<Page>

Exhibit 10.3.1

Amendments dated August 30, 2002 and September 16, 2002 to Revolving Credit
Agreement by and among TRC Companies, Inc. and its subsidiaries and Wachovia
Bank, N.A.

<Page>

AMENDMENT NO. 1 TO REVOLVING CREDIT AGREEMENT

This AMENDMENT NO. 1 ("Amendment") dated as of August 30, 2002 is by and
between WACHOVIA BANK, NATIONAL ASSOCIATION (formerly known as First Union
National Bank), as an individual Lender and as Sole Lead Arranger and
Administrative Agent ("Wachovia"), Wachovia in its capacity as the Lead Arranger
and Administrative Agent is hereinafter the "Agent", and TRC COMPANIES, INC., a
Delaware corporation ("TRC") and the subsidiaries of TRC listed therein, (each a
"Borrower" and collectively the "Borrowers").

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

WHEREAS, the Borrowers, Agent and Wachovia, as the then sole Lender (the
"Existing Lender") are parties to a certain Revolving Credit Agreement dated as
of March 25, 2002 (said agreement, as amended and modified from time to time,
the "Credit Agreement") and certain other Credit Documents executed and
delivered in connection therewith; and

WHEREAS, the Borrowers, the Agent and the Existing Lender desire to amend
the Credit Agreement for the purpose of (i) increasing the Commitments to an
aggregate amount not to exceed $38,000,000 and admitting Merrill Lynch Business
Financial Services Inc. as an additional Lender with a Commitment not to exceed
$8,000,000 (the "New Lender") and (ii) modifying the Consolidated Net Worth
requirement set forth in the Credit Agreement;

NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration (the receipt and sufficiency of which are hereby
acknowledged), the parties hereto hereby agree as follows:

1. DEFINED TERMS; EFFECT OF AMENDMENT.

(a) Unless otherwise modified hereby, all capitalized terms used herein
which are defined in the Credit Agreement, and not otherwise defined herein, are
used herein as defined in the Credit Agreement. All capitalized terms used
herein which are defined in the Credit Agreement and modified herein shall have
the meaning assigned to such terms in the Credit Agreement as so modified.

(b) This Amendment is an amendment to the Credit Agreement. Unless the
context of this Amendment otherwise requires, the Credit Agreement and this
Amendment shall be read together and shall have effect as if the provisions of
the Credit Agreement and this Amendment were contained in one agreement. After
the effective date of this Amendment, all references in the Credit Agreement to
the "Credit Agreement", "this Agreement", "hereto", "hereof", "hereunder" or
words of like import referring to the Credit Agreement shall mean the Credit
Agreement as amended by this Amendment, and all references in the Notes and the
other Credit Documents to the Credit Agreement shall mean the Credit Agreement
as amended by this Amendment.

2. AMENDMENTS TO CREDIT AGREEMENT.

(a) The defined terms "Commitment", "Commitments" and "Lender" set forth in
Section 1.01 of the Credit Agreement are hereby amended and restated in their
entirety to read as follows:

<Page>

""COMMITMENT" shall mean, with respect to each Lender, the amount set
forth on SCHEDULE "A" attached hereto, which is such Lender's Pro Rata
Share of the Maximum Available Revolving Credit Amount that such
Lender has agreed to advance hereunder, as the same may be (i) reduced
from time to time pursuant to Section 2.04 hereof or (ii) adjusted
from time to time as a result of assignments to and from the Lenders
pursuant to Section 11.08 hereof and increases in the Commitments
pursuant to Section 2.17 hereof. "COMMITMENTS" shall mean the
aggregate of each Commitment of each Lender hereunder, and shall
include (without duplication) the Swingline Commitment of the
Swingline Lender."

""LENDER" shall mean each Lender listed on SCHEDULE "A" attached hereto,
each assignee which becomes a Lender pursuant to Section 11.08 hereof, and their
respective successors and assigns."

