation and will begin on the next regular
          Company payday which is at least five business days following the
          later of the effective date of this Agreement or the date it is
          received by the Company. The first payment will be retroactive to the
          day following the Separation Date.

     (B)  If you were enrolled in the Company's medical and dental plans on the
          Separation Date, the Company will continue these benefits through the
          earlier of (i) September 8, 2002; or (ii) the date you become eligible
          for coverage under the health plan of another employer. Upon
          termination pursuant to (i) or (ii) above, you may, at your own
          expense, elect to continue your participation and that of your
          eligible dependents in those plans for a period of time under the
          federal law known as "COBRA."

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MR. GARY NADEAU
MARCH 13, 2002
PAGE 2 OF 7

     (C)  The services of the Colony Group will continue to be available to you
          at the current level for the balance of 2002. These services will
          terminate December 31, 2002.

     (D)  Your contributions and the Company's matching contributions to the
          Mykrolis Corporation Savings and Investment Plan terminate as of the
          Separation Date. The balances in your accounts under the Savings and
          Investment Plan will be paid out to you in accordance with the terms
          of that Plan. You will have a number of options with respect to the
          payment of these balances; T. Rowe Price, the Trustee of the Savings
          and Investment Plan, has been instructed to mail a distribution kit to
          your home. You should expect to receive this in approximately two
          weeks. This distribution kit will include detailed information
          regarding your payment options, instructions and necessary forms.

     (E)  As of the Separation Date no options outstanding under the Mykrolis
          Corporation 2001 Equity Incentive Plan are vested. On the Separation
          Date, the Company will cause any options to purchase common stock of
          the Company to which you were entitled before the Separation Date
          under the Mykrolis Corporation 2001 Equity Incentive Plan that would
          have vested during the period commencing with the Separation Date and
          ending on the first anniversary of the Separation Date had you
          continued to be employed throughout that period (the "Separation
          Vested Options") to become exercisable, subject to your signing and
          returning this Agreement in a timely manner and to your not revoking
          it in a timely manner thereafter. You may exercise the Separation
          Vested Options as of the date immediately following the later of: (i)
          the effective date of this Agreement (which shall occur upon the day
          immediately following the expiration of seven days following the date
          that the Vice President, Human Resources of the Company receives this
          Agreement, signed by you) or (ii) April 1, 2002 (the date on which the
          Company's out-sourced systems to process exercises of stock options
          becomes operational). The Separation Vested Options shall remain
          exercisable until the close of the New York Stock Exchange on April 1,
          2003, after which time any portion of the Separation Vested Options
          not exercised shall be forfeited and shall terminate. Except as
          otherwise expressly provided in this paragraph, the terms and
          conditions of the Separation Vested Options shall remain unchanged and
          shall be governed by the terms of the Mykrolis Corporation 2001 Equity
          Incentive Plan and the applicable stock option grant letter and any
          other requirements and restrictions generally applicable to shares
          purchased by Company employees, as these may be amended from time to
          time by the Company for participants generally.

     (F)  The Company will provide you, at the Company's cost, outplacement
          services through Keystone Associates for a period of six months or, if
          earlier, until the date you accept new employment.

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MR. GARY NADEAU
MARCH 13, 2002
PAGE 3 OF 7

     3.   WITHHOLDING. All payments made by the Company under this Agreement
shall be reduced by any tax or other amounts required to be withheld by the
Company under applicable law and all other deductions authorized by you.

     4.   ACKNOWLEDGEMENT OF FULL PAYMENT. You acknowledge and agree that the
payments provided under paragraph 1 of this Agreement are in complete
satisfaction of any and all compensation due to you from the Company, whether
for services provided to the Company or otherwise, through the Separation Date
and that, except as expressly provided under this Agreement, no further
compensation is owed to you. Without limiting the generality of the foregoing,
you expressly waive and relinquish any and all rights you have, or might have,
to any bonus or other incentive compensation, severance pay benefits, or other
compensation, of any kind or description, under any plan or program of the
Company.

     5.   STATUS OF EMPLOYEE BENEFITS, PAID TIME OFF AND STOCK OPTIONS. Except
as otherwise expressly provided in paragraphs 2(b) and 2(c) of this Agreement,
your participation in all employee benefit plans of the Company has ended as of
the Separation Date, in accordance with the terms of those plans. You will not
continue to earn vacation or other paid time off after the Separation Date. Your
rights with respect to all stock options to which you were entitled under the
Mykrolis Corporation 2001 Equity Incentive Plan that do not vest in accordance
with paragraph 2(e) hereof have been cancelled as of the Separation Date.

     6.   RESIGNATION You hereby resign, effective as of the Separation Date,
all positions and offices held by you with the Company or any of its Affiliates.

     7.   CONFIDENTIALITY AND NON-DISPARAGEMENT. You agree that you will
continue to protect Confidential Information, as defined below, and that you
will not, directly or indirectly, use or disclose it. You also agree that you
will not disclose this Agreement or any of its terms or provisions, directly or
by implication, except to members of your immediate family and to your legal and
tax advisors, and then only on condition that they agree not to further disclose
this Agreement or any of its terms or provisions to others. Further, you agree
that, during the Severance Pay Period and thereafter, you will not disparage or
criticize the Company or its Affiliates, their business, management or products,
and that you will not otherwise do or say anything that could disrupt the good
morale of Company employees or harm the interests or reputation of the Company
or any of its Affiliates.

     8.   RETURN OF COMPANY DOCUMENTS AND OTHER PROPERTY. In signing this
Agreement, you represent and warrant that you have returned to the Company any
and all documents, materials and information (whether in hardcopy, on electronic
media or otherwise) related to business of the Company or any of its Affiliates
and all keys, access cards, credit cards, computer hardware and software,
telephones and telephone-related equipment and all other property of the Company
and its Affiliates in your possession or control. Further, you represent and
warrant that

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MR. GARY NADEAU
MARCH 13, 2002
PAGE 4 OF 7

you have not retained any copy of any documents, materials or information of the
Company or any of its Affiliates (whether in hardcopy, on electronic media or
otherwise). Recognizing that your employment with the Company has ended, you
agree that you will not, for any purpose, attempt to access or use any Company
computer or computer network or system. Further, you acknowledge that you have
disclosed to the Company all passwords necessary or desirable to enable the
Company to access all information which you have password-protected on any of
its computer equipment or on its computer network or system.

     9.   RESTRICTED ACTIVITIES. You acknowledge that during your employment
with the Company you have had access to Confidential Information which, if
disclosed, would assist in competition against the Company and agree that the
following restrictions on your activities are necessary to protect the goodwill,
Confidential Information and other legitimate interests of the Company:

     (A)  You agree that, during the period from the Separation Date through
          September 30, 2003, you will not, directly or indirectly, whether as
          owner, partner, investor, consultant, agent, employee, co-venturer or
          otherwise, compete with the Company within the United States or in any
          other country in which the Company was doing business, or planning to
          do business, as of the Separation Date. Specifically, but without
          limiting the foregoing, you agree not to work or provide services, in
          any capacity, whether as an employee, independent contractor or
          otherwise, whether with or without compensation, to any Person, as
          defined below, that is engaged in any business that is competitive
          with the business of the Company, as conducted or in planning during
          your employment with the Company, unless the Company agrees, in
          advance and in writing, signed by an expressly authorized
          representative of the Company, to your working or providing services
          for a specified Person. The Company will so agree provided that it
          determines, in its sole discretion, that your acceptance of a position
          with such person or your provision of such work or services will not
          result in the use or disclosure of Confidential Information. You agree
          to seek the Company's consent at least ten (10) business days prior to
          accepting any such position or commencing any business activity which
          could be inconsistent with your obligations under this Agreement and
          to provide the Company with all information that it may reasonably
          request in order to make a determination as contemplated under the
          immediately preceding sentence. Further, in signing this Agreement,
          you represent and warrant to the Company that you have complied fully
          with all of your obligations under this paragraph 9 and under
          paragraph 7 of this Agreement during the period from the Separation
          Date through the effective date of this Agreement.

     (B)  In signing this Agreement, you give the Company assurance that you
          have carefully read and considered all the terms and conditions of
          this Agreement, including the restraints imposed on you under this
          paragraph 9. You agree without reservation that

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MR. GARY NADEAU
MARCH 13, 2002
PAGE 5 OF 7

          these restraints are necessary for the reasonable and proper
          protection of the Company and that each and every one of the
          restraints is reasonable in respect to subject matter, length of time
          and geographic area. You further agree that, were you to breach any of
          the covenants contained in paragraph 7 above or of this paragraph 9,
          the damage to the Company would be irreparable. You therefore agree
          that the Company, in addition to any other remedies available to it,
          shall be entitled to preliminary and permanent injunctive relief
          against any breach or threatened breach by you of any of those
          covenants, without having to post bond. You and the Company further
          agree that, in the event that any provision of paragraph 7 above or of
          this paragraph 9 is determined by any court of competent jurisdiction
          to be unenforceable by reason of its being extended over too great a
          time, too large a geographic area or too great a range of activities,
          that provision shall be deemed to be modified to permit its
          enforcement to the maximum extent permitted by law.

     10.  EMPLOYEE COOPERATION. You agree to cooperate with the Company
          hereafter with respect to all matters arising during or related to
          your employment, including but not limited to all matters in
          connection with any governmental investigation, litigation or
          regulatory or other proceeding which may have arisen or which may
          arise following the signing of this Agreement. The Company will
          reimburse your out-of-pocket expenses incurred in complying with
          Company requests hereunder, provided such expenses are authorized by
          the Company in advance.

     11.  RELEASE OF CLAIMS.

     (A)  In exchange for the special severance pay and other benefits provided
          you under this Agreement, to which you would not otherwise be
          entitled, on your own behalf and that of your heirs, executors,
          administrators, beneficiaries, personal representatives and assigns,
          you agree that this Agreement shall be in complete and final
          settlement of any and all causes of action, rights or claims that you
          have had in the past, now have, or might now have, whether known or
          unknown, of any kind or description, including without limitation any
          causes of action, rights or claims in any way related to, connected
          with or arising out of your employment or its termination or pursuant
          to Title VII of the Civil Rights Act, the Americans with Disabilities
          Act, the Age Discrimination in Employment Act, the fair employment
          practices statutes of the state or states in which you have provided
          services to the Company or any of its Affiliates or any other federal,
          state or local law, regulation or other requirement and you hereby
          release and forever discharge the Company and its Affiliates and all
          of their respective past and present directors, shareholders,
          officers, employees, general and limited partners, members, managers,
          agents and representatives, their successors and assigns, and all
          others connected with them, and all employee benefit plans maintained
          by the Company and all trustees and plan administrators of such plans,
          both individually and in their official capacities, from any and all
          such causes of action, rights or claims.

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MR. GARY NADEAU
MARCH 13, 2002
PAGE 6 OF 7

     (B)  This Agreement, including the release of claims set forth in the
          paragraph directly above, creates legally binding obligations and the
          Company advises you to consult an attorney before signing this
          Agreement. In signing this Agreement, you give the Company assurance
          that you have signed it voluntarily and with a full understanding of
          its terms; that you have had sufficient opportunity, before signing
          this Agreement, to consider its terms and to consult with an attorney,
          if you wished to do so, or to consult with any other of those persons
          to whom reference in made in the second sentence of paragraph 7 above;
          and that, in signing this Agreement, you have not relied on any
          promises or representations, express or implied, that are not set
          forth expressly in this Agreement.

     12.  DEFINITIONS.  As used in this Agreement:

          "Affiliates" means any and all persons and entities controlling,
controlled by or under common control with the Company, where control may be by
management authority or equity interest.

          "Confidential Information" means any and all information of the
Company and its Affiliates that is not generally known to the public including,
without limitation, all strategic business plans, marketing and sales data and
information, all financial, technical personnel, manufacturing, operations,
product and systems information. Confidential Information also includes all
information received by the Company or any of its Affiliates from customers or
other third parties with any understanding, express or implied, that the
information would not be disclosed.

          "Person" means an individual, a corporation, a limited liability
company, an association, a partnership, an estate, a trust or any other entity
or organization, other than the Company or any of its Affiliates.

     13.  COMPLIANCE WITH SECTION 16(A) OF THE SECURITIES EXCHANGE ACT. You
acknowledge that it is your responsibility to make all required filings with the
Securities and Exchange Commission and with the New York Stock Exchange with
respect to all holdings of and transactions in Mykrolis common stock not
previously reported. You agree to make all such required filings in accordance
with the rules of the Securities and Exchange Commission.

     14.  MISCELLANEOUS.

     (A)  This Agreement constitutes the entire agreement between you and the
          Company and supersedes all prior and contemporaneous communications,
          agreements and understandings, whether written or oral, with respect
          to your employment, its termination and all related matters, excluding
          only any loans to you which are outstanding on the effective date
          hereof and your obligations with respect to the securities of the
          Company, all of which shall remain in full force and effect in

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MR. GARY NADEAU
MARCH 13, 2002
PAGE 7 OF 7

accordance with their terms.

     (B)  This Agreement may not be modified or amended, and no breach shall be
          deemed to be waived, unless agreed to in writing by you and the Chief
          Executive Officer of the Company or his expressly authorized designee.
          The captions and headings in this Agreement are for convenience only
          and in no way define or describe the scope or content of any provision
          of this Agreement. This is a Massachusetts contract and shall be
          governed and construed in accordance with the laws of the Commonwealth
          of Massachusetts, without regard to the conflict-of-law principles
          thereof.

     (C)  The obligation of the Company under paragraph 2 of this Agreement are
          expressly conditioned upon your continued full performance of your
          obligations under this Agreement.

     If the terms of this Agreement are acceptable to you, please sign, date and
return it to me within twenty-one (21) days of the date you receive it. You may
revoke this Agreement at any time during the seven (7) day period immediately
following the date of your signing. If you do not revoke it, then, at the
expiration of that seven (7) day period, this letter will take effect as a
legally-binding agreement between you and the Company on the basis set forth
above. The enclosed copy of this letter, which you should also sign and date, is
for your records.

                                    Sincerely,

                                    MYKROLIS CORPORATION

                                    By:     [GRAPHIC REMOVED HERE]
                                            Robert Crook
                                            Vice President, Human Resources

Accepted and agreed:

Signature:  ____________________________

Date:  ________________________________<PAGE>

                                                                  Exhibit 10.1.3

                                 LEASE AGREEMENT

                                     BETWEEN

                           NORTEL NETWORKS HPOCS INC.

                                   AS LANDLORD

                                       AND

                              MYKROLIS CORPORATION

                                    AS TENANT

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                                 LEASE AGREEMENT

         Executed effective as of April 1, 2002, between NORTEL NETWORKS HPOCS
INC., a Delaware corporation ("Landlord"), and, MYKROLIS CORPORATION, a Delaware
corporation ("Tenant").

                              W I T N E S S E T H:
                              - - - - - - - - - -

     1. Definitions. As used in this Lease, the following terms shall have the
meanings set forth below:

     (a) "RiverTech Park" shall mean the RiverTech Park, 129 Concord Rd.,
Billerica, MA which is comprised of the two manufacturing buildings
(respectively "Building 1" and "Building 2") containing approximately 287,242
square feet of rentable space and Building 3, situated on approximately
30.5 acres.

     (b) "Premises" shall mean Building 2 of RiverTech Park, containing
approximately 175,088 square feet of rentable space, situated on 13.89 acres of
land, together with (i) all appurtenances and rights of access over streets,
ways, drives and parking facilities including the parking lots on either side of
Building 2; (ii) the right to use and maintain all pipes, ducts, conduits,
utility lines, wires and appurtenant equipment and other utilities and systems
serving Building 2 which are located within RiverTech Park (including within
areas potentially leased to the tenant of Building 3 but made subject to this
right) and serving Building 2 including without limitation the Facilities; and
(iii) the right to install pipes, ducts, conduits, utility lines, wires and the
like serving Building 2 which are located in the Snow Area (including within
areas potentially leased to the tenant of Building 3) which do not materially
affect the tenant of Building 3's use of its leased premises. Tenant shall have
the right to access the Facilities at all times. Any action taken by Tenant
pursuant to rights granted in clause (ii) or (iii) of the above definition of
Premises shall be taken in a manner so as to not interfere unreasonably with the
tenant of Building 3's use and occupation of its leased premises.
Notwithstanding the foregoing, Landlord, other occupants of and visitors to
RiverTech Park and all others with a legal right to do so (including emergency
vehicles) shall have a reasonable right of access over the shared access road
constituting the Common Areas for the purposes of access to other areas of
RiverTech Park. A site plan depicting the Premises and RiverTech Park is
attached hereto as Exhibit A.

