<PAGE>   1

                                                                    EXHIBIT 10.1



                                 THREE RIVERWAY


                                 LEASE AGREEMENT

                                     BETWEEN

                             HOUSTON OFFICE 90, INC.

                                       AND

                                CHEMCONNECT, INC.



<PAGE>   2

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                             Page
                                                                             ----
<S>                                                                          <C>
Preamble

        Lease.................................................................1
        Landlord..............................................................1
        Tenant................................................................1

1.01    Leased Premises.......................................................1
        Leased Premises.......................................................1
        Building..............................................................1
        Land..................................................................1
        Property..............................................................1
        Net Rentable Area.....................................................1
        Exterior Boundary.....................................................1
        Usable Area...........................................................1
        Service Areas.........................................................1
        General Common Areas..................................................1
        On-Floor Common Areas.................................................2
        Parking Facilities....................................................2

1.02    Term..................................................................2
        Commencement Date.....................................................2

1.03    Use...................................................................2

1.04    Condition of Leased Premises..........................................3

1.05    Quiet Enjoyment.......................................................3

2.01    Rental Payments...................................................... 3
        Rent..................................................................3
        Rent..................................................................3
        month.................................................................4
        year..................................................................4

2.02    Base Rental...........................................................4

2.03    Additional Rental.....................................................4
        Tenant's Forecast Additional Rental...................................4
        Tenant's Additional Rental............................................4
        Base Year.............................................................4
        Tenant's Percentage Share.............................................4
        Tenant's Additional Rental Adjustment.................................5
</TABLE>



<PAGE>   3

<TABLE>
<S>                                                                                      <C>
2.04    Operating Expenses................................................................5
        Operating Expenses................................................................5

2.05    Security Deposit..................................................................8
        Security Deposit..................................................................8

3.01    Services..........................................................................8
        Building Standard Services........................................................8
        Comparable Buildings..............................................................8
        ASSOCIATED PARTIES................................................................8
        Building Standard Rated Electrical Design Load....................................9
        Building Standard Circuits........................................................9
        Additional Electrical Equipment...................................................9

3.02    Keys and Locks...................................................................10

3.03    Graphics, Building Directory Board and Name......................................10

3.04    Parking..........................................................................10
        Reserved Permits.................................................................10
        Unassigned Permits...............................................................10
        Reserved Parking Rent............................................................11
        Unassigned Parking Rent..........................................................11
        Parking Rent.....................................................................11
        Parking Permits..................................................................11

4.01    Care of Leased Premises; Condition on Expiration.................................11

4.02    Entry for Repairs and Inspection.................................................12

4.03    Nuisance.........................................................................12

4.04    Laws and Regulations: Rules of Building..........................................12

4.05    Legal Use and Violations of Insurance Coverage; Hazardous Materials..............12
        Asbestos Records.................................................................13
        Hazardous Substances.............................................................14
        Environmental Laws...............................................................14
        release..........................................................................14

4.06    Telecommunications Providers.....................................................14

5.01    Leasehold Improvements; Furnishings..............................................14

5.02    Repairs; Alterations and Improvements by Landlord................................15
</TABLE>



<PAGE>   4

<TABLE>
<CAPTION>
<S>                                                                            <C>
5.03    Repairs by Tenant......................................................15

6.01    Condemnation...........................................................16

6.02    Damages from Certain Causes............................................16

6.03    Casualty Clause........................................................16
        Damaged Property.......................................................16
        Building Standard......................................................17

6.04    Casualty Insurance.....................................................17

6.05    Liability Insurance....................................................18

6.06    Other Insurance........................................................10

6.07    Hold Harmless..........................................................18

6.08    Waiver of Subrogation Rights...........................................18

7.01    Default and Remedies...................................................19
        affiliate..............................................................21

7.02    Lien for Rent..........................................................22

7.03    Late Payments..........................................................23
        Highest Lawful Rate....................................................23

7.04    Attorney's Fees........................................................23

7.05    No Waiver of Rights....................................................23

7.06    Holding Over...........................................................23

8.01    Landlord's Mortgagee...................................................24

8.02    Subordination..........................................................24

8.03    Cure Rights for Landlord Default.......................................24

8.04    Estoppel Certificate or Three-Party Agreement..........................24

9.01    Sublease or Assignment by Tenant.......................................25
        Notice.................................................................25
        Sublet Space...........................................................25
</TABLE>



<PAGE>   5

<TABLE>
<CAPTION>
<S>                                                                                 <C>
9.02    Assignment by Landlord......................................................27

9.03    Limitation of Landlord's Personal Liability.................................27

10.01   Notices.....................................................................27

10.02   Force Majeure...............................................................28

10.03   Relocation..................................................................28

10.04   Miscellaneous...............................................................29

10.05   Waiver of Trial by Jury.....................................................31

10.06   Real Estate Broker..........................................................31


EXHIBITS:

A.      Property Description......................................................(A)1

B.      Leased Premises...........................................................(B)1

C.      Work Letter Agreement......................................................(C)

D.      Airconditioning and Heating Services
               Building Operating Hours...........................................(D)1
               Holidays...........................................................(D)1

E.      Building Rules and Regulations............................................(E)2
</TABLE>



<PAGE>   6

                                 LEASE AGREEMENT



        This Lease Agreement (this "Lease") made and entered into on this _____
day of __________, _____, by and between HOUSTON OFFICE 90, INC., a Delaware
corporation (hereinafter called "Landlord") and ChemConnect, Inc., a Delaware
corporation (hereinafter called "Tenant").

                                   WITNESSETH:

        1.01. Leased Premises.

                (a) Subject to and upon the terms hereinafter set forth,
Landlord does hereby lease and demise to Tenant and Tenant does hereby lease and
take from Landlord those certain premises (the "Leased Premises") containing
approximately 1,350 square feet of "Net Rentable Area" (hereinafter defined) on
the twelfth (12th) floor, Suite No. 1285, in the building known as Three
Riverway (the "Building") which Building is located at Three Riverway, Houston,
Harris County, Texas, on Tract I (Tract I, and the easement parcels appurtenant
to Tract I and designated as Tract II, are more particularly described on
EXHIBIT A attached hereto and shall be collectively referred to as the "Land".
The Leased Premises is outlined on the floor plan drawing attached hereto as
EXHIBIT B. The Land, Building, Parking Facilities (hereinafter defined) and all
other improvements now or hereafter on the Land and all appurtenances to the
foregoing are collectively referred to herein as the "Property".

                (b) "Net Rentable Area" shall mean (i) in the case of an entire
floor leased to a single tenant, the total square footage of all floor area
measured from the inside surface of the exterior glass line or finished outer
walls (the "Exterior Boundary of the Building to the inside surface of the
opposite Exterior Boundary, excluding Service Areas (defined below) and General
Common Areas (defined below), plus an allocation of the square footage of the
General Common Areas as hereinafter provided, and (ii) in the case of a floor
leased or held for lease to more than one tenant, the total square footage of
all floor areas within the inside surface of the Exterior Boundary of the
Building enclosing the Leased Premises and measured to the mid-point of demising
walls (i.e., walls separating the Leased Premises from areas leased or held for
lease to other tenants, from On-Floor Common Areas [defined below], or from
General Common Areas), excluding Service Areas, plus allocations of the square
footage of the General Common Areas and On-Floor Common Areas as hereinafter
provided. No deductions from Net Rentable Area shall be made for columns or
projections necessary to the Building. The term "Usable Areas" as used in this
Lease shall mean the Net Rentable Area of the Leased Premises minus all On-Floor
Common Areas and General Common Areas or allocations thereof which were included
therein.

                "Service Areas" shall mean the areas within (and measured from
the midpoint of the walls enclosing, or from the inside surface of the Exterior
Boundary enclosing, as the case may be) Building stairs, elevator shafts, flues,
vents, stacks, pipe shafts, and vertical ducts. Areas for the specific use of
Tenant or other tenants of the Building or installed by or at the request of
Tenant or such other tenants, such as special stairs or elevators, are not
included within the definition of Service Areas.



                                       1
<PAGE>   7

                "General Common Areas" shall mean those areas within (and
measured from the midpoint of the walls or from the inside surface of the
Exterior Boundary enclosing) the Building's elevator machine rooms, main
mechanical rooms, electrical rooms, and public lobbies (other than elevator
foyers), that portion of the on-site Building management office or that portion
of the off-site management office reasonably allocated to the Building by
Landlord, engineering and cleaning staging areas, and other areas not leased or
held for lease within the Building but which are reasonably necessary for the
proper operation of the Building or to provide customary or required services to
the Building; provided, however, that in no event shall General Common Areas
ever include any On-Floor Common Areas. The allocation of the square footage of
the General Common Areas shall be equal to the total square footage of the
General Common Areas multiplied by a fraction, the numerator of which is the Net
Rentable Area of the Leased Premises (excluding the allocation of the General
Common Areas) and the denominator of which is the total of all Net Rentable Area
contained in the Building (excluding the allocation of the General Common
Areas).

                "On-Floor Common Areas" shall mean those areas within (and
measured from the midpoint of the walls enclosing) public corridors, elevator
foyers, rest rooms, mechanical rooms, janitor closets, telephone and equipment
rooms, and other similar facilities for the use of all tenants on the floor on
which the Leased Premises are located. The allocation of the square footage of
the On-Floor Common Areas shall be equal to the total On-Floor Common Areas on
said floor multiplied by a fraction, the numerator of which is the Net Rentable
Area of the portion of the Leased Premises (excluding the allocations of General
Common Areas and On-Floor Common Areas) located on said floor and the
denominator of which is the total of all Net Rentable Area on said floor
(excluding the allocations of General Common Areas and On-Floor Common Areas).

                "Parking Facilities" shall mean the parking structure(s) located
on the Land from time to time, together with any connecting or covered walkways,
or other means of access to the Building, if any, the grounds related thereto
and any additional improvements at any time related thereto.

                        (c) The Net Rentable Area in the Leased Premises has
been calculated on the basis of the foregoing definition and is hereby
stipulated and agreed for all purposes to be 1,350 square feet of Net Rentable
Area, regardless of whether the same is actually more or less. Likewise, the Net
Rentable Area of space in the Building leased or held for lease has been
calculated on the basis of the foregoing definition and is hereby stipulated and
agreed for all purposes to be 395,637 square feet of Net Rentable Area,
regardless of whether the same is actually more or less.

        1.02. Term.

                        (a) Subject to and upon the terms and conditions set
forth in this Lease, the term of this Lease shall commence on the Commencement
Date (defined below) and shall expire thirty-six (36) months after the
Commencement Date at 6:00 P.M. (Houston, Texas time), unless sooner terminated
in accordance with this Lease.



                                       2
<PAGE>   8

                        (b) As used herein, "Commencement Date" means the
earlier of (i) the Completion Date, as such term is defined in Exhibit C
attached hereto or (ii) the date upon which Tenant commences conducting its
business from all or any portion of the Leased Premises. The Commencement Date
is estimated to be August 1, 1999.

        1.03. Use.

        The Leased Premises shall be used and occupied by Tenant (and its
permitted assignees and subtenants) solely as administrative and executive
offices (including customary ancillary uses which are in keeping with the
standards for tenants of Comparable Buildings, as such term is defined in
Section 3.01) and for no other purpose. Notwithstanding the preceding sentence,
however, in no event shall any of the following be permitted in the Leased
Premises: (i) offices or agencies of a foreign government or political
subdivision thereof; (ii) offices of any governmental bureau or agency of the
United States or any state or political subdivision thereof; (iii) personnel
agencies; (iv) customer service offices of any public utility company; (v)
retail facility or restaurant; (vi) doctor's or dentist's office or clinic, or
other health-care facility of any kind; (vii) airline or travel agency
reservation center; (viii) studios for radio, television or other media, or for
recording; or (ix) except to the extent customary and incidental to an otherwise
permitted use, data processing activities, training or educational uses, or
clerical support services. Further, and notwithstanding the first sentence of
this Section 1.03, the Leased Premises shall not be used for any purpose or in
any manner which would, in Landlord's reasonable opinion, lower the character of
the Property or any part thereof, create unreasonable or excessive elevator or
floor loads, unreasonably interfere with any of the operations of the Building
or any part thereof, or the proper or economic heating, air-conditioning,
cleaning or other servicing of the Building or any part thereof, or unreasonably
interfere with the use of other areas of the Property by any other tenants or
occupants, or by Landlord. The uses permitted by this Section shall also be
subject to the requirements and limitations imposed elsewhere in this Lease,
including those imposed in Sections 4.03, 4.04 and 4.05.

        1.04. Condition of Leased Premises.

        As a material inducement to Landlord to execute and deliver this Lease,
Tenant agrees that it will accept the Leased Premises and leasehold improvements
therein (other than any leasehold improvements to be constructed by Landlord in
accordance with EXHIBIT C hereto) in its AS IS condition, WITH ALL FAULTS.
Tenant acknowledges that neither Landlord nor anyone acting or purporting to act
as Landlord's representative or agent has made (and Landlord hereby specifically
disclaims any and all) representations and warranties of any kind or character
as to the condition of the Leased Premises (other than any leasehold
improvements to be constructed by Landlord in accordance with EXHIBIT C hereto)
or the Property, either express or implied, including without limitation,
warranties of fitness of the Leased Premises or any other portion of the
Property for any particular purpose or use, or commercial habitability of the
Leased Premises or any other portion of the Property. Without the foregoing,
Tenant acknowledges that Landlord does not warrant that the Leased Premises or
the Property is free from Hazardous Substances (as such term is defined in
Section 4.05 [d] below), and Tenant agrees that no presence of any such
materials shall constitute an eviction, actual or constructive, of Tenant nor
entitle Tenant to an offset, credit or defense against any of its obligations
hereunder. Upon request, Landlord will provide Tenant with a copy of the most
recent



                                       3
<PAGE>   9

environmental engineering report, if any, obtained by Landlord or its
predecessor in interest with respect to the Property, but without any
representation or warranty whatsoever as to the accuracy, correctness or
completeness of such report or any information, statements or recommendations
set forth therein (Tenant hereby agreeing that if Tenant elects to rely thereon
it does so at Tenant's sole risk, and that Landlord shall have no liability or
responsibility for any error, inaccuracy or incompleteness thereof or therein).

        1.05. Quiet Enjoyment

        Provided that Tenant pays the Rent and other sums required to be paid by
Tenant herein and performs all of Tenant's covenants and agreements herein
contained, Landlord covenants that Tenant shall and may peacefully have, hold
and enjoy the Leased Premises during the term of this Lease, subject to the
other terms and conditions hereof, without hindrance by Landlord or any other
person or entity claiming title to the Property, Leased Premises, or any part
thereof by, through or under Landlord, but not otherwise. It is understood and
agreed that this covenant and any and all other covenants of Landlord of any
kind contained in this Lease shall be binding upon Landlord and its successors
and assigns only with respect to breaches occurring during its and their
respective ownership of Landlord's interest hereunder.

                                       II

        2.01. Rental Payments.

                (a) Commencing on the Commencement Date, and continuing
thereafter throughout the term of this Lease, Tenant hereby agrees to pay the
Base Rental (defined below) in accordance with this Section 2.01 and Section
2.02, and Tenant's Forecast Additional Rental (defined below) and Tenant's
Additional Rental Adjustment (defined below) in accordance with this Section
2.01 and Section 2.03. Upon execution of this Lease by Tenant, Tenant shall
deliver to Landlord the installment of Base Rental for the first month of the
Lease plus the Security Deposit required to be paid under Section 2.05. For
purposes of this Lease, the Base Rental, Tenant's Forecast Additional Rental,
Tenant's Additional Rental Adjustment and the Parking Rent (defined below), and
installments of the foregoing, are individually and collectively referred to as
"Rent". The Base Rental and Tenant's Forecast Additional Rental shall be due and
payable in advance in equal monthly installments, sufficient to fully pay the
Base Rental and Tenant's Forecast Additional Rental, respectively, for the year
or partial year in question, on the first day of each month during the initial
term of this Lease and any extensions or renewals hereof. Tenant agrees to so
pay all Rent to Landlord at Landlord's address as provided herein (or such other
address as may be designated by Landlord from time to time).

                (b) If the Commencement Date is other than the first day of a
month or if this Lease expires or terminates on other than the last day of a
month, then the installments of Base Rental and Tenant's Forecast Additional
Rental for such month or months shall be prorated and the installment or
installments so prorated shall be paid in advance. Said installments for such
prorated month or months shall be calculated by multiplying the equal monthly
installment by a fraction, the numerator of which shall be the number of days of
the Lease term occurring during said commencement or expiration month, as the
case may be, and the denominator of which shall be thirty (30). If the term of
this Lease commences or expires on other than the first



                                       4
<PAGE>   10

day of a year, the Base Rental, Tenant's Forecast Additional Rental and Tenant's
Additional Rental shall be prorated for such commencement or expiration year, as
the case may be, by multiplying the Base Rental, Tenant's Forecast Additional
Rental, and Tenant's Additional Rental, respectively, by a fraction, the
numerator of which shall be the number of whole and partial months of the Lease
term during the commencement or expiration year, as the case may be, and the
denominator of which shall be twelve (12). In such event, the calculation
described in Section 2.03(d) shall be made as soon as possible after the
expiration or termination of this Lease. The provisions of this Section 2.01 (b)
shall survive the expiration or termination of this Lease.

                (c) Tenant agrees to pay all Rent and other sums of money as
shall become due from and payable by Tenant to Landlord under this Lease at the
times and in the manner provided in this Lease, without abatement, demand,
set-off or counterclaim. All Rent and other sums of whatever nature owed by
Tenant to Landlord under this Lease shall bear interest from the fifth (5th) day
after the due date thereof until paid at the lesser of eighteen percent (18%)
per annum, or the maximum interest rate per annum allowed by law.

                (d) As used in this Lease, "month" shall mean a calendar month,
and "year" shall mean a calendar year.

        2.02. Base Rental.

        Throughout the term of this Lease, Tenant hereby agrees to pay a base
annual rental equal to Twenty-Three and 00/100 Dollars ($23.00) [the rental rate
set forth in the following schedule] (the "Base Rental Rate"), multiplied by the
number of square feet of Net Rentable Area of the Leased Premises, in accordance
with the terms hereof.

<TABLE>
<CAPTION>
                                                                     Monthly Installments
Lease Period                        Base Rental                      of Base Rental
------------                        -----------                      --------------
<S>                                 <C>                              <C>
Months 1-36                         $23.00                           $2,587.50
</TABLE>

        2.03. Additional Rental.

                (a) Commencing with the year in which the Commencement Date
occurs and continuing thereafter for each year during the term of this Lease,
Landlord shall present to Tenant prior to the beginning of said year (or for the
year in which the Lease term commences, on the Commencement Date) a statement of
Tenant's Forecast Additional Rental.

                (b) As used herein, "Tenant's Forecast Additional Rental" shall
mean Landlord's reasonable estimate of Tenant's Additional Rental (defined
below) for the coming year (or, in the year in which the Lease term commences,
for such year).

                (c) "Tenant's Additional Rental," as that term is used herein,
shall be computed on a year basis and shall mean Tenant's Percentage Share
(defined below) of Operating Expenses (defined below), to the extent such sum
exceeds Tenant's Percentage Share of Operating Expenses during the "Base Year".
The "Base Year" for purposes of this Lease is the year 1999. As used herein,
"Tenant's Percentage Share" shall mean a fraction, the numerator of which is the
total number of square feet of Net Rentable Area within the Leased



                                       5
<PAGE>   11

Premises and the denominator of which is the total square footage of all Net
Rentable Area in the Building. For the purposes of this Lease, the "Tenant's
Percentage Share" is stipulated and agreed to be 0.3412%; provided, however,
that in the event that the amount of space leased by Tenant shall increase or
decrease subsequent to the Commencement Date, whether pursuant to an option to
expand or otherwise, Tenant's Proportionate Share shall be appropriately
adjusted by Landlord.