(b) The following new defined terms are hereby inserted into Section 1.01
in their respective appropriate alphabetical order:

""CONSOLIDATED CURRENT ASSETS" shall mean all assets of the Borrowers, on a
consolidated basis, which may properly be classified as current assets in
accordance with GAAP."

""CONSOLIDATED NET WORTH" shall mean the excess of Consolidated Total
Assets over Consolidated Total Liabilities, determined in accordance with GAAP.
For the avoidance of doubt, Consolidated Net Worth shall be determined without
consideration of the Specified Preferred Stock."

""CONSOLIDATED TOTAL ASSETS" shall mean all assets of the Borrowers, on a
consolidated basis, determined in accordance with GAAP."

""CONSOLIDATED TOTAL LIABILITIES" shall mean all liabilities of the
Borrowers, on a consolidated basis, determined in accordance with GAAP."

"8.10 NET WORTH. The Borrowers will not permit Consolidated Net Worth at
any time to be less than (a) $105,000,000 PLUS (b) the sum of (i) 75% of
quarterly positive net income on a cumulative basis commencing with results
reported with respect to the fiscal quarter ending March 31, 2002 and (ii) 100%
of the value of all property received by the Borrowers in exchange for the
issuance of new equity securities (or the sale of treasury shares) of any of the
Borrowers issued subsequent to December 31, 2001, measured quarterly."

(d) SCHEDULE "A" attached hereto is hereby incorporated into, and made a
part of, the Credit Agreement.

<Page>

Lender of any kind or description, an interest in the Revolving Credit
Loans and L/C Participations owing to the Existing Lender as of the Effective
Date (but excluding accrued interest and fees to and including the Effective
Date) equal to its Pro Rata Share of said outstanding obligations. In connection
with said assignment and purchase, the New Lender shall pay to the Existing
Lender such amounts as may be necessary such that after given effect to such
payment, each of the Existing Lenders and the New Lender shall be owed from the
Borrowers outstanding Revolving Credit Obligation equal to their respective Pro
Rata Shares therein as of the Effective Date.

(b) To evidence the obligations of the Borrowers owing to the Existing
Lender and the New Lender, respectively, as of the Effective Date, the Borrowers
shall issue to each Lender new Revolving Credit Notes substantially in the form
of EXHIBIT A to the Credit Agreement. Each such note shall be dated the
Effective Date and shall be in an original principal amount of up to the
Commitment of the Lender to which such note is being issued.

5. FULL FORCE AND EFFECT. Except as expressly modified by this Amendment,
all of the terms and conditions of the Credit Agreement shall continue in full
force and effect, and all parties hereto shall be entitled to the benefits
thereof. This Amendment is limited as written and shall not be deemed (i) to be
an amendment of or a consent under or waiver of any other term or condition of
the Credit Agreement or (ii) to prejudice any right or rights which the Lenders
now have or may have in the future under or in connection with the Credit
Agreement or such other agreements.

6. REPRESENTATIONS AND WARRANTIES. In order to induce the Lenders to enter
into this Amendment, the Borrower makes the following representations and
warranties to the Lenders, which shall survive the execution and delivery
hereof:

(i) The execution and delivery of this Amendment has been
authorized by all necessary corporate action on its part,
this Amendment has been duly executed and delivered by it,
and this Amendment and the Credit Agreement, as amended
hereby, constitutes the legal, valid and binding obligations
of it enforceable against it in accordance with its terms
subject to applicable bankruptcy, insolvency, reorganization
and other laws affecting creditors' rights generally,
moratorium laws from time to time in effect and general
principles of equity (regardless of whether such
enforceability is considered in a proceeding in equity or at
law);

(ii) No Event of Default has occurred and is continuing under the
Credit Agreement, and no event has occurred which, with
notice, lapse of time or both, would constitute such an Event
of Default; and

(iii) The representations and warranties set forth in the Credit
Agreement and the other Credit Documents are true and correct
as of the date hereof in all material respects.