     (c) "Rent" shall mean an annual sum of $2,451,232.00 for Lease Years 1 - 6
based on a rate of $14.00 prsf, NNN and $2,801,408.00 for Lease Years 7 - 12
based on a rate of $16.00 prsf, NNN, payable in monthly installments of
$204,269.33 for Lease Years 1 - 6 and $233,450.67 for Lease Years 7 - 12.
Landlord and Tenant agree that, for the purposes of this Lease, the rentable
areas set forth in Section 1(a) and 1(b) shall be deemed conclusive. The Rent
for any partial month at the beginning of the Lease Term shall be pro rated and
paid at the rental rate applicable during the first full month of the Lease
Term. Any such pro-rated Rent shall be due upon receipt of an invoice from
Landlord.

     (d) "Commencement Date" shall mean the later of (x) April 1, 2002 and (y)
date on which both (a) (i) all work listed on Exhibit B attached hereto and
depicted or described in the plans and specifications, listed thereon has been
substantially completed within the

                                       2

<PAGE>

meaning of that term under the current General Conditions promulgated by the
American Institute of Architects and (ii) a licensed architect of the Landlord
has certified the same in writing to the Tenant (Landlord and Tenant
acknowledging such certification was delivered to Tenant) and (b) a certificate
of occupancy has been issued for Building 2 (which certificate may exclude the
Cave Area) by applicable governmental authorities (Landlord and Tenant
acknowledging permanent certificates of occupancy for Building 2 were issued).
Such certificate may be temporary or conditional provided that it permits legal
occupancy of all of Building 2 except the Cave Area. Notwithstanding the
foregoing, if such certificate is temporary or conditional and Landlord fails to
cause such certificate to be made permanent or to have the appropriate authority
acknowledge that the conditions therein have been satisfied (excluding any
conditions related to completion of work in the Cave Area) such that occupancy
of any material portion of Building 2 other than the Cave Area is not legally
permitted and Tenant is forced to vacate the same (any such event being referred
to herein as a "CO Failure"), then, unless such CO Failure was due to any
actions or omissions of Tenant or those claiming by, through or under Tenant,
the condition set forth in clause (b) of this paragraph (d) shall not be deemed
to have been satisfied by the temporary or conditional certificate of occupancy
under which legal occupancy so ceased to be permitted, and any Rent paid by
Tenant on the basis of the presumed occurrence of the Commencement Date based on
such certificate of occupancy shall be credited against the obligations of
Tenant next arising under this Lease. Furthermore, Landlord agrees to reimburse
Tenant for any actual out-of-pocket costs incurred by it to the extent not
covered by Tenant's business interruption insurance (including by way of example
and not limitation, reasonable rent for substitute space leased by Tenant and
moving and relocation costs) incurred by Tenant as a result thereof. It is
understood that the elevator in Building 2 may not as of the Commencement Date
have received a certificate of inspection or license from the applicable state
agency with jurisdiction over the operation of such elevator which certificate
or license is necessary for its operation. However, Landlord shall remain
responsible to obtain such certificate or license to allow operation of such
elevator.

     (e) "Lease Term" shall mean a term commencing on the Commencement Date and
continuing for Twelve (12) years, unless otherwise terminated pursuant to the
terms herein.

     (f) "Lease Year" shall mean a period of twelve (12) consecutive calendar
months. The first Lease Year shall begin on the 1st day of the month following
the Commencement Date unless the Commencement Date occurs on the 1st day of a
month, in which event the first Lease Year shall begin on the Commencement Date.

     (g) "Basic Operating Costs" shall have the meaning given to such term in
Section 8.

     (h) "Common Areas" shall mean the Shared Access Road and the appurtenances
and rights of access over streets, ways, drives and the like serving RiverTech
Park and the other facilities provided in the future (if any) for the common use
or benefit of all tenants of RiverTech Park generally and/or the public (but
shall not include any such areas for the exclusive use of a particular tenant or
any areas within the Premises). The Common Areas, as of the date hereof are
depicted on Exhibit A as the "Shared Access Road". The Common Areas may from
time to time be reduced, expanded, modified or relocated provided that at all
times

                                       3

<PAGE>

Tenant shall have the use and enjoyment of Common Areas facilities not
materially less functional than those facilities which presently exist and
provided that Tenant is notified in advance of any material changes to be made
to the Common Areas.

     (i) "Security Deposit" shall have the meaning set forth in Section 6(a).

     (j) "Broker" shall mean Fischer & Company and Meredith & Grew as
representatives of Landlord and CB Richard Ellis as representative of Tenant.

     (k) "Tenant's Share" shall be 61%.

     (l) "Rent Commencement Date" shall mean the date sixty (60) days after the
Commencement Date.

     (m) "Snow Area" shall mean the area of River Tech Park used for piling snow
removed from River Tech Park including snow removed from time to time from the
Common Areas and the Premises.

     (n) "Cave Area" shall mean the portion of Building 2 shown as "Unfinished
Areas" depicted on the plan attached hereto as a portion of Exhibit A.

     (o) "Facilities" shall mean the Pads, the Shed and the Electric Lines.

     (p) "Pads" shall mean those certain four separate concrete pads located in
RiverTech Park to the North of Building 2 between Building 2 and Concord Road
and to the three electrical transformers and generator and associated equipment
located thereon or surrounding such transformers and generator including all
appurtenances thereto.

     (q) "Shed" shall mean that Shed located in RiverTech Park just to the North
of Building 2 between Building 2 and Concord Road including all appurtenances
thereto.

     (r) "Electric Lines" shall mean both those certain electric lines which
(i) run from Building 2 to the Pads and (ii) run from the Pads to poles,
transformers or other interconnections owned and maintained by the utility
company supplying electrical power to Building 2 including all appurtenances
thereto.

     2. Lease Grant. Upon the terms of this Lease, Landlord leases to Tenant,
and Tenant leases from Landlord, the Premises, including the right to use the
Common Areas in common with others having a right to so use the same. Tenant
shall also have the right in common with others to place snow removed from the
Premises in the Snow Area.

     3. Lease Term. This Lease shall continue in force during a period beginning
on the effective date of this Lease (though no Rent shall accrue until the
Commencement Date) and continuing until the expiration of the Lease Term, unless
this Lease is sooner terminated or extended to a later date under any other term
or provision hereof

     4. Use. The Premises shall be used for office, manufacturing, research and
development and warehouse purposes and other lawful uses incidental thereto.

                                       4

<PAGE>

     5. Payment of Rent. The term "Rent" shall mean, collectively, the Rent, and
all other sums of money becoming due and payable to Landlord under this Lease.
Except as otherwise expressly provided in this Lease, from and after the Rent
Commencement Date, the Rent shall be due and payable to Landlord in advance in
monthly installments on the first day of each calendar month during the Lease
Term, in legal tender of the United States of America, or to such other person
or at such other address as Landlord may from time to time designate in writing.
The Rent shall be paid without notice, demand, abatement, deduction or offset,
except as otherwise expressly provided in this Lease or under Massachusetts law.
In the event that Tenant fails to pay any payment of Rent within 5 days after
its due date (provided; however that (i) no more than one such 5 day grace
period will be available on late payments of Rent (as defined in Section 1(c)
hereof) hereunder in any 12 month period and after such grace period has
occurred then interest shall in the event of any other late payments of Rent (as
defined in Section 1(c) hereof) in such 12 month period commence to accrue on
and from the Rent due date and (ii) no more than three such 5 day grace periods
will be available on late payments of other Rent in any 12 month period and
after three such grace periods have occurred then interest shall in the event of
any other late payments of other Rent in such 12 month period commence to accrue
on and from the Rent due date), then, immediately upon demand, Tenant shall pay
Landlord, as additional Rent hereunder, interest on such amount from its due
date until the date so paid at a rate of interest equal to the lesser of (a) the
then current "Prime Rate" of Fleet Bank, N.A. (or its successor) plus four
percent (4%) per annum or (b) the highest rate of interest allowed by law. If
the Rent Commencement Date occurs on a date other than the first day of a
calendar month, then the installment of Rent for such partial month shall be
prorated as provided in Section 1(c).

     6. Security Deposit.

     (a) Tenant shall deliver to Landlord concurrent with Tenant's execution of
this Lease, an unconditional, clean, irrevocable standby letter of credit
(together with any replacement letter of credit, the "L-C") in the initial
amount of $1,000,000 (which amount Tenant may reduce by $125,000 effective on
each of the first six anniversaries of the Commencement Date, provided the
amount thereof may never be reduced to less than $250,000 and provided that no
such reduction shall be permitted while an Event of Default exists hereunder)
(the "Security Deposit"), which L-C shall be issued by Fleet National Bank or
another bank satisfactory to Landlord in its sole discretion, and which L-C may
be presented for payment in Boston, Massachusetts or such other U.S. location
proposed by Tenant and acceptable to Landlord. The L-C shall be in form and
content as attached hereto as Exhibit C for a term of not less than one year.
Tenant shall pay all expenses, points and/or fees incurred by Tenant or payable
by Tenant or Landlord to the L-C bank in obtaining and transferring any L-C
hereunder.

     (b) The L-C shall be held by Landlord as security for the faithful
performance by Tenant of all the terms, covenants, and conditions of this Lease
to be kept and performed by Tenant during the Term. If an Event of Default by
Tenant occurs with respect to any provisions of this Lease, including, but not
limited to, the provisions relating to the payment of Rent, or if Tenant fails
to renew or replace the L-C (such that the amount of the L-C is always in
accordance with paragraph (a) above) at least thirty (30) days before its
expiration, Landlord may, but shall not be required to, draw upon all or any
portion of the L-C for payment of any Rent or any other sum in default, or for
the payment of any amount that Landlord may spend or may become obligated to
spend by reason of such Event of Default, or to compensate Landlord for any
other

                                       5

<PAGE>

loss, cost or damage that Landlord may suffer and be entitled to collect under
this Lease by reason of Tenant's Event of Default. The use, application or
retention of the L-C, or any portion thereof by Landlord shall not prevent
Landlord from exercising any other right or remedy provided by this Lease or by
law, it being intended that Landlord shall not first be required to proceed
against the L-C and shall not operate as a limitation on any recovery to which
Landlord may otherwise be entitled. Any amount of the L-C that is drawn upon by
Landlord, but is not used or applied by Landlord, shall be held by Landlord and
deemed a security deposit (the "L-C Security Deposit"). If any portion of the
L-C is drawn upon, Tenant shall, within five (5) business days after written
demand therefor, either (i) deposit cash with Landlord (which cash shall be
applied by Landlord to the L-C Security Deposit) in an amount sufficient to
cause the sum of the L-C Security Deposit and the amount of the remaining L-C to
be equivalent to the amount of the Security Deposit required under this Lease or
(ii) reinstate the L-C to the amount which together with the L-C Security
Deposit is equal to the amount of the Security Deposit then required under this
Lease, and thereafter if any portion of the L-C Security Deposit is used or
applied as allowed herein, Tenant shall, within five (5) business days after
written demand therefor, deposit cash with Landlord (which cash shall be applied
by Landlord to the L-C Security Deposit) in an amount sufficient to restore the
L-C Security Deposit together with any L-C then held to the Security Deposit
amount required under this Lease, and Tenant's failure to do so shall be a
default under this Lease. If Tenant shall fully and faithfully perform every
provision of this Lease to be performed by it, the L-C Security Deposit and/or
the L-C, or any balance thereof, shall be returned to Tenant within thirty (30)
days following the later of the expiration of the Lease Term or the vacating of
the Premises by Tenant.

     7. Condition of Premises.

     (a) Landlord shall deliver the Premises to Tenant on the Commencement Date,
but except as provided herein makes no representation or warranty regarding the
condition of the Premises. On the Commencement Date, the Premises will be
delivered to Tenant with the work listed on Exhibit B sufficiently complete so
as to satisfy the standard for the Commencement Date set forth in the definition
thereof above.

     (b) Immediately following the Lease Commencement Date (except as set forth
in the third sentence of this Section 7(b)), Landlord shall continue any
remaining work listed on Exhibit B, in a reasonable and diligent manner until
completed. The Landlord shall not be responsible for landscaping, finishes,
sidewalks or berms. In addition to the foregoing, as soon as seasonal weather
conditions allow in the Spring of 2002 Landlord shall seal and stripe the
parking lots and roadways around the Premises in accordance with the provisions
with respect thereto in Exhibit B and complete all such work as soon as
reasonably practicable and in any event no later than July 1, 2002. Landlord
shall undertake all such remaining work after the Commencement Date in a manner
so as to not unreasonably interfere with, and to schedule around, Tenant's
construction activities and Tenant's use of the Premises for business purposes.
With the exception of such sealing and striping and the work listed on Exhibit B
Landlord has stopped making further improvements to the Premises and the
Premises are leased on an "as-is"/"where-is" basis.

     (c) Except for Landlord's covenants and representations expressly set forth
herein, Tenant hereby accepts the Premises in its condition as of the
Commencement Date or the

                                       6

<PAGE>

date that Tenant takes possession of the Premises, whichever is earlier, subject
to all applicable zoning, municipal, county and state laws, ordinances and
regulation governing and regulating the use of the Premise, and any easements,
covenants or restrictions of records and accepts this Lease subject thereto and
to all matters disclosed thereby and by any exhibits attached hereto. Except for
Landlord's covenants and representations herein, Tenant acknowledges that it has
satisfied itself by its own independent investigation that once Landlord has
completed the work described in clauses (a) and (b) above the Premises are
suitable for its intended use, and that neither Landlord nor Landlord's agents
has made any representation or warranty as to the present or future suitability
of the Premises for the conduct of Tenant's business.

     (d) Landlord hereby agrees that prior to the Commencement Date the Tenant
may begin construction, renovation and move in activities at the Premises
(without being liable for occupying the Premises or causing the Rent or any
additional Rent to commence) provided that such activities are undertaken in a
manner so as to not interfere with, and to schedule around, Landlord's
construction activities at the Premises. To the extent that any such activities
by Tenant prior to the Commencement Date interfere with or delay the work
Landlord is required to do under this Lease (i) the Commencement Date shall be
the date it would have been (as reasonably determined by Landlord) but for such
delay and (ii) Tenant shall promptly, as additional Rent, reimburse Landlord for
any direct actual and reasonable loss, cost or damage suffered by Landlord in
connection therewith.

     8. A. Basic Operating Costs.

     (a) In addition to the Rent referred to in Section 1(c), from and after the
Rent Commencement Date Tenant shall also pay Tenant's Share of the Basic
Operating Costs. Landlord may, at its option, provide Tenant with a current good
faith estimate of Basic Operating Costs, and thereafter Tenant shall pay, as
additional rental, in monthly installments in accordance with Section 5,
Landlord's reasonable estimate of the Basic Operating Costs for the calendar
year in question. The failure of Landlord to estimate Basic Operating Costs and
bill Tenant on a monthly basis shall in no event relieve Tenant of its
obligation to pay Tenant's Share of the Basic Operating Costs.

     (b) By June 1 of each calendar year during the Lease Term (including the
calendar year following the year in which the Lease Term is terminated),
Landlord shall furnish to Tenant a statement of actual Basic Operating Costs for
the prior calendar year, and within thirty (30) days thereafter an appropriate
adjustment shall be made between Landlord and Tenant to reflect any overpayment
or underpayment of Basic Operating Costs for the prior calendar year because of
any difference between the amount, if any, collected by Landlord from Tenant for
Tenant's Share of Basic Operating Costs and the actual amount of Tenant's Share
of Basic Operating Costs. In the event of an underpayment by Tenant, Tenant
shall pay the amount of such underpayment to Landlord within thirty (30) days
following delivery of such statement. In the event of an overpayment by Tenant,
Landlord shall give Tenant a credit for such sum against the next installment of
Rent or, if after the Lease Term, Landlord shall pay such amount to Tenant.