                (d) No later than one hundred twenty (120) days after the end of
the year in which the Commencement Date occurs and of each year thereafter
during the term of this Lease, Landlord shall provide Tenant statements prepared
by or on behalf of Landlord comparing (i) the Base Year's Operating Expenses and
Operating Expenses for such year, and (ii) Tenant's Forecast Additional Rental
and Tenant's Additional Rental for such year. In the event that Tenant's
Forecast Additional Rental actually paid by Tenant exceeds Tenant's Additional
Rental for said year, Landlord shall pay Tenant (in the form of a credit against
Rents or other Lease obligations of Tenant due or to become due, as selected by
Landlord, or, upon expiration or termination of this Lease if Tenant is not then
in default under this Lease, in the form of Landlord's check) an amount equal to
such excess. In the event that Tenant's Additional Rental exceeds Tenant's
Forecast Additional Rental for said year, Tenant hereby agrees to pay Landlord,
within thirty (30) days of receipt of the statement, an amount equal to such
difference ("Tenant's Additional Rental Adjustment"). The provisions of this
Section 2.01(d) shall survive any expiration or termination of this Lease.

                (e) Tenant, at tenant's sole cost and expense, shall have the
right, to be exercised by notice given to Landlord within ninety (90) days after
receipt of the aforesaid statement showing Operating Expenses for the preceding
year, to audit, at the place where Landlord maintains its books and records,
Landlord's books and records, but only with respect to Operating for such
preceding year, provided that (i) such audit commences within thirty (30) days
after Tenant's notice to Landlord and thereafter proceeds regularly and
continuously to conclusion, (ii) Tenant or Tenant's employee is present at such
location at all times during the audit, (iii) such audit does not unreasonably
interfere with the conduct of Landlord's business, (iv) such audit is performed
by an auditing firm with an established and favorable reputation in the Houston,
Texas area, and (v) said auditing firm signs a nondisclosure agreement in favor
of Landlord, acceptable to Landlord in all respects, agreeing that such audit
and information derived from such audit shall not be used directly or indirectly
in connection with soliciting additional auditing business from other existing,
prior or future tenants in the Building, and containing such other agreements
and representations as Landlord may require. Landlord agrees to cooperate in
good faith with Tenant in the conduct of any such audit. Notwithstanding
anything to the contrary set forth in this Section 2.03(e), however, in no event
shall Tenant ever be permitted to audit or cause to be audited Landlord's
records concerning Operating Expenses through, or with the assistance of,
auditors or others whose compensation is contingent upon, or the amount of whose
compensation is affected by, the outcome of such audit, in whole or in part, or
on any payment or reimbursement by Landlord to Tenant in connection with such
audit, or which is otherwise done in whole or in part on any basis other than
reasonable hourly charges for the hours expended in the performance of such
audit, and reimbursement of reasonable out-of-pocket expenses incurred by such
auditors in connection with such audit.



                                       6
<PAGE>   12

                (f) Notwithstanding the foregoing provisions of this Section
2.03, in the event that the Base Year's Operating Expenses shall ever be greater
than the Operating Expenses for any year of the Lease term, Tenant shall not be
entitled to any reduction in Base Rental, nor any credit, refund, reduction of
obligations, or other benefit in respect thereof.

        2.04. Operating Expenses.

                (a) For the purposes of this Lease, "Operating Expenses" for any
calendar year shall mean all (or where specified by Landlord as hereinafter
permitted or required, an amortized portion of all) expenses, costs and accruals
of every kind and nature, computed on an accrual basis, incurred or accrued in
connection with, or relating to, the ownership, maintenance, or operation of the
Property and related assets, during such year, including, but not limited to,
the following:

                        (1) management fees of the Building manager;

                        (2) wages, salaries, taxes, insurance, benefits and
related expenses of all on and off-site employees and personnel engaged in
operations, maintenance, access or traffic control, as reasonably allocated by
Landlord;

                        (3) cost of all supplies, tools, equipment and materials
to the extent used in operations and maintenance, as reasonably allocated by
Landlord;

                        (4) actual cost of all utilities including, but not
limited to, the cost of electricity, water, sanitary sewer services, natural
gas, telecommunications services, and power for heating, lighting, air
conditioning and ventilating;

                        (5) cost of all maintenance and service agreements and
the equipment used in connection therewith including, but not limited to, access
control service, traffic control service, garage or parking operations, window
cleaning, elevator maintenance, janitorial service and landscaping maintenance;

                        (6) cost of repairs and general maintenance (excluding
repairs and general maintenance paid by proceeds of insurance), or if and to the
extent Landlord so elects in order to reduce the amount of Operating Expenses
paid by tenants of the Building in any particular year or years, Landlord may at
its option amortize such cost based upon any amortization schedule chosen by
Landlord in its sole and absolute discretion, in which event the amortized
portion of such repair and maintenance costs (whether such costs were incurred
in the same year or in any prior year) shall be included as an Operating Cost in
each year of the amortization schedule as selected by Landlord;

                        (7) amortization of the cost (together with reasonable
interest or financing charges, and installation and related costs). based upon
any amortization schedule selected by Landlord in its sole and absolute
discretion, of any system, apparatus, device, equipment or other capital
investment item which is for the principal purpose of (i) reducing Operating
Expenses, (ii) promoting safety or (iii) complying with applicable laws, rules,
regulations, codes or ordinances of any federal, state, municipal, local or
other governmental



                                       7
<PAGE>   13

authority (whether heretofore, now or hereafter applicable or in effect), in
each case whether such costs were incurred in the same year or in any prior
year;

                        (8) the cost of all insurance, including, but not
limited to, the cost of casualty, flood, rental abatement and liability
insurance, and insurance on Landlord's personal property, plus the cost of all
deductible payments made by Landlord in connection therewith;

                        (9) reasonable legal, accounting and other professional
fees and expenses;

                        (10) all taxes, assessments and governmental charges of
any kind or nature, whether or not directly paid by Landlord, whether federal,
state, municipal, local or other, and whether they be by taxing districts or
authorities presently taxing the Property or such other land or facilities or by
others subsequently created or otherwise, and any other taxes, assessments and
governmental changes attributable to the Property or such other land or
facilities or their operation, excluding taxes and assessments attributable to
the personal property of other tenants, federal and state taxes on income, death
taxes, franchise taxes, and any taxes imposed or measured on or by the income of
Landlord from the operation of the Property or such other land or facilities;
provided, however, that if at any time during the term of this Lease, the
present method of taxation or assessment shall be changed such that the whole or
any part of the taxes, assessments, or governmental charges now levied, assessed
or imposed on real estate, improvements or personal property shall be
discontinued or reduced, in whole or in part, and as a substitute therefor, or
in lieu of or in addition thereto, taxes, assessments, or governmental charges
shall be levied, assessed or imposed, wholly or partially, on (or shall be
calculated with reference to) the rents received from the Property or such other
land or facilities, or the rents reserved herein, or the income of Landlord in
respect of the Property, such other land or facilities, or any such rents, or on
Landlord's franchise, then such substitute, additional or increased taxes,
assessments, or governmental charges, to the extent so levied, assessed or
imposed, shall be deemed to be included within the Operating Expenses.
Consultation, legal fees and costs in connection with any challenge of tax
assessments as reasonably allocated by Landlord shall also be included in
Operating Expenses. Tenant will be responsible for and shall timely pay all ad
valorem taxes on its personal property and on the value of the leasehold
improvements in the Leased Premises to the extent that the same exceed Building
Standard (and if the taxing authorities do not separately assess Tenant's
leasehold improvements, Landlord may make a reasonable allocation of the ad
valorem taxes allocated to the Property and such other land and facilities, to
give effect to this sentence). In the case of special taxes and assessments
which may be payable in installments, only the amount of each installment
accruing during a year shall be included in the Operating Expenses for such
year.

                (b) Notwithstanding the foregoing provisions of this Section
2.04(b), "operating costs" shall not include any of the following:

                        (i) Any costs or expenditures for which Landlord is
entitled to reimbursement by Tenant (other than pursuant to this Section
2.04(b), any other tenant of the Property (other than for general reimbursement
of operating costs or increases therein) or any other third parties, or from
insurance or condemnation proceeds;



                                       8
<PAGE>   14

                        (ii) Any overhead, administrative or general office
expense other than that provided for in this Section 2.04(b);

                        (iii) The cost of completing initial construction of the
Building or the cost of constructing leasehold improvements for specific
tenants, including all common areas and tenant occupied spaces;

                        (iv) The cost of correcting defects in construction of
the Property or in the Building or Parking Facilities equipment (including
abatement of asbestos if present), except that conditions not occasioned by
construction defects resulting from ordinary wear and tear and use shall not be
deemed defects for the purpose of this category;

                        (v) Leasing commissions, ground rentals, non-cash items,
debt service and other debt costs, and advertising and promotional expenditures;

                        (vi) Any cost or expenditure attributable to a breach by
Landlord of its covenants, obligations and duties under this lease that would
not have been incurred but for such breach;

                        (vii) The cost of any work or service performed for, or
materials, items, or facilities furnished to, any tenant of the Property to a
materially greater extent or in a materially more favorable manner than that
furnished generally to all tenants of the Property;

                        (viii) Landlord's central office or its operations
conducted, or employees engaged therein (except to the extent provided in
Section 2.04(b)(1);

                        (ix) Capital improvements and additions to the Property
or any non-cash items such as depreciation and amortization, except to the
extent permitted by Section 2.04(b)(7);

                        (x) Expenses and wages of leasing personnel and leasing
commissions, attorneys' fees and other costs and expenses incurred by Landlord
in (i) leasing space in the Property (including, without limitation, cost of
tenant improvements made in the Property by Landlord in connection therewith or
any amounts paid by Landlord in the settlement of, or by assumption of, any
prior lease obligations of a prospective tenant) or (ii) any litigation, or the
negotiation or settlement of any dispute, between Landlord and any person or
entity with respect to the ownership, sale, financing or refinancing, operation
or maintenance of the Property including, without limitation the enforcement of
any lease obligation except to the extent that such litigation, dispute or cost
incurred in the operation or maintenance of the Property is caused by the
negligence or willful misconduct of Tenant, its agents, contractors or
employees;

                        (xi) Any costs incurred in connection with the sale,
refinancing, mortgaging or change in ownership of the Property or any portion
thereof, including, without limitation, brokerage commissions, attorneys' and
other professional fees, appraisals, closing costs and interest charges;

                        (xii) Overhead or profits increment paid to subsidiaries
of affiliates of Landlord for services on or to the Property to the extent such
overhead or profit



                                       9
<PAGE>   15

increment exceeds that which would have been earned or paid to an independent,
third party provider of the same or similar services; and

                        (xiii) Costs incurred due to any violation by Landlord
of the terms and conditions of any lease in the Property or of any ground lease
or mortgage encumbering the Property unless caused by the acts or omissions of
Tenant, its contractors, agents or employees, or any cost, fines or penalties
incurred by Landlord due to any failure by Landlord to comply with all federal,
state and local laws, Rules and regulations in its ownership, operation or
maintenance of the Property unless caused by the acts or omissions of Tenant,
its agents, contractors and employees in the performance of its obligations
under this Lease;

                (c) Tenant hereby WAIVES any and all rights under Section 41.413
of the Texas Property Tax Code granting to tenants the right to contest
appraised values, or to receive notice of reappraised values, of all or any
portion of the Property irrespective of whether Landlord has elected to contest
the same. To the extent such waiver is prohibited by applicable law, Tenant
hereby appoints Landlord as Tenant's attorney in fact, coupled with interest, to
appear and take all actions on behalf of Tenant which Tenant may take under said
Code.

        2.05. Security Deposit.

        Tenant hereby agrees to pay to Landlord, in cash or by certified check,
a security deposit of TWO THOUSAND FIVE HUNDRED EIGHTY SEVEN AND 50/100 DOLLARS
($2,587.50) on the day this Lease is executed by Tenant (the "Security
Deposit"). Upon the occurrence of any event of default by Tenant, Landlord may,
from time to time, without prejudice to any other remedy, use the Security
Deposit to the extent necessary to make good any arrears of Base Rental,
Tenant's Forecast Additional Rental, or Tenant's Additional Rental Adjustment,
or to pay any other sums owed to Landlord, including any sums described in
Section 7.01, or to pay the cost of any damage, injury, expense, or liability
caused by any event of default by Tenant. Any remaining balance of the Security
Deposit, along with an accounting of such, shall be returned by Landlord to
Tenant within a reasonable period of time after the termination or expiration of
this Lease, and fulfillment by Tenant of all obligations of Tenant under this
Lease. The Security Deposit shall not be considered an advance payment of rental
or a measure of Landlord's damages in the case of an event of default by Tenant.
Tenant shall not be entitled to receive and shall not receive any interest on
the Security Deposit, and Landlord may co-mingle the same with other monies of
Landlord. In the event Landlord applies the Security Deposit or any portion
thereof to the payment of any sum described above and this Lease is not
terminated, Tenant shall immediately deposit with Landlord an amount of money
equal to the amount so applied and such amount shall be deemed to be part of the
Security Deposit. Tenant shall not assign or encumber the Security Deposit
without the prior written consent of Landlord, and Landlord shall not be bound
by any such assignment or encumbrance made without the prior written consent of
Landlord. In connection with any sale or transfer of the Building, Landlord
shall have the right to transfer the Security Deposit to the purchaser or other
transferee of the Building, in which event Landlord shall be released from any
responsibility for the return of the Security Deposit and Tenant agrees to look
solely to the purchaser or transferee of the Building for the return of the
Security Deposit.



                                       10
<PAGE>   16

                                       III

        3.01. Services.

        So long as Tenant is not in default hereunder and is in actual occupancy
of the Leased Premises, Landlord shall furnish the following services during the
term of this Lease (such services, excluding any services referenced as being
optional, extra-cost or above-standard, being herein called "Building Standard
Services"):

                (a) Hot and cold domestic water and common use rest rooms and
toilets at locations provided for general use by tenants as reasonably deemed by
Landlord to be necessary for the comfortable use and occupancy of the Building.

                (b) Subject to curtailment as required by governmental laws,
rules or regulations, central heat and air conditioning in season, at such
temperatures and in such amounts as are reasonably deemed by Landlord to be
necessary for the comfortable use and occupancy of the Building, and on such
dates and at such times as are more particularly described on Exhibit D attached
hereto.

                (c) Electric lighting service for public areas and special
service areas of the Building in the manner and to the extent reasonably deemed
by Landlord to be necessary for the comfortable use and occupancy of the
Building.

                (d) Janitorial service to the Leased Premises on a five (5) day
per week basis, exclusive of Holidays (as defined in Exhibit D), in a manner
that Landlord reasonably deems to be consistent with that provided in
multi-tenant office buildings similar to the Building which are located in the
Galleria area of Houston, Texas ("Comparable Buildings"); provided, however, if
Tenant's floor coverings or other improvements are other than Building Standard,
Tenant shall pay Landlord upon demand one hundred and fifteen percent (115%) of
the actual additional cleaning cost, if any, attributable thereto.

                (e) Access control services for the Building which Landlord
reasonably deems to be comparable as to coverage, control and responsiveness
(but not necessarily as to means for accomplishing same) to those provided in
Comparable Buildings; PROVIDED, HOWEVER, LANDLORD SHALL HAVE NO RESPONSIBILITY
TO PREVENT, AND SHALL NOT BE LIABLE TO TENANT, ITS OFFICERS, DIRECTORS,
SHAREHOLDERS, PARTNERS, AGENTS, EMPLOYEES, PERSONNEL, REPRESENTATIVES, INVITEES,
VISITORS, LICENSEES, CUSTOMERS AND CONTRACTORS (ALL OF THE FOREGOING BEING
HEREINAFTER INDIVIDUALLY AND COLLECTIVELY REFERRED TO AS "ASSOCIATED PARTIES")
FOR ANY LOSSES, DAMAGES, COSTS, CLAIMS AND LIABILITIES ARISING OUT OF OR IN
CONNECTION WITH THEFT, BURGLARY, INJURY OR DAMAGE TO PERSONS OR PROPERTY, OR
UNLAWFUL ACTIVITY OF ANY KIND, CAUSED BY PERSONS GAINING ACCESS TO THE LEASED
PREMISES, THE BUILDING OR THE PROPERTY (REGARDLESS OF WHETHER OR NOT CAUSED OR
ALLEGED TO BE CAUSED BY THE NEGLIGENCE OF LANDLORD OR ANYONE FOR WHOM LANDLORD
IS



                                       11
<PAGE>   17

RESPONSIBLE) AND TENANT HEREBY RELEASES LANDLORD FROM ALL LIABILITY FOR OR IN
CONNECTION WITH THE FOREGOING.

                (f) Sufficient electrical capacity distributed to a panel box
located at the core of the floor(s) on which the Leased Premises are located to
operate (i) incandescent lights, typewriters, calculating machines, photocopying
machines and other machines of similar low voltage electrical connected load
(120/208 volts), provided that the total rated electrical design load for said
lighting and machines of low electrical voltage shall not exceed one (1.00) watt
per square foot of Usable Area of the Leased Premises; and (ii) lighting and
equipment of high voltage electrical connected load (277/480 volts), provided
that the total rated electrical design load for said lighting and equipment of
high electrical voltage shall not exceed three and five tenths (3.50) watts per
square foot of Usable Area of the Leased Premises (each such rated electrical
design load to be hereinafter referred to as the "Building Standard Rated
Electrical Design Load"). Tenant shall be allocated Tenant's pro rata share of
the circuits provided on such floor(s) ("Building Standard Circuits").

        Should Tenant's total rated electrical design load exceed the Building
Standard Rated Electrical Design Load for either low or high voltage electrical
consumption, or if Tenant's electrical design requires low voltage or high
voltage circuits in excess of Tenant's share of the Building Standard Circuits,
Landlord may elect, at its option (and at Tenant's expense), to install one (1)
additional high voltage panel and/or one (i) additional low voltage panel with
associated feeders and equipment, subject to a maximum of two (2) such
additional panels per floor for all tenants on the floor (which additional
panels, feeders and equipment shall be hereinafter referred to as the
"Additional Electrical Equipment". If the Additional Electrical Equipment is
installed because Tenant's low or high voltage rated electrical design load
exceeds the applicable Building Standard Rated Electrical Design Load, then a
meter shall also be added (at Tenant's expense) to measure the electricity used
through the Additional Electrical Equipment.

        The design and installation of any Additional Electrical Equipment
required by Tenant (or any related matter) shall be subject to the prior
approval of Landlord (which approval shall not be unreasonably withheld). All
expenses incurred by Landlord in connection with the review and approval of any
Additional Electrical Equipment shall also be reimbursed to Landlord by Tenant
upon demand. Tenant shall also pay on demand the actual metered cost of
electricity consumed through the Additional Electrical Equipment (if
applicable), plus any actual accounting expenses incurred by Landlord in
connection with the metering thereof.

        If any of Tenant's electrical equipment requires conditioned air in
excess of air conditioning in the amounts, times or specifications normally
provided by Landlord as part of Building Standard Services, the same shall be
installed by Landlord (on Tenant's behalf, and Tenant shall pay on demand all
design, installation, metering and operating costs relating thereto.

        If Tenant requires that certain areas within the Leased Premises operate
in excess of the normal Building Operating Hours (as defined in Exhibit D
attached hereto, and hereinafter so called), the electrical service to such
areas shall be separately circuited and metered such that Tenant shall be billed
the costs associated with electricity consumed during hours other than Building
Operating Hours.



                                       12
<PAGE>   18

                (g) Building Standard fluorescent bulb replacement in all areas,
and incandescent bulb replacement in General Common Areas, Service Areas and
On-Floor Common Areas.

                (h) Non-exclusive multiple cab passenger elevator service to the
floor(s) on which the Leased Premises are located during Building Operating
Hours and at least one (1) cab passenger elevator service to the such floor(s)
twenty-four (24) hours per day and non-exclusive freight elevator service during
Building Operating Hours (all subject to temporary cessation for ordinary repair
and maintenance and during times when life safety systems override normal
Building operating systems) with such freight elevator service available at
other times upon reasonable prior notice and the payment by Tenant to Landlord
of any additional expense actually incurred by Landlord in connection therewith.