7. COUNTERPARTS. This Amendment may be executed in any number of
counterparts, each of which when so executed shall be deemed to be an original,
and all which when taken together shall constitute one and the same agreement.

8. GOVERNING LAW. This Amendment, including the validity thereof and the
rights and obligations of the parties hereunder, shall be construed in
accordance with and governed by the laws of the State of New Jersey.

<Page>

9. CONDITIONS PRECEDENT. This Amendment shall not be effective until (i)
the Agent shall have received counterparts of this Amendment, duly executed by
each of the parties hereto, (ii) each Lender shall have received a Revolving
Credit Note reflecting its Commitment as of the Effective Date duly executed and
delivered by the Borrowers, (iii) the New Lender shall have duly completed and
submitted to the Agent an Administrative Reply Form, (iv) the Existing Lender
shall have received from the New Lender the payments required pursuant to
Section 4(a) hereof, (v) the New Lender shall have received from the Borrowers
all of the fees and expenses owing to the New Lender pursuant to its Commitment
dated August 5, 2002, and (vi) Borrowers shall have paid all reasonable fees and
expenses of the Agent's counsel incurred in connection with the preparation,
negotiation, execution and delivery and review of this Amendment. The date on
which all of the foregoing conditions are satisfied as determined by the Lenders
is referred to herein as the "EFFECTIVE DATE".

10. EXECUTION CERTIFICATION. The parties hereto certified that this
Amendment was executed and delivered in the State of New Jersey.

[SIGNATURE PAGES TO FOLLOW]

<Page>

IN WITNESS WHEREOF, the undersigned have executed this Amendment as of the
day and year first above written.

THE BORROWERS:

TRC COMPANIES, INC. TRC ENVIRONMENTAL CORPORATION

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
----------------------------- ---------------------------
Harold C. Elston, Jr., Senior Harold C. Elston, Jr., Vice
Vice President President & Treasurer

TRC ENGINEERS, INC. TRC ENVIRONMENTAL SOLUTIONS, INC.

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
--------------------------- ---------------------------
Harold C. Elston, Jr., Vice Harold C. Elston, Jr.,
President & Treasurer Assistant Treasurer

TRC MARIAH ASSOCIATES INC. TRC GARROW ASSOCIATES, INC.

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
--------------------------- --------------------------------
Harold C. Elston, Jr., Vice Harold C. Elston, Jr., Treasurer
President & Treasurer

TRC ALTON GEOSCIENCE, INC. VECTRE CORP.

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
--------------------------- --------------------------------
Harold C. Elston, Jr., Harold C. Elston, Jr., Treasurer
Assistant Treasurer

HUNTER ASSOCIATES TEXAS, LTD. LOWNEY ASSOCIATES
By Hunter Associates, Inc.,
its General Partner

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

OMNI ENVIRONMENTAL IMBSEN & ASSOCIATES
CORPORATION

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Assistant
Treasurer

<Page>

ENGINEERED AUTOMATION ECON CAPITAL, LP
SYSTEMS, INCORPORATED By TRC Companies, Inc.,
its General Partner

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

TRC ENERGYSOLVE LLC GBF HOLDINGS LLC
By TRC Companies, Inc., By TRC Companies, Inc.,
its Managing Member its Managing Member

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

PBWO HOLDINGS, LLC CO-ENERGY GROUP LLC
By TRC Companies, Inc.,
its Managing Member

HUNTER ASSOCIATES, INC. METUCHEN REALTY ACQUISITION, LLC
By TRC Companies, Inc.,
its Managing Member

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

E/PRO ENGINEERING AND CARSON-SALCEDO-MCWILLIAMS, INC.
ENVIRONMENTAL CONSULTING LLC

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

NEW CENTURY ENGINEERING SITE-BLAUVELT ENGINEERS, INC.
SUPPORT SERVICES, LLC (New Jersey)