     (c) "Basic Operating Costs" shall mean all direct and, to the extent
provided in subsection (c)(1) below, indirect costs and expenses incurred in
each calendar year of

                                       7

<PAGE>

maintaining, repairing, and operating the Common Areas, including without
limitation, the following:

     (1) Wages and salaries of all on-site or off-site employees (with
appropriate adjustments to be made if an employee devotes material time to
properties other than RiverTech Park) at the grade of building manager and below
engaged in the direct operation and maintenance of the Building, parking areas
or Common Areas, employer's social security taxes, unemployment taxes or
insurance and any other taxes which may be levied on such wages and salaries,
and the cost of disability and hospitalization insurance and pension or
retirement benefits for such employees; provided, however, if such services are
provided by Landlord or an affiliate of Landlord all such costs shall be capped
at an amount not to exceed the lesser of (x) such actual costs incurred and (y)
the reasonable and customary amount charged for providing such services (whether
as wages and salaries or a management fee) based on similar services provided
for similar common areas at similarly situated properties in the Billerica area;

     (2) Cost of leasing or purchasing all supplies, tools, equipment and
materials used in the operation, maintenance, repair and management of the
Common Areas;

     (3) Cost of all utilities for the Common Areas, including the cost of water
and power, sewage, heating, lighting for the Common Areas;

     (4) Cost of all maintenance and service agreements for the Common Areas,
including, but not limited to, equipment leasing and landscape maintenance, and;

     (5) Cost of all customary liability insurance relating to the Common Areas
excluding rental interruption insurance, plus the cost of all deductible
payments made by Landlord in connection therewith (but only to the extent not
already deducted as a Basic Operating Cost);

     (6) All taxes and assessments and governmental charges, whether federal,
state, county or municipal and whether they be by taxing districts or
authorities presently taxing the Common Areas or by others, subsequently created
or otherwise and any other taxes, association dues and assessments attributable
to the Common Areas or its operation (excluding therefrom taxes, assessments and
charges, payable under Section 8.B hereof), excluding, however, federal and
state income taxes, franchise taxes, inheritance, estate, gift, corporation, net
profits or any similar tax for which Landlord becomes liable and/or which may be
imposed upon or assessed against Landlord;

     (7) Cost of repairs and general maintenance for the Common Areas (excluding
such repairs and general maintenance paid by insurance proceeds or by Tenant or
other third parties);

     (8) Expenses incurred in order to comply with any federal, state or
municipal laws, codes or ordinances, or regulations promulgated under any of the
same, which first become applicable to the Common Areas after the date of this
Lease;

     Tenant, at Tenant's expense, shall have the right, no more frequently than
once per calendar year, following thirty (30) days' prior written notice to
Landlord, to audit Landlord's

                                       8

<PAGE>

books and records relating to Basic Operating Costs; provided that such audit
must be commenced and concluded by December 31 of the year following the year to
which such audit relates unless at least 90 days prior to such December 31 date
Tenant has not received the statement of actual Basic Operating Costs as
proposed in Section 8(b), in which event the Tenant shall have at least 90 days
after receiving such statement to notify Landlord of such audit. Unless Landlord
disputes the results of such audit, an appropriate adjustment shall be made
between Landlord and Tenant to reflect any overpayment or underpayment of Basic
Operating Costs within thirty (30) days after delivery of such audit to
Landlord. In the event of an overpayment by Tenant, Landlord shall give Tenant a
credit towards the next installment of Rent in the amount of such overpayment.
In the event Landlord disputes the results of any such audit, the parties shall
in good faith attempt to resolve any discrepancies and final settlement shall be
made within ten (10) days thereafter. If the parties are unable to resolve any
discrepancy, any sum on which there is no longer dispute shall be paid and any
remaining discrepancies shall be referred to a mutually satisfactory third party
certified public accountant for final resolution. The cost of such certified
public accountant shall be paid by Tenant; provided, however if such audit shows
that Tenant had been overbilled by more than 15% of Tenant's Share of Basic
Operating Costs, then Landlord shall pay all of Tenant's third party out of
pocket costs in connection with such certified public accountant and Tenant's
audit.

     Nothing in this Section 8 shall be construed at any time to reduce the Rent
set forth in Section 1(c) below the amount set forth in Section 1(c) above.

     (d) To the extent that any expenditure that would constitute Basic
Operating Costs hereunder would be treated as a capital expense under generally
accepted accounting principles, such expenditure shall be amortized on a
straight line basis over the applicable useful life thereof (as reasonably
determined by Landlord), and the amortized portion shall be included in Basic
Operating Costs for each applicable period of time.

     8. B. Additional Rent/Taxes.

     (a) In addition to the Rent set forth in Section 1(c) of this Lease and as
part of the Rent due pursuant to the provisions of this Lease, from and after
the Rent Commencement Date Tenant shall pay Landlord as additional Rent Tenant's
Proportionate Share of Taxes as set forth in this Section 8B. For the purposes
of this Section 8B, the following words and terms shall have the following
meaning:

     (1) "Taxes" shall mean the real estate taxes and assessments imposed upon
Landlord with respect to the parcel consisting of RiverTech Park, as such parcel
is defined in the records of the Assessor's Office of Billerica on January 1,
2001, even if the designation of such parcel is changed from time to time,
including all structures located thereon, and any and all other taxes, levies,
betterments, assessments and charges arising from the ownership and/or operation
of said parcel and all the structures located thereon which are or shall be
imposed by national, state, municipal or other authorities which are or may
become a lien upon Landlord and/or said parcel, but excluding any fee, penalty
or interest levied on Landlord for late payment thereof. If, or to the extent
that, due to a future change in the method of taxation any franchise, income,
profit or other tax

                                       9

<PAGE>

shall be levied against Landlord in substitution or in lieu of any tax which
would otherwise constitute a real estate tax, such franchise, income, profit or
other tax shall be deemed to constitute "Taxes" for the purposes hereof. It is
recognized and agreed by Landlord and Tenant that it is their intention by this
paragraph to include in "Taxes" that which in fiscal tax year 2002 was commonly
known in Town of Billerica as "real estate taxes", including any portion covered
by the school tax rate, and any type of tax or assessment which may, throughout
the term hereof be substituted, in whole or in part therefor. If, in any fiscal
tax year after the fiscal tax year 2002, the Town of Billerica or any of its
departments, shall require Landlord to pay for any service which during the
fiscal tax year 2002 was provided by said Town of Billerica or any of its
departments without requiring payment by Landlord, then all such payments due on
account of services rendered during any fiscal tax year after the fiscal tax
year 2002 shall, for purposes of this Section 8B be considered and treated as
real estate taxes for the fiscal tax year for which such payments are due.
Without in any way limiting the generality of the preceding sentence some of the
services for which the Town of Billerica or any of its departments might require
payment are: police protection, fire protection, public schools, library
services, park services, building inspections. Water and sewer use charges are
covered elsewhere in this Lease and the same shall not enter into the
calculations made under this Section 8B.

     (2) "Tax Year" shall mean the twelve (12) month period commencing July 1,
2001, and each twelve (12) month period commencing on an anniversary of said
date during the term of the lease.

     (3) "Tenant's Proportionate Share of Taxes" in any Tax Year shall, for so
long as all of RiverTech Park is included in a single taxable lot with a single
tax bill with such tax bill including separate assessed values for each of
Buildings 1, 2 and 3 and a separate assessed value for the land, be calculated
as follows: the total of (x) the Taxes attributable to Building 2 based on the
then assessed value of Building 2, plus (y) 45.44% of the Taxes on the land
based on the then assessed value of the land (for the Premises), plus (z)
Tenant's Share of 2.88% of the Taxes on the land based on the then assessed
value of the land (for the Common Areas); and if at any time Taxes were assessed
on some other basis or separate assessments for the Buildings or the land was
not available, then Tenant's Proportionate Share of Taxes would be equitably
determined based on a methodology reasonably acceptable to Landlord and Tenant
which is intended to result in a similar allocation of Taxes to the foregoing
arrangement.

     (4) "Tax Statement" shall mean a statement setting forth in reasonable
detail the amount payable by Tenant as Tenant's Proportionate Share of Taxes.

     Tenant shall make monthly payments of Additional Rent to Landlord to cover
Tenant's Proportionate Share of Taxes that are expected to be incurred during
the current Tax Year and each subsequent Tax Year thereafter falling entirely or
partly within the term of this Lease. The amount of such monthly payments shall
be determined as follows: On or about the Rent Commencement Date, and at the
beginning of each Tax Year thereafter, Landlord shall submit to Tenant a
statement setting forth Landlord's reasonable estimate of the amount of Taxes
that are expected to be incurred during such Tax Year, and the computation of
the anticipated Tenant's Proportionate Share of Taxes for such Tax Year. Tenant
shall pay to Landlord on the first day of each calendar month following receipt
of such statement an appropriate amount to amortize on a monthly basis the
anticipated Tenant's Proportionate Share of Taxes. Except as otherwise provided
in Sections 24 and 25 hereof, Tenant's payment of its Proportionate Share of
Taxes shall be made without deduction, setoff or demand in accordance with the
provisions of

                                       10

<PAGE>

Section 5 of this Lease. If at any time during the term of this Lease, Landlord,
in Landlord's reasonable discretion, determines it appropriate to revise the
estimates of Taxes which have been submitted, then Landlord may submit such
revised reasonable estimates to Tenant, and then commencing with the next
monthly payment to be made by Tenant, appropriate adjustment shall be made to
the amount being paid by Tenant on account of the anticipated Tenant's
Proportionate Share of Taxes. Within one hundred eighty (180) days after the
expiration of each Tax Year during the term of this Lease, Landlord shall submit
to Tenant a statement certified by Landlord stating (i) Tenant's Proportionate
Share of the actual Taxes incurred during the preceding Tax Year, (ii) the
aggregate amount of the estimated payments, if any, made by Tenant on account
thereof, and (iii) any credit to which Tenant is entitled. Tenant shall deduct
any overpayment from its next estimated payment or payments for Taxes. If
Tenant's actual liability for such Taxes exceeds the estimated payments, if any,
made by Tenant on account thereof, then Tenant shall pay to Landlord within ten
(10) days after notice thereof the total amount of such deficiency as additional
Rent. If Landlord owes any amount to Tenant with respect to Taxes after the
Lease Term, Landlord shall pay such amount to Tenant

     Appropriate credit against Taxes shall be given for any overpayment or
refund obtained by reason of a reduction in any Taxes by the Courts or other
governmental agency responsible therefor. The original computation as well as
reimbursement or payments of additional charges, if any, or allowances, if any
under the provisions of this Section 8.B shall be based on the original assessed
valuations with adjustments to be made at a later date when the tax refund, if
any, shall be paid to Landlord by the taxing authority. Expenditures for legal
fees and for other similar or dissimilar expenses incurred in obtaining the tax
refund shall be charged against the tax refund before the adjustments are made
for the Tax Year. In no event shall Tenant be entitled to receive a credit
against Taxes for any fiscal Tax Year in an amount greater than Tenant's
Proportionate Share of Taxes for such fiscal Tax Year.

     (5) If the Commencement Date or the Termination Date of this Lease occurs
in the middle of a Tax Year, Tenant shall be liable for only that portion of the
Taxes in respect of such Tax Year represented by a fraction, the numerator of
which is the number of days of the herein term which falls within said Tax Year,
and the denominator of which is three hundred sixty-five (365).

     (6) In the event the first day of the Tax Year in the Town of Billerica
should be changed after the Commencement Date to a day other than July 1 so as
to change the twelve (12) month period comprising the Tax Year, in determining
Tenant's Proportionate Share of Taxes with respect to Taxes payable for the
period between July 1 and such changed first day of the Tax Year, Tenant's
Proportionate Share of Taxes shall be multiplied by a fraction, the numerator of
which shall be the number of days elapsing during such period, and the
denominator of which shall be three hundred sixty-five (365).

     (7) Any obligation under this Section 8.B of Tenant or Landlord which shall
not have been paid at the expiration of the term of this Lease shall survive
such expiration and shall be paid when and as the amount of same shall be
determined to be due.

     (8) Tenant shall have the right from time to time to directly contest the
amount of Taxes due and to pursue a tax abatement, reduction or refund with
respect to Taxes;

                                       11

<PAGE>

provided, however, Tenant shall timely pay the amount of Taxes due unless the
law allows such Taxes to not be so paid without interest or penalty accruing and
without a lien arising or being placed against RiverTech Park. Landlord agrees
to reasonably cooperate with Tenant in any such action. If Landlord so elects it
may participate with Tenant in any such action but in such case Landlord shall
do so at its own cost and expense. If Tenant does not inform Landlord at least
five (5) business days before the last day applications for abatements may be
timely made that it will pursue a tax abatement, reduction or refund of Taxes
with respect to any given Tax Year, then Landlord may pursue the same and Tenant
will reasonably cooperate with Landlord in any such action.

     (9) If an abatement, reduction or refund of taxes occurs (whether as a
result of an action of Tenant or Landlord or otherwise) such refund shall first
be used to reimburse the expenses of obtaining the same and thereafter
appropriately allocated as a credit to the parties paying Taxes for RiverTech
Park with such allocation to be equitably determined in good faith based on the
reasons for the granting of such refund, if reasonably determinable, and
otherwise based on a reasonable allocation mutually acceptable to Landlord and
Tenant.

     9. Signs. Tenant shall have the right at its sole cost and expense to
install signs on the Premises, subject to any applicable laws, ordinances,
regulations, codes and other governmental requirements, and subject to
Landlord's approval which shall not be unreasonably withheld. Tenant's
installation and removal of signs shall be made in a manner as to avoid material
injury, defacement and structural overloading of Building 2. Tenant shall also
have the right at its sole cost and expense to install a sign at the entrance to
RiverTech Park, and a sign at the point on the access road where the drive
branches off to Building 2, in each case subject to any applicable laws,
ordinances, regulations, codes and other governmental requirements, and subject
to Landlord's approval which shall not be unreasonably withheld, it being
acknowledged that Landlord shall be deemed reasonable in considering the effect
of such signage on other occupants or potential occupants of RiverTech Park.
Tenant shall maintain such signs in good condition and repair at its sole cost
and expense. Upon the termination or expiration of the Lease, Tenant shall
remove such signage, and Tenant shall repair any damage caused to the Premises
by such removal, including, but not limited to, the cosmetic restoration of the
area on the face of Building 2 where any such sign was removed to eliminate any
remaining name imprint.

     10. Cost of Improvements. All installations and improvements now or
hereafter placed on the Premises at the request of Tenant shall be at Tenant's
cost and if Landlord performs such installations or improvements at Tenant's
request on Tenant's behalf, such cost shall be payable by Tenant to Landlord
within thirty (30) days following Tenant's receipt of an invoice as additional
Rent. No construction management fee shall be payable with respect to any
installations or improvements.

     11. Performance Obligations of Landlord. Landlord shall perform all of the
obligations of Landlord as set forth in this Lease. Landlord shall be
responsible for (i) the maintenance, repair and operation of the Common Areas
(ii) the maintenance, repair and replacement of the roof and (iii) capital
expenditures and replacements of the foundation, structural supports, exterior
and load-bearing walls of the Premises as set forth in Section 12. Landlord
shall if Tenant so requests provide snow plowing services for the driveway and
parking areas of the Premises during the balance of the winter of 2001 to 2002
and thereafter Tenant shall

                                       12

<PAGE>

make its own arrangements for such services. The cost of such snowplowing
services will be paid by Tenant.