        To the extent the services described above consist of, or reasonably
require the availability or use of, electricity, natural gas, water or other
utility services supplied by third party utility providers, Landlord's
obligations hereunder shall be subject to the providing of such utility services
by the applicable utility provider. Landlord agrees, however, to use reasonable
efforts to cause the utility providers to furnish the same. Failure by Landlord
to furnish the services described in this Section 3.01, or any cessation
thereof, shall not render Landlord liable for losses or any injuries or damages
to persons or property, nor be construed as an eviction, actual or constructive,
of Tenant, nor work an abatement of rent, nor relieve Tenant from fulfillment of
any covenant or agreement hereof. In addition to the foregoing, should any
equipment or machinery, for any cause, fail to operate, or function properly,
Tenant shall have no claim for abatement of rent or for losses or any injuries
or damages to persons or property on account of an interruption in service
occasioned thereby or resulting therefrom, nor shall such malfunction or
interruption be construed as an eviction, actual or constructive, of Tenant, nor
relieve Tenant from fulfillment of any covenant or agreement of this Lease.
Landlord agrees, however, to use reasonable efforts to promptly repair said
equipment or machinery and to restore said services.

        3.02. Keys and Locks.

        Landlord shall furnish Tenant with two (2) keys for each Building
Standard lockset on doors required by applicable building codes and ordinances
entering the Leased Premises from public areas. Additional keys will be
furnished by Landlord upon an order signed by Tenant and payment by Tenant of
Landlord's reasonable charge therefor. All such keys shall remain the property
of Landlord. No additional locks shall be allowed on any door of the Leased
Premises without Landlord's permission, and Tenant shall not make or permit to
be made any duplicate keys. Upon termination of this Lease, Tenant shall
surrender to Landlord all keys and access cards to any locks or doors entering
or within the Leased Premises, and give to Landlord the combination or other
means of access of all locks for safes, safe cabinets, vault doors, and other
secured areas, if any, in the Leased Premises.

        3.03. Graphics, Building Directory Board and Name.

        Landlord shall provide and install, at Tenant's cost, all graphics,
letters, and numerals at the entrance to the Leased Premises and one (1)
identification strip(s) containing a



                                       13
<PAGE>   19

listing of Tenant's name and such other information as Tenant shall reasonably
require on the Building directory board in the main lobby of the Building. All
such letters and numerals shall be in the Building Standard graphics. Tenant
agrees that Landlord shall not be liable for any inconvenience, loss or damage
occurring as a result of any error or omission in any directory or graphics. No
signs, numerals, letters or other graphics on the exterior of, or which may be
visible from anywhere outside, the Leased Premises shall be used or permitted
unless provided by Landlord or approved in writing by Landlord.

        3.04. Parking.

                (a) Landlord agrees to provide, and Tenant obligates itself to
pay for, for the term of this Lease, the numbers of assigned parking permits
("Reserved Permits") and unassigned parking permits ("Unassigned Permits")
described in Section 3.04(b) for the parking of automobiles in spaces or areas
in the Parking Facilities as are from time to time designated by Landlord. At
the sole and absolute discretion of Landlord, upon request of Tenant, Landlord
may provide Tenant additional parking permits as needed from time to time, in
which event Tenant shall pay for all such permits for the term of this Lease
unless Landlord and Tenant should agree otherwise. Notwithstanding any contrary
provisions hereof, the rights of Tenant hereunder shall terminate or expire
simultaneously with the termination or expiration of this Lease. Tenant shall
provide to Landlord such information and documentation evidencing the number of
Tenant's full-time employees located within the Leased Premises as Landlord
shall reasonably request from time to time. Landlord shall also provide
unassigned parking for visitors of the Building in a portion of the Parking
Facilities on a pay basis at such rates and upon such conditions as Landlord
shall establish or permit to be established in its sole and absolute discretion
from time to time.

                (b) The rent for parking permits provided to Tenant hereunder
shall initially be as follows, and the number of such permits shall be as
follows:

<TABLE>
<CAPTION>
                                                          Total Initial
                                     Initial Monthly      Monthly Rate for
                       Number        Rate Per Permit      Such Permits
                       ------        ---------------      ------------
<S>                    <C>           <C>                  <C>
Unassigned Permits     4             $50.00               $200.00
</TABLE>

        The total monthly rent for Reserved Permits and Unassigned Permits is
hereinafter called the "Reserved Parking Rent" and "Unassigned Parking Rent",
respectively, and the Reserved Parking Rent and Unassigned Parking Rent are
hereinafter collectively referred to as the "Parking Rents". Tenant shall also
be responsible for, and shall simultaneously pay, all federal, state and local
sales, use and other taxes on, or related to, the Parking Rent. Tenant shall pay
the Parking Rent in advance on the first day of each calendar month during the
term of this Lease (or, in the event the term of this Lease commences on a date
other than the first day of a calendar month, a pro rata portion of said rentals
shall be due and payable on the Commencement Date). The Parking Rent shall be
adjusted by Landlord from time to time to the then prevailing rates being
charged by Landlord for reserved and unassigned parking permits in the Parking
Facilities.



                                       14
<PAGE>   20

                (c) In the event the parking spaces in the Parking Facilities
required to accommodate parking pursuant to the Unassigned Permits and the
Reserved Permits (collectively, the "Parking Permits"), are not available to
Tenant due to causes beyond the control of Landlord during any portion of the
Term, then Landlord shall make available to Tenant, at the Parking Rent as set
forth above, sufficient unassigned spaces (not to exceed the number of Parking
Permits set forth above) in other parking facilities to meet Tenant's needs
until such spaces in the Parking Facilities are again made available to Tenant.
Subject to availability and reasonableness of cost to Landlord, such other
parking facilities shall be located in reasonable proximity to the Building.

                (d) Landlord or the operator of the Parking Facilities may make,
modify and enforce reasonable rules and regulations relating to the use and
parking of vehicles in the Parking Facilities, and Tenant agrees to abide by,
and to cause its personnel, agents, employees, contractors, visitors and
invitees to abide by, such rules and regulations. Tenant shall indemnify and
hold harmless Landlord from and against all claims, demands, actions, losses,
liabilities, damages, costs and expenses (including attorneys' fees and expenses
and other costs and expenses of defending against, settling, or otherwise
dealing with such claims, demands, actions and liabilities) arising or alleged
to arise out of the use of any such parking permits or the Parking Facilities by
Tenant or its Associated Parties. The agreements of Tenant set forth in the
preceding sentence shall survive the expiration or any earlier termination of
this Lease.

                                       IV

        4.01. Care of Leased Premises; Condition on Expiration.

        Tenant shall not commit, or allow to be committed by Tenant's Associated
Parties, any waste or damage to any portion of the Leased Premises or the
Property. Upon the expiration or any earlier termination of this Lease, Tenant
shall surrender the Leased Premises to Landlord in as good condition as existed
on the date on which Tenant commenced conducting its business from the Leased
Premises (or if later, the Completion Date), ordinary wear and tear excepted,
and subject as otherwise provided in the following sentence. In the event Tenant
shall have made alterations, physical additions or improvements to the Leased
Premises after such date, Landlord shall have the right to require Tenant to
either leave such alterations, physical additions or improvements in place, or
(except to the extent Landlord may have expressly and specifically agreed to
waive its right to require removal of such alteration, physical addition or
improvement) to remove all or any portion of such improvements and physical
additions and restore any or all areas affected by such alterations or removal,
as Landlord may elect in its sole and absolute discretion by notice to Tenant;
provided, however, that in the event Landlord fails to so notify Tenant prior
to, or within sixty (60) days after, the expiration or earlier termination of
this Lease, then Landlord shall be deemed to have elected to leave all such
improvements, physical additions and alterations in place. In the event Landlord
elects to cause Tenant to remove all or any portion of such improvements and
physical additions or to restore any or all areas affected by such alterations,
then Tenant shall complete such removal and restoration in accordance with this
Lease and in accordance with the requirements of Landlord within thirty (30)
days after Tenant receives such notice. Any improvements, physical additions and
alterations which Landlord does not require Tenant to remove or restore shall
become property



                                       15
<PAGE>   21

of Landlord. Upon expiration or any earlier termination of this Lease, Landlord
shall have the right to re-enter and resume possession of the Leased Premises
immediately.

        4.02. Entry for Repairs and Inspection.

        Tenant shall permit Landlord and its contractors, officers, employees,
agents, representatives and invitees to enter into and upon any part of the
Leased Premises during reasonable hours (or in the event of an emergency
involving potential injury, loss or damage to persons or property, at any time)
to inspect or clean the same, make repairs, alterations or additions thereto, or
(in the event of an emergency) to take other appropriate remedial steps, and,
upon reasonable prior notice to Tenant, for the purpose of showing the same to
prospective tenants, purchasers or lenders or their officers, employees, agents,
representatives or contractors, and Tenant shall not be entitled to any
abatement or reduction of Rent, or any other sums required to be paid by Tenant
pursuant to this Lease, by reason thereof. Landlord shall use reasonable efforts
not to interfere materially with the operation of Tenant's business during any
such entry. Landlord shall have no liability to Tenant for any damages to the
Leased Premises or Tenant's property therein which occurs in connection with any
forced entry to the Leased Premises due to an emergency, Tenant hereby WAIVING
any claim against Landlord therefor.

        4.03. Nuisance.

        Tenant shall occupy the Leased Premises, conduct its business and
control Tenant's Associated Parties, all in such a manner as not to create or
permit any public or private nuisance, or interfere with, annoy, or disturb the
quiet enjoyment of, any other tenant or occupant or Landlord in their respective
use, enjoyment or operation of the Property. Tenant will not keep any substance
or apparatus, or carry on or permit any activity, which emits or might emit
offensive odors, noise or vibrations into other portions of the Property.

        4.04. Laws and Regulations; Rules of Building.

        Tenant shall comply with, and Tenant shall cause Tenant's Associated
Parties to comply with, all existing and future laws, ordinances, orders, rules
and regulations of all state, federal, municipal, local and other governmental
or judicial agencies or bodies relating to the use, condition or occupancy of
the Leased Premises, and with the Rules of the Building reasonably adopted and
altered by Landlord from time to time for the safety, care and cleanliness of
the Building and other portions of the Property and for the preservation of good
order therein, and with the rules and regulations adopted for the Parking
Facilities from time to time in accordance with Section 3.04. The initial rules
of the Building are attached hereto as Exhibit E. To the extent to which
Landlord may do so reasonably and without violating the provisions of any
existing or future lease with any other tenant of the Building, Landlord shall
employ its good faith efforts to enforce the Building Rules in a consistent and
even-handed manner as to all tenants of the Building whose use of their premises
is similar to Tenant's use of the Leased Premises.

        4.05. Legal Use and Violations of Insurance Coverage; Hazardous
Materials.

                (a) Tenant shall not occupy or use the Leased Premises, or
permit any portion of the Leased Premises to be occupied or used, for any
business or purpose which is,



                                       16
<PAGE>   22

directly or indirectly, forbidden by any applicable law, code, ordinance, rule,
regulation or order of any federal, state, municipal or local governmental
authority or court having jurisdiction thereof, or which is disreputable, or
which may be dangerous to life, health or property, or do or permit anything to
be done anything which would in any way violate the requirements of, or increase
the rate of, fire, liability, or any other insurance policy on the Property or
its contents. If Tenant commits any act or permits any use that increases the
cost of any such policy, then in addition to Landlord's other rights and
remedies in respect thereof, Landlord may require Tenant to pay such increased
cost, which sum shall be due and payable by Tenant upon demand.

                (b) Tenant acknowledges that Landlord does not warrant that the
Leased Premises or the Building are free from asbestos or asbestos containing
material or from any other Hazardous Substances (as defined in Section 4.05(d)
below). However, if, subsequent to the date hereof, other than as a result of
any act or omission of Tenant, its agents, contractors, employees, licensees or
invitees, Hazardous Substances are found to exist in the Leased Premises, and
the same are of a nature and quantity that they constitute a present threat to
the health or safety of Tenant's employees, as determined by or set forth in the
applicable enforceable standards promulgated or adopted by the City of Houston,
State of Texas or other health or governmental officials with jurisdiction over
the Leased Premises, or otherwise render the Leased Premises unusable in
substantially the same manner as prior to the discovery of such Hazardous
Substance, then, promptly after receiving written notice thereof, Landlord shall
commence taking such action as Landlord chooses which will cause such threat to
cease, including (if Landlord so elects) removing such Hazardous Substances from
the Leased Premises and disposing of such Hazardous Substances, in compliance
with all applicable laws. Base Rental and other rentals due under this Lease
shall abate commencing the later to occur of (x) one (1) business day after the
date such Hazardous Substances are determined to constitute such a present
threat or the Leased Premises have been rendered unusable, or (y) the date upon
which Tenant ceases to make use of the Leased Premises, to the extent and in the
proportion that the Leased Premises are unusable until they are again usable.
[Moreover, if Landlord is unable to remedy the same during the Environmental
Cure Period (as hereinafter defined), Tenant shall have the right (in addition
to its right to abate rent as described above), to terminate this Lease by
providing written notice to Landlord to such effect within thirty (30) days
after the expiration of the Environmental Cure Period. As used herein, the term
"Environmental Cure Period" shall mean a period of sixty (60) days commencing on
the date Landlord receives written notice of such Hazardous Substance, or such
longer period (not to exceed one year) as may be reasonably required to remedy
such condition provided that Landlord commences such remedial efforts within
said sixty (60) day period and thereafter diligently prosecutes the same to
completion.] Tenant shall notify Landlord of the existence of such Hazardous
Substance within ten (10) days after Tenant becomes aware of such condition. For
the purpose of this Section 1.04(b), Tenant and Landlord agree that in no event
shall any substances or materials be considered hazardous which are commonly
used in the operation, maintenance or repair of buildings similar to the
Building, the presence of which is not prohibited by applicable laws,
ordinances, codes, rules or regulations.

                (c) Tenant hereby acknowledges it has reviewed or has had an
opportunity to review reports and records in Landlord's possession relating to
the presence or potential presence of asbestos containing materials in the
Property (the "Asbestos Records"). Landlord hereby disclaims any and all
representations or warranties, whether express or implied,



                                       17
<PAGE>   23

regarding the accuracy or completeness of the Asbestos Records or any
information or recommendations set forth therein. Upon Tenant's written request,
Landlord will make available such Asbestos Reports at the Building management
office, at any time during Building Operating Hours. Tenant agrees that no other
duties of disclosure or notification are created or implied by Landlord's
agreement to make the Asbestos Records available to Tenant.

                (d) As used herein, the term "Hazardous Substances" shall mean,
without limitation, any material, waste or substance defined, listed, or
regulated as a "hazardous substance", "hazardous waste", "toxic substance",
"pollutant", "contaminant", "oil", or "petroleum substance" under any of the
Environmental Laws (as hereinafter defined). As used herein, the term
"Environmental Laws" shall mean any and all statutes, rules, regulations,
ordinances, orders, permits, licenses, and other applicable legal requirements,
relating directly or indirectly to human health or safety or the environment, or
the presence, handling, treatment, storage, disposal, recycling, reporting,
remediation, investigation, or monitoring of Hazardous Substances. As used
herein, the term "release" shall have the same meaning as under the
Comprehensive Environmental Response, Compensation and Liability Act of 1980, as
amended, 42 U.S.C. Section 9601 et al.

        4.06. Telecommunications Providers

        In the event Tenant wishes to use, at anytime during the term of this
Lease, the services of a telecommunication provider whose equipment or service
is not then in the Building, no such provider shall be entitled to enter the
Building or commence providing such service without first obtaining the written
consent of Landlord. Landlord may condition its consent on such matters as
Landlord deems appropriate including, without limitation, (i) such provider
agreeing to an easement in form and substance satisfactory to Landlord, (ii)
Landlord having been provided and approved the plans and specifications for the
equipment to be installed in the Building, (iii) Landlord having received, prior
to the commencement of such work, such indemnities, bonds or other financial
assurances as Landlord may require, (iv) the provider agreeing to abide by all
Building rules and regulations, and agreeing to provide Landlord an "as built"
set of plans and specifications, (v) the provider agreeing to pay Landlord such
compensation as Landlord determines to be reasonable, and (vi) Landlord having
determined that there is adequate space in the Building for the placement of
such provider's lines and equipment.


                                        V

        5.01. Leasehold Improvements; Furnishings.

                (a) Landlord and Tenant hereby agree that the provisions of
Exhibit C attached hereto shall govern the construction of Tenant's initial
leasehold improvements.

                (b) Notwithstanding anything contained in this Lease to the
contrary, if for any reason the Leased Premises should not be ready for
occupancy by the estimated Commencement Date set forth in Section 1.02(b), or by
any required Completion Date set forth in this Lease, Landlord shall not be
liable or responsible to Tenant or any third party for any claims, damages,
losses or liabilities in connection therewith or by reason thereof, Tenant
hereby RELEASING Landlord from any such liability and responsibility to Tenant.



                                       18
<PAGE>   24

                (c) Tenant shall not make or allow to be made any alterations,
physical additions (including fixtures) or improvements in or to the Leased
Premises, or place safes, vaults or heavy furniture or equipment within the
Leased Premises, without first obtaining the written consent of Landlord. Tenant
shall deliver to Landlord a copy of the "as built" plans and specifications for
all alterations, physical additions (including fixtures) or improvements so made
in or to the Leased Premises, within thirty (30) days after the substantial
completion thereof. Tenant further agrees that no food, soft drink or other
vending machine will be installed within the Leased Premises without the written
consent of Landlord.

                (d) All alterations, physical additions (including fixtures), or
improvements in or to the Leased Premises shall become the property of Landlord
upon the expiration or any earlier termination of this Lease, except as may be
otherwise provided in Section 4.01; provided, however, that this Subsection
shall not apply to Tenant's trade fixtures, or movable equipment or furniture.

                (e) Tenant shall indemnify and hold Landlord harmless, and
defend Landlord with counsel reasonably selected by Landlord, from and against
all costs (including reasonable attorneys' fees and expenses and costs of suit),
losses, liabilities, claims, demands, actions or causes of action arising out of
or relating to any alterations, physical additions or improvements made by
Tenant in or to the Leased Premises, including any mechanics' or materialmen's
liens asserted in connection therewith. The obligations of Tenant under this
Subsection shall survive the expiration or any earlier termination of this
Lease.

                (f) Should any mechanic's, materialman's or other liens be filed
or asserted against any portion of the Property by reason of Tenant's or it's
contractor's acts or omissions (including any alterations, physical additions or
improvements in or to the Leased Premises by or on behalf of Tenant or its
contractors) or because of a claim arising by, through or under Tenant or its
contractor, Tenant shall cause the same to be canceled or discharged of record
by bond, payment or otherwise within thirty (30) days after notice by Landlord.
If Tenant shall fail to cancel or discharge said lien or liens within said
thirty (30) day period, Landlord may, at its sole option, cancel or discharge
the same (including, if Landlord so elects, by paying the amount claimed, or by
bonding around such liens) and Tenant shall reimburse Landlord upon demand for
all costs incurred (including reasonable attorneys' fees and out of pocket
expenses of Landlord's legal counsel, and sums paid by Landlord to discharge or
settle such lien claims) in canceling or discharging such liens. The obligations
of Tenant under this Subsection shall survive the expiration or any earlier
termination of this Lease.

        5.02. Repairs; Alterations and Improvements by Landlord.

        Landlord, by and through its contractor, shall have the sole right to
make any repairs, alterations or additions that affect the Property's structural
components, or the Property's mechanical, electrical and plumbing systems
(excluding Tenant's personal property, fixtures and appliances, and nonstandard
plumbing, electrical and mechanical equipment in or serving the Leased
Premises). In the event of any damage to such components or systems caused by
any act or omission of Tenant or Tenant's Associated Parties, the cost of repair
or restoration of such damage shall be paid for solely by Tenant in an amount
equal to Landlord's costs plus fifteen percent (15%) for administrative cost
recovery. Except in the case of a casualty, condemnation or



                                       19
<PAGE>   25

other event referred to in Sections 6.01 or 6.03 (as to which such Sections
shall control as to any obligation of repair or rebuilding in connection
therewith), Landlord agrees to make such repairs, and to perform such other
work, to or upon the Building's structural components and mechanical, electrical
and plumbing systems (excluding any such Tenant property and nonstandard
equipment), as may be deemed necessary by Landlord for normal maintenance
operations and Landlord shall not otherwise be obligated to make any
improvements, physical additions or alterations to, or repairs of, the Leased
Premises or the Property; provided, however, Landlord may (but shall not be
obligated to), at its option, upon request of Tenant and at Tenant's expense,
make such alterations, physical additions and improvements to, or repairs of,
the Leased Premises as Tenant shall request in writing, at a cost equal to the
costs incurred by Landlord in making such alterations, physical additions,
improvements, or repairs, plus an additional charge of fifteen percent (15%) for
administrative cost recovery, which amount shall be due and payable from Tenant
to Landlord upon demand.