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

<Page>

SITE CONSTRUCTION SERVICES INC. SITE-BLAUVELT ENGINEERS, INC.
(New York)

By: /S/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

SITE-BLAUVELT ENGINEERS, INC.
(Virginia)

By: /S/ HAROLD C. ELSTON, JR.
--------------------------------
Harold C. Elston, Jr., Treasurer

WACHOVIA BANK, NATIONAL ASSOCIATION,
(formerly known as First Union National
Bank), AS AGENT

BY: /s/ PAUL J. BAKEY
-----------------------------
Paul J. Bakey, Vice President

THE EXISTING LENDERS:
WACHOVIA BANK, NATIONAL ASSOCIATION,
(formerly known as First Union National
Bank), INDIVIDUALLY

BY: /s/ PAUL J. BAKEY
-----------------------------
Paul J. Bakey, Vice President

JOINDER OF NEW LENDER
ACCEPTED AND AGREED AS THE NEW LENDER:

MERRILL LYNCH BUSINESS FINANCIAL SERVICES INC.

BY: /s/ CHRISTOPHER M. MCLAUGHLIN
-----------------------------------------
Christopher M. McLaughlin, Vice President

<Page>

SCHEDULE "A"

LENDERS AND COMMITMENTS

LENDER COMMITMENT
- ------ -----------

Wachovia Bank, National Association $30,000,000
(includes $5,000,000 Swingline Commitment)

Merrill Lynch Business Financial Services Inc. $8,000,000
</Table>

<Page>

AMENDMENT NO. 2 TO
REVOLVING CREDIT AGREEMENT

This AMENDMENT NO. 2 ("Amendment") dated as of September 16, 2002 is by and
between WACHOVIA BANK, NATIONAL ASSOCIATION (formerly known as First Union
National Bank), as an individual Lender and as Sole Lead Arranger and
Administrative Agent ("Wachovia"), Wachovia in its capacity as the Lead Arranger
and Administrative Agent is hereinafter the "Agent", MERRILL LYNCH BUSINESS
FINANCIAL SERVICES INC., as an individual Lender ("Merrill"), Merrill and
Wachovia in their respective capacities as Lenders are hereinafter the "Existing
Lenders" and TRC COMPANIES, INC., a Delaware corporation ("TRC") and the
subsidiaries of TRC listed herein, (each a "Borrower" and collectively the
"Borrowers").

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

WHEREAS, the Borrowers, Agent and Existing Lenders are parties to a certain
Revolving Credit Agreement dated as of March 25, 2002, as amended by an
Amendment No. 1 thereto dated as of August 30, 2002 (said agreement, as so
amended, and as further as amended and modified from time to time, the "Credit
Agreement") and certain other Credit Documents executed and delivered in
connection therewith; and

WHEREAS, the Borrowers, the Agent and the Existing Lenders desire to amend
the Credit Agreement for the purpose of increasing the Commitments to an
aggregate amount not to exceed $40,000,000 and admitting Banknorth, N.A. as an
additional Lender with a Commitment not to exceed $12,000,000 (the "New
Lender");

NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration (the receipt and sufficiency of which are hereby
acknowledged), the parties hereto hereby agree as follows:

1. DEFINED TERMS; EFFECT OF AMENDMENT.

2. AMENDMENT TO CREDIT AGREEMENT.

(a) For the purpose of establishing the New Lender as a Lender under the
Credit Agreement,

<Page>

increasing the aggregate Commitments of all of the Lenders to $40,000,000 and
adjusting the Commitment of Wachovia accordingly, SCHEDULE "A" to the Credit
Agreement is hereby deleted in its entirety and SCHEDULE "A" attached hereto is
hereby substituted into, and made a part of, the Credit Agreement, in its place.