     12. Roof, Repair, Maintenance and Replacement; Capital Expenditures and
Replacement of Structural Items. Landlord shall use reasonable diligence to
undertake necessary snow removal from the Common Areas and Landlord shall, at
its own cost and expense, maintain and make such repairs and replacements to the
roof (including the roof membrane so as to maintain a watertight structure) and
structural roof systems and other roof systems serving the Premises as may be
necessary to keep them in good order and repair, except to the extent such
repairs are necessary as a result of the negligent or wrongful acts of Tenant or
its agents in breach of this Lease or as a result of Alterations made by,
through or under Tenant not made in accordance with plans and specifications
therefor approved by Landlord, it being acknowledged that, to the extent
reasonable, Landlord may condition any such approval on a certification
reasonably satisfactory to Landlord, from an engineer or architect engaged by
Tenant, that such Alterations shall not lead to any additional expense to
Landlord under this Section 12. Landlord shall, at its own cost and expense,
make such capital expenditures and replacements to the foundation, structural
support, exterior walls and exterior load bearing walls serving the Premises as
may be necessary to keep them in good order and repair, except for ordinary
course repairs and maintenance not constituting a capital expense which shall be
performed by Tenant at its cost and expense and except to the extent such
replacements are necessary as a result of negligent or wrongful acts of Tenant
or its agents in breach of this Lease or as a result of Alterations made by,
through or under Tenant not made in accordance with plans and specifications
therefor approved by Landlord. All costs and expenses incurred by Landlord
pursuant to this Section 12 for snow plowing only shall be payable by Tenant in
the same manner as Basic Operating Costs.

     13. Performance Obligations of Tenant. Tenant shall perform all of the
obligations of Tenant as set forth in this Lease and pay when due all Rent,
including Basic Operating Costs and all charges, fees and other sums, which by
the terms of this Lease are to be paid by Tenant.

     14. A. Repairs and Yield Up. Tenant shall keep the Premises in good order,
repair and condition and in compliance with applicable laws, Landlord's
obligations under Section 12 hereof, reasonable wear and tear and takings and
casualty only excepted, and all glass in windows and doors (including glass in
exterior walls of Building 2 unless the damage thereto is attributable to
Landlord's negligence, misuse or faulty workmanship) of the Premises whole and
in good condition with glass of the same quality as that injured or broken, and
at the expiration or termination of this Lease peaceably to yield up the
Premises and all alterations and additions thereto in good order, repair and
condition, Landlord's obligations under Section 12 hereof, reasonable wear and
tear and casualty and takings excepted, first removing all Tenant's personal
property and, at Tenant's election upon such expiration or termination, such
portion(s) or all of such other alterations, additions and partitions installed
by Tenant as Tenant elects to remove, and repairing any damage caused by such
removal and restoring the Premises to its original condition except for
Alterations permitted hereunder which need not be removed, leaving the Premises
broom clean, and to reimburse Landlord within thirty (30) days after the date of
any demand by Landlord for reimbursement of the cost of repairing any damage to
the Premises, Building 2 or RiverTech Park caused by Tenant or its agents,
employees, or invitees in removing such personal property, alterations,
additions and partitions.

                                       13

<PAGE>

     At the expiration of the Lease Term Tenant need not remove or pay for the
removal of the Initial Alterations from the Premises. For all other Alterations,
if at the expiration of the Lease Term (i) such Alterations are actually removed
by Landlord and (ii) the total of (x) the cost of such removal plus (y) the cost
of demolition of Building 2 back to Shell Condition (provided such demolition
actually occurs) plus (z) any Excess Rent Costs, exceeds the Demolition
Allowance, the Tenant upon presentation with a calculation of the amount of the
demolition and removal costs plus invoices supporting all such costs shall pay
an amount equal to the lesser of (x) such excess and (y) the actual cost of
removal of such Alterations to Landlord. As used in this paragraph the phrase
"Excess Rent Costs" means Rent at the rate provided for in the Lease immediately
prior to expiration of the Lease Term for any period of time needed to remove
Tenant's Alterations (excluding Initial Alterations) which materially exceeds
the time otherwise needed to demolish Building 2 back to shell condition without
being required to remove such Alterations. As used in this paragraph the phrase
"Demolition Allowance" means an amount equal to $1,300,000 increased by the
consumer price index for each Lease Year after 2002 that has occurred through
the date such amount is calculated. As used in this paragraph the phrase "Shell
Condition" means on the upper level of Building 2 remove all tenant fit-out
items to bottom of roof joist including all non-bearing walls, partitions, floor
finishes, and infrastructure. Toilet facilities and mechanical and electrical
services that support space lighting, heating and cooling requirements shall
remain. Lighting fixtures integral to ceilings removed shall also be removed.
HVAC distribution and return integral to walls and ceilings to be removed shall
be stripped back to secondary branches. Electrical infrastructure integral to
walls and ceilings to be removed shall be stripped back to main panels.
Trenches, sumps, and other depressions in floor slab shall be filled or covered
to the same floor bearing rating as the general floor slab. The lower level of
Building 2, except for the Lobby and Elevator areas (where there will be no
stripout work), will also be stripped of all tenant fit out items as for the
upper level of Building 2, except those deemed appropriate for administrative
and office support activities. Any damage or perforations of floor, roof or
cladding caused by removal of these tenant improvements shall be repaired.

     Tenant shall not conduct any activity or make any improvements or
installations, in any manner which would void or violate a roof membrane
warranty.

     All articles of personal property and all trade fixtures, office machines
and equipment, furniture and movable partitions owned by Tenant or installed by
Tenant at its expense in the Premises shall be and remain the property of Tenant
and may be removed by Tenant at any time during the Lease Term provided that
Tenant shall repair any damage caused by such removal. If Tenant shall fail to
remove all of its personal property from the Premises upon termination of this
Lease, Landlord may, at its option, remove, store and dispose of said personal
property without liability to Tenant for any loss thereof, and Tenant agrees to
pay Landlord within thirty (30) days after the date of any demand by Landlord
for reimbursement of any and all expenses incurred by Landlord in such removal,
storage and disposal, including reasonable storage rental costs, disposal costs,
court costs and attorneys' fees.

     14. B. Utilities, Maintenance, Repairs And Yield Up. Tenant acknowledges
that Landlord has provided Tenant with the opportunity to examine the utility
services connected to Building 2 and available at the Premises. Tenant shall
make all arrangements for all utilities

                                       14

<PAGE>

furnished and to be furnished to the Premises and shall pay for all utilities,
which may include, gas, water, sewer, electricity, and telephone services.

     14 C. Tenant's Obligations. Except to the extent of Landlord's obligations
set forth in Sections 7, 12 and 27 hereof, Tenant shall be responsible for
cleaning, operating, maintaining and repairing in good order and condition in
its existing condition or such better condition in which it may be put
reasonable wear and tear and casualty and takings excluded, the entire Premises,
including (but not limited to) the following: (i) heating, ventilating and air
conditioning systems and equipment; (ii) mechanical systems and equipment; (iii)
life safety systems and equipment; (iv) hot water heater(s), plumbing system and
equipment; (v) electrical system and equipment; (vi) sprinkler system and
equipment; (vii) elevator system and equipment; (viii) exterior walls and
windows; (ix) building entry security system; (x) provision of all cleaning,
trash removal and exterminating services; such obligations shall include all
aspects of the operation and management of Building 2, except as specifically
set forth in this Lease including Section 12 hereof. Tenant shall provide
Landlord with copies of all service contracts, if any, maintained by Tenant
during the term of this Lease. If Tenant fails to maintain and perform its
obligations under this Section, Landlord may after the occurrence and during the
continuance of an Event of Default, but is not required to, perform such
obligations and bill Tenant the cost thereof, which shall be due and payable as
additional Rent within ten (10) days of rendition of such bills. Tenant shall
further use all reasonable precautions to prevent waste to the Premises.
Notwithstanding the foregoing, in the event any part of the above-mentioned
building systems which was part of the premises at the commencement of the Lease
Term and which has been properly maintained by Tenant as hereinabove called for
no longer can be maintained by Tenant, but based on industry standards must be
replaced, then (provided Landlord's Deemed Approval has occurred) Tenant shall
promptly and properly replace the same; and to the extent, reasonably
determined, the useful life of such replaced part exceeds the remaining Lease
Term (including option periods, whether exercised or not) then upon completion
of such replacement and the payment of the cost thereof to the supplier by
Tenant, Landlord will reimburse to Tenant so much of the actual and reasonable
costs thereof as is proportionately attributable to that portion of the useful
life of such part as extends beyond the then remaining term (including option
periods, whether exercised or not) of this Lease (and if any option period is
not eventually exercised, Landlord shall make an additional payment to reimburse
Tenant on the basis of the term of this Lease without such option period);
provided, however, if Landlord does not so reimburse Tenant as required under
this provision then Tenant may set off such amount against the payment of Rent,
Basic Operating Costs and Taxes next due. As used in this paragraph "Landlord's
Deemed Approval" means (a) if the Landlord's reimbursable share of any single
capital expenditure proposed is greater than $100,000 that Landlord has been
advised of and has approved such capital expenditure, such approval not to be
unreasonably withheld; (b) the Landlord's reimbursable share of any single
capital expenditure is less than $100,000; or (c) such capital expenditure is
required by applicable law. If Landlord's Deemed Approval does not occur as to
any capital expenditure then Tenant shall be relieved from any requirement to
make such capital expenditure.

     15. Alterations, Additions, Improvements.

     (a) Tenant will make no alteration, change, improvement, replacement or
addition to the Premises (collectively, "Alterations"), without the prior
written consent of

                                       15

<PAGE>

Landlord, which consent shall not be unreasonably withheld or delayed. All
Alterations shall be done in a good and workmanlike manner and in compliance
with all applicable laws and ordinances and shall not void any of Landlord's
warranties. Tenant shall require that any contractors used by Tenant carry a
comprehensive liability (including builder's risk) insurance policy in such
amounts as Landlord may reasonably require. Tenant has provided Landlord with
the preliminary information regarding the initial alterations Tenant intends to
undertake a copy of which is attached hereto as Exhibit D (the "Initial
Alterations"). Landlord acknowledges its assent, in principle, thereto, and
agrees that it must and shall grant promptly its consent and that Tenant may
proceed with its initial alterations provided that such alterations as described
in the final plans and specifications submitted to Landlord for review are
consistent with the preliminary information regarding such initial alterations
attached as Exhibit D, and if Landlord has not granted its consent within 10
business days of receipt of such plans and specifications such consent shall be
deemed to be given.

     (b) Notwithstanding the foregoing, Tenant may, at its sole expense, make
any nonstructural Alterations in, on and to the Premises with a per project cost
of $100,000 or less without the consent of Landlord, so long as (i) Tenant
complies with the second and third sentences of Section 15(a), (ii) Tenant
provides ten (10) days' prior written notice of the commencement thereof with a
description of the contemplated work in the form presented to the contractor,
(iii) such Alterations do not materially affect the mechanical, electrical or
plumbing systems in Building 2 and (iv) Tenant provides Landlord with "as built"
drawings of all such Alterations promptly upon completion thereof.

     (c) Notwithstanding the foregoing if Alterations need to be undertaken to
address an emergency situation or so as not to be in violation of Section 14.C.
hereof, then Tenant may undertake such Alterations without Landlord's prior
written consent. Landlord agrees to cooperate with Alterations allowed hereunder
by signing, or authorizing Tenant to sign on its behalf, at Tenant's cost,
expense and risk building and other Alterations related permit applications.

     (d) Tenant may remove its trade fixtures, office supplies and movable
office furniture and equipment and Tenant shall promptly repair all damage
caused by such removal.

     16. Laws and Regulations.

     (a) Except as provided in Section 27, Landlord makes no representation or
warranty to Tenant regarding the condition of the Premises or with respect to
whether or not the Premises, or the use for which Tenant will occupy the
Premises, will violate any covenants or restrictions of record, or any
applicable building code, regulation, law or ordinance in effect on the
Commencement Date or at any other time.

     (b) Except for Landlord's remaining work under Section 7, which shall be
Landlord's responsibility to properly complete in compliance with law at its
sole cost and expense including (subject to the provisions of Section 7) to
obtain a unconditional permanent certificate of occupancy for Landlord's work at
the Premises, Tenant shall, from and after the Commencement Date at Tenant's
expense (except for Landlord's obligations in Section 12 and subject to sharing
of any capital expenditures as provided in Section 14C) promptly comply with all
applicable statutes, ordinances, rules, regulations, orders, covenants and
restrictions of record,

                                       16

<PAGE>

and requirements of any fire insurance underwriters or rating bureaus, now in
effect or which may hereafter come into effect, whether or not they reflect a
change in policy from that now existing, during the term or any part hereof,
relating in any manner to the occupation and use by Tenant of the Premises.
including, without limitation, compliance with any laws with respect to the
discharge of sewage and any permits now or hereafter issued in connection
therewith. Tenant shall use the Premises in a lawful manner and shall not use or
permit the use of the Premises in any manner that will tend to create waste or a
nuisance.

     17. Entry by Landlord. Subject to any reasonable security procedures of
Tenant, Tenant agrees to permit Landlord and its employees, agents, contractors
or representatives to enter into and upon any part of the Premises at all
reasonable hours upon reasonable prior notice (and in the case of emergencies at
all times and without notice) to inspect the Premises, or to show the Premises
to prospective purchasers, mortgagees, insurers or tenants, or to perform its
obligations hereunder, and Tenant shall not be entitled to any abatement or
reduction of Rent by reason thereof. Landlord shall use reasonable efforts to
minimize any disruption to the conduct of Tenant's business by reason of any
such entry.

     18. Assignment and Subletting.

     (a) Except as otherwise provided herein, Tenant shall not assign this Lease
or sublease the Premises or any part thereof or mortgage, pledge or hypothecate
its leasehold interest or grant any concession or license within the Premises
(any such assignment, sublease, mortgage, pledge, hypothecation, or grant of a
concession or license being hereinafter referred to in this Section 18 as a
"Transfer") without the prior written consent of Landlord, which consent shall
not be unreasonably withheld and any attempt to effect a Transfer without such
consent of Landlord shall be void and of no effect. In order for Tenant to make
a Transfer, Tenant must request in writing Landlord's consent at least thirty
(30) days in advance of the date on which Tenant desires to make a Transfer.
Such request shall include the name of the proposed assignee or sublessee,
current financial information on the proposed assignee or sublessee and the
terms of the proposed Transfer. Landlord shall then have a period of thirty (30)
days following receipt of such request within which to notify Tenant in writing
that Landlord elects (i) to permit Tenant to assign or sublet such space in
accordance with the terms provided to Landlord, or (ii) to refuse consent to
Tenant's requested Transfer and to continue this Lease in full force and effect
as to the entire Premises. If Landlord shall fail to notify Tenant in writing of
such election within said thirty (30) day period, Landlord shall be deemed to
have elected option (ii) above.

     (b) Notwithstanding the foregoing or anything else to the contrary in this
Lease, Tenant shall have the right, without prior notice to Landlord or
Landlord's consent, to assign this Lease or sublet all or any portion of the
Premises or grant any concession or license within the Premises to (x) any
person or entity who controls, is controlled by, or is under common control with
the Tenant or (y) any entity into which Tenant merges or to which Tenant sells
substantially all its assets provided that any such entity immediately after
such assignment, subleasing, granting of concession or license has a net worth
at least equal to $200 million. The term "control" shall mean (i) with respect
to a corporation, the right to exercise, directly or indirectly, more than fifty
percent (50%) of the voting rights attributable to the shares of the controlled
corporation, and (ii) with respect to a person or entity that is not a
corporation, the possession, directly or indirectly, of the power to direct or
cause the direction of the management and requirements of any fire insurance
underwriters

                                       17

<PAGE>

or policies of the controlled person or entity. Tenant shall provide Landlord
with written notice of any transfer pursuant to clause (x) or (y) above within
ten (10) days after the effective date thereof.

     (c) Notwithstanding the foregoing, Tenant shall have the right without
Landlord consent to sublease up to a total of 35,000 rentable square feet of
space in Building 2 with associated parking and the right to use in common with
others the Common Areas, provided that such right shall only apply if (i) such
subleases are for a term (including all extension options) not extending beyond
the first 6 Lease Years of this Lease, (ii) such subleases are to subtenants who
do not have a bad business reputation and with proposed uses not materially more
hazardous or detrimental to the Premises than the Tenant's then actual use of
the Premises and (iii) Tenant has provided at least 10 business days prior
notice to Landlord stating the sublease terms and the identity of the subtenant,
stating that the subtenant satisfies the two applicable criteria and providing
Landlord, on a confidential basis and subject to any restrictions on further
disclosure or dissemination thereof as applies to Tenant, with copies of the
materials about the proposed subtenant which Tenant reviewed.