        5.03. Repairs by Tenant.

        Tenant shall, at its own cost and expense, keep the Leased Premises and
all leasehold improvements in the Leased Premises in as good a condition as the
condition thereof on the Commencement Date, normal wear and tear excepted, and
shall perform all repairs, alterations, physical additions and improvements
required to or in respect of the Leased Premises by any existing or future
federal, state, municipal or local governmental law, code, ordinance, rule or
regulation; provided, however, that this Section 5.03 shall not obligate Tenant
to make any repairs, alterations, physical additions or improvements to the
Property's structural components to the extent, if any, to which Landlord is
obligated to make such repairs, alterations, physical additions or improvements
pursuant to Sections 5.02, 6.01 or 6.03. Tenant shall be responsible for the
repair and maintenance of all non-standard plumbing, mechanical and electrical
equipment in or serving the Leased Premises including private toilets,
lavatories, wetbars, appliances and special HVAC systems. If Tenant fails to
commence any repairs or other work which Tenant is required to do under this
Section 5.03 within ten (10) days after written notice from Landlord to Tenant,
or if Tenant fails to thereafter diligently prosecute such repairs or other work
until completion in accordance with all applicable laws, codes, ordinances,
rules and regulations, Landlord may, at its option, make such repairs or perform
such other work, and Tenant shall pay to Landlord on demand Landlord's cost
thereof plus a charge of fifteen percent (15%) for administrative cost recovery.

                                       VI

        6.01. Condemnation.

        If all or substantially all of the Leased Premises, or such portion of
the Leased Premises or the Property as would render, in Landlord's reasonable
judgment, the continuance of Tenant's business from the Leased Premises
impracticable, shall be permanently taken or condemned for any public purpose,
then Landlord shall give written notice thereof to Tenant within thirty (30)
days from the date of such condemnation or taking, and this Lease shall
terminate. If less than all or substantially all of the Leased Premises, or less
than such portion of the Property, shall be permanently taken or condemned for
any public purpose, then Landlord shall have the option of terminating this
Lease by written notice to Tenant within thirty (30) days



                                       20
<PAGE>   26

from the date of such condemnation or taking. If this Lease is terminated
pursuant to this Section 6.01, this Lease shall expire on the date of transfer
of possession of the Leased Premises, the Property, or any portion thereof. In
the event of a permanent taking or condemnation for public purpose of a portion
of the Leased Premises, if this Lease is not terminated pursuant to this Section
6.01, Tenant shall pay all Rent up to and including the date of transfer of
possession of such portion of the Leased Premises so taken or condemned and this
Lease shall terminate with respect to such portion of the Leased Premises on the
date of transfer of possession of such portion of the Leased Premises.
Thereafter the Base Rental, Tenant's Forecast Additional Rental and Tenant's
Additional Rental shall be adjusted on a pro rata, square feet of Net Rentable
Area basis. In the event of any permanent condemnation or taking contemplated by
this Section 6.01, if this Lease is not terminated pursuant to this Section,
Landlord shall promptly repair the Leased Premises or the Property, as the case
may be, to Building Standard condition, or any other condition as Landlord may
reasonably elect, so that the remaining portion of the Leased Premises or
Property, as the case may be, shall constitute an architectural unit, fit for
the intended use; provided, however, that Landlord's obligation to repair
hereunder shall be limited to the extent of the net proceeds made available to
Landlord for such repair from any such condemnation or taking and subject to the
rights of Landlord's mortgagees. In the event of any temporary taking or
condemnation for any public purpose of the Leased Premises or any portion
thereof, then this Lease shall continue in full force and effect except that
Base Rental, Tenant's Forecast Additional Rental, and Tenant's Additional Rental
shall be adjusted on a pro rata, square foot of Net Rentable Area basis for the
period of time that the Leased Premises or such portion thereof are so taken and
Landlord shall be under no obligation to make any repairs or alterations. In the
event of any condemnation or taking of the Leased Premises or any portion
thereof, Tenant hereby assigns to Landlord the value of all or any portion of
the unexpired term of the Lease and all leasehold improvements and Tenant may
not assert a claim for a condemnation award therefor; provided, however, Tenant
may pursue a separate attempt to recover an award or compensation against or
from the condemning authority for (i) the value of any fixtures, furniture,
furnishings, and other personal property which when condemned but which under
the terms of this Lease Tenant is permitted to remove at the end of the term of
this Lease, and (ii) Tenant's relocation and moving expenses, and (iii)
compensation for loss to Tenant's business; and provided, further, that Tenant's
pursuit of such claim or award does not delay the delivery of or amount of any
award to Landlord.

        6.02. Damages from Certain Causes.

        Landlord shall not be liable or responsible to Tenant or any of Tenant's
Associated Parties for any loss or damage to any property or injury to any
person occasioned by theft, fire, act of God, public enemy, riot, strike,
insurrection, trespasser, other tenants in the Building, war, requisition or
order of governmental body or authority, court order or injunction, or any cause
beyond Landlord's control, or for any damage or inconvenience which may arise
through repair, alteration, maintenance or improvement of any part of the
Property, REGARDLESS OF WHETHER OR NOT CAUSED OR ALLEGED TO BE CAUSED IN WHOLE
OR IN PART BY THE NEGLIGENCE OF LANDLORD, OR ANYONE FOR WHOM LANDLORD IS
RESPONSIBLE, and Tenant hereby forever RELEASES Landlord from any and all
liability therefor, except to the extent such loss or damage arises from the
intentional misconduct of Landlord.



                                       21
<PAGE>   27

        6.03. Casualty Clause.

                (a) In the event all or any portion of the Leased Premises or
Property (excluding space in the Building leased or held for lease to others) is
damaged by fire, earthquake, flood or other casualty, or by any other cause of
any kind or nature (such damaged property being hereinafter referred to as the
"Damaged Property"), and the Damaged Property can, in the opinion of Landlord's
architect, be repaired within ninety (90) calendar days from the date of
issuance of Landlord's architect's opinion, then, this Lease shall not be
terminated and Landlord shall proceed to rebuild or restore the Damaged Property
to Building Standard condition, or to such other condition as Landlord may
reasonably elect, subject to subsections (c) and (d) hereof, and subject to
proceeds being made available to Landlord by Landlord's mortgagee. Landlord
shall cause its architect to issue such architect's opinion concerning such
matter to Landlord and Tenant within thirty (30) days after Landlord learns of
the occurrence of such damage.

                (b) In the event the Damaged Property cannot, in the opinion of
Landlord's architect, be repaired within ninety (90) days from the date of
issuance of Landlord's architect's opinion, Landlord, at Landlord's sole option,
shall have the right (i) to terminate this Lease by notifying Tenant of such
termination within thirty (30) days after issuance of Landlord's architect's
opinion, or (ii) to restore or rebuild the Damaged Property to Building Standard
condition, or to such other condition as Landlord may reasonably elect, subject
to subsection (d) hereof, and subject to proceeds being made available to
Landlord by Landlord's mortgagees.

                (c) Notwithstanding the provisions of subsection (a) hereof, if
at the time of any such damage, less than one (1) year remains in the term of
this Lease, exclusive of any renewal options which have not been effectively
exercised by Tenant prior to the occurrence of such damage, then Landlord, at
Landlord's sole option, shall have the right to terminate this Lease.

                (d) In the event this Lease is not terminated as provided
hereunder, (i) Landlord shall be obligated to rebuild or restore the Damaged
Property only to the extent of the net insurance proceeds made available to
Landlord for the purpose of rebuilding and restoration, (ii) if the Damaged
Property is all or any portion of the Leased Premises, Landlord shall be
obligated to rebuild or restore the Damaged Property only to Building Standard
condition, except that Tenant shall have the right to require Landlord to
rebuild or restore the Damaged Property substantially to the condition which
existed immediately prior to such damage, provided that Tenant bears all costs
and expenses, including without limitation, rentals that are lost due to
extended construction time, in excess of the lesser of (A) any net insurance
proceeds made available to Landlord for the purpose of rebuilding or
restoration, or (B) the cost to Landlord of rebuilding and restoring the Damaged
Property to Building Standard condition; and (iii) Tenant shall be entitled to a
pro rata abatement of Base Rental, Tenant's Forecast Additional Rental, and
Tenant's Additional Rental during the period of time the Leased Premises, or any
portion thereof, are untenantable due to such damage. As used in this Lease, the
term "Building Standard" shall mean such condition as Landlord shall in good
faith select from time to time as standard for the Building, provided that the
aggregate cost of labor and materials



                                       22
<PAGE>   28

and other costs associated with such work does not exceed Twelve and 00/100
Dollars ($12.00) per square foot of Net Rentable Area.

                (e) In the event of any termination of this Lease under this
Section 6.03, this Lease shall terminate on the date of such damage.
Notwithstanding any contrary language in this Section 6.03, if all or any
portion of the Damaged Property was damaged through any act or omission of
Tenant or any of Tenant's Associated Parties, Tenant shall pay Landlord the cost
to repair such damage and (unless Landlord elects to terminate this Lease as
provided in this Section 6.03) Rent shall continue hereunder unabated.

        6.04. Casualty Insurance.

        At all times during the term of this Lease, Landlord shall maintain
insurance on the Property (excluding "Tenant's Work" and any leasehold
improvements which are not Building Standard) against loss or damage by fire or
other insurable hazards and contingencies, all as desired by Landlord. Said
insurance may, at Landlord's option, include rental interruption insurance as
desired by Landlord. Said insurance shall be maintained with an insurance
company authorized to do business in Texas, in amounts and with such deductibles
as are desired by Landlord and payments for losses thereunder shall be made
solely to Landlord, subject to rights of Landlord's mortgagees. Tenant shall
maintain at its expense so-called "All Risk" property insurance, including
damage due to flood, on all its personal property, including removable trade
fixtures, located in the Leased Premises and on Tenant's Work and all other
additions and improvements (including fixtures) made by Tenant and not required
to be insured by Landlord above, on a full replacement value basis (subject to
reasonable deductibles). Any insurance required of Tenant under this Article VI
shall be written by insurers authorized to conduct business in Texas who are
acceptable to Landlord or who have an A.M. Best Company rating of "A-" or better
and financial size category of not less than VIII. Such coverage may be under
blanket insurance policies covering other properties of Tenant, provided that
(1) any such blanket insurance policy shall specify therein, or the insurer
under such policy shall certify to Landlord, any material sublimits in such
blanket policy applicable to the Property, which amounts shall not be less than
the amounts required pursuant to this Article VI, and (2) any such blanket
insurance policy shall comply in all respects with the other applicable
provisions of this Article VI. Tenant shall cause Landlord to be named as an
additional insured on all policies maintained by Tenant under this Article VI,
and shall cause said policies to be endorsed to provide that Landlord shall be
given at least thirty (30) days' prior written notice of any cancellation or
modification of said policies. If the annual premiums to be paid by Landlord on
any insurance maintained by Landlord under this Article VI shall exceed the
standard rates because of Tenant's operations within, or contents of, the Leased
Premises or because the improvements to the Leased Premises are in excess of
Building Standard, Tenant shall promptly pay the excess amount of the premium
upon request by Landlord (and if necessary, Landlord may allocate the insurance
costs of the Property to give effect to this sentence). Tenant shall deliver to
Landlord a duly executed certificate of insurance, reflecting Tenant's
maintenance of the insurance required under this Article VI, at least fifteen
(15) days prior to the Commencement Date, and at such other times as Landlord
may request, and Tenant shall provide to Landlord a duly executed certificate
reflecting renewal of such insurance at least fifteen (15) days prior to the
expiration of any such insurance policy.



                                       23
<PAGE>   29

        6.05. Liability Insurance.

        At all times during the term of this Lease, Landlord and Tenant shall
each maintain a policy or policies of commercial general liability insurance (or
successor comparable form of coverage in the broadest form then reasonably
available) with the premiums thereon fully paid on or before the due date. Such
insurance shall be written on an "occurrence" basis including, without
limitation, blanket contractual liability coverage, broad form property damage,
independent contractors coverage and personal injury coverage occasioned by any
occurrence on or about the Property. Such insurance shall afford minimum
protection of not less than $1,000,000 combined single limit for bodily injury
or property damage in any one occurrence and not less than $2,000,000 aggregate
for all occurrences.

        6.06. Other Insurance.

        At all times during the term of this Lease, Tenant shall maintain
statutory workers' compensation insurance (unless applicable law does not
require Tenant to maintain such insurance, and Tenant obtains Landlord's consent
to Tenant's election not to maintain such insurance), and employers' liability
insurance with respect to all of Tenant's employees working at the Leased
Premises. Tenant shall also maintain such other or additional amounts of
insurance with respect to the Leased Premises, Tenant's property and the
business of Tenant operated at the Leased Premises as may be customary for
entities or persons having properties or exposures similar to those owned or
faced by Tenant, or as Landlord may otherwise reasonably require from time to
time.

        6.07. Hold Harmless.

        To the fullest extent permitted by applicable law, Tenant will indemnify
and hold Landlord, its affiliates, and their respective officers, directors,
shareholders, agents, representatives, employees and personnel (individually and
collectively the "Indemnified Parties") harmless from and against, (i) all
claims, demands, liabilities, and actions (including attorneys' fees and
expenses and other costs and expenses of defending against, settling, or
otherwise dealing with such claims, demands, actions and liabilities) resulting
or alleged to result from any breach, violation or non-performance by Tenant of
any covenant or condition of this Lease, and (ii) all claims, demands, actions,
damages, losses, costs, liabilities, expenses and judgments suffered, incurred
or paid by, recovered from or asserted against the Indemnified Parties on
account of injury or damage to person or property to the extent that any such
damage or injury may be incident to, arise out of, or be caused, either
proximately or remotely, wholly or in part, by (x) an act or omission which
constitutes negligence or misconduct on the part of Tenant or any of Tenant's
Associated Parties or of any other person entering upon the Property under or
with the express or implied invitation or permission of Tenant, (y) the
violation by Tenant or any of Tenant's Associated Parties, or any such other
person, of any law, rule, regulation, ordinance or governmental order of any
kind or of any of the Building Rules and Regulations described in Exhibit E to
this Lease (as such Rules and Regulations may hereinafter be amended or
supplemented from time to time) or (z) the occupancy or use by Tenant, or any of
Tenant's Associated Parties, of the Property, or any other property owned by
Landlord or any of its affiliates.



                                       24
<PAGE>   30

        6.08. Waiver of Subrogation Rights.

        Anything in this Lease to the contrary notwithstanding, Landlord and
Tenant each hereby waives any and all rights of recovery, claim, action or cause
of action against the other, its agents, servants, shareholders, officers,
directors or employees, for any loss or damage that may occur to the Leased
Premises, the Property, or any personal property or fixtures of such party
therein or thereon, by reason of fire, the elements, or any other cause to the
extent same is required to be insured against under the terms of the casualty
insurance policies referred to in Section 6.04, or to the extent otherwise
actually insured against under a casualty insurance policy maintained by the
party suffering such loss or damage, regardless of cause or origin, including
negligence, but excluding gross negligence or willful misconduct, of the other
party hereto, its agents, officers, shareholders, directors, servants or
employees, and covenants that no insurer shall hold any right of subrogation
against such other party. The foregoing waiver shall not be applicable to
reasonable insurance deductibles, nor shall it be applicable to the extent to
which such waiver requires consent or endorsement on the part of any insurer and
such consent or endorsement is not obtained. Each party agrees to use reasonable
efforts to obtain from its insurer any consent or endorsement which is necessary
to give effect to the foregoing waiver of subrogation.

                                       VII

        7.01. Default and Remedies.

        The occurrence of any of the following shall constitute an event of
default under this Lease:

                        (1) Any monthly installment of Base Rental or Tenant's
Forecast Additional Rental, any Tenant's Additional Rental Adjustment, or any
other sum of money payable by Tenant under this Lease is not paid when due;

                        (2) The Leased Premises are deserted, vacated, or not
used as regularly or consistently as would normally be expected for similar
premises put to general office use, even though Tenant continues to pay the Rent
and other sums of money payable by Tenant under this Lease;

                        (3) Tenant's interest in this Lease or the Leased
Premises, or any personal property or fixtures of Tenant in the Leased Premises,
shall be subjected to any attachment, levy, or sale pursuant to any order or
decree entered against Tenant in any legal proceeding and such order or decree
shall not be vacated within fifteen (15) days of entry thereof;

                        (4) Tenant breaches or fails to comply with any term,
provision, condition, or covenant of this Lease, other than as described in
Section 7.01(a)(1), or with any of the Rules and Regulations now or hereafter
established to govern the operation of the Building, Parking Facilities, or
other portion of the Property;

                        (5) There shall occur an event of default on the part of
Tenant (or any entity controlling, controlled by, or under common control with,
Tenant) under any other



                                       25
<PAGE>   31

lease between Landlord (or any entity controlling, controlled by, or under
common control with Landlord) and Tenant (or any entity controlling, controlled
by, or under common control with, Tenant) covering space in the Building or
elsewhere;

                        (6) Any guarantor of any obligations of Tenant under
this Lease (each a "Guarantor") breaches or fails to comply with any term,
provision, condition or covenant of any guaranty or other instrument or
agreement guaranteeing all or any portion of any obligations of Tenant under
this Lease (each a "Guaranty"), or there shall occur an event of default under
any Guaranty;

                        (7) Tenant or any Guarantor shall file a petition under
any section or chapter of the Bankruptcy Code or under any similar law or
statute of the United State or any State thereof, or Tenant or any Guarantor
shall be adjudged bankrupt or insolvent in proceedings filed against Tenant or
any Guarantor thereunder, or a petition or answer proposing the adjudication of
Tenant or any Guarantor as a bankrupt or its reorganization under any present or
future federal or state bankruptcy or similar law shall be filed in any court
and such petition or answer shall not be discharged or denied within thirty (30)
days after the filing thereof; or

                        (8) A receiver or trustee shall be appointed for all or
substantially all of the assets of Tenant or any Guarantor, or for Tenant's
interest in the Leased Premises or any of Tenant's property located therein, in
any proceeding brought by Tenant or any Guarantor, or any such receiver or
trustee shall be appointed in any proceeding brought against Tenant or any
Guarantor and shall not be discharged within thirty (30) days after such
appointment or Tenant or such Guarantor shall consent to or acquiesce in such
appointment.