(b) Clause (c) of Section 7.02 of the Credit Agreement shall be amended and
restated to read as follows:

"(c) Contemporaneously with the quarterly financial statements
delivered pursuant to clause (b) of this Section 7.02, an accounts
receivable aging summary report in a form reasonably acceptable to the
Agent;"

(c) For the avoidance of doubt, the bracketed dollar figure appearing in
clause (ii) of Section 8.06 of the Credit Agreement is deleted and replaced with
the following dollar figure (without brackets):

"$1,000,000"

4. JOINDER OF NEW LENDER; NEW NOTES. (a) By its signature below and upon
satisfaction of the condition precedent set forth in Section 9 hereof, as of the
Effective Date (as defined in said Section 9), the New Lender shall become a
Lender party to, shall be bound as a Lender by, and shall be entitled to all the
benefits of a Lender pursuant to, the provisions of the Credit Agreement and the
other Credit Documents. As of the Effective Date, the New Lender shall be deemed
to have taken by assignment and purchased from the Existing Lenders, without
recourse to, or representation or warranty, by any of the Existing Lenders of
any kind or description, an interest in the Revolving Credit Loans and L/C
Participations owing to the Existing Lenders as of the Effective Date (but
excluding accrued interest and fees to and including the Effective Date) equal
to its Pro Rata Share of said outstanding obligations. In connection with said
assignment and purchase, the New Lender shall pay to the Existing Lenders such
amounts as may be necessary such that after given effect to such payment, each
of the Existing Lenders and the New Lender shall be owed from the Borrowers
outstanding Revolving Credit Obligation equal to their respective Pro Rata
Shares therein as of the Effective Date.

(b) To evidence the obligations of the Borrowers owing to the Existing
Lenders and the New Lender, respectively, as of the Effective Date, the
Borrowers shall issue to each Lender new Revolving Credit Notes substantially in
the form of EXHIBIT A to the Credit Agreement. Each such note shall be dated the
Effective Date and shall be in an original principal amount of up to the
Commitment of the Lender to which such note is being issued.

<Page>

(ii) No Event of Default has occurred and is continuing under the
Credit Agreement, and no event has occurred which, with
notice, lapse of time or both, would constitute such an Event
of Default; and

(iii) The representations and warranties set forth in the Credit
Agreement and the other Credit Documents are true and correct
as of the date hereof in all material respects.

9. CONDITIONS PRECEDENT. This Amendment shall not be effective until (i)
the Agent shall have received counterparts of this Amendment, duly executed by
each of the parties hereto, (ii) each Lender shall have received a Revolving
Credit Note reflecting its Commitment as of the Effective Date duly executed and
delivered by the Borrowers, (iii) the New Lender shall have duly completed and
submitted to the Agent an Administrative Reply Form, (iv) the Existing Lenders
shall have received from the New Lender the payments required pursuant to
Section 4(a) hereof, and (v) Borrowers shall have paid all reasonable fees and
expenses of the Agent's counsel incurred in connection with the preparation,
negotiation, execution and delivery and review of this Amendment. The date on
which all of the foregoing conditions are satisfied as determined by the Lenders
is referred to herein as the "EFFECTIVE DATE".

10. EXECUTION CERTIFICATION. The parties hereto certified that this
Amendment was executed and delivered in the State of New Jersey.

[SIGNATURE PAGES TO FOLLOW]

<Page>

IN WITNESS WHEREOF, the undersigned have executed this Amendment as of the
day and year first above written.

THE BORROWERS:

TRC COMPANIES, INC. TRC ENVIRONMENTAL CORPORATION

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
----------------------------- --------------------------------
Harold C. Elston, Jr., Senior Harold C. Elston, Jr., Vice
Vice President President & Treasurer

TRC ENGINEERS, INC. TRC ENVIRONMENTAL SOLUTIONS, INC.

