Document:

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                                  EXHIBIT 10.31

                      SECOND AMENDMENT TO CREDIT AGREEMENT
                      ------------------------------------

         This SECOND AMENDMENT TO CREDIT AGREEMENT (this "Amendment") is made as
of the 19th day of November, 2000, by and among CECO GROUP, INC., CECO FILTERS,
INC., AIR PURATOR CORPORATION, NEW BUSCH CO., INC., THE KIRK & BLUM
MANUFACTURING COMPANY and KBD/TECHNIC, INC. (the "Borrowers"), and PNC BANK,
NATIONAL ASSOCIATION ("PNC"), individually and as agent for itself and the other
banks (collectively, the "Banks") which from time to time are parties to the
hereinafter defined Credit Agreement (in such capacity, the "Agent").

                                   BACKGROUND
                                   ----------

         A. The Agent, the Banks and the Borrowers are parties to a Credit
Agreement dated as of December 7, 1999 as amended by Amendment to Credit
Agreement, date as of March 28, 2000 (as amended, the "Credit Agreement").

         B. The Borrowers have requested and the Agent and the Banks have agreed
to amend the Credit Agreement on the terms and conditions set forth herein.

         Now, Therefore, in consideration of the foregoing and for good and
valuable consideration, the legality and sufficiency of which is hereby
acknowledged, the parties hereto, intending to be legally bound hereby, agree as
follows:

         1. Definitions. Capitalized terms used herein and not otherwise defined
herein shall have the meanings assigned to them in the Credit Agreement.

         2. Amendments to Credit Agreement. The Credit Agreement is hereby
amended as follows:

         (a) Section 5.2 of the Credit Agreement is hereby amended by inserting
the following new subsection (f):

         "(f) (i) internally prepared consolidated financial projections for
         CECO for the quarter ending December 31, 2000 on or before December 15,
         2000; (ii) internally prepared preliminary consolidated financial
         projections for CECO for the fiscal year ending December 31, 2001 on or
         before December 15, 2000; (iii) internally prepared final consolidated
         financial projections for CECO for the fiscal year ending December 31,
         2001 on or before January 31, 2001, together with a written explanation
         of any changes to the preliminary projections for such period; (iv)
         internally prepared financial statements of CECO for the quarter and
         fiscal year ending December 31, 2000, and covenant compliance
         calculations for such periods, on or before February 15, 2001.
         Notwithstanding any provision to the contrary contained in this
         Agreement, the Borrowers' failure to deliver any of the items required
         by this subsection (f) shall constitute and immediate Event of Default
         without any required notice or cure period."

         (b) Section 6.1(c) of the Credit Agreement is hereby amended and
restated in its entirety as follows:
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"Interest Coverage Ratio. Permit the Interest Coverage Ratio for the period (i)
beginning January 1, 2000 and ending June 30, 2000 to be less than 1.50 to 1, or
(ii) beginning January 1, 2000 and ending September 30, 2000 to be less than
1.50 to 1, or permit the Interest Coverage Ratio, as of the end of any fiscal
quarter ending during the periods specified below, for the prior four
consecutive fiscal quarters, to be less than the ratio set forth opposite such
period:

--------------------------------------------------------------------------------
Last Day of Fiscal Quarter During Period       Interest  Coverage  Ratio Not
                                               To Be Less Than
--------------------------------------------------------------------------------
December 31, 2000 through December 30, 2001              2.50 to 1
--------------------------------------------------------------------------------
December 31, 2001 through December 30, 2002              3.25 to 1
--------------------------------------------------------------------------------
December 31, 2002 through December 30, 2003              3.75 to 1
--------------------------------------------------------------------------------
December 31, 2003 through Termination Date               4.00 to 1
--------------------------------------------------------------------------------

         (c) Section 6.1(e) of the Credit Agreement is hereby amended by
deleting the "$5,100,000" amount in the third row of the table with respect to
the period from January 1, 2000 through September 30, 2000, and inserting
"$3,900,000" in its place.

         (d) Section 6.8 of the Credit Agreement is hereby amended by inserting
the following sentence at the end of such Section:

         "Notwithstanding anything herein to the contrary, the Borrowers shall
         not pay management fees to CECO in excess of $40,000 for each of the
         months of October, November and December, 2000."