                (b) Upon the occurrence of any event of default and (i) if the
event of default described in Section 7.01(a)(1) is not cured within five (5)
days after written notice to Tenant from Landlord of such event of default, (ii)
if the event of default described in Section 7.01(a)(4) is not cured within
thirty (30) days after written notice to Tenant from Landlord of such event of
default, or (iii) if any other event of default is not cured immediately,
Landlord shall have the option to do and perform any one or more of the
following in addition to, and not in limitation of, any other remedy or right
provided it by law or in equity or by this Lease:

                        (1) Terminate this Lease by giving notice thereof to
Tenant in which event Tenant shall immediately vacate and deliver possession of
the Leased Premises to Landlord and if Tenant fails to do so Landlord may,
without prejudice to any other remedy which it may have for possession or
arrearages in Rent or other sums owed under this Lease enter upon and take
possession of the Leased Premises and expel or remove Tenant and any other
person who may be occupying the Leased Premises, or any part thereof, by force,
if necessary, without being liable for prosecution or any claim of damages
therefor, and Tenant hereby agrees to pay to Landlord on demand the amount of
all loss and damage which Landlord may suffer by reason of such termination,
whether through inability to relet the Leased Premises on satisfactory terms or
otherwise, including (i) all reasonable expenses necessary to relet the Leased
Premises which shall include the cost of renovating, repairing and altering the
Leased Premises for a new tenant or tenants, advertisements and brokerage fees
and (ii) any increase in insurance premiums caused by the vacancy of the Leased
Premises. If such termination is caused



                                       26
<PAGE>   32

by the failure to pay any Rent or other sums owed under this Lease the
abandonment of any substantial portion of the Leased Premises, Landlord may
elect, by sending notice thereof to Tenant, to receive as liquidated damages,
and not as a penalty, an amount equal to the Rent payable hereunder for the
month during which the Lease is terminated times the lesser of (x) twelve (12),
or (y) the whole number of months which, but for such termination, would have
remained in the term of this Lease, which shall be in lieu of the payment of
loss and damage Landlord may suffer by reason of such termination as provided in
the preceding sentence (it being agreed that the exact amount of such loss or
damage will be difficult to ascertain and that said liquidated damages amount is
a reasonable forecast of Landlord's loss or damage in such event) but which
shall not be in lieu of or reduce in any way any amount (including accrued Rent)
or damages due to breach of covenant (whether or not liquidated) payable by
Tenant to Landlord which accrued prior to the termination of this Lease. Nothing
contained in this Lease shall limit or prejudice the right of Landlord to prove
for and obtain in proceedings for bankruptcy or insolvency by reason of the
termination of this Lease, 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, equal
to, or less than the amount of the loss or damages referred to above.

                        (2) Enter upon and take possession of the Leased
Premises and expel or remove Tenant or any other person who may be occupying the
Leased Premises, or any part thereof, by force, if necessary, without having any
civil or criminal liability therefor and, without terminating this Lease,
Landlord may (but shall be under no obligation to, Tenant hereby WAIVING any
such obligation on the part of Landlord) relet the Leased Premises or any part
thereof for the account of Tenant, in the name of Tenant or Landlord or
otherwise, without notice to Tenant for such term or terms (which may be greater
or less than the period which would otherwise have constituted the balance of
the term of this Lease) and on such conditions (which may include concessions or
free rent) and for such uses as Landlord in its sole and absolute discretion may
determine and Landlord may collect and receive any rents payable by reason of
such reletting; and Tenant agrees to pay Landlord on demand all reasonable
expenses necessary to relet the Leased Premises which shall include the costs of
renovating, repairing and altering the Leased Premises for a new tenant or
tenants, advertisements and brokerage fees, and Tenant further agrees to pay
Landlord on demand any deficiency that may arise by reason of such reletting.
Landlord shall not be responsible or liable for any failure to relet the Leased
Premises or any part thereof or for any failure to collect any rent due upon any
such reletting. No such re-entry or taking of possession of the Leased Premises
by Landlord shall be construed as an election on Landlord's part to terminate
this Lease unless a notice of such termination is given to Tenant pursuant to
Section 7.01(b)(1) above.

                        (3) Enter upon the Leased Premises by force if necessary
without having any civil or criminal liability therefor, and do whatever Tenant
is obligated to do under the terms of this Lease and Tenant agrees to reimburse
Landlord on demand for any expenses which Landlord may incur in thus effecting
compliance with Tenant's obligations under this Lease, and Tenant further agrees
that Landlord shall not be liable for any damages resulting to Tenant from such
action (Tenant hereby WAIVING any claim against Landlord therefor), EVEN IF
CAUSED OR ALLEGED TO BE CAUSED IN WHOLE OR IN PART BY THE NEGLIGENCE OF LANDLORD
OR ANYONE FOR WHOM LANDLORD IS RESPONSIBLE.



                                       27
<PAGE>   33

                        (4) No repossession of or re-entering on the Leased
Premises or any part thereof pursuant to this Section 7.01 and no reletting of
the Leased Premises or any part thereof pursuant to this Section 7.01 shall
relieve Tenant or any Guarantor of its liabilities and obligations hereunder,
all of which survive such repossession or re-entering.

                        (5) Landlord shall have the right and option, upon the
occurrence of an event of default hereunder, to change the locks and other
security devices within or about the Leased Premises without notice to Tenant.
Landlord shall have no obligation to provide Tenant access to the Leased
Premises subsequent thereto or provide Tenant keys therefor or to post any
notices of any kind on the door to the Leased Premises. The provisions hereof
shall supersede any conflicting provisions of the Texas Property Code, including
without limitation the provisions of Section 93.002 thereof.

                        (6) No right or remedy herein conferred upon or reserved
to Landlord is intended to be exclusive of any other right or remedy, and each
and every right and remedy shall be cumulative and in addition to any other
right or remedy given hereunder or now or hereafter existing at law or in
equity. In addition to other remedies provided in this Lease, Landlord shall be
entitled, to the extent permitted by applicable law, to injunctive relief in
case of the violation, or attempted or threatened violation, of any of the
covenants, conditions or provisions of this Lease, or to a decree compelling
performance of any of the covenants, conditions or provisions of this Lease, or
to any other remedy allowed to Landlord at law or in equity.

        Notwithstanding the preceding provisions of this Section 7.01(b): (i)
Tenant shall not be entitled to receive, nor shall Landlord be obligated to
furnish, any notice or opportunity to cure provided for in the preceding
provisions of this Section 7.01(b) with respect to an event of default, and
Landlord may proceed to exercise any or all of its rights and remedies in
respect of such event of default without furnishing any notice or opportunity to
cure, if the same or similar type of event of default shall have occurred two
(2) or more times during the immediately preceding twelve (12) month period; and
(ii) if the event of default is one described in Section 7.01(a)(4) and such
event of default consists of, or causes or involves, annoyance or disturbance
of, or interference with, any other tenant's or occupant's, or Landlord's, use
or enjoyment of space in the Building leased or occupied by such other tenant or
occupant, or Landlord, or the Parking Facilities, or other portions of the
Property, then the period of Tenant's opportunity to cure shall be reduced from
thirty (30) days to such lesser period of any length as Landlord in its sole and
absolute discretion shall deem to be the minimum appropriate amount of time to
cure such event of default, as specified by Landlord in such notice.

                (c) In connection with the exercise by Landlord of its rights
and remedies in respect of any event of default on the part of Tenant, to the
extent (but no further) that Landlord is required by applicable Texas law to
mitigate damages, or to use efforts to do so, and such requirement cannot be
lawfully and effectively waived (it being the intention of Landlord and Tenant
that such requirements be and are hereby WAIVED to the maximum extent permitted
by applicable law), Tenant agrees in favor of Landlord that Landlord shall not
be deemed to have failed to mitigate damages, or to have used the efforts
required by law to do so, because:



                                       28
<PAGE>   34

                        (1) Landlord leases other space in the Building which is
vacant prior to re-letting the Leased Premises;

                        (2) Landlord refuses to relet the Leased Premises to any
affiliate of Tenant, or any principal of Tenant, or any affiliate of such
principal (for purposes of this Lease, "affiliate" shall mean and refer to any
person or entity controlling, under common control with, or controlled by, the
party in question);

                        (3) Landlord refuses to relet the Leased Premises to any
person or entity whose creditworthiness Landlord in good faith deems
unacceptable;

                        (4) Landlord refuses to relet the Leased Premises to any
person or entity because the use proposed to be made of the Leased Premises by
such prospective tenant is not general office use of a type and nature
consistent with that of the other tenants in the portions of the Building leased
or held for lease for general office purposes as of the date Tenant defaults
under this Lease (by way of illustration, but not limitation, government
offices, consular offices, doctor's or dentist's offices or medical or dental
clinics or laboratories, or schools would not be uses consistent with that of
other tenants in the Building), or because such use would, in the good faith
opinion of Landlord, impose unreasonable or excessive demands upon the Building
systems, equipment or facilities;

                        (5) Landlord refuses to relet the Leased Premises to any
person or entity, or any affiliate person or entity, who has been engaged in
litigation with, or who has threatened litigation against, Landlord or any of
its affiliates, or whom Landlord in good faith deems to be unreasonably or
excessively litigious;

                        (6) Landlord refuses to relet the Leased Premises
because the tenant or the terms and provisions of the proposed lease are not
approved by the holders of any liens or security interests in the Property or
any part thereof, or would cause Landlord to breach or be in default of, or to
be unable to perform any of its covenants under, any agreements between Landlord
and any third party;

                        (7) Landlord refuses to relet the Leased Premises
because the proposed tenant is unwilling to execute and deliver Landlord's
standard lease form without tenant-oriented modifications or such tenant
requires improvements to the Leased Premises to be paid at Landlord's cost and
expense; or

                        (8) Landlord refuses to relet the Leased Premises to a
person or entity whose character or reputation, or the nature of whose business,
Landlord in good faith deems unacceptable;

and it is further agreed that each and all of the grounds for refusal set forth
in clauses (1) through (8), both inclusive, of this sentence are reasonable
grounds for Landlord's refusal to relet the Leased Premises, or (as to all other
provisions of this Lease) for Landlord's refusal to issue any approval, or take
any other action, of any nature whatsoever under this Lease.

        In the event the waiver set forth in the preceding sentence shall be
ineffective, Tenant further agrees in favor of Landlord, to the maximum extent
to which it may lawfully and



                                       29
<PAGE>   35

effectively do so, that the following efforts to mitigate damages if made by
Landlord (and without obligating Landlord to render such efforts) shall be
conclusively deemed reasonable, and that Landlord shall be conclusively deemed
to have used the efforts to mitigate damages required by applicable law if:
Landlord places the Leased Premises on its inventory of available space in the
Building; Landlord makes such inventory available to brokers who request same;
and Landlord shows the Leased Premises to prospective tenants (or their brokers)
who request to see it.

        7.02. Lien for Rent.

        Tenant hereby grants to Landlord a security interest in and to all of
Tenant's tangible personal property now or hereafter located within the Leased
Premises, but not on Tenant's business records (such contractual security
interest being in addition to and cumulative of any other lien granted Landlord
by statute or otherwise), and upon the occurrence of an event of default by
Tenant, Landlord may, in addition to any other remedies provided herein, enter
upon the Leased Premises and take possession of any and all such goods, wares,
equipment, fixtures, furniture, improvements and other personal property owned
by Tenant and situated on the Leased Premises, without liability for trespass or
conversion (and Tenant hereby waives any right to notice or hearing prior to
such taking of possession by Landlord), foreclose the security interest hereby
granted and sell the same at public or private sale, with or without having such
property at the sale, after giving Tenant reasonable notice of the time and
place of any public sale or of the time after which any private sale is to be
made, at which sale Landlord or its assigns may purchase unless otherwise
prohibited by law. Unless otherwise provided by law, and without intending to
exclude any other manner of giving Tenant reasonable notice, the requirement of
reasonable notice shall be met if such notice is given in the manner prescribed
in this Lease at least five (5) days before the date of sale. Any sale made
pursuant to the provision of this Section 7.02 shall be deemed to have been a
public sale conducted in a commercially reasonable manner if held in the Leased
Premises after the time, place and method of sale and a general description of
the types of property to be sold have been advertised in a daily newspaper
published in the county where the Property is located for five (5) consecutive
days prior to the date of sale. The proceeds from any such disposition, less any
and all expenses connected with the taking of possession, holding and selling of
the property (including reasonable attorneys fees and other expenses) shall be
applied as a credit against the indebtedness secured by the security interest
granted in this Section 7.02. Landlord shall have all of the rights of a secured
party under the Texas Business and Commerce Code, as the same may be amended
from time to time. Any surplus shall be paid to Tenant or as otherwise required
by law; and the Tenant shall pay any deficiency forthwith. Notwithstanding the
foregoing, Landlord hereby agrees to subordinate its liens herein retained (as
well as any statutory landlord's lien) to an existing lien as of the date the
lease is executed by Tenant or any future liens, securing bona fide financing of
Tenant's trade fixtures, movable personal property or equipment placed in the
Leased Premises provided that the equipment, movable personal property and trade
fixtures to which such subordination extends is identified with specificity.

        7.03. Late Payments.

        In the event any installment of Base Rental or Tenant's Forecast
Additional Rental, or any Tenant's Additional Rental Adjustment or any other
charge owed by Tenant



                                       30
<PAGE>   36

hereunder is not paid when due, Tenant shall pay upon demand as a late charge an
amount equal to five percent (5%) of the amount due. In addition, all past due
Rent and other sums of any kind or nature owing by Tenant under this Lease shall
bear interest from the date due until paid at the rate of eighteen percent (18%)
per annum, or such lesser rate as is provided for in the following sentence.
Notwithstanding the foregoing, however, in no event shall the aggregate of all
interest, and all sums (howsoever denominated) which are deemed to constitute
interest for purposes of applicable usury laws, which are paid, received,
charged or contracted for under this Lease ever exceed, on a per annum basis,
the highest per annum rate of interest permitted by applicable law (the "Highest
Lawful Rate"). Should Tenant make a partial payment of past due amounts, the
amount of such partial payment shall be applied to reduce the obligations of
Tenant, in such order and manner as Landlord may elect, in its sole and absolute
discretion.

        7.04. Attorney's Fees.

        Tenant agrees to pay to Landlord upon demand all reasonable attorney's
fees and out-of-pocket expenses of Landlord's legal counsel incurred in
connection with or as a result of any event of default under this Lease, or the
enforcement of this Lease against Tenant.

        7.05. No Waiver of Rights.

        No failure of Landlord to exercise, or delay of Landlord in exercising,
any right or power given it herein, or failure of Landlord to insist, or delay
of Landlord in insisting, upon strict compliance by Tenant of any obligation
imposed on it herein, and no custom or practice of either party hereto at
variance with any term hereof, shall constitute a waiver or a modification of
the terms hereof by Landlord or any right it has herein to demand strict
compliance with the terms hereof by Tenant. No waiver of any right of Landlord
or any event of default by Tenant on one occasion shall operate as a waiver of
any of Landlord's other rights or of any subsequent event of default by Tenant.
No express waiver shall affect any condition, covenant, term, provision, rule,
or regulation other than the one specified in such waiver and then only for the
time and in the manner specified in such waiver. No person has or shall have any
authority to waive any provision of this Lease unless such waiver is expressly
made in writing and signed by an authorized officer of Landlord.

        7.06. Holding Over.

        In the event of any holding over by Tenant after the expiration or
earlier termination of this Lease without the consent of Landlord, Tenant shall
pay as liquidated damages, and not as a penalty solely for such holding over,
twice the Rent (including all Base Rental, Tenant's Forecast Additional Rental
and Tenant's Additional Rental Adjustment) as would have been payable if this
Lease had not so terminated or expired for the entire hold over period (it being
agreed that Landlord's actual damages in such event will be difficult to
ascertain, and that the foregoing amount is a reasonable forecast of Landlord's
actual damages in such event). No holding over by Tenant after the term of this
Lease shall be construed to extend this Lease. In the event of any unauthorized
holding over, Tenant shall indemnify and hold harmless Landlord from and against
all claims for damages, and all other claims, demands, actions and causes of
action of any kind, by any other tenant to whom Landlord shall have leased all
or part of the Leased Premises effective upon the expiration or earlier
termination of this Lease. Any



                                       31
<PAGE>   37

holding over with the express consent of Landlord shall constitute this Lease to
be a lease from month to month at a Base Rental, Tenant's Forecast Additional
Rental, Tenant's Additional Rental Adjustment, and all other sums required to be
paid by Tenant prior to the expiration or earlier termination of this Lease, as
may be determined by Landlord in its sole and absolute discretion.

                                      VIII

        8.01. Landlord's Mortgagee.

        Tenant acknowledges that the Property, this Lease and the rents payable
hereunder have been pledged by Landlord to Nationwide Life Insurance Company as
security for a loan by Nationwide Life Insurance Company to Landlord in
connection with the ownership of the Property.

        8.02. Subordination.

        Tenant agrees that the rights of Tenant under this Lease are subject and
subordinate to, and upon the request of Landlord made in writing Tenant will
confirm the subordination of this Lease to, each ground lease now or hereafter
covering all or any part of the Land and each mortgage or deed of trust which
may now or hereafter encumber the Property or any portion thereof, as well as to
all renewals, modifications, consolidations, replacements and extensions
thereof, in a written form reasonably acceptable to the lessor under any such
ground lease or the holder of any such mortgage or deed of trust. Tenant
expressly recognizes and agrees that (i) the holder of any such mortgage or deed
of trust may sell the Property or any portion thereof, and the lessor under any
such ground lease may terminate such lease or the ground lessee's right of
possession thereunder, in the manner provided for by law in such instrument, and
(ii) such sale or other action may be made subject to this Lease. In the event
of the enforcement by the lessor under any such ground lease or the holder of
any such mortgage or deed of trust of the remedies provided for by law or by
such ground lease, mortgage or deed of trust, Tenant will, upon request of said
lessor, or any person or party succeeding to the interest of said holder as a
result of such enforcement, automatically become Tenant of said lessor, or such
successor in interest, without change in the terms or provisions of this Lease;
provided, however, that said lessor, or such successor in interest, shall not be
bound by (x) any payment of Rent for more than one month in advance except
prepayments in the nature of security for the performance by Tenant of its
obligations under this Lease, or (y) any amendment or modification of this Lease
made without the written consent of such lessor, holder or successor in interest
if such lessor, holder or successor in interest had previously notified Tenant
in writing of its interest. Upon request by such lessor, holder or successor in
interest, Tenant shall execute and deliver an instrument or instruments
confirming the attorment herein provided for in a form reasonably acceptable to
such lessor, holder or successor in interest.

        8.03. Cure Rights for Landlord Default.

        Notwithstanding anything contained in this Lease to the contrary, in the
event of any default by Landlord in performing its covenants or obligations
hereunder which would give Tenant any right to terminate this Lease, or any
other right under this Lease, Tenant shall not



                                       32
<PAGE>   38

exercise such right unless and until (a) Tenant gives written notice of such
default (which notice shall specify the default in reasonable detail) to
Landlord, and each lessor under any such ground lease and holder of any such
mortgage or deed of trust who has theretofore notified Tenant in writing of its
interest and an address to which notices are to be sent, and (b) Landlord and
said lessors and holders fail to commence action to cure said default within
thirty (30) days from the giving of such notice by Tenant, or having timely
commenced such action, fail to prosecute such efforts to completion with
reasonable diligence thereafter. The provisions of Section 10.01 shall govern
the manner and effective date of any notice to be given by Tenant to any such
parties. Tenant's sole remedy for any such default shall be an action against
Landlord for damages, and Tenant hereby WAIVES, to the maximum extent allowed by
law, the benefits of any laws granting Tenant a lien upon property of Landlord,
or upon Rent due Landlord.

        8.04. Estoppel Certificate or Three-Party Agreement.

        At the request of Landlord from time to time, Tenant will execute an
estoppel certificate certifying to such facts (if true) as Landlord may
reasonably require, and containing such agreements and acknowledgments as may be
reasonably required by any existing or proposed holder of a mortgage or deed of
trust on the Properly or Land or any portion thereof. In the event Tenant fails
to execute and deliver the same within five (5) business days after request
therefor, Landlord shall have the right (and Tenant hereby empowers Landlord) to
execute and deliver such certificate for and on behalf of and as the binding act
of Tenant.

                                       IX

        9.01. Sublease or Assignment by Tenant.

                (a) Tenant shall not, without Landlord's prior written consent:
(i) assign, convey, mortgage, encumber, or otherwise transfer (whether
voluntarily, by operation of law, or otherwise) this Lease or any interest of
Tenant hereunder; (ii) allow any lien to be placed upon this Lease or any
interest of Tenant hereunder; (iii) sublet the Leased Premises or any part
thereof; or (iv) permit the use or occupancy of the Leased Premises or any part
thereof by anyone other than Tenant. Any attempt to consummate any of the
foregoing without Landlord's consent shall be of no force or effect. For
purposes hereof, the transfer of the ownership or voting rights in a controlling
interest of the voting stock of Tenant (if Tenant is a corporation), or the
transfer of a majority of the membership interests in Tenant (if Tenant is a
limited liability company), or the transfer of a general partnership interest or
a majority of the limited partnership interest in Tenant (if Tenant is a
partnership), at any time throughout the term of this Lease, shall be deemed to
be an assignment of this Lease.