     (d) The consent by Landlord to a particular Transfer shall not be deemed a
consent to any other subsequent Transfer. If this Lease, the Premises or the
Tenant's leasehold interest therein, or if any portion of the foregoing is
transferred, or if the Premises are occupied in whole or in part by anyone other
than Tenant without the prior consent of Landlord as provided herein, Landlord
may nevertheless collect rent from the transferee or other occupant and apply
the net amount collected to the Rent payable hereunder, but no such transaction
or collection of rent or application thereof by Landlord shall be deemed a
waiver of the provisions hereof or a release of Tenant from the further
performance by Tenant of its covenants, duties and obligations hereunder.

     19. Mechanic's Liens. Tenant will not permit any mechanic's liens or other
liens to be placed upon the Premises for any work performed by or at the request
of Tenant, or any assignee, subtenant or licensee of Tenant, and nothing in this
Lease shall be deemed or construed in any way as constituting the consent or
request of Landlord, express or implied, by inference or otherwise, to any
person for the performance of any labor or the furnishing of any materials to
the Premises, or any part thereof. In the event any such lien is attached to the
Premises and not discharged by payment, bonding or otherwise within ten (10)
days after receipt of written notice from Landlord, then, in addition to any
other right or remedy of Landlord, Landlord may, but shall not be obligated to,
discharge the lien.

     20. Property Insurance.

     (a) Landlord shall maintain fire and extended coverage insurance on
Building 2, and, if requested by Tenant and available, including Alterations by
Tenant, in an amount equal to not less than one hundred percent (100%) of the
replacement cost, and Tenant shall (if Landlord procures the same) as additional
Rent, pay Landlord the entire cost thereof within ten (10) days of billing
therefor. Landlord may also obtain business interruption and/or rental value
insurance in an amount equal to the Rent and additional Rent anticipated by
Landlord to be due from Tenant in any twelve (12) month period and if Landlord
does maintain such insurance, Tenant shall, as additional Rent, pay Landlord the
entire cost thereof within ten (10) days of

                                       18

<PAGE>

billing therefor. Landlord shall from time to time as requested by Tenant advise
Tenant of the current or expected future insurance premiums and other costs for
the fire and extended coverage property insurance on Building 2. Notwithstanding
the foregoing, if Tenant notifies Landlord that it is able to obtain coverage
from insurers reasonably satisfactory to the Landlord and any mortgagee of the
Leased Premises in their reasonable discretion which will provide substantially
the same type of coverage in the same dollar amount to the Landlord and such
mortgagees as would otherwise be provided by the insurance to be taken out by
the Landlord pursuant to this paragraph, Tenant shall have the right to so take
out such coverage in lieu of the Landlord taking out the coverage referred to in
this paragraph and, as soon as such Landlord's coverage can be terminated,
Tenant shall not be required to reimburse Landlord for such coverage for the
period that Tenant keeps in effect such alternative coverage and otherwise
complies with the provisions of this paragraph. Such alternative coverage shall
include commercially customary conditions required by Landlord or its Mortgagees
with respect thereto including, without limitation, for appropriate
identification of named insureds and additional insureds and customary
provisions regarding notices of cancellation, amendment and modification.

     (b) Tenant shall maintain fire and extended coverage insurance on all of
its personal property, including removable trade fixtures, located on the
Premises, in an amount equal to full replacement cost or such lesser amount as
is usual and customary for companies in its industry. Such insurance shall be
maintained at the expense of Tenant and payment for losses thereunder shall be
made solely to Tenant or the mortgagees of Tenant as their interests shall
appear. Tenant shall, at Landlord's request from time to time, provide Landlord
with a current certificate of insurance evidencing Tenant's compliance with this
Section 20. Tenant shall obtain the agreement of Tenant's insurers to use its
best endeavors to notify Landlord that a insurance policy is due to be canceled
or expire at least thirty (30) days prior to such cancellation or expiration.
Tenant shall, at Landlord's request from time to time, provide Landlord with a
current certificate of insurance evidencing Tenant's compliance with this
Section 20.

     21. Liability Insurance. Tenant and Landlord shall (Landlord as a part of
Basic Operating Costs and Tenant at its own expense) maintain a policy or
policies of commercial general liability insurance with respect to the
respective activities of each in or on the Premises, with the premiums thereon
fully paid on or before the due date. Such insurance shall provide minimum
protection of not less than $5,000,000 combined single limit through a
combination of primary liability and umbrella coverage per occurrence of bodily
injury, property damage or combination thereof. Tenant shall, at Landlord's
request from time to time, provide Landlord with a current certificate of
insurance evidencing Tenant's compliance with this Section 21.

     22. Indemnity.

     (a) Tenant shall indemnify, defend and hold harmless Landlord and any
officer, director, partner or employee of Landlord (herein collectively called a
"Landlord Related Party") from and against any and all liabilities, obligations,
damages, claims, suits, losses, causes of action, liens, judgments and expenses
(including court costs, reasonable attorney's fees and costs of investigation)
of any kind, nature or description resulting from any injuries to or death of
any person or any damage to tangible property which arises, or is claimed to
arise from the negligence or willful misconduct of Tenant (collectively, the
"Claims"). If any such Claim is made against any Landlord Related Party, Tenant
shall, at Tenant's sole cost and expense, defend

                                       19

<PAGE>

such Claim by or through attorneys reasonably acceptable to Landlord. The
indemnity obligations of Tenant under this subsection shall not apply to a claim
(1) waived by Landlord under Section 23 below or any other provision of this
Lease, (2) arising out of the negligence or intentional misconduct of any
Landlord Related Party or (3) for matters for which Landlord is responsible
under Section 27, below.

     (b) Without in any way limiting the provisions of Section 27, Landlord
shall indemnify, defend and hold harmless Tenant and any officer, director,
partner or employee of Tenant (herein collectively called a "Tenant Related
Party") from and against any and all liabilities, obligations, damages, claims,
suits, losses, causes of action, liens, judgments and expenses (including court
costs, reasonable attorneys' fees and costs of investigation) of any kind,
nature or description resulting from any injuries to or death of any person or
any tangible damage to property which arises, or is claimed to arise from, the
negligence or willful misconduct of Landlord (collectively, the "Claims"). If
any such Claim is made against any Tenant Related Party, Landlord shall, at
Landlord's sole cost and expense, defend such Claim by or through attorneys
reasonably acceptable to Tenant. The indemnity obligations of Landlord under
this subsection shall not apply to a claim (1) waived by Tenant under Section 23
below or any other provision of this Lease, or (2) arising out of the negligence
or intentional misconduct of any Tenant Related Party.

     23. Waiver of Subrogation Rights. Notwithstanding anything in this Lease to
the contrary, to the extent that and so long as the same is permitted under the
laws and regulations governing the writing of insurance within the state where
the Premises is located and, if available, at no material additional cost, all
property insurance carried by either Landlord or Tenant shall provide for a
waiver of rights of subrogation against Landlord and Tenant on the part of the
insurance carrier. Unless the waivers contemplated by this sentence are not
obtainable for the reasons described in this Section 23, Landlord and Tenant
each hereby waive any and all rights of recovery, claims, actions or causes of
action against the other, its agents, officers, or employees, for any loss or
damage to property which is covered or would have been covered under the
property insurance policies required under this Lease. The foregoing release
shall not apply to losses or damages in excess of actual or required policy
limits (whichever is greater), but shall apply to any deductible applicable
under any policy obtained by the waiving party. The failure of either party (the
"Defaulting Party") to take out or maintain any insurance policy required under
this Lease shall be a defense to any Claim asserted by the Defaulting Party
against the other party hereto by reason of any loss sustained by the Defaulting
Party that would have been covered by any such required policy. The waivers set
forth in the second sentence of this paragraph shall be in addition to, and not
in substitution for, any other waivers, indemnities, or exclusions of
liabilities set forth in this Lease.

     24. Casualty Damage. If the Premises or any part thereof shall be damaged
by fire or other casualty, Tenant shall give prompt written notice thereof to
Landlord. In case Building 2 shall be so damaged by fire or other casualty that
substantial alteration or reconstruction of Building 2 (i.e., alteration or
reconstruction which is estimated to cost in excess of the product found by
multiplying the rentable area in square feet of Building 2 by $5.00) shall, in
the judgment of an independent architect selected by Landlord, be required
(whether or not the Premises shall have been damaged by such fire or other
casualty), or in the event any mortgagee under a first mortgage or first deed of
trust covering Building 2 should require that substantially

                                       20

<PAGE>

all of the insurance proceeds payable as a result of said fire or other casualty
be used to retire the mortgage debt, or in the event of the occurrence of a
casualty which is not insured under the fire and extended coverage insurance
required to be carried pursuant to the terms of Section 20, Landlord may, at its
option, terminate this Lease by notifying Tenant in writing of such termination
within ninety (90) days after the date of such damage or determination by such a
mortgagee to take the proceeds, in which event the Rent, Basic Operating Costs
and Taxes hereunder shall be abated as of the date of such termination. If
Landlord does not elect to terminate this Lease, Landlord shall within ninety
(90) days after the date of such damage, commence to repair and restore Building
2 and shall proceed with reasonable diligence to restore Building 2 to
substantially the same condition which it was in immediately prior to the
happening of the fire or other casualty, except that Landlord shall not be
required to rebuild, repair, or replace any part of Tenant's furniture, fixtures
and equipment removable by Tenant under the provisions of this Lease or any
Alterations, unless insurance proceeds from Landlord's or Tenant's property
insurance are available to rebuild the Alterations. If Landlord determines that
insurance proceeds available to Landlord will be insufficient to restore
Building 2 as required by this Section 24, Landlord may, at its option, elect to
either (i) terminate this Lease by written notice to Tenant, or (ii) provide the
extra funds necessary to complete the restoration; provided, however, Landlord
shall restore if Tenant provides the necessary extra funds. If Landlord receives
insufficient funds and elects therefore not to restore it shall so notify Tenant
and Tenant shall have 30 days to elect to provide the extra funds needed. If
Building 2 is to be restored each of Landlord and Tenant shall contribute the
insurance proceeds it received and retained (net of any costs and expenses
incurred in obtaining the same) to the cost of such restoration. If Tenant does
not elect to provide the necessary extra funds the Lease shall terminate. In the
event Landlord does not either (i) commence the repairs to Building 2 within the
time required herein, or (ii) complete the repairs to Building 2 within one
hundred eighty (180) days after the date of such damage, Tenant may terminate
the Lease by written notice thereof to Landlord given no later than thirty (30)
days following the date on which Landlord was to commence or complete such
repairs, as the case may be. Landlord shall not be liable for any inconvenience
or annoyance to Tenant or injury to the business of Tenant resulting in any way
from such damage or the repair thereof, except that, Landlord shall allow Tenant
a proportional abatement of Rent, Basic Operating Costs and Taxes from the date
of damage until the time the Premises are restored or the Lease is terminated.

     Landlord agrees to use reasonably diligent good faith efforts to have its
mortgagees agree to allow the insurance proceeds from any casualty of Building 2
to be used to restore such damaged or destroyed improvements.

     25. Condemnation. If (i) the whole or substantially the whole of Building
2, or (ii) the whole or such portion of the Premises (including parking areas
and access roadways) as shall render the remainder reasonably unfit for Tenant's
use, shall be taken for any public or quasi-public use, by right of eminent
domain or otherwise, or sold in lieu of condemnation, then this Lease shall
terminate as of the date when physical possession of Building 2 or the Premises
are taken by the condemning authority. If the Lease is not so terminated upon
any such taking or sale, the Rent, Basic Operating Costs and Taxes payable
hereunder shall be diminished by an amount representing that portion of Rent
applicable to the portion of the Premises subject to such taking or sale, and
Landlord shall to the extent Landlord deems feasible and to the extent Landlord
has available to it the award in connection therewith, restore Building 2

                                       21

<PAGE>

and the Premises to substantially their former condition, except that Landlord
shall not be required to rebuild, repair or replace any Alterations to the
Premises made by Tenant if the award received by Landlord is insufficient to
undertake such restoration. All amounts awarded upon a taking of any part or all
of RiverTech Park, Building 2 or the Premises shall belong to Landlord, and
Tenant shall not be entitled to and expressly waives all claims to any such
compensation except that Tenant may make a separate claim upon the condemning
authority for expenses related to relocation, interruption of the conduct of its
business and (if not rebuilt by Landlord) the unamortized cost of leasehold
improvements paid for by Tenant.

     26. Environmental Matters/Hazardous Materials.

     (a) Hazardous Materials Disclosure Certificate. Prior to executing this
Lease, Tenant has delivered to Landlord Tenant's executed initial Hazardous
Materials Disclosure Certificate (the "Initial HazMat Certificate"), a copy of
which is attached hereto as Exhibit F. Tenant covenants, represents and warrants
to Landlord that the information in the Initial HazMat Certificate is true and
correct in all material respects as of the date made and accurately describes in
all material respects as of the date made the Hazardous Materials which Tenant
reasonably contemplates or expects will be made and/or used on the Premises by
Tenant. Tenant shall once every calendar quarter after the Commencement Date
(and in any event no later than 20 weeks after delivery of the prior
certificate) deliver to Landlord an executed Hazardous Materials Disclosure
Certificate ("the HazMat Certificate") describing Tenant's Hazardous Materials
then used or reasonably contemplated or expected to be used on the Premises. The
HazMat Certificates required hereunder shall be in substantially the form
attached hereto as Exhibit F. Tenant will also provide a HazMat Certificate to
Landlord from time to time when reasonably requested by Landlord in good faith
for a legitimate business purpose. The Tenant shall also deliver to the Landlord
reasonably promptly following filing of the same with applicable governmental
authorities copies of any flammable materials and RCRA reports related to
Tenant's activities at the Premises filed with such authorities. It is
understood that Tenant in preparing and updating HazMat Certificates shall not
be required to more rigorously review or update the same than Tenant would
normally undertake at such time in compliance with its internal environmental
review procedures and applicable law.

     (b) Definition of Hazardous Materials. As used in this Lease, the term
Hazardous Materials shall mean and include (a) any hazardous or toxic wastes,
materials or substances, and other pollutants or contaminants, which are or
become regulated by any Environmental Laws; (b) petroleum, petroleum by
products, gasoline, diesel fuel, crude oil or any fraction thereof; (c) asbestos
and asbestos containing material, in any form, whether friable or non-friable;
(d) polychlorinated biphenyls; (e) radioactive materials; (f) lead and
lead-containing materials; (g) any other material, waste or substance displaying
toxic, reactive, ignitable or corrosive characteristics, as all such terms are
used in their broadest sense, and are defined or become defined by any
Environmental Law (defined below); or (h) any materials which cause or threatens
to cause a nuisance upon or waste to any portion of RiverTech Park or any
surrounding property; or poses or threatens to pose a hazard to the health and
safety of persons on the Premises, any other portion of RiverTech Park or any
surrounding property. For purposes of this Lease, the term "Hazardous Materials"
shall not include nominal amounts of ordinary household cleaners, office
supplies and janitorial supplies.