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
--------------------------- --------------------------------
Harold C. Elston, Jr., Vice Harold C. Elston, Jr., Assistant
President & Treasurer Treasurer

TRC MARIAH ASSOCIATES INC. TRC GARROW ASSOCIATES, INC.

TRC ALTON GEOSCIENCE, INC. VECTRE CORP.

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------- --------------------------------
Harold C. Elston, Jr., Assistant Harold C. Elston, Jr., Treasurer
Treasurer

HUNTER ASSOCIATES TEXAS, LTD. LOWNEY ASSOCIATES
By Hunter Associates, Inc.,
its General Partner

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

OMNI ENVIRONMENTAL IMBSEN & ASSOCIATES
CORPORATION

By: /S/ HAROLD C. ELSTON, JR. By: /S/ HAROLD C. ELSTON, JR.
-------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Assistant
Treasurer

<Page>

ENGINEERED AUTOMATION ECON CAPITAL, LP
SYSTEMS, INCORPORATED By TRC Companies, Inc.,
its General Partner

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

TRC ENERGYSOLVE LLC GBF HOLDINGS LLC
By TRC Companies, Inc., By TRC Companies, Inc.,
its Managing Member its Managing Member

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

PBWO HOLDINGS, LLC CO-ENERGY GROUP LLC
By TRC Companies, Inc.,
its Managing Member

By: /s/ HAROLD C. ELSTON, JR. By: /S/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Assistant
Treasurer

HUNTER ASSOCIATES, INC. METUCHEN REALTY ACQUISITION, LLC
By TRC Companies, Inc.,
its Managing Member

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

E/PRO ENGINEERING AND CARSON-SALCEDO-MCWILLIAMS, INC.
ENVIRONMENTAL CONSULTING LLC

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
--------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

NEW CENTURY ENGINEERING SITE-BLAUVELT ENGINEERS, INC.
SUPPORT SERVICES, LLC New Jersey)

By: /s/ HAROLD C. ELSTON, JR. By: /S/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

<Page>

SITE CONSTRUCTION SERVICES INC. SITE-BLAUVELT ENGINEERS, INC.
(New York)

By: /s/ HAROLD C. ELSTON, JR. By: /s/ HAROLD C. ELSTON, JR.
-------------------------------- --------------------------------
Harold C. Elston, Jr., Treasurer Harold C. Elston, Jr., Treasurer

SITE-BLAUVELT ENGINEERS, INC.
(Virginia)

By: /s/ HAROLD C. ELSTON, JR.
--------------------------------
Harold C. Elston, Jr., Treasurer

THE AGENT:
WACHOVIA BANK, NATIONAL ASSOCIATION,
(formerly known as First Union National
Bank), AS AGENT

BY: /s/ PAUL J. BAKEY
-----------------------------
Paul J. Bakey, Vice President

THE EXISTING LENDERS:
WACHOVIA BANK, NATIONAL ASSOCIATION,
(formerly known as First Union National
Bank), INDIVIDUALLY

BY: /s/ PAUL J. BAKEY
-----------------------------
Paul J. Bakey, Vice President

MERRILL LYNCH BUSINESS FINANCIAL
SERVICES INC.

BY: /s/ CHRISTOPHER M. MCLAUGHLIN
--------------------------------
Christopher M. McLaughlin,
Vice President

JOINDER OF NEW LENDER
ACCEPTED AND AGREED AS THE NEW LENDER:

BANKNORTH, N.A.

BY: /S/ JEFFREY R. WESTLING
---------------------------------------
Jeffrey R. Westling, Sr. Vice President

<Page>

SCHEDULE "A"

LENDERS AND COMMITMENTS

LENDER COMMITMENT
- ------ ----------

Wachovia Bank, National Association $20,000,000
(includes $5,000,000 Swingline Commitment)

Merrill Lynch Business Financial Services Inc. $8,000,000

Banknorth, N.A. $12,000,000
-----------

AGGREGATE COMMITMENTS: $40,000,000
===========
</Table>