                (b) Notwithstanding anything herein to the contrary, if at any
time or from time to time during the term of this Lease Tenant desires to sublet
all or any portion of the Leased Premises or assign Tenant's interest in this
Lease, Tenant shall notify Landlord in writing (hereinafter referred to in this
Section 9.01 as the "Notice") of the terms of the proposed subletting or
assignment, the identity of the proposed sublessee or assignee, the area
proposed to be sublet or covered by the assignment (hereinafter referred to as
"Sublet Space"), and such other information as Landlord may request to evaluate
Tenant's request to sublet or assign. The Notice shall be accompanied by a
$500.00 payment to Landlord as an administrative fee for



                                       33
<PAGE>   39

Landlord's consideration of Tenant's request, which payment shall be
nonrefundable to Tenant under all circumstances, and regardless of whether or
not Landlord grants the requested consent. Landlord shall then have the option
(i) to sublet the Sublet Space from Tenant as provided in subsection (c) hereof
at the same Base Rental and Tenant's Additional Rental as Tenant is required to
pay to Landlord under this Lease for the Sublet Space, (ii) to terminate this
Lease as to the Sublet Space as provided in subsection (d) hereof, or (iii) to
conditionally allow the proposed sublease or assignment subject to the review
and approval provided in subsection (e) hereof. Landlord's option to sublet, to
terminate, or to conditionally allow the proposed sublease or assignment subject
to such review and approval, as the case may be, shall be exercisable by
Landlord by written notice to Tenant within a period of thirty (30) calendar
days after Landlord's receipt of a complete and accurate Notice with respect
thereto and the required administrative fee and any failure by Landlord to
exercise any of such options within said thirty (30) day period shall be deemed
to constitute the election of option (iii) above.

                (c) In the event Landlord exercises the option to sublet the
Sublet Space as set forth above, the term of the subletting from Tenant to
Landlord shall be the term set forth in the Notice (which shall not be longer
than the then current term of this Lease unless Landlord expressly agrees in
writing that any extension or renewal option contained in this Lease will apply
to such Sublet Space) and shall be on such terms and conditions as are contained
in this Lease to the extent applicable, except that Landlord shall have the
right to further sublet the Sublet Space freely and without any consent or
approval from Tenant and upon such terms and for such rent as Landlord shall
agree upon in its sole and absolute discretion.

                (d) If Landlord elects to terminate this Lease as set forth
above, then this Lease shall terminate as to the Sublet Space on the date set
forth in Landlord's notice to Tenant, which date shall be no less than thirty
(30) days and no more than ninety (90) days after the date of such notice. If
the Sublet Space does not constitute the entire Leased Premises and Landlord
exercises its option to terminate this Lease with respect to the Sublet Space,
as to that portion of the Leased Premises which is not part of the Sublet Space,
this Lease shall remain in full force and effect except that Rent shall be
calculated on the difference between the Net Rentable Area prior to such
termination and the Net Rentable Area of the Sublet Space.

                (e) If Landlord elects or is deemed to have elected to
conditionally allow the proposed sublease or assignment subject to Landlord's
review, then within twenty (20) calendar days after Tenant's receipt of
Landlord's notice of election (or the expiration of said thirty (30) day period
if no notice of Landlord's election is received by Tenant during such period),
Tenant shall deliver to Landlord (1) a copy of the proposed sublease or
assignment agreement which agreement provides for the assumption of all (or in
the case of a sublease, the appropriate portion on Tenant's obligations under
this Lease, (2) recent financial statements (including most recent available
annual and quarterly income statements and balance sheets) Or the proposed
sublessee or assignee, and (3) such additional information concerning the
business, character, reputation and creditworthiness of the proposed sublessee
or assignee and its principals as shall be sufficient to allow Landlord to form
a commercially reasonable judgment with respect thereto (but the foregoing shall
not be construed to require Landlord to be reasonable in approving or
disapproving any sublease or assignment). In the event Landlord fails to approve
or disapprove in writing any such sublease or assignment within thirty (30) days
after Landlord's receipt of a complete and accurate submission from Tenant, such
sublease or



                                       34
<PAGE>   40

assignment shall be deemed to be disapproved. If Landlord approves any proposed
sublease or assignment, Landlord shall receive from Tenant one hundred percent
(100%) of any rents or other sums received by Tenant pursuant to said sublease
or assignment in excess of the Rent payable to Landlord by Tenant under this
Lease with respect to the Sublet Space (after deducting all of Tenant's
reasonable costs associated therewith, including reasonable brokerage fees and
the reasonable cost of remodeling or otherwise improving the Leased Premises for
said sublessee or assignee), as such rents or other sums are received by Tenant
from the approved sublessee or assignee, and Base Rental shall be increased
accordingly under this Lease.

                (f) If Landlord approves in writing the proposed sublease or
assignment as provided in subsection (e) hereof, but a fully executed
counterpart of such sublease or assignment is not delivered to Landlord within
sixty (60) days after the date of Landlord's written approval, then Landlord's
approval of the proposed sublease or assignment shall be deemed null and void
and Tenant shall again comply with all the conditions of this Section 9.01 as if
the Notice and options herein referred to had not been given, received or
exercised.

                (g) In addition to the administrative fee payable to Landlord
pursuant to Subsection 9.01(b), Tenant agrees to pay the reasonable fees and
out-of-pocket expenses of Landlord's counsel incurred for or in connection with
any request for Landlord's consent or approval, or any other submission by or
for Tenant, pursuant to this Article IX (regardless of whether or not Landlord
provides or agrees to provide the requested consent or approval), including any
such fees and expenses for or in connection with the review (or preparation, as
the case may be) and negotiation of any such consent or approval, and any Lease
amendment, sublease, assignment or other documentation related to such request
or submission or the transactions contemplated thereby. Tenant shall pay such
fees and expenses within fifteen (15) days after request by Landlord to Tenant
therefor accompanied by invoices or other supporting documentation. Any consent
or approval furnished or agreed to be furnished by Landlord in connection with
such request or submission may, at Landlord's option, be withheld pending the
payment of such fees and expenses, or if such consent or approval is furnished
prior to the payment of such fees and expenses, Landlord may at its option
retract such consent or approval effective ab initio if such fees and expenses
are not timely paid.

                (h) Notwithstanding the giving by Landlord of its consent to any
sublease or assignment with respect to the Leased Premises, no sublessee or
assignee may exercise any expansion option, right of first refusal option,
preferential right, renewal option, or other similar right or option under this
Lease, unless Landlord in its sole and absolute discretion shall agree otherwise
in a separate written agreement entered into directly between such sublessee or
assignee and Landlord.

                (i) Notwithstanding the giving by Landlord of its consent to any
subletting, assignment or occupancy as provided hereunder or any language
contained in such sublease, assignment or occupancy agreement to the contrary,
unless this Lease is expressly terminated by Landlord, Tenant shall not be
relieved of any of Tenant's obligations under this Lease and Tenant shall remain
fully liable hereunder.



                                       35
<PAGE>   41

                (j) If, with the consent of Landlord, the Leased Premises or any
part thereof is sublet to or occupied by any person or entity other than Tenant
or if Tenant's interest in this Lease is assigned, Landlord may, after default
by Tenant, collect rent from the subtenant, assignee or occupant, and apply the
net amount collected to the Rent and any other sums required to be paid by
Tenant under this Lease. No such subletting, assignment, occupancy, or
collection shall be deemed (i) a waiver of any of Tenant's obligations contained
in this Lease, (ii) a release of Tenant from further performance by Tenant of
any of its obligations contained in this Lease, or (iii) a waiver of any of
Landlord's other rights hereunder.

        9.02. Assignment by Landlord.

        Landlord, its successor or assign shall have the right to transfer and
assign, in whole or in part, all its rights and obligations hereunder, and in
the Property and other property referred to herein, and in such event and upon
such transfer (any such transferee to have the benefit of the provisions of this
Lease, including the provisions of Section 9.03 hereof) no further liability or
obligation shall thereafter accrue against Landlord or such successor or assign
hereunder.

        9.03. Limitation of Landlord's Personal Liability.

        Tenant specifically agrees to look solely to the interest of Landlord or
its successor or assign in the Property for the recovery of any judgment against
Landlord, its successors and assigns, it being agreed that Landlord and its
successors and assigns (and its and their respective shareholders, officers,
directors, employees and agents) shall never be personally liable for any such
judgment and that Tenant shall not seek or obtain any such judgment. The
foregoing sentence is not intended to, and shall not, limit any right that
Tenant might otherwise have to obtain injunctive relief against Landlord or its
successors or assigns or to maintain any suit or action to enforce against, or
collect from, any insurer any amounts which may be or become owing or payable
under or on account of insurance maintained by Landlord or its successors or
assigns with such insurer.

                                        X

        10.01. Notices.

        Any notices or other communications required or permitted to be given
under this Lease must be in writing and shall be effectively given or delivered
if hand delivered to the addresses for Landlord and Tenant stated below, or if
sent by certified or registered United States Mail, return receipt requested, to
said addresses, or if sent by electronic facsimile transmission to the facsimile
numbers for Landlord and Tenant set forth below. Any such notice or other
communication from Landlord shall be effective if given by Landlord, or by
Landlord's property manager or legal counsel acting on Landlord's behalf. Any
notice mailed shall be deemed to have been given upon the earlier of (i) receipt
or refusal thereof, or (ii) three days after depositing the same in the U.S.
Mail as aforesaid. Notice effected by hand delivery shall be deemed to have been
given at the time of actual delivery. Notice effected by electronic facsimile
transmission shall be deemed to have been given upon electronic transmission and
electronic confirmation of the receipt of such transmission by the receiving
party; provided, however, that a



                                       36
<PAGE>   42

counterpart of any notice sent by electronic facsimile transmission shall be
contemporaneously sent by the transmitting party to the receiving party by
United States Mail, first class postage prepaid, to the address for such
receiving party set forth below; and provided, further, that any such notice
sent outside of normal business hours (i.e., prior to 8:00 a.m. or after 5:00
p.m., recipient's time, or on weekends or holidays) shall not be deemed given
until the next following 8:00 a.m., recipient's time, excluding weekends and
holidays. Either party shall have the right to change its address to which
notices shall thereafter be sent and the party to whose attention such notices
shall be directed by giving the other party notice thereof in accordance with
the provisions of this Section 10.01.

To Landlord:                                   With copy to:


Houston Office 90, Inc.                        Locke Liddell & Sapp LLP
c/o Transwestern Property Company SW, L.P.     600 Travis, Suite 3400
d/b/a Transwestern Commercial Services         Houston, Texas 77002
Three Riverway, Suite 150                      Attention:  Scott Hunsaker
Houston, Texas  77056                          Fax No.:  (713) 223-3717
Attention:  Don Foster
Fax No. (713) 840-1810


To Tenant:
ChemConnect, Inc.
Three Riverway, Suite 1285
Houston, Texas  77056
Attention:  Mr. Art Peabody
Fax No.:  __________

Additionally, Tenant agrees to send copies of all notices required or permitted
to be given to Landlord under this Lease to Landlord's current mortgagee (as
hereinafter set forth) and to each lessor under any ground or land lease
covering all or part of the Land and each other holder of a mortgage or deed of
trust encumbering the Property or any interest therein that notifies Tenant in
writing of its interest and the address to which notices are to be sent.

The name and address of Landlord's current mortgagee is as follows:

               Nationwide Life Insurance Co.
               One Nationwide Plaza
               Columbus, Ohio 43215
               Attn:  Real Estate Investments 34T


        10.02. Force Majeure

        Except in each case for the obligation to pay Rent, or any other
obligation to pay money to the other party or to any third party under this
Lease (including any obligation to pay money pursuant to Exhibit C hereto),
Landlord and Tenant shall be excused for the period of any



                                       37
<PAGE>   43

delay in performing, and shall not be deemed in default with respect to the
performance of, any of the terms, covenants and conditions of this Lease when
prevented from so doing by a cause or causes beyond Landlord's or Tenant's (as
the case may be) reasonable control, which shall include all labor disputes,
governmental regulations or controls, fire or other casualty, inability to
obtain any material or services, acts of God, or any other cause not within the
reasonable control of Landlord or Tenant (as the case may be); provided,
however, that any Tenant Delay (defined in Exhibit C) shall be conclusively
deemed to be due to a cause or causes within Tenant's reasonable control.

        10.03. Relocation.

        Upon ninety (90) days written notice to Tenant, Landlord may substitute
for the Leased Premises other premises in the Building (the "New Premises"), in
which event the New Premises shall be deemed to be the Leased Premises for all
purposes hereunder, provided:

                        (i) The New Premises shall be similar in area and in
appropriateness for Tenant's purposes such that the New Premises and the
improvements shall be similar in character to that of the Leased Premises;

                        (ii) Landlord and Tenant shall cooperate in good faith
in making any changes to the Tenant Program, Space Plan, Preliminary Working
Drawings, and/or Working Drawings (as defined herein and as may be applicable
depending upon which, if any, of the foregoing has then been prepared at the
time of Landlord's election to relocate the Leased Premises) so as to conform
the leasehold improvements in the New Premises as closely as practicable to
those planned for the Leased Premises;

                        (iii) To the extent Tenant shall have incurred any
expense in the preparation of the Tenant Program, Space Plan, Preliminary
Working Drawings, Working Drawings and/or leasehold improvements (as defined
herein and as may be applicable depending upon which, if any, of the foregoing
has then been prepared, purchased or installed at the time of Landlord's
election to relocate the Leased Premises), Landlord shall, at Landlord's
expense, cause each of such applicable items to be reproduced for the New
Premises so that Tenant shall not incur expenses in connection therewith by
reason of the exercise by Landlord of the relocation right contained herein; and
Landlord shall reimburse Tenant for Tenant's actual upfront moving costs,
including, but not limited to, the physical move and the reprinting of
stationery and business cards, as well as, the cost to relocate Tenant's
telephone system, computer cabling and notification to clients, creditors and
vendors.

                        (iv) The Base Rental and other rentals payable under
this lease shall remain the same for the New Premises as are stated herein to be
applicable for the Leased Premises.

        10.04. Miscellaneous.

                (a) This Lease shall be binding upon and inure to the benefit of
Landlord and its successors and assigns, and shall be binding upon and inure to
the benefit of Tenant, its successors and, to the extent assignment may be
approved by Landlord hereunder, Tenant's assigns.



                                       38
<PAGE>   44

                (b) This Lease contains the entire agreement of the parties
pertaining to the subject matter hereof and supersedes all other prior and
contemporaneous agreements and understandings, both oral and written, of the
parties in connection therewith. No oral, and no other written, promises or
representations have been made and none have been relied upon, and none shall be
binding. Landlord's agents and representatives do not and will not have
authority to (a) make or agree to make any exceptions, changes or amendments to
this Lease, or any representations not expressly contained in this Lease, (b)
waive any right, requirement, or provision of this Lease, or (c) release Tenant
from all or any part of this Lease, unless any such action is in writing. Each
party warrants and represents to the other that said party has fully informed
itself of the terms, contents, conditions, and effects of this Lease, that in
executing this Lease such party has had the benefit of, or the opportunity for,
advice of attorneys of its own choosing, and that such party has relied solely
and completely upon its own judgment and the advice of its own advisors in
entering into this Lease.

                (c) TENANT HEREBY WAIVES ANY AND ALL WARRANTIES, EXPRESS OR
IMPLIED, WITH RESPECT TO THE LEASED PREMISES OR THE PROPERTY WHICH MAY OTHERWISE
EXIST BY OPERATION OF LAW, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OR
HABITABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

                (d) All rights and remedies of Landlord under this Lease shall
be cumulative and none shall exclude any other rights or remedies allowed by
applicable law. This Lease is declared to be a contract, which shall be governed
by and construed in accordance with the laws of the State of Texas (other than
its conflict of laws principles, to the extent such principles would require
application of the law of another state). This Lease may not be modified or
waived, in whole or in part, except by an instrument in writing executed by the
party against which such modification or waiver is sought to be enforced.
Inasmuch as Tenant has been afforded full opportunity for review and negotiation
of this Lease by its legal counsel, Tenant agrees that the rule of construction
requiring that any ambiguity in an agreement be resolved against the party which
drafted such agreement shall be inapplicable to this Lease.

                (e) If Tenant is a corporation, limited liability company,
partnership or other entity, Tenant represents and warrants to Landlord that all
consents or approvals required of third parties (including its Board or
Directors or other governing body, or partners) for the execution, delivery and
performance of this Lease have been obtained and that Tenant has the right and
authority to enter into and perform its covenants contained in this Lease.
Likewise, if Landlord is a corporation, limited liability company, partnership
or other entity, Landlord represents and warrants that all consents or approvals
required of third parties (including but not limited to its Board of Directors
or other governing body, or partners, but excluding Landlord's current
mortgagee) for the execution, delivery and performance of this Lease have been
obtained and that Landlord has the right and authority to enter into and perform
its covenants contained in this Lease. In addition, each person executing this
Lease on behalf of either party individually represents to the other party
hereto that such individual has been duly authorized to do so by and on behalf
of such party, and to bind such party to this Lease, and that such individual
holds the office or position with respect to such party which is indicated next
to his or her signature on this Lease.



                                       39
<PAGE>   45

                (f) Wherever in this Lease there is imposed upon Landlord the
obligation to use best or reasonable efforts or diligence, such obligation shall
not be construed to require Landlord to take any actions which are not
economically feasible or which would otherwise impose upon Landlord extreme
financial or other burdens. Landlord shall have no obligation to use best or
reasonable efforts or diligence when the application of such standard of care to
persons or circumstances is invalid or unenforceable under applicable law. Every
provision of this Lease shall be valid and shall be enforceable to only the
extent permitted by applicable law.

                (g) The obligation of Tenant to pay all Rent and other sums due
from time to time hereunder, and all other obligations of Tenant under this
Lease, constitute independent, unconditional covenants and are not dependent
upon performance by Landlord of its obligations and covenants hereunder.

                (h) 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 provision
to persons or circumstances other than those as to which it is invalid or
unenforceable, shall not be affected thereby, and each provision of this Lease
shall be valid and shall be enforceable to the extent permitted by applicable
law.

                (i) Time is of the essence of the performance of Tenant's
obligations pursuant to this Lease.

                (j) Any claim, cause of action, liability or obligation of a
party accruing under this Lease during the term of this Lease shall survive the
expiration or any earlier termination of this Lease. In addition, any covenant
of a party pursuant to this Lease which expressly so survives, or which is
otherwise clearly required by the context to so survive, shall survive the
expiration or any earlier termination of this Lease.

                (k) Tenant agrees not to record any memorandum or other evidence
of this Lease in the Real Property Records of Harris County, Texas without
Landlord's prior written consent.

                (l) Landlord reserves the right at anytime and from time to time
to change the name by which the Building, or all or any portion of the Property,
is designated, in Landlord's sole and absolute discretion.

                (m) The submission of this Lease by Landlord to Tenant does not
constitute a reservation of or option for the Leased Premises, or a binding
offer of Landlord to lease the Leased Premises, and this Lease shall become
effective only if and when executed by all parties hereto and (1) if first
executed by Tenant, a fully executed counterpart of this Lease has been
delivered by Landlord to Tenant, or (2) if first executed by Landlord, a fully
executed counterpart of this Lease has been delivered by Tenant to Landlord and
Landlord has subsequently acknowledged to Tenant in a writing executed by
Landlord that this Lease is in effect.

                (n) All payment obligations of Landlord or Tenant (including any
payment obligation of Landlord or Tenant for damages arising from any breach of
the respective



                                       40
<PAGE>   46

covenants or obligations of Landlord or Tenant hereunder) are performable
exclusively in Harris County, Texas.

                (o) There shall be no merger of this Lease or of the leasehold
estate hereby created with the fee estate in the Leased Premises or any part
thereof by reason of the fact that the same person may acquire or hold, directly
or indirectly, this Lease or the leasehold estate hereby created or any interest
in such leasehold estate as well as the fee estate in the Leased Premises or any
interest in such fee estate.