                                       22

<PAGE>

     (c) Prohibition; Environmental Laws. Except for materials set forth on the
latest HazMat Certificate, Tenant shall not be entitled to use or store any
Hazardous Materials on, in, or about any portion of the Premises and RiverTech
Park without, in each instance, obtaining Landlord's prior written consent
thereto, Landlord hereby acknowledging its consent to the matters set forth on
the Initial HazMat Certificate. Tenant shall be permitted to use and/or store
only those Hazardous Materials that are necessary for Tenant's business and to
the extent disclosed in the HazMat Certificate. Any such usage and storage may
only be to the extent of the quantities of Hazardous Materials as specified in
the then applicable HazMat Certificate. Notwithstanding the foregoing, Tenant
may bring into and use at the Premises, from time to time other Hazardous
Materials not identified on the HazMat Certificate or the same materials in
differing quantities provided (i) such materials are intended to be used in
Tenant's operations at the Premises, (ii) are in limited quantities, (iii)
comply with the other provisions of this Section 26, (iv) do not present a
materially increased risk of material harm to persons or property if such
additional Hazardous Materials are not properly used which is substantially
different in kind or scope from the risks associated with materials then listed
on the HazMat Certificate and (v) are properly labeled, handled, used, stored,
and disposed of in accordance with applicable law. In all events such usage and
storage must at all times be in full compliance with any and all local, state
and federal environmental, health and/or safety-related laws, statutes, orders,
standards, courts' decisions, ordinances, rules and regulations (as interpreted
by judicial and administrative decisions), decrees, directives, guidelines,
permits or permit conditions, currently existing and as amended, enacted, issued
or adopted in the future which are or become applicable to Tenant or all or any
portion of the Premises (collectively, the "Environmental Laws"). Tenant shall
not be entitled nor permitted to install any underground tanks, or any tanks
with a capacity in excess of 60 gallons (except for one tank with a capacity not
in excess of 270 gallons) on or about the Premises for the storage of Hazardous
Materials without the express written consent of Landlord, which may be given or
withheld in Landlord's sole discretion with respect to underground tanks and in
Landlord's reasonable discretion with respect to above-ground tanks. For tanks
outside of Building 2, without Landlord's consent (which may be withheld in
Landlord's sole discretion),only so-called double-wall, spill containing tanks
may be so installed. Notwithstanding the foregoing, if applicable legal and
regulatory wastewater disposal requirements necessitate the placement of an
equalization tank on the Premises such tank may be installed below grade (but
not underground) without Landlord's consent provided it is installed and
maintained in compliance with all applicable legal requirements. If required in
connection with financings, sales, equity investments in the owner of Building 2
or upon reasonable grounds (as documented by a written opinion from a licensed
site professional reasonably acceptable to the parties and addressed to Tenant
and Landlord), Landlord shall have the right during the Lease Term to (i)
inspect the Premises upon reasonable advanced notice, (ii) conduct tests and
investigations to determine whether Tenant is in compliance with the provisions
of this Section 26 or to determine if Hazardous Materials are present in, on or
about RiverTech Park, and (iii) request lists of all Hazardous Materials used,
stored or otherwise located on, under or about any portion of the Premises
and/or the Common Areas by Tenant or Tenant's Representatives other than common
materials typically found in office premises (i.e., cleaning materials, copier
supplies and similar materials in nominal quantities). All of such activities
shall be undertaken by Landlord and its consultants in a manner that will
reasonably minimize interference with and disruptions of Tenant's use of the
Premises and, except in the case of emergencies, Landlord shall not compromise
Tenant's activities or the atmosphere within so-called "clean rooms". Landlord
and the consultants undertaking such activities shall not disclose

                                       23

<PAGE>

any information regarding Tenant's business activities on and use of the
Premises, all of which information constitutes trade secrets and is and shall be
kept confidential except that such consultants may disclose such information as
is required by the standard of care and performance standards applicable to
reports prepared by licensed site professionals pursuant to the Massachusetts
Contingency Plan. The cost of all such inspections, tests and investigations
shall be borne by Tenant, if it is reasonably determined that Tenant or any
employee, agent, supplier, vendor, director, officer, invitee, licensee,
subtenant, assignee or other party claiming by, through or under Tenant
(collectively, "Tenant's Representatives") are directly or indirectly
responsible for any contamination or non-compliance with law revealed by such
inspections, tests and investigations, otherwise Landlord shall bear all such
costs. The aforementioned rights granted herein to Landlord and its
representatives shall not create (a) a duty on Landlord's part to inspect, test,
investigate, monitor or otherwise observe the Premises or the activities of
Tenant and Tenant's Representatives with respect to Hazardous Materials,
including without limitation, Tenant's operation, use and any remediation
related thereto, or (b) liability on the part of Landlord and its
representatives for Tenant's use, storage, disposal or remediation of Tenant's
Hazardous Materials, it being understood that Tenant shall be solely responsible
for all liability in connection therewith.

     (d) Tenant's Environmental Obligations. Tenant shall give to Landlord
immediate verbal and follow-up written notice of any spills, releases,
discharges, disposals or emissions of Hazardous Materials on, under or about any
portion of the Premises or in any Common Areas, provided that Tenant has
knowledge of such event(s). Tenant, at its sole cost and expense, covenants and
warrants to promptly investigate, clean up, remove, restore and otherwise
remediate (including, without limitation, preparation of any feasibility studies
or reports and the performance of any and all closures) (collectively,
"Remediation") any spill, release, discharge, disposal, emission, migration or
transportation of Hazardous Materials arising from or related to the intentional
or negligent acts or omissions of Tenant or Tenant's Representatives such that
the affected portions of RiverTech Park and any adjacent property are returned
to the condition existing prior to the release of such Hazardous Materials to
the extent such Remediation is required by applicable law. Any such Remediation
shall (to the extent not in violation of applicable law) only be performed after
Tenant has obtained Landlord's prior written consent, which consent shall not be
unreasonably withheld or delayed so long as such actions would not potentially
have a material adverse long-term or short-term effect on any portion of
RiverTech Park. Notwithstanding the foregoing, Tenant shall be entitled to
respond immediately to an emergency without first obtaining Landlord's prior
written consent. For Hazardous Materials for which Tenant is liable hereunder
Tenant, at its sole cost and expense, shall conduct and perform, or cause to be
conducted and performed, all response actions (which phrase shall mean and
include any legally required closeout activities) as required by any
Environmental Laws or any agencies or other governmental authorities having
jurisdiction thereof. If Tenant fails to conduct such response action in
accordance with law, Landlord may (i) after an Event of Default and (ii) if
there exists an imminent threat (1) to human health or (2) of material
additional harm to the environment (provided simultaneously with acting Landlord
notifies Tenant of such threat and of the actions Landlord intends to take), but
without obligation to do so, take any and all steps necessary to rectify the
same and Tenant shall promptly reimburse Landlord, within thirty (30) days of
demand, for all costs and expenses to Landlord of performing such investigation,
clean up, removal, restoration, closure and remediation work. All such work
undertaken by Tenant, as required herein, shall, to the extent allowed by
applicable law, be

                                       24

<PAGE>

performed in such a manner so as to avoid impairing the full economic use of the
Premises and the other portions of RiverTech Park for commercial and industrial
uses after the satisfactory completion of such work.

     Notwithstanding the foregoing and other provisions of this Lease, Tenant
shall have the right to contest in good faith and by proper means allowed by law
the validity, applicability or interpretation of any legal or regulatory
requirements relating to Hazardous Materials present at the Premises, RiverTech
Park and any adjacent property including any requirements which a governmental
authority may seek to assert without Tenant being deemed in violation of or in
default under the terms of this Lease.

     (e) Environmental Indemnity. In addition to Tenant's obligations as set
forth hereinabove, Tenant agrees to, and shall, protect, indemnify, defend (with
counsel reasonably acceptable to Landlord) and hold Landlord, Landlord's
employees, agents, invitees, officers, directors and employees and any person or
entity claiming by, through or under Landlord, or any of the foregoing, harmless
from and against any and all Claims (including, without limitation, diminution
in value of any portion of the Premises or RiverTech Park, damages for the loss
of or restriction on the use of rentable or usable space, and from any adverse
impact of Landlord's marketing of any space within RiverTech Park) arising at
any time during or after the Term of this Lease in connection with or related
to, directly or indirectly, the use, presence, transportation, storage,
disposal, migration, removal, spill, release or discharge of Hazardous Materials
on, in or about any portion of RiverTech Park as a result (directly or
indirectly) of the intentional or negligent acts or omissions of Tenant or any
of Tenant's Representatives. Neither the written consent of Landlord to the
presence, use or storage of Hazardous Materials in, on, under or about any
portion of RiverTech Park nor the strict compliance by Tenant with all
Environmental Laws shall excuse Tenant from its obligations of indemnification
pursuant hereto. Tenant shall not be relieved of its indemnification obligations
under the provisions of this Section 26(e) due to Landlord's status as either an
"owner" or "operator" under any Environmental Laws; provided, however, that
Tenant's indemnification obligation under this paragraph shall exclude any
liability with respect to Hazardous Materials which existed on the Premises or
RiverTech Park on or before the Commencement Date.

     (f) Survival. Tenant's obligations and liabilities pursuant to the
provisions of this Section 26 shall survive the expiration or earlier
termination of this Lease. If it is reasonably determined by Landlord after
reasonable investigation by a licensed site professional (or the equivalent
properly qualified and licensed in Massachusetts) that the condition of all or
any portion of RiverTech Park is not in compliance with the provisions of this
Lease with respect to Hazardous Materials, including without limitation, all
Environmental Laws, because of Tenant's or Tenant's Representatives' actions
with respect thereto or breach of any provision hereof at the expiration or
earlier termination of this Lease or otherwise, then Landlord may require Tenant
to bring the Premises into compliance with applicable Environmental Laws,
including without limitation, the conduct or performance of any response actions
as required by any Environmental Laws.

     (g) Exculpation of Tenant. Tenant shall not be liable to Landlord for nor
otherwise obligated to Landlord under any provision of the Lease with respect to
the following: (i) any claim, remediation, obligation, investigation,
obligation, liability, cause of action,

                                       25

<PAGE>

attorney's fees, consultants' cost, expense or damage resulting from any
Hazardous Materials present in, on or about the Premises, Building 2 or
RiverTech Park to the extent not caused or otherwise permitted, directly or
indirectly, by Tenant or any of Tenant's Representatives; (ii) the removal,
investigation, monitoring or remediation of any Hazardous Material present in,
on or about the Premises or Building 2 caused by any source, including third
parties, other than Tenant or Tenant's Representatives or (iii) any claim,
remediation, obligation, investigation, liability, course of action, attorneys'
fees, consultants' costs, expense or damage resulting from any Hazardous
Materials present in, on or about the Premises or Building 2 on the Commencement
Date; provided, however, Tenant shall be fully liable for and otherwise
obligated to Landlord under the provisions of this Lease for all Claims to the
extent (a) Tenant or any of Tenant's Representatives permits the release of any
additional Hazardous Materials or subject to clause (h) below of this Section
26, otherwise knowingly and intentionally or negligently exacerbates any release
of, or liability with respect to, Hazardous Materials on the Premises or in
RiverTech Park, (b) Tenant and/or Tenant's Representatives allows or permits
persons over which Tenant has control, and/or for which Tenant or any of
Tenant's Representatives are legally responsible (excluding trespassers), to
cause such Hazardous Materials to be present in, on, under, through or about any
portion of the Premises, the Common Areas, Building 2 or RiverTech Park, or (c)
Tenant and/or any of Tenant's Representatives does not take all reasonably
appropriate actions to prevent such persons over which Tenant or any of Tenant's
Representatives has control (excluding trespassers) and/or for which Tenant or
any of Tenant's Representatives is legally responsible (excluding trespassers)
from causing a release of Hazardous Materials in, on, under, through or about
any portion of the Premises, the Common Areas, Building 2 or RiverTech Park.

     (h) Notwithstanding the foregoing or any other term or provision of this
Lease, Tenant shall not be liable for exacerbating any oil or Hazardous Material
contamination existing on the Premises (or any liability with respect thereto)
as of the Commencement Date, provided such exacerbation: (1) Results from
above-ground activities undertaken by Tenant that are both (i) within Tenant's
normal business operations and (ii) in compliance with environmental laws; or
(2) Results from subsurface activities undertaken by Tenant in compliance with
environmental laws provided that prior to commencing such work, Tenant obtains
from a licensed site professional (LSP) reasonably acceptable to the parties a
report, addressed to Tenant, Landlord, and Landlord's lenders that either (i)
finds that the proposed work will have no adverse effect on any preexisting
contamination, or (ii) recommends means and methods for avoiding any such
adverse effect, and Tenant follows those recommendations.

     27. Landlord's Responsibilities. Landlord represents and warrants that
except as set forth in any environmental reports made available to Tenant which
are listed on Exhibit 27A attached hereto, (a) any handling, transportation,
storage, treatment, or use of hazardous or toxic substances or wastes that have
occurred on the Premises prior to the Commencement Date have been in compliance
with all applicable federal, state and local laws, regulations and ordinances;
(b) no leak, spill, release, discharge, emission or disposal of Hazardous
Materials has occurred on the Premises while Landlord has been the owner of
RiverTech Park; and (c) that as of the date hereof (and later but solely to the
extent of and within the areas of any work done on the Premises by Landlord),
the Premises do not contain any asbestos, radon gas or PCBs.

     Landlord covenants to comply with all legal requirements with respect to
any Hazardous Materials which may be discovered in, on, or under the Premises,
unless and to the

                                       26

<PAGE>

extent such substances were introduced by Tenant, or any Tenant's
Representative. Landlord further covenants to conduct any investigation, removal
and/or remediation activities in a manner so as to reasonably minimize any
disruption of Tenant's operations on the Premises. Landlord shall indemnify,
defend and hold Tenant and all Tenant's Representatives harmless from and
against all claims, costs and liabilities, including attorneys' fees arising out
Landlord's breach of its obligations under this Section and including for any
Hazardous Materials present, in, on, under, through or about any portion of the
Premises, Building 2 or RiverTech Park as of the date hereof (and later but
solely to the extent of and within the areas of any work done on the Premises by
Landlord). Further, Landlord expressly acknowledges that the costs of any such
removal of Hazardous Materials shall be at Landlord's sole cost and expense and
shall not be included in Basic Operating Costs or otherwise passed on to Tenant
as additional Rent.

     Landlord agrees to cooperate with Tenant in connection with Tenant filing
for and seeking to obtain and/or renew any required flammable materials storage
permit including if so required signing the application from and other
submission materials and applying for such permit in Landlord's name; provided
that (1) Landlord shall not incur any liability with respect thereto Tenant
agreeing to indemnify, defend and hold Landlord harmless with respect thereto
and (2) all of the foregoing shall be at Tenant's sole expense and Tenant shall
reimburse Landlord for any expenses reasonably incurred by Landlord.

     28. Renewal Option.

     (a) Tenant may extend the Term for two additional five (5) year terms such
extended term to be subject to the same terms and conditions as are contained in
the Lease except the Rent set forth in Section 1(c) shall be the prevailing Fair
Market Rate, as hereinafter defined. Provided that Tenant requests the same no
more than eighteen (18) months and no less than seventeen (17) months prior to
the expiration of the then current Lease Term, Landlord, no later than fifteen
(15) months prior to the expiration of the then current Lease Term, shall give
Tenant written notice of its proposed Fair Market Rate. Tenant shall give
Landlord written notice if it intends to exercise this option, which notice must
be given at least twelve months prior to the expiration of the initial Term for
the first option to renew and twelve months prior to the expiration of the first
renewal term for the second option to renew; each such notice shall state
whether Landlord's proposed Fair Market Rate is acceptable to Tenant. If
Landlord's proposed Fair Market Rate is acceptable to Tenant, then this Lease
shall be renewed with such proposed Fair Market Rate as the Rent payable
pursuant to Section 1(c). The Fair Market Rate as used herein shall mean the
fair market rental rate then being charged for like space similarly situated in
industrial/manufacturing buildings giving due consideration to all matters as
are customarily and appropriately considered by landlords and tenants engaged in
leasing similar space of approximately the same size and within a 5-mile radius
of RiverTech Park as of the time of such determination and the terms of this
Lease, including, without limitation, age and condition of the building, rental
and other concessions, finish allowances, the creditworthiness and net worth of
tenant, offered inducements and the Lease Term which would be offered for
comparable properties. In the event the parties cannot reach an agreement as to
the prevailing Fair Market Rate within thirty (30) days of Tenant's notice to
renew, then the Fair Market Value shall be determined by the procedure described
below.