                (p) Unless (and only to the extent) otherwise expressly so
provided in this Lease, any consent, approval or agreement of Landlord
contemplated by this Lease may be granted, withheld or conditioned by Landlord
in Landlord's sole and absolute discretion.

                (q) All references in this Lease to Articles, Sections and
Subsections shall mean and refer to Articles, Sections and Subsections of this
Lease, except as otherwise expressly stated in this Lease.

                (r) As used in this Lease: words of the masculine gender shall
be construed to include the feminine and neutral gender, and vice versa, and
words of the neutral gender shall be construed to include the masculine and
feminine, unless otherwise required by the context, the plural shall be deemed
to include the singular, and vice versa; the words "hereof", "herein",
"hereunder", and similar words mean and refer to this Agreement rather than only
a particular Section or other portion of this Agreement; and "including" and
similar words mean "including by way of example only and not limitation."

                (s) All Exhibits attached to this Lease are incorporated in this
Lease by reference.

                (t) This Lease may be executed by the parties hereto in several
identical counterparts and by the parties hereto on separate counterparts, and
each counterpart, when so executed and delivered, shall constitute an original
agreement, and all such separate counterparts shall constitute but one and the
same instrument.

        10.05. Waiver of Trial by Jury.

        To the maximum extent to which the parties may lawfully and effectively
so agree under applicable law, Landlord and Tenant each (1) covenants and agrees
not to elect a trial by jury in any suit, action or proceeding arising out of
this Lease or the relationship between the parties as landlord and tenant, and
(2) waives any right to a trial by jury in any such suit, action or proceeding
with respect to any issue triable of right by a jury, to the extent that any
such right exists now or in the future. This waiver of rights to trial by jury
is separately given by each party, knowingly and voluntarily and with the advice
or opportunity for advice of the parties' respective legal counsel.

        10.06. Real Estate Broker.

        Each party hereto warrants and represents to the other that no real
estate broker or salesman has been involved in this Lease other than TerraPro
Companies, on behalf of Landlord,



                                       41
<PAGE>   47

and each party agrees to indemnify and hold the other harmless from and against
any and all claims of any other real estate broker or salesman for commissions
or other compensation in respect of this Lease due to acts of the indemnifying
party or its representatives:

        IN WITNESS WHEREOF, Landlord and Tenant, acting herein by duly
authorized representatives, have caused this Lease to be executed as of the date
aforesaid.

TENANT:


ChemConnect, Inc.
a Delaware corporation


By:    /s/ Philip J. Ringo
       Name:  Philip J. Ringo
       Title:  President


LANDLORD:


HOUSTON OFFICE 90, INC.,
a Delaware corporation


By:
       Robert Curran, Vice President


Exhibit A             Property Description
Exhibit B             Leased Premises
Exhibit C             Work Letter Agreement
Exhibit D             Air Conditioning and Heating Services
Exhibit E             Building Rules and Regulations



                                       42
<PAGE>   48

                                    EXHIBIT A

                              PROPERTY DESCRIPTION
                                 Three Riverway



THE STATE OF TEXAS:

COUNTY OF HARRIS:

FIELDNOTE DESCRIPTION OF TRACT 1

Being a 4.8088 acre tract or parcel of land situated in the William White
Survey, Abstract No. 836, Harris County, Texas and being out of and a part of
Lots 5 and 6, Block D of the W. M. Levy Corrected Subdivision of the R. B. Gaut
Subdivision per plat recorded in Volume 1, Page 29 of the Harris County Map
Records, said 4.8088 acre tract comprising of (i) that certain 4.7876 (called
4.7834) acres of land out of that certain 27.38007 acre tract of land conveyed
from Seymour Sacks, et al, to John P. Hansen, by instrument filed for record in
the Office of the County Clerk of Harris County, Texas ("CIerk's Office") under
Clerk's File No. E 726740 and recorded under Film Code No. 138-14-1120 in the
Harris County Real Property Records (the "Records"), and (ii) that certain
0.0212 acre tract conveyed by Seymour Sacks and wife Sylvia Sacks to VPM 1990-1,
LTD., by instrument filed for record in the Clerk's Office under Clerk's File
No. M721629, and recorded under Film Code No. 182-63-0785 of the Records, said
4.8088 acre tract being more particularly described by metes and bounds as
follows;

COMMENCING at a 3/4-inch iron pipe found in the Easterly right-of-way line of
South Post Oak Lane (60-foot wide right-of-way) at the Southwest corner of said
27.38007 acre tract;

THENCE, North 83 degrees32'33" East, departing the said Easterly right-of-way
line of South Post Oak Lane and along the southerly line of said 27.38007 acre
tract for a distance of 580.18 feet to a 5/8-inch iron rod found for the POINT
OF BEGINNING of the herein described 4.8088 acre tract of land;

THENCE, North 06 degrees23'05" West, for a distance of 230.36 feet to an "X" cut
in concrete found for corner;

THENCE, South 83 degrees32'33" West, for a distance of 165.02 feet to a 5/8-inch
iron rod found for corner;

THENCE, North 06 degrees27'27," West, for a distance of 33.00 feet to a 5/8-inch
iron rod found for corner;

THENCE, North 83 degrees32'33" East, for a distance of 83.33 feet to a 5/8-inch
iron rod found for corner at the point of curvature of a curve to the left;

THENCE, along said curve to the left having a radius of 10.00 feet, a central
angle of 90 degrees00'00" for an arc length of 15.71 feet (chord bears North 38
degrees32'33" East, 14.14 feet) to a 5/8-inch iron rod found for corner at the
point of tangency;



                                  Page 1 of 3
<PAGE>   49

THENCE, North 06 degrees27'27" West, for a distance of 12.67 feet to an "X" cut
in concrete found for corner at the point of curvature of a curve to the left;

THENCE, along said curve to the left having a radius of 20.00 feet, a central
angle of 44 degrees59'16" for an arc length of 15.70 feet (chord bears North 28
degrees57'07" West, 15.30 feet) to a 5/8-inch iron rod found for corner at the
point of tangency;

THENCE, North 51 degrees26'43" West, for a distance of 148.89 feet to a 5/8-inch
iron rod found for corner;

THENCE, North 06 degrees27'27" West, for a distance of 59.38 feet to an "X" cut
in concrete found for corner at the point of curvature of a curve to the left;

THENCE, along said curve to the left having a radius of 10.00 feet, a central
angle of 90 degrees00'00" for an arc length of 15.71 feet (chord bears North 51
degrees27'27" West, 14.14 feet) to an "X" cut in concrete found for corner;

THENCE, North 06 degrees27'27" West, for a distance of 5.00 feet to an "X" cut
in concrete found for corner;

THENCE, South 83 degrees32'33" West, for a distance of 136.39 feet to an "X" cut
in concrete found for corner;

THENCE, North 06 degrees27'27" West, for a distance of 28.00 feet to an "X" cut
in concrete found for corner;

THENCE, North 83 degrees32'33" East, for a distance of 151.40 feet to an "X" cut
in concrete found for corner at the point of curvature of a curve to the left;

THENCE, along said curve to the left having a radius of 125.00 feet, a central
angle of 41 degrees51'29" for an arc length of 91.32 feet (chord bears North 62
degrees36'49" East, 89.30 feet) to an "X" cut in concrete found for corner;

THENCE, North 83 degrees32'33" East, for a distance of 67.22 feet to a 5/8-inch
iron rod found for corner in a curve to the right and being a Westerly line of
that certain 1.50519 acre option tract from Seymour Sacks, et al, to John P.
Hansen as recorded in instrument executed April 1, 1976, filed for record in the
Clerk's Office under Clerk's File No. E 726740, and recorded under Film Code No.
###-##-#### in the Records;

THENCE, along a Westerly line of said 1.50519 acre tract and said curve to the
right having a radius of 553.13 feet, a central angle of 07 degrees03'00" for an
arc length of 68.06 feet (chord bears South 11 degrees48'41" West, 68.02 feet)
to a 5/8-inch iron rod found for corner at the point of tangency;

THENCE, South 15 degrees20'11" West, continuing along Westerly line of said
1.50519 acre tract for a distance of 93.70 feet to an "X" cut in concrete found
for corner;



                                  Page 2 of 3
<PAGE>   50

THENCE, South 89 degrees43'01" East, along the South line of said 1.50519 acre
tract for a distance of 109.57 feet to a railroad spike found for corner;

THENCE, North 83 degrees33'17" East, for a distance of 315.99 feet to a 5/8-inch
iron rod found for comer;

THENCE, South 51 degrees26'43" East, for a distance 265.25 feet to a 518-inch
iron rod found for comer;

THENCE, South 00 degrees08'54" East, for a distance of 55.87 feet to a 5/8-inch
iron rod found for corner;

THENCE, South 83 degrees32'33. West, for a distance of 82.42 feet to an "X" cut
in concrete found for corner;

THENCE, South 06 degrees27'27" East, for a distance of 132.00 feet to a 5/8-inch
iron rod found for comer, on the Southerly line of the aforementioned 27.38007
acre tract;

THENCE, South 83 degrees32'33" West, for a distance of 441.68 feet to the POINT
OF BEGINNING, CONTAINING 4.8088 acres (209,473 square feet) of land area within
these metes and bounds.

TRACT II

The easement tracts appurtenant to Tract I as such tracts are described in, and
as such easements were created by the following instruments: Private Street
Agreement filed for record in the Clerk's Office under Clerk's File No. F623211,
as amended by instrument filed for record in the Clerk's Office under Clerk's
File No. J989642; Access Easement Agreement filed for record in the Clerk's
Office under Clerk's File No. F900720, as amended by instruments filed for
record in the Clerk's Office under Clerk's File No. J989642; Access Easement
Agreement filed for record in the Clerk's Office under Clerk's File No. F900720,
as amended by instruments filed for record in the Clerk's Office under Clerk's
File Nos. G320627 and J989642; Second Access Easement Agreement filed for record
in the Clerk's Office under Clerk's File No. G320629, as amended by instrument
filed for record in the Clerk's Office under Clerk's File No. J989642; Easement
Grant filed for record in the Clerk's Office under Clerk's File No. G170702; and
Declaration of Covenants, Restrictions and Easement filed for record in the
Clerk's Office under Clerk's File No. K274934.



                                  Page 3 of 3
<PAGE>   51

                                    EXHIBIT B

                                 LEASED PREMISES

                     1,350 Square Feet of Net Rentable Area
                              Twelfth (12th) Floor
                                 Three Riverway
                                 Houston, Texas



                            [DIAGRAM OF LEASED SPACE]



                                  Page 1 of 1
<PAGE>   52

                                    EXHIBIT C

                              WORK LETTER AGREEMENT



Tenant accepts the Leased Premises "as is" "WITH ALL FAULTS", however; Landlord
will construct and install at no cost to Tenant the following leasehold
improvements:

1.      Provide and install building standard paint and carpet throughout the
        Leased Premises.

2.      Refinish the hardwood floors in one single office.

3.      Provide and install up to a maximum of five (5) 110 volt electrical
        outlets in areas designated by Tenant (excluding perimeter walls).

Tenant, at Tenant's cost, shall install the following leasehold improvements:

1.      Six (6) telephone jacks to be located within the Leased Premises in
        areas designated by Tenant.

2.      Six (6) voice/data drops to be located within the Leased Premises in
        areas designated by Tenant.

DEFINITIONS

(1)     "Change Order" shall be a written order that changes the scope of the
        Landlord's Work, that sets forth the total costs or reduction of costs
        for the change, and that is approved by Landlord and Tenant, all in
        accordance with this Agreement.

(2)     "Completion Date" means the date the Landlord's Work is substantially
        complete so that Tenant may use the Leased Premises for its intended
        purposes without material interference to Tenant conducting its ordinary
        business activities. The only incomplete items shall be minor or
        insubstantial details of construction, mechanical adjustments, or
        finishing touches like touch-up painting as such items are reflected on
        the Punch List (herein defined).

(3)     "Landlord's Work" shall mean the alterations and physical additions to
        the Leased Premises and the Property reflected in the Working Drawings.
        The Landlord's Work includes all labor and materials necessary to
        produce the construction required by the Working Drawings.

I.      LANDLORD DELAY AND TENANT DELAY

(1)     If the Landlord's contractor is delayed at any time in the progress of
        the Landlord's Work by any act or neglect or delay or failure to timely
        comply herewith by Tenant, any of its employees, any separate contractor
        employed by Tenant, or by changes ordered in the Landlord's Work, the
        delay shall constitute a "Tenant Delay". It is expressly agreed and
        understood that the Lease Commencement Date and Tenant's obligations
        under the Lease



                                  Page 1 of 3
<PAGE>   53

        including without limitation the obligation to pay Rent, shall not be
        adjusted or delayed as a result of a Tenant Delay. Tenant Delay shall
        also include, without limitation, a delay in the progress of the
        Landlord's Work as a result of Tenant's failure to furnish information
        necessary for Tenant's selection of materials, finishes, or
        installations, or delays caused by Tenant's changes in space plans,
        construction documents, or Change Orders.

(2)     If the Landlord's Contractor is delayed at any time in the progress of
        the Landlord's Work solely by any act or neglect by Landlord, the
        Landlord's representative, or any of Landlord's employees, then the
        delay shall be deemed "Landlord Delay". It is expressly understood and
        agreed that Tenant's sole remedy as a result of a Landlord Delay shall
        be a corresponding postponement of the Lease Commencement Date,
        including Tenant's obligation for the payment of Rent, for the number of
        days the Landlord's Contractor was delayed in the progress of the
        Landlord's Work thereby, and such postponement shall operate as a
        corresponding extension of the expiration date of the Term specified in
        Section 1.02 of the Lease in order to give full effect to the stated
        duration of the Term.

(3)     Any claim for a delay shall be made in writing by the claiming party to
        the other not more than ten (10) days after the commencement of such
        delay; otherwise it shall be conclusively deemed to be waived. In the
        event of a continuing delay, only one claim is necessary. In the event a
        claim for delay is based upon the failure to respond to or approve an
        item of the construction documents, there shall be no claim for delay
        until five (5) days following written request is made to the other party
        for a response.

II.     TENANT REIMBURSEMENT OF EXCESS COSTS

        If Landlord agrees to perform or provide additional improvements or any
        architectural or interior design services, the costs of which exceed the
        scope of the work described in Exhibit C, such services shall be
        performed and provided by Landlord at Tenant's sole cost and expense,
        and Tenant shall upon written request by Landlord provide Landlord with
        adequate assurances of payment of such excess cost and security therefor
        in form satisfactory to Landlord. Tenant agrees to pay Landlord the cost
        of all such services, together with Landlord's Coordination Fee of 6.5%,
        within thirty (30) days after receipt of Landlord's invoice, and
        thereafter such amount shall be considered additional Rent due Landlord
        by Tenant and shall be subject to all provisions of the Lease which are
        applicable to the payment of Rent, and such sums shall be collectible as
        additional Rent pursuant to the Lease and in default of payment thereof,
        Landlord shall (in addition to all other remedies have the same rights
        as in case of default in Rent. The architectural services contemplated
        herein specifically exclude the selection and design of interior
        finishes or furniture.

III.    COMPLETION

        When the Landlord's Work is nearing completion, the Landlord will notify
        the Tenant requesting a discrepancy list (the "Punch List") of the items
        of the Landlord's Work, if any, which the Tenant or the Architect
        (acting reasonably) deem incomplete or not substantially in accordance
        with the Working Drawings. The Tenant may accompany the



                                  Page 2 of 3
<PAGE>   54

        landlord's representative on the Punch List walk through or Tenant may
        issue its own Punch List provided, however, that Tenant's Punch List is
        delivered to Landlord not later than five (5) days after Tenant's
        receipt of notice from Landlord that the Landlord's Work is ready for a
        Punch List walk through. In the event that Tenant does not participate
        in Landlord's walk through and does not issue its own Punch List, Tenant
        shall be deemed to have agreed that Landlord's Punch List items (if any)
        are the only incomplete items which may, in fact, exist which are not
        specifically listed on the Punch List. However, failure to include any
        items on the Punch List shall not alter Landlord's obligation to perform
        the Landlord's Work substantially in accordance with the Working
        Drawings.

        When Landlord considers the Landlord's Work to be complete, and the
        Punch List has been issued, Landlord shall deliver to the Tenant, for
        the Tenant's confirmation (which shall not be unreasonably withheld),
        notice thereof (the "Certificate of Final Completion" which shall be
        accompanied by the Punch List) which will set forth such date of Final
        Completion and contain a Punch List of those items, if any, which remain
        incomplete. Failure of the Tenant to execute the Certificate of Final
        Completion within three (3) business days after delivery to Tenant shall
        constitute Tenant's acceptance that Final Completion has occurred.

        Notwithstanding any provisions hereof to the contrary, if Tenant
        occupies any portion of the Leased Premises prior to Final Completion
        thereof, it is agreed that Final Completion shall be deemed to have been
        achieved in respect thereto and Landlord shall have no further
        responsibility hereunder in respect to such portions of the Leased
        Premises other than to complete Punch List items in respect thereto.



                                  Page 3 of 3
<PAGE>   55

                                    EXHIBIT D

                      AIR CONDITIONING AND HEATING SERVICES



Subject to the provisions of Section 3.01(b) of the Lease, Landlord will furnish
Building Standard air conditioning and heating to the Leased Premises between
7:00 a.m. and 6:00 p.m. on weekdays (from Monday through Friday, inclusive) and
between 8:00 a.m. and 1:00 p.m. on Saturdays, all exclusive of Holidays as
defined below (the "Building Operating Hours"). Upon request of Tenant made in
accordance with the rules and regulations for the Building, Landlord will
furnish air conditioning and heating to the Leased Premises at times other than
Building Operating Hours, in which event Tenant shall reimburse Landlord for
Landlord's actual cost of furnishing such service, plus fifteen percent (15%) of
such amount to cover Landlord's overhead costs; provided, however, that Landlord
shall have the right to limit the hours outside of Building Operating Hours
during which Landlord will furnish such service, if Landlord in good faith
determines that such limitations are necessary to avoid excessive wear and tear
on Building air conditioning, heating, ventilating, or other systems, or to
maintain the character and quality of the Building, or to permit Landlord to
perform any necessary repairs or maintenance to the Building or any such
systems.

The following dates shall constitute "Holidays" as said term is used in this
lease:

(a)     New Year's Day
(b)     Memorial Day
(c)     Independence Day
(d)     Labor Day
(e)     Thanksgiving Day
(f)     Friday following Thanksgiving Day
(g)     Christmas
(h)     Any other day generally recognized as a holiday by landlords of office
        space in the metropolitan Houston office market, as determined by
        Landlord in good faith.

If in the case of any holiday described in (a) through (g) above, a different
day shall be observed than the respective day above described, then that day
which constitutes the day observed by national banks in Houston, Texas on
account of such holiday shall constitute the holiday under this Lease.



                                  Page 1 of 1
<PAGE>   56

                                     EXHIBIT E

                          BUILDING RULES AND REGULATIONS



1.      Sidewalks, doorways, vestibules, halls, stairways, and other similar
        areas shall not be used for the disposal of trash, be obstructed by
        tenants, or be used by tenants for any purpose other than entrance to
        and exit from the Leased Premises and for going from one part of the
        Building to another part of the Building.

2.      Plumbing fixtures shall be used only for the purposes for which they are
        designed, and no sweepings, rubbish, rags or other unsuitable materials
        shall be disposed into them. Damage resulting to any such fixtures from
        misuse by a tenant shall be the liability of said tenant.

3.      No signs, advertisements, or notices shall be painted or affixed on or
        to any windows or doors or any other part of the Building or Property,
        except of such color, size, and style and in such places as shall be
        first approved in writing by Landlord. No nails, hooks, or screws shall
        be driven or inserted into any part of the Building or Property except
        by the Building maintenance personnel, nor shall any part of the
        Building or Property be defaced by tenants. No curtains or other window
        treatments shall be placed between the glass and the Building standard
        or other approved window treatments.

4.      Movement in or out of the Building or Property of furniture, once
        equipment, or any other bulky or heavy materials shall be restricted to
        such hours as Landlord shall in good faith designate, and by movers
        approved by Landlord. Landlord will determine the method and routing of
        said items. Advance written notice of intent to move such items must be
        made to the Building management office. Delivery vehicles shall be
        permitted only in such areas as are designated by Landlord from time to
        time for deliveries to the Building.

5.      Building management shall have the authority to prescribe the
        positioning of, and any other special requirements applicable to, heavy
        furniture and equipment.

6.      Corridor doors, when not in use, shall be kept closed.

7.      Tenant space that is visible from public areas must be kept neat and
        clean. Tenant shall provide reasonable cooperation to Landlord's
        cleaning personnel in keeping all areas of the Leased Premises neat and
        clean.

8.      All elevator lobbies and foyers must be kept neat and clean. The
        disposal of trash or storage materials in these areas is prohibited.

9.      No animals shall be brought into or kept in, on or about the Building or
        Property, except for seeing-eye dogs.



                                  Page 1 of 3
<PAGE>   57

10.     Tenant shall not tamper with or attempt to adjust temperature control
        thermostats in their leased premises. Landlord may (or upon reasonable
        request of Tenant, Landlord shall) adjust thermostats as Landlord shall
        deem necessary or appropriate to maintain the Building standard
        temperature. Landlord requests that all window blinds, if any, remain
        down and tilted at a 45 degree angle toward the street, and that all
        draperies remain closed, to help maintain comfortable room temperatures
        and conserve energy.

11.     Tenant will at all times comply with all security procedures (if any)
        which Landlord may elect to adopt from time to time.

12.     Tenants are requested to lock all office doors leading to corridors and
        to turn out all lights at the close of their working day.

13.     Tenant shall not place any additional locks on any door in or about the
        Leased Premises without Landlord's prior written consent, and Tenant
        shall furnish a duplicate of all such keys to Landlord.

14.     All requests for overtime air conditioning or heating must be submitted
        in writing by a duly authorized representative of Tenant to the Building
        management office by 2:00 p.m. on the business day prior to the day
        desired for weekday requests, by 2:00 p.m. Friday for weekend requests
        and by 2:00 p.m. on the preceding business day for holiday requests.
        Landlord shall be entitled to rely on any list of authorized
        representatives furnished by Tenant.

15.     No flammable or explosive fluids or materials shall be kept or used
        within the Building or elsewhere on the Property except as approved in
        writing by Landlord, and Tenant shall comply with all applicable
        building and fire codes and other applicable laws and industry
        standards, relating thereto.

16.     Tenant may not place any items on any balconies of the Building that
        alter the exterior appearance of the Building without obtaining
        Landlord's prior written consent.

17.     Parking permits are to be used solely for the parking of automobiles. As
        used herein, the term "automobile" in addition to its usual and
        customary meaning, shall be deemed to include pick-up trucks, station
        wagons, vans and similar vehicles used primarily for passengers and of
        no greater height than 7' and no greater width than American full-sized
        passenger automobiles. Any motor vehicle exceeding the height or width
        restrictions of the Parking Facilities shall not be parked at any
        location within the Property.

18.     Tenant may not make any modifications, additions or repairs to the
        Leased Premises and may not install any furniture, fixtures or equipment
        in the Leased Premises which is in violation of any applicable building
        or fire code governing the Leased Premises or the Property.

19.     All contractors of any kind and their representatives performing any
        work, maintenance, cleaning, delivery, or other service of any kind in
        or to the Leased Premises shall be subject to Landlord's prior written
        approval.



                                  Page 2 of 3
<PAGE>   58

20.     No portion of the Leased Premises shall be used or occupied at any time
        as sleeping or lodging quarters.

21.     Landlord will not be responsible for any loss, theft, injury, or
        wrongful death occurring to Tenant or its personnel, invitees, agents or
        contractors, or their respective property, which may occur in or about
        the Leased Premises, Building or Property.

22.     Tenant shall not unreasonably interfere with other tenants or their
        personnel or invitees in their use or enjoyment of their leased
        premises, or any common areas.

Landlord reserves the right to rescind or modify any of these rules and
regulations and to make such other and further rules and regulations as in its
good faith judgement shall, from time to time, be required for the safety,
protection, care and cleanliness of the Building, the operation thereof, the
preservation of good order therein and the protection and comfort of the tenants
of the Property and their respective agents, employees and invitees. Such rules
and regulations, when made and written notice thereof is given to tenant, shall
be binding upon it in like manner as if originally herein prescribed. No rules
or regulations shall be construed, however, to impose any duty upon Landlord
with respect to the adoption, monitoring or enforcement thereof.

<PAGE>   59
                       FIRST AMENDMENT TO LEASE AGREEMENT


                This First Amendment to Lease Agreement ("Amendment") is made
and entered into effective as of Sept. 14, 1999 ("Effective Date"), by and
between Houston Office 90, Inc., a. Delaware corporation ("Landlord"), and
ChemConnect, Inc., a Delaware corporation ("Tenant").

RECITALS:

                Landlord and Tenant entered into a Lease Agreement dated July
13, 1999, covering approximately 1,350 square feet of Net Rentable Area on the
12th floor, Suite 1285, in the building known as "Three Riverway" (the
"Building"). Said Lease Agreement is hereinafter called the "Lease".

                Landlord and Tenant now desire to amend the Lease so as to (i)
extend the term of the Lease, (ii) relocate and expand the Leased Premises,
(iii) modify the Base Year and Tenant's Percentage Share, (iv) amend Tenant's
parking rights under the Lease, and (v) make certain other modifications to the
Lease, all as more fully set forth hereinafter.

AGREEMENTS:

                In consideration of the mutual agreements herein set forth, and
for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, Landlord and Tenant hereby agree as follows, effective
as of the Effective Date (except as otherwise specifically provided):

                1. Defined Terms and References. All capitalized terms used
herein that are not defined herein but are defined in the Lease shall have the
same meanings herein as in the Lease.

                2. Leased Premises. Effective as of the Commencement Date
(hereinafter defined), the first sentence of Section 1.01(a) of the Lease is
hereby amended to reflect that the Leased Premises shall consist of
approximately 3,588 square feet of Net Rentable Area, Suite 1330 (sometimes
referred to in this Amendment as the "Expanded Leased Premises") rather than
1,350 square feet of Net Rentable Area, Suite 1285 (sometimes referred to in
this Amendment as the "Original Premises) as shown on Exhibit "B" of the Lease.
The Expanded Leased Premises is outlined on the floor plan drawings attached
hereto as Exhibit "B- 1" and made a part hereof for all purposes. Effective as
of the Commencement Date, Exhibit "B-1" shall be substituted for Exhibit "B" to
the Lease, and Exhibit "B" to the Lease shall be deleted.



                                  Page 3 of 3
<PAGE>   60
                Effective as of the Commencement Date, Section 1.01(c) of the
Lease is hereby amended to provide that the stipulated Net Rentable Area of the
Leased Premises is agreed to be 3,588 square feet, regardless of whether the
same may be actually more or less.

                3. Term. Section 1.02 of the Lease is hereby amended as follows.
The term of the Lease shall expire thirty-six (36) months after the Commencement
Date, subject to earlier termination as provided in the Lease. The "Commencement
Date" as used in this Amendment


shall mean the earlier of (i) the Completion
Date, as such term is defined in Exhibit "C-l" attached to this Amendment and
made a part hereof (which Exhibit "C-l" is hereby added to and made a part of
the Lease for all purposes), or (ii) the date upon which Tenant commences
conducting its business from all or any portion of the Expanded Leased Premises.
On or before the Commencement Date, Tenant shall vacate the Original Premises,
and shall surrender the Original Premises to Landlord in accordance with Section
4.01 and other applicable provisions of the Lease.

                4. Base Rental. Tenant shall continue to pay Base Rental in
accordance with the existing terms of Section 2.02 of the Lease through, but not
including, the Commencement Date. Effective as of the Commencement Date, the
schedule of Base Rental set forth after the first sentence of Section 2.02 is
amended in its entirety to read as follows:

<TABLE>
<CAPTION>
 Lease Period                 Base Rental                 Monthly Installments
 ------------                 -----------                 --------------------
<S>                           <C>                         <C>
 Months* 1-36                 $22.50                      $6,727.50
</TABLE>

*Months beginning with Commencement Date (as modified in the First Amendment to
this Lease)

                5. Base Year and Tenant's Percentage Share. The Base Year with
respect to the Expanded Leased Premises shall be 1999. Effective as of the
Commencement Date, Section 2.03(c) of the Lease is amended to provide that the
"Tenant's Percentage Share" shall be 0.90689%, provided, however, that in the
event the amount of space leased by Tenant shall increase or decrease subsequent
to the Commencement Date, Tenant's Percentage Share shall be appropriately
adjusted by Landlord.

                6. Parking. Effective as of the Commencement Date, the first
sentence of Section 3.04(a) of the Lease are hereby amended in their entireties
to read as follows:

"Landlord agrees to provide and Tenant agrees to lease during the term of this
Lease two (2) assigned parking permits ("Reserved Permits") and eight (8)
unassigned parking permits ("Unassigned Permits") for the parking of automobiles
in spaces in the Parking Facilities from time to time designated by Landlord."
<PAGE>   61

<PAGE>   62

"Tenant, at Tenant's option, shall have the right to lease an additional two (2)
unreserved parking permits as needed by Tenant from time-to-time."

                Effective as of the Commencement Date, the first sentence of
Section 3.04(b) of the Lease is hereby amended in its entirety to be and read as
follows:

"The rent for parking permits leased by Tenant hereunder shall initially be at
the rate of (i) Seventy-Five and 00/100 Dollars ($75.00) per assigned parking
space per month (the "Reserved Parking Rent"), for a total initial monthly
Reserved Parking Rent of $150.00, and (ii) Fifty Dollars ($50.00) per unassigned
parking space per month (the "Unassigned Parking Rent"), for a total initial
monthly Unassigned Parking Rent of $550.00 (the Reserved Parking Rent and
Unassigned Parking Rent are hereinafter referred to as the "Parking Rent")."


                Effective as of the Commencement Date, the second sentence of
Section 3.04(b) of the Lease is hereby deleted.

                7. Construction of Leasehold Improvements to Expanded Leased
Premises. Exhibit "C-1" shall be applicable to the leasehold improvements to be
performed in the Expanded Leased Premises. Exhibit "C" to the Lease is hereby
deleted. Landlord shall provide to Tenant, subject to the terms of Exhibit "C-1"
and other provisions of the Lease, a Leasehold Improvement Allowance in an
aggregate amount not to exceed Five Dollars ($5.00) times the number of square
feet of Net Rentable Area in the Expanded Leased Premises only, for the
performance of the work contemplated by Exhibit "C-1". Such Leasehold
Improvement Allowance shall be payable in accordance with the terms of such
Exhibit "C-1", and Tenant shall comply with its obligations thereunder, and
under the other provisions of this Lease.

                8. Miscellaneous. Except as expressly amended by this Amendment,
all terms, conditions, agreements and considerations set forth in the Lease
shall remain in full force and effect. In the event of a conflict between the
terms of this Amendment and the terms of the Lease, the terms of this Amendment
shall control. This Amendment (i) shall be binding upon the Landlord and Tenant
and their respective heirs, legal representatives, successors and permitted
assigns; (ii) may be renewed, modified or amended only by a writing signed by
each party hereto; (iii) shall be governed by and construed in accordance with
the laws of the State of Texas and the United States of America; (iv) may be
executed in several counterparts, and each counterpart when so executed and
delivered shall constitute an original agreement, and all such separate
counterparts shall constitute one and the same agreement; and (v) embodies the
entire agreement and understanding between the parties with respect to the
subject matter hereof and supersedes all prior agreements, consents and
understandings relating to such subject matter. All capitalized terms used
herein and not otherwise defined herein which are defined in the Lease shall
have the meanings ascribed to them in the Lease. The term "Lease" as used in the
Lease or in any other instrument,
<PAGE>   63
document or writing executed in connection therewith or herewith shall mean the
Lease as amended by this Amendment, unless clearly otherwise required by the
context.

                9. Additional Covenants, Representations and Warranties.

Tenant hereby covenants, represents and warrants to Landlord that:

                        a. Tenant is solvent; no bankruptcy or insolvency
proceedings are pending or contemplated by or against Tenant; and this Amendment
and the Lease are the legal, valid and binding obligations of Tenant enforceable
against Tenant in accordance with their terms, except as enforceability hereof
or thereof may be limited by bankruptcy, insolvency, reorganization or
moratorium or other similar laws relating to the rights of creditors generally
and by general principles which may limit the right to obtain equitable
remedies.

                        b. The covenants, representations and warranties
contained in the Lease are true and correct in all material respects on and as
of the date hereof as though made by Tenant and made on and as of this date, and
Tenant is not in default in any manner under the Lease or under any document,
writing or instrument executed in connection herewith or therewith.

                        c. All information, reports, statements and other data
furnished by or on behalf of Tenant prior to, contemporaneously with, or
subsequent to the execution of the Lease or this Amendment are and shall be true
and correct and do not and shall not omit to state any fact or circumstance
necessary to make the information contained therein or herein not misleading.

                        d. As of the date hereof, Tenant has no claims or
demands against Landlord or Landlord's predecessors in interest, nor any claims,
demands, counterclaims, defenses, allowances, adjustments or offsets arising out
of or in any way related to the Leased Premises or the Lease or arising out of
any document, writing or instrument executed in connection therewith or
herewith.





<PAGE>   64

                IN WITNESS WHEREOF, the Amendment has been executed in multiple
counterparts as of the date first above written.

HOUSTON OFFICE 90, INC.


By:    /s/ Robert Curran
Printed Name:  Robert Curran
Title: Vice President


CHEMCONNECT, INC.


By:    /s/ John F. Elliott
Printed Name:  John F. Elliott
Title: Vice President of Sales
<PAGE>   65

                                   EXHIBIT B-1

                            EXPANDED LEASED PREMISES



                     3,588 Square Feet of Net Rentable Area
                             Thirteenth (13th) Floor
                                 Three Riverway
                                 Houston, Texas

                            [DIAGRAM OF LEASED SPACE]



                                   Page 1 of 1
<PAGE>   66

                                   EXHIBIT C-1

                              WORK LETTER AGREEMENT



Tenant accepts the Expanded Leased Premises "as is" "WITH ALL FAULTS", however;
Landlord will construct and install at no cost to Tenant the leasehold
improvements shown on the Working Drawings attached hereto as EXHIBIT C-2.

DEFINITIONS

"Change Order" shall be a written order that changes the scope of the Landlord's
Work, that sets forth the total costs or reduction of costs for the change, and
that is approved by Landlord and Tenant, all in accordance with this Agreement.

"Completion Date" means the date the Landlord's Work is substantially complete
so that Tenant may use the Expanded Leased Premises for its intended purposes
without material interference to Tenant conducting its ordinary business
activities. The only incomplete items shall be minor or insubstantial details of
construction, mechanical adjustments, or finishing touches like touch-up
painting as such items are reflected on the Punch List (herein defined).

"Landlord's Work" shall mean the alterations and physical additions to the
Expanded Leased Premises and the Property reflected in the Working Drawings. The
Landlord's Work includes all labor and materials necessary to produce the
construction required by the Working Drawings.

1.      LANDLORD DELAY AND TENANT DELAY

If the Landlord's contractor is delayed at any time in the progress of the
Landlord's Work by any act or neglect or delay or failure to timely comply
herewith by Tenant, any of its employees, any separate contractor employed by
Tenant, or by changes ordered in the Landlord's Work, the delay shall constitute
a "Tenant Delay". It is expressly agreed and understood that the Lease
Commencement Date and Tenant's obligations under the Lease including without
limitation the obligation to pay Rent, shall not be adjusted or delayed as a
result of a Tenant Delay. Tenant Delay shall also include, without limitation, a
delay in the progress of the Landlord's Work as a result of Tenant's failure to
furnish information necessary for Tenant's selection of materials, finishes, or
installations, or delays caused by Tenant's changes in space plans, construction
documents, or Change Orders.

If the Landlord's Contractor is delayed at any time in the progress of the
Landlord's Work solely by any act or neglect by Landlord, the Landlord's
representative, or any of Landlord's employees, then the delay shall be deemed
"Landlord Delay". It is expressly understood and agreed that Tenant's sole
remedy as a result of a Landlord Delay shall be a corresponding postponement of
the Lease Commencement Date, including Tenant's obligation for the payment of
Rent, for the number of days the Landlord's Contractor was delayed in the
progress of the Landlord's Work thereby, and such postponement shall operate as
a corresponding extension of the expiration date of the Term specified in
Section 1.02 of the Lease in order to give full effect to the stated duration of
the Term.




<PAGE>   67

Any claim for a delay shall be made in writing by the claiming party to the
other not more than ten (10) days after the commencement of such delay;
otherwise it shall be conclusively deemed to be waived. In the event of a
continuing delay, only one claim is necessary. In the event a claim for delay is
based upon the failure to respond to or approve an item of the construction
documents, there shall be no claim for delay until five (5) days following
written request is made to the other party for a response.

2.      TENANT REIMBURSEMENT OF EXCESS COSTS.

If Landlord agrees to perform or provide additional improvements or any
architectural or interior design services, the costs of which exceed the scope
of the work described in EXHIBIT C-2, such services shall be performed and
provided by Landlord at Tenant's sole cost and expense, and Tenant shall upon
written request by Landlord provide Landlord with adequate assurances of payment
of such excess cost and security therefor in form satisfactory to Landlord.
Tenant agrees to pay Landlord the cost of all such services, together with
Landlord's Coordination Fee of 5%, within thirty (30) days after receipt of
Landlord's invoice, and thereafter such amount shall be considered additional
Rent due Landlord by Tenant and shall be subject to all provisions of the Lease
which are applicable to the payment of Rent, and such sums shall be collectible
as additional Rent pursuant to the Lease and in default of payment thereof,
Landlord shall (in addition to all other remedies have the same rights as in
case of default in Rent. The architectural services contemplated herein
specifically exclude the selection and design of interior finishes or furniture.

3.      COMPLETION

When the Landlord's Work is nearing completion, the Landlord will notify the
Tenant requesting a discrepancy list (the "Punch List") of the items of the
Landlord's Work, if any, which the Tenant or the Architect (acting reasonably)
deem incomplete or not substantially in accordance with the Working Drawings.
The Tenant may accompany the landlord's representative on the Punch List walk
through or Tenant may issue its own Punch List provided, however, that Tenant's
Punch List is delivered to Landlord not later than five (5) days after Tenant's
receipt of notice from Landlord that the Landlord's Work is ready for a Punch
List walk through. In the event that Tenant does not participate in Landlord's
walk through and does not issue its own Punch List, Tenant shall be deemed to
have agreed that Landlord's Punch List items (if any) are the only incomplete
items which may, in fact, exist which are not specifically listed on the Punch
List. However, failure to include any items on the Punch List shall not alter
Landlord's obligation to perform the Landlord's Work substantially in accordance
with the Working Drawings.

When Landlord considers the Landlord's Work to be complete, and the Punch List
has been issued, Landlord shall deliver to the Tenant, for the Tenant's
confirmation (which shall not be unreasonably withheld), notice thereof (the
"Certificate of Final Completion" which shall be accompanied by the Punch List)
which will set forth such date of Final Completion and contain a Punch List of
those items, if any, which remain incomplete. Failure of the Tenant to execute
the Certificate of Final Completion within three (3) business days after
delivery to Tenant shall constitute Tenant's acceptance that Final Completion
has occurred.



<PAGE>   68

Notwithstanding any provisions hereof to the contrary, if Tenant occupies any
portion of the Expanded Leased Premises prior to Final Completion thereof, it is
agreed that Final Completion shall be deemed to have been achieved in respect
thereto and Landlord shall have no further responsibility hereunder in respect
to such portions of the Expanded Leased Premises other than to complete Punch
List items in respect thereto.



<PAGE>   69

                                   EXHIBIT C-2

                            [Diagram of Leased Space]