                                       27

<PAGE>

     (b) Landlord and Tenant shall each appoint an individual professional real
estate broker duly licensed by the Commonwealth of Massachusetts who has not
less than five (5) years experience in the sale and/or leasing of
industrial/manufacturing building complexes within a 5-mile radius of RiverTech
Park, whose clients involve to a substantial extent publicly held corporations,
and who has not personally acted as a broker on behalf of either Landlord or
Tenant (each such selected person being called a "Broker"). Each Broker so
appointed shall be instructed to determine independently the Fair Market Rent as
defined herein. Within twenty (20) days after the appointment of the Brokers by
Landlord and Tenant, the Brokers shall notify both Landlord and Tenant of each
Broker's determination of the Fair Market Rent. If the difference between the
amounts determined by the two Brokers does not exceed ten percent (10%) of the
lesser of the two amounts, then Fair Market Rent shall be an amount equal to the
average of the two amounts so determined. If the difference between the amounts
determined by the two Brokers exceeds ten percent (10%) of the lesser of the two
amounts, then the two Brokers shall appoint a third Broker who satisfies the
above qualifications within ten (10) days thereafter. The third Broker shall
within twenty (20) days after his or her appointment make his or her
determination of the Fair Market Rent as defined herein. The determination of
the Broker which differs most from the determinations of the other two (2)
Brokers shall be excluded, and the average of the two remaining determinations
shall be the Fair Market Rent. If the initial two Brokers fail to agree upon a
third Broker within the time period specified above or if such third Broker
fails to render his determination in accordance with the provisions of this
paragraphs, then a replacement or new Broker shall be selected jointly by
Landlord and Tenant. If Landlord and Tenant are unable to agree upon a third
Broker within ten (10) days after the date such determination is required, then
they shall in lieu thereof each select the names of two (2) willing Brokers
qualified to be Brokers hereunder, and from the four (4) Broker's names, one (1)
name shall be drawn by a lot by a representative of Landlord in the presence of
a representative of Tenant, and the person whose name is so drawn shall be the
third Broker.

     (c) The Brokers selected hereunder shall deliver a signed, detailed and
completed written report on each of their appraisals, including the final
determination resulting from such appraisals, to each of Landlord and Tenant not
later than one hundred ninety (190) days prior to the expiration of the then
Lease Term (subject to any extensions reasonably required as a result of the
selection process set forth in paragraph (b) above). The Fair Market Rent of the
Premises, determined in accordance with the provisions of this section, shall be
binding and conclusive on Tenant and Landlord. The provisions for appraisal
hereunder shall be specifically enforceable to the extent such remedy is
available under applicable law. If, for any reason, the decision of the Brokers
shall not be determined before the commencement of the Renewal Term, then Tenant
shall pay base rent in monthly installments at the rate in effect immediately
prior to the commencement of such Renewal Term until such decision of the
Brokers shall be made, and upon the decision by the Brokers, an appropriate
adjustment shall be made, retroactive to the first day of such Renewal Term.

     (d) Each party shall be obligated to pay the fees of the Broker selected by
such party. The fees of the third Broker shall be shared equally by Tenant and
Landlord.

     29. Events of Default/Remedies.

                                       28

<PAGE>

     (a) The following events shall be deemed to be events of default by Tenant
under this Lease (hereinafter called an "Event of Default").

     (1) Tenant shall fail to timely pay any Rent or any additional Rent when
due and such failure shall continue for a period of ten (10) days after written
notice of such default shall have been delivered to Tenant;

     (2) Tenant shall fail to comply with any provision of this Lease not
requiring the payment of Rent, all of which terms, provisions and covenants
shall be deemed material, and such failure shall continue for a period of thirty
(30) days after written notice of such failure is delivered to Tenant unless
that if such failure cannot reasonably be cured within such 30-day period,
Tenant shall not be in default hereunder as long as Tenant commences the
remedying of such failure within such thirty (30) day period and diligently
prosecutes such cure to completion;

     (3) Tenant takes any action to, or notifies Landlord that Tenant intends to
file a petition under any section or chapter of the United States Bankruptcy
Code, as amended from time to time, or under any similar law or statute of the
United States or any state thereof; or a petition shall be filed against Tenant
under any such statute and not be dismissed within sixty (60) days thereafter;

     (4) a receiver or trustee shall be appointed for Tenant's leasehold
interest in the Premises or for all or a substantial part of the assets of
Tenant; or

     (b) Upon the occurrence of any Event of Default, Landlord may, utilizing
judicial process, at its option, in addition to all other remedies given
hereunder or by law or equity, do any one or more of the following: (1)
terminate this Lease, in which event Tenant shall immediately surrender
possession of the Premises to Landlord; (2) enter upon and take possession of
the Premises and remove Tenant therefrom, with or without having terminated this
Lease.

     (c) Exercise by Landlord of any one or more remedies hereunder shall not
constitute forfeiture or an acceptance of surrender of the Premises by Tenant,
it being understood that such surrender can be effected only with the written
agreement of Landlord and Tenant.

     (d) In the event that this Lease is terminated by reason of an Event of
Default, Tenant covenants to pay forthwith to Landlord upon demand, as
compensation, all Rent and additional Rent which Tenant covenants in this Lease
to pay and to perform in the same manner and to the same extent and at the same
time as if this Lease had not been terminated. In calculating the amounts to be
paid by Tenant pursuant to the preceding sentence Tenant shall be credited with
the net proceeds of any rent and additional rent obtained by Landlord by
reletting the Premises, after deducting all of Landlord's reasonable expenses in
connection with such reletting, including, without limitation, all repossession
costs, brokerage commissions, fees for legal services and expenses of preparing
the Premises for such reletting, it being agreed by Tenant that Landlord may,
but shall not be obligated to, (i) relet the Premises or any part or parts
thereof, for a term or terms which may at Landlord's option be equal to or less
than or exceed the period which would otherwise have constituted the balance of
the Lease Term and may grant such concessions and free rent as Landlord in its
reasonable judgment considers advisable or

                                       29

<PAGE>

necessary to relet the same, and (ii) make such alterations, repairs and
decorations in the Premises as Landlord in its reasonable judgment considers
advisable or necessary to relet the same. No action of Landlord in accordance
with the foregoing or failure to relet or to collect rent under reletting shall
operate or be construed to release or reduce Tenant's liability as aforesaid.

     Nothing contained in this Lease shall, however, limit or prejudice the
right of Landlord to prove for and obtain in proceedings under any federal or
state law relating to bankruptcy or insolvency or reorganization or arrangement,
an amount equal to the maximum allowed by any statute or rule of law in effect
at the time when, and governing the proceedings in which, the damages are to be
proved, whether or not the amount be greater than the amount of the loss or
damages referred to above.

     (e) If, after an Event of Default, Tenant should fail to make any payment,
perform any obligation, or cure any default hereunder, Landlord, without
obligation to do so and without thereby waiving such failure or default, may
make such payment, perform such obligation, and/or remedy such other default for
the account of Tenant (and enter the Premises for such purpose), and Tenant
shall, within thirty (30) days following written demand, pay all costs, incurred
by Landlord in taking such remedial action.

     30. Default by Landlord. Landlord shall be in default under this Lease if
Landlord fails to perform any of its obligations hereunder and such failure
continues for a period of thirty (30) days after Tenant delivers written notice
of such failure to Landlord, provided that if such failure cannot reasonably be
cured within such thirty (30) day period, Landlord shall not be in default
hereunder as long as Landlord commences the remedying of such failure within
such thirty (30) day period and diligently prosecutes the same to completion.
If, Landlord should fail to make any payment, perform any obligation, or cure
any default hereunder, after 30 days notice to Landlord or such longer period as
is necessary to cure the same provided Landlord commences such cure within said
thirty (30) days and thereafter diligently prosecutes the same, Tenant, without
obligation to do so and without thereby waiving such failure or default, may,
after giving fifteen (15) days additional notice to Landlord and any mortgagee
of whose address Tenant has been informed (unless such cure is completed within
said fifteen (15) days or, if the same cannot reasonably be cured within said
fifteen (15) day period, unless such cure is commenced within such fifteen (15)
days and thereafter diligently prosecuted) make such payment, perform such
obligation, and/or remedy such other default for the account of Landlord.
Landlord shall immediately pay to Tenant upon demand all costs of Tenant
remedying such default of Landlord. If Landlord does not promptly pay such costs
upon demand or if Landlord disputes whether such default occurred or costs are
due then the parties hereby agree that either party may submit such dispute to
binding arbitration before the American Arbitration Association with such
arbitration to be heard on an expedited basis and in accordance with the then
applicable rules of the American Arbitration Association for arbitrating
commercial disputes. To the extent of any arbitration decision or award
determined in favor of Tenant, Tenant shall be entitled to apply all costs
incurred by Tenant in taking such remedial action as an offset against up to 25%
of the Rent (as defined in Section 1(c) hereof) at any time next due from time
to time hereunder until all of such costs have been so applied or otherwise
reimbursed to Tenant.

     31. Quiet Enjoyment. Provided an Event of Default has not occurred, Tenant
shall and may peaceably and quietly occupy and use the Premises during the Lease
Term subject to the

                                       30

<PAGE>

provisions of this Lease and Landlord agrees to warrant and forever defend
Tenant's right to such occupancy against the claims of any and all persons
whomsoever claiming the same or any part thereof, by, through, or under Landlord
(including Landlord's predecessors in title to RiverTech Park) but not
otherwise, subject only to the provisions of this Lease.

     32. Holding Over. Should Tenant continue to occupy the Premises after the
expiration of the Lease Term without the prior written consent of Landlord, such
occupancy shall be a month to month tenancy under all of the terms, covenants
and conditions of this Lease, but at a daily Rent proportionately calculated at
a rate equal to one hundred fifty percent (150%) of the Rent for the final month
of the Lease Term.

     33. Subordination to Mortgage; Estoppel Agreement.

     (a) Landlord represents to Tenant that there are currently no deed of trust
liens or mortgages against the Premises or the Common Areas.

     (b) This Lease shall be subordinate to any mortgage, deed of trust or other
lien hereafter placed upon the Premises, or upon RiverTech Park or any portion
of the Common Areas and to any renewals, modifications, consolidations,
refinancings, and extensions thereof; provided that such mortgagee or deed of
trust beneficiary shall execute in favor of Tenant a non-disturbance agreement
as set forth in Section 33(d). Tenant agrees that any such mortgagee or deed of
trust beneficiary shall have the right at any time to subordinate such mortgage,
deed of trust or other lien to this Lease on such terms and subject to such
conditions as such mortgagee or deed of trust beneficiary may deem appropriate
in its discretion. In the event any proceedings are brought for the foreclosure
of, or in the event of the exercise of the power of sale under, any such
mortgage, deed of trust or other lien, Tenant agrees to attorn to the purchaser
upon such foreclosure (or any deed in lieu of foreclosure) and recognize such
purchaser as the Landlord under this Lease; provided that such purchaser agrees
in writing to recognize and perform the obligations of Landlord hereunder as set
forth in Section 33(d).

     (c) Tenant agrees that it will from time to time within fifteen (15) days
after written request by Landlord execute and deliver to such persons as
Landlord shall request an estoppel agreement in recordable form certifying that
this Lease is unmodified and in full force and effect (or if there have been
modifications, that the same is in full force and effect as so modified),
stating the dates to which Rent and other charges payable under this Lease have
been paid, stating to the best of Tenant's knowledge Landlord is not in default
hereunder (or if Tenant alleges a default stating the nature of such alleged
default) and further stating such other matters as Landlord shall reasonably
require.

     (d) Notwithstanding anything in Section 33(b) to the contrary, Tenant's
agreement that this Lease will be subordinate to any mortgage, deed of trust or
other lien hereafter placed upon the Premises or RiverTech Park shall be
conditioned upon the receipt by Tenant from the holder of the mortgage, deed of
trust or other lien to which this Lease will be subordinate of a non-disturbance
agreement in commercially reasonable form whereby said holder agrees that, in
the event of foreclosure or deed in lieu of foreclosure, said owner, whether it
is the holder or a party acquiring the Premises or RiverTech Park from the
holder, shall not disturb Tenant and shall honor the covenants and agreements of
Landlord under this Lease. Tenant shall agree in such non-disturbance agreement
to attorn to the new owner under the same

                                       31

<PAGE>

terms and provisions of this Lease and shall promptly (and in any event within
ten (10) business days) execute and deliver the same upon Landlord's request.

     34. No Implied Waiver. The failure of either party to insist at any time
upon the strict performance of any covenant or agreement in this Lease or to
exercise any right, power or remedy contained in this Lease shall not be
construed as a waiver or a relinquishment thereof for the future. The acceptance
by Landlord of late payments shall not be construed as a waiver by Landlord of
the requirement for timely payment nor create a course of dealing. No payment by
Tenant or receipt by Landlord of a lesser amount than the monthly installment of
Rent due under this Lease shall be deemed to be other than on account of the
earliest Rent due hereunder, nor shall any endorsement or statement on any check
or any letter accompanying any check or payment as Rent be deemed an accord and
satisfaction, and Landlord may accept such check or payment without prejudice to
Landlord's right to recover the balance of such Rent or pursue any other remedy
provided in this Lease. No payment or performance by Tenant hereunder shall be
deemed to be a waiver of Tenant's right (whether or not stated at the time of
payment or performance) to protest, contest and otherwise seek to recover any
costs for performance by Tenant of any action required by Landlord with respect
to the Premises or under this Lease or any amounts paid by Tenant, but in either
case not properly required of Tenant or due from Tenant under the terms of this
Lease.

     35. Recourse Limitation. Tenant specifically agrees to look solely to
Landlord's interest in the Premises (and any proceeds from the sale thereof),
including any insurance proceeds paid in connection therewith, for the recovery
of any judgment from Landlord, it being agreed that Landlord shall never be
personally liable for any such judgment. The provision contained in the
foregoing sentence shall not limit any right that Tenant might otherwise have to
obtain specific performance of Landlord's obligations under this Lease.

     36. Notices. Any notice under the Lease must be in writing, and shall be
given or be served by (a) personal delivery, (b) delivery via a recognized
overnight courier, or (c) depositing the same in the United States mail, postage
prepaid, certified mail, return receipt requested, addressed to the party to be
notified at the address stated in this Lease or such other address in the
continental United States of which notice has been given to the other party in
the manner provided herein. Notice by personal delivery or overnight courier
shall be effective upon receipt, and notice by mail shall be effective upon
deposit in the United States mail in the manner above described.

     37. Severability. If any term or provision of this Lease, or the
application thereof to any person or circumstance shall, to any extent, be
invalid or unenforceable, the remainder of this Lease, or the application of
such term or provision to persons or circumstances other than those as to which
it is held invalid or unenforceable, shall not be affected thereby, and each
term and provision of this Lease shall be valid and enforced to the fullest
extent permitted by law.

     38. Recordation. Tenant agrees not to record this Lease or any memorandum
hereof. Landlord and Tenant agree to cooperate to prepare and record a
memorandum of this Lease with the Middlesex North District Registry of Deeds.

                                       32

<PAGE>

     39. Governing Law. This Lease and the rights and obligations of the parties
hereto shall be interpreted, construed, and enforced in accordance with the laws
of the State in which the Premises is located.

     40. Force Majeure. Whenever a period of time is herein prescribed for the
taking of any action by Landlord or Tenant, the party responsible for taking
such action shall not be liable or responsible for, and there shall be excluded
from the computation of such period of time, and delays due to strikes, riots,
acts of God, shortages of labor or materials, war, governmental laws,
regulations or restrictions, or any other cause whatsoever beyond the reasonable
control of the party responsible for taking such action; provided, however, the
provisions of this Section 40 shall never be construed as allowing an extension
of time with respect to Tenant's obligation to pay Rent when and as due under
this Lease.

     41. Time of Performance. Except as otherwise expressly provided herein,
time is of the essence under this Lease, including all Exhibits.

     42. Transfers by Landlord. Landlord shall have the right to transfer and
assign, in whole or in part, all its rights and obligations hereunder and in the
Premises, and in such event and upon such transfer, Landlord shall be released
from any further obligations accruing after the date of transfer, and Tenant
agrees to look solely to such successor in interest of Landlord for the
performance of such obligations.

     43. Commissions. Landlord and Tenant agree that Broker are the only brokers
involved in the procurement, negotiation or execution of this Lease, whose
commission shall be paid by Landlord pursuant to a separate commission
agreement. Landlord and Tenant hereby agree to defend, indemnify and hold each
other harmless against any loss, claim, expense or liability with respect to any
commissions or brokerage fees claimed on account of the execution and/or renewal
of this Lease or the expansion of the Premises due to any action of the
indemnifying party.

     44. Effect of Delivery of This Lease. This Lease shall not be effective
until a copy of this Lease executed by both Landlord and Tenant is delivered by
Landlord to Tenant.

     45. Merger of Estates. The voluntary or other surrender of this Lease by
Tenant or a mutual cancellation thereof, shall not constitute a merger; and upon
such surrender or cancellation of this Lease, Landlord shall have the option, in
Landlord's sole discretion, to (a) either terminate all or any existing
subleases or subtenancies, or (b) assume Tenant's interest in any or all
subleases or subtenancies.

     46. Survival of Covenants. Any and all covenants of Tenant and Landlord not
fully performed on the date of the expiration or termination of this Lease shall
survive such expiration or termination.

     47. Headings. Descriptive headings are for convenience only and shall not
control or affect the meaning or construction of any provision of this Lease.

     48. Entire Agreement; Amendments. This Lease, including the exhibits and
addenda, if any, listed in Section 51 below, embodies the entire agreement
between the parties hereto with

                                       33

<PAGE>

relation to the transaction contemplated hereby, and there have been and are no
covenants, agreements, representations, warranties or restrictions between the
parties hereto other than those specifically set forth herein. Any amendment or
modification of this Lease must be in writing and signed by Landlord and Tenant.

     49. Joint and Several Liability. If Tenant consists of more than one person
or entity, the obligations of such parties under this Lease shall be joint and
several.

     50. Multiple Counterparts. This Lease may be executed in multiple
counterparts, each of which shall constitute an original instrument, but all of
which shall constitute one and the same agreement.

     51. List of Exhibits.

         Exhibit A   -  Site Plan depicting RiverTech Park, the Premises and the
                        Common Areas and Plan showing the Cave Area
         Exhibit B   -  List of Landlord's Work
         Exhibit C   -  Form of Letter of Credit
         Exhibit D   -  Description of Tenant's Initial Alterations
         Exhibit E   -  Intentionally Omitted
         Exhibit F   -  Form of HazMat Certificate
         Exhibit 27A -  List of Environmental Reports

                                       34

<PAGE>

         IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease as of
the date first above written.

<TABLE>
<CAPTION>
Address:                              LANDLORD:
-------

<S>                                <C>
Nortel Networks HPOCS Inc.            NORTEL NETWORKS HPOCS INC., a Delaware corporation
2370 Performance Drive
M.S. 087/05/A30                       By:  /s/  Adrian Donoghue                   .
Richardson, TX  75082                      ----------------------------------------
Attn:  Real Estate Department                  Name:  Adrian Donoghue
                                               Title:  Vice President
With a copy to:

Nortel Networks HPOCS Inc.
200 Athens Way
Nashville, TN  37228
Attn:  Law Department

Address:
-------                               TENANT

Mykrolis Corporation
One Patriots Park                     MYKROLIS CORPORATION
Bedford, MA  01730
Attn:  General Counsel                By:  /s/  C. William Zadel                    .
                                           ------------------------------------------------
                                               Name:  C. William Zadel
                                               Title:  Chairman & Chief Executive Officer
</TABLE>

<PAGE>

                                    Exhibit A

      Site Plan depicting RiverTech Park, the Premises and the Common Areas
      ---------------------------------------------------------------------
                         and Plan Showing the Cave Area
                         ------------------------------

<PAGE>

                                    Exhibit B

                                 Landlord's Work

RiverTech Park, Building 2

Expectation of work to be completed by the Landlord prior to Mykrolis Occupancy:

1.   All work will be completed ALL IN ACCORDANCE WITH CERTAIN SPECIFIED PLANS
     AND SPECIFICATIONS included and listed in s.8.1 below.

2.   Sitework:

     2.1. The Landlord will complete only that sitework required to achieve a
          Certificate of Occupancy (COO) for Building 2.
     2.2. The Landlord will complete parking lot seal and re-striping, it being
          agreed that overtime will not be required and that the Landlord must
          finish such work by June 1, 2002.
     2.3. No other landscaping and hardscaping are included in the Landlord's
          final scope of work.

3.   Building Exterior:
     3.1. The two temporary emergency exits in the office areas will be removed,
          and the exterior walls and glass will be restored to match the rest of
          the building.
     3.2. The exterior glass curtain wall at the southwest corner of the
          building will be installed and all finish trim will be completed.
     3.3. The lobby exterior and entrance doors will be completed.

4.   Lobby:

     4.1. The interior of the lobby will be completed, including elevator,
          staircase, firewalls, tile flooring, drywall, painting, electrical,
          lighting, HVAC, controls, and security.
     4.2. The landing at the top of the lobby stairs will be finished with
          matching flooring, doors, lighting, and wall finishes.
     4.3. The interior vestibule will not be completed.

5.   Vacant Space: The COO will not include and no further work will be done on
     the following portions of Building 2 that are to remain unfinished. The
     unfinished spaces to include the "Dead Zone", portions of the Clean
     Manufacturing Area, the Machine Shop Area, and lower level spaces other
     than the Lobby and Elevator Area. The electrical rooms located in the "Dead
     Zone" will be fire rated for 2 hours. The unfinished spaces are referenced
     on Dwg. A1.2 as noted by Joel Kelfer and dated Feb. 19, 2002.

6.   Mechanical and Electrical: The building systems will be brought on line by
     Mykrolis. It is noted that said systems, except for those required to heat
     the building have been shut down since Sept. of 2001. Insulation and heat
     tracing of the cooling tower piping will be completed by the Landlord. The
     Landlord is not required to perform any additional work with respect to
     building systems.

<PAGE>

7.   General Building Issues:

     7.1. The Landlord will complete all "Life Safety" systems necessary to
          obtain a COO.

          7.1.1. Specifically, the fire alarm system will be completely
               operational for all areas of the building including the
               unfinished spaces, all emergency exit signs, exit lighting and
               all fire suppression systems will be completed by the Landlord.
          7.1.2. Code required egresses including handrails will be completed to
               the extent necessary to obtain a COO.
          7.1.3. The Landlord will provide clean out covers at floor level by
               for all test holes located within Building 2 used for groundwater
               sampling.

     7.2. The Landlord will not be responsible for any items on final
          architectural and/or engineering "punch lists" unless required to
          complete scope of work applicable to the lower level of building 2 as
          shown on plans listed in s.8 or as required for Certificate of
          Occupancy.

8.   Included documents:
     8.1. List of construction drawings specifying work to be competed (a copy
          of which is attached).
     8.2. Set of construction drawings specifying work to be completed (landlord
          and tenant are in possession of copies of this set).
     8.3. Copy of Purchase Order, describing work to be completed, and
          specifying construction drawings (8.1 above).
     8.4. Sketch drawing A1.2, indicating "dead zone" as referenced in s.5
          above.
     8.5. Landlord / tenant signoff sheet.
     8.6. Landlord and Tenant acknowledge and agree that they have received and
          reviewed copies of all of the items listed in this Article 8.

                                       2

<PAGE>
                                    Exhibit C

                      IRREVOCABLE STANDBY LETTER OF CREDIT

LETTER OF CREDIT NO.:               [INSERT NUMBER]

DATE OF ISSUE:                      [INSERT DATE]

APPLICANT:                          [INSERT APPLICANT NAME AND ADDRESS]

BENEFICIARY:                        [INSERT BENEFICIARY NAME AND ADDRESS]

AMOUNT:                             [INSERT AMOUNT]

EXPIRATION DATE                     [INSERT DATE]

PLACE FOR PRESENTATION OF DOCUMENTS:        [INSERT LOCAL ADDRESS]

BANK HEREBY ESTABLISHES AN IRREVOCABLE STANDBY LETTER OF CREDIT IN FAVOR OF THE
BENEFICIARY BY ORDER AND FOR THE ACCOUNT OF THE APPLICANT FOR A SUM OR SUMS NOT
TO EXCEED $_____________ IN THE AGGREGATE.

THIS CREDIT IS AVAILABLE WITH BANK AGAINST THE PRESENTATION OF DRAFTS DRAWN AT
SIGHT, SIGNED BY THE BENEFICIARY, AND ACCOMPANIED BY THE FOLLOWING DOCUMENTS:

1. THE ORIGINAL OF THIS STANDBY LETTER OF CREDIT AND ALL AMENDMENT(S), IF ANY.

2. THE WRITTEN STATEMENT PURPORTEDLY SIGNED BY THE BENEFICIARY STATING THAT:

     "BENEFICIARY IS ENTITLED TO DRAW UNDER THIS LETTER OF CREDIT PURSUANT TO
     THE TERMS OF THAT CERTAIN LEASE BETWEEN _________ AND _________ DATED
     __________ WITH RESPECT TO PROPERTY LOCATED AT _________.

PARTIAL DRAWINGS MAY BE MADE UNDER THIS LETTER OF CREDIT.

IT IS A CONDITION OF THIS STANDBY LETTER OF CREDIT THAT IT SHALL BE DEEMED
AUTOMATICALLY EXTENDED WITHOUT AMENDMENT FOR ONE YEAR PERIODS FROM THE PRESENT
EXPIRATION DATE HEREOF, UNLESS, AT LEAST 30 DAYS PRIOR TO ANY SUCH EXPIRATION
DATE, WE SHALL NOTIFY YOU IN

<PAGE>

WRITING BY CERTIFIED MAIL OR COURIER SERVICE AT THE ABOVE LISTED ADDRESS THAT WE
ELECT NOT TO CONSIDER THIS IRREVOCABLE LETTER OF CREDIT RENEWED FOR ANY SUCH
ADDITIONAL PERIOD. UPON RECEIPT BY YOU OF SUCH NOTICE, YOU MAY DRAW HEREUNDER BY
MEANS OF YOUR DRAFT(S) ON US AT SIGHT, SIGNED BY THE BENEFICIARY, ACCOMPANIED BY
A STATEMENT, SIGNED BY THE BENEFICIARY, STATING THAT:

     AS OF THE DATE OF THIS DRAWING, THE BENEFICIARY HAS NOT RECEIVED A
     SUBSTITUTE LETTER OF CREDIT OR OTHER INSTRUMENT ACCEPTABLE TO THE
     BENEFICIARY AS SUBSTITUTE FOR BANK LETTER OF CREDIT NO. [INSERT L/C NO.]

NOTWITHSTANDING THE ABOVE, THE FINAL EXPIRATION DATE SHALL BE NO EARLIER THAN
_________, 200___ [SIXTY DAYS AFTER EXPIRATION DATE].

THIS LETTER OF CREDIT IS TRANSFERABLE IN FULL AND NOT IN PART. ANY TRANSFER MADE
HEREUNDER MUST CONFORM STRICTLY TO THE TERMS HEREOF AND TO THE CONDITIONS OF
ARTICLE 48 OF THE UNIFORM CUSTOMS AND PRACTICE FOR DOCUMENTARY CREDITS (1993
REVISION) FIXED BY THE INTRNATIONAL CHAMBER OF COMMERCE, PUBLICATION NO. 500.

SHOULD YOU WISH TO EFFECT A TRANSFER UNDER THIS CREDIT, SUCH TRANSFER WILL BE
SUBJECT TO THE RETURN TO US OF THE ORIGINAL CREDIT INSTRUMENT, ACCOMPANIED BY
OUR FORM OF TRANSFER, PROPERLY COMPLETED AND SIGNED BY AN AUTHORIZED SIGNATORY
OF YOUR FIRM, BEARING YOUR BANKERS STAMP AND SIGNATURE AUTHENTICATION AND
SUBJECT TO YOUR PAYMENT OF OUR CUSTOMARY TRANFER CHARGES OF 1/4 OF 1% MINIMUM
$250.00.

IN THE EVENT THIS LETTER OF CREDIT IS TRANSFERRED, THE TRANSFEREE SHALL BE THE
BENEFICIARY HEREOF AND DRAFTS AND DOCUMENTS PURSUANT HERETO MUST BE EXECUTED BY
A REPRESENTATIVE OF THE TRANSFEREE.

ALL DRAFTS, ACCOMPANYING DOCUMENTS AND OTHER COMMUNICATIONS REQUIRED OR
PERMITTED UNDER THIS LETTER OF CREDIT MUST BE MARKED: "DRAWN UNDER BANK LETTER
OF CREDIT NO. [INSERT L/C NO.]"

ALL DRAFTS AND ACCOMPANYING DOCUMENTS MAY BE REPRESENTED AT, AND ALL
COMMUNICATIONS WITH RESPECT TO THIS LETTER OF CREDIT SHALL BE IN WRITING AND
DELIVERED TO, OUR OFFICES AT [INSERT ADDRESS OF A BANK LOCATION ACCEPTABLE TO
BENEFICIARY].

THIS LETTER OF CREDIT SETS FORTH IN FULL THE TERMS OF OUR UNDERTAKING, AND SUCH
UNDERTAKING SHALL NOT BE IN ANY WAY MODIFIED, AMENDED OR AMPLIFIED BY REFERENCE
TO ANY DOCUMENT, INSTRUMENT OR AGREEMENT REFERRED TO HEREIN OR IN WHICH THIS
LETTER OF CREDIT IS REFERRED TO OR TO WHICH THIS LETTER OF CREDIT RELATES, AND
ANY SUCH REFERENCE SHALL

                                       2

<PAGE>

NOT BE DEEMED TO INCORPORATE HEREIN BY REFERENCE ANY DOCUMENT, INSTRUMENT OR
AGREEMENT. BANK SHALL HAVE NO OBLIGATION TO INVESTIGATE THE FACTUAL
REPRESENTATIONS CONTAINED IN A DRAW REQUEST.

WE HEREBY ENGAGE WITH YOU THAT ALL DRAFTS DRAWN UNDER AND IN COMPLIANCE WITH THE
TERMS OF THIS CREDIT WILL BE DULY HONORED IF DRAWN AND PRESENTED FOR PAYMENT AT
THE OFFICES SPECIFIED ABOVE ON OR BEFORE THE EXPIRATION DATE OF THIS LETTER OF
CREDIT.

EXCEPT SO FAR AS OTHERWISE EXPRESSLY STATED, THIS CREDIT IS SUBJECT TO THE
UNIFORM CUSTOMS AND PRACTICE FOR DOCUMENTARY CREDITS (1993 REVISION),
INTERNATIONAL CHAMBER OF COMMERCE PUBLICATION NO. 500 (THE "UCP 500").

                                       3

<PAGE>

                                    Exhibit D

                          Tenant's Initial Alterations

<PAGE>

                                    Exhibit E

                              Intentionally Omitted

<PAGE>
                                    Exhibit F

                           Initial HazMat Certificate

<PAGE>

                                   Exhibit 27A

                          List of Environmental Reports

<TABLE>
<CAPTION>

Deliverable                                                                             Delivery Date*
-----------                                                                             -------------
<S>                                                                                   <C>
Report on Phase 1 Environmental Site Assessment                                         3/29/01
129 Concord Road; Billerica, MA
Haley  & Aldrich March 2000

Monitoring Well Survey Worksheet                                                        11/16/01
129 Concord Road; Billerica, MA
Golder Associates November 2001

Borehole records and monitoring well installation logs for borings                      11/16/01
 P-1 to P-22 and wells MW-1 to MW-22
(vicinity of Buildings 1 and 2/4) Golder associates

Borehole records for borings B-1 to B-9 used as temporary monitoring 11/16/01
wells TW-1 to TW-9 (Building 2/4 vicinity) Golder Associates

Laboratory analyses for borings P-1 to P-22 and monitoring wells                        11/16/01
MW-1 to MW22 Golder Associates

Laboratory analyses for temporary monitoring wells TM-1 to TM-9                         11/16/01
Golder Associates

Lab analyses for wells installed within Building 2/4                                    12/21/01(part)
Golder Associates                                                                       1/3/02 (all)

Indoor Air Sampling and Screening Evaluation, River-Tech Building 2/4,                  1/4/02
129 Concord Road Billerica, Massachusetts
Golder Associates January 3, 2002

*Sent to Mykrolis
</TABLE>

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