         3. Additional Covenant. The Borrowers and Green Diamond Oil Corp.
("Green Diamond") agree that the scheduled payment to Green Diamond on the
Subordinated Debt (as defined in the Subordination Agreement) due on or about
September 30, 2000 shall be deferred until December 31, 2000, and no payment of
principal or interest on the Subordinated Debt may be made to or received by
Green Diamond before December 31, 2000. Notwithstanding any provision to the
contrary contained in the Credit Agreement, the Borrowers' failure to comply
with this Section 3 shall constitute an immediate Event of Default without any
required notice or cure period.

         4. Amendment to the Loan Documents. All references to the Credit
Agreement in the Loan Documents and in any documents executed in connection
therewith shall be deemed to refer to the Credit Agreement as amended by this
Amendment.

         5. Ratification of the Loan Documents.Notwithstanding anything to the
contrary herein contained or any claims of the parties to the contrary, the
Agent, the Banks and the Borrowers agree that the Loan Documents and each of the
documents executed in connection therewith are in full force and effect and each
such document shall remain in full force and effect, as further amended by this
Amendment, and each of the Borrowers hereby ratifies and confirms its
obligations thereunder.
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         6. Representations and Warranties.

         (a) Each Borrower hereby certifies that (i) the representations and
warranties of such Borrower in the Credit Agreement are true and correct in all
material respects as of the date hereof, as if made on the date hereof and (ii)
no Event of Default and no event which could become an Event of Default with the
passage of time or the giving of notice, or both, under the Credit Agreement or
the other Loan Documents exists on the date hereof.

         (b) Each Borrower further represents that it has all the requisite
power and authority to enter into and to perform its obligations under this
Amendment, and that the execution, delivery and performance of this Amendment
have been duly authorized by all requisite action and will not violate or
constitute a default under any provision of any applicable law, rule,
regulation, order, writ, judgment, injunction, decree, determination or award
presently in effect or of the Articles of Incorporation or by-laws of such
Borrower, or of any indenture, note, loan or credit agreement, license or any
other agreement, lease or instrument to which such Borrower is a party or by
which such Borrower or any of its properties are bound.

         (c) Each Borrower also further represents that its obligation to repay
the Loans, together with all interest accrued thereon, is absolute and
unconditional, and there exists no right of set off or recoupment, counterclaim
or defense of any nature whatsoever to payment of the Loans.

         (d) Each Borrower also further represents that there have been no
changes to the Articles of Incorporation, by-laws or other organizational
documents of each such Borrower since the most recent date true and correct
copies thereof were delivered to the Agent.

         7. Conditions Precedent. The effectiveness of the amendments set forth
herein is subject to the fulfillment, to the satisfaction of the Agent and its
counsel, of the following conditions precedent:

         (a) The Borrowers shall have delivered to the Agent the following, all
of which shall be in form and substance satisfactory to the Agent and shall be
duly completed and executed:

             (i) This Amendment and the consent of the Guarantor and the
         Subordinated Creditor listed on the consents attached hereto; and

             (ii) Such additional documents, certificates and information as the
         Agent may require pursuant to the terms hereof or otherwise reasonably
         request. (b) The Borrowers shall have received not less than $120,000
         in cash from Green Diamond as a repayment of interest previously paid
         to Green Diamond by the Borrowers.

         (c) After giving effect to the amendments contained herein, the
representations and warranties set forth in the Credit Agreement shall be true
and correct on and as of the date hereof.

         (d) After giving effect to the amendments contained herein, no Event of
Default hereunder, and no event which, with the passage of time or the giving of
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notice, or both, would become such an Event of Default shall have occurred and
be continuing as of the date hereof.

         (e) The Borrowers shall have paid the reasonable fees and disbursements
of the Agent's counsel incurred in connection with this Amendment.

         6. No Waiver. Except as expressly provided herein, this Amendment does
not and shall not be deemed to constitute a waiver by the Agent or the Banks of
any Event of Default, or of any event which with the passage of time or the
giving of notice or both would constitute an Event of Default, nor does it
obligate the Agent or the Banks to agree to any further modifications to the
Credit Agreement or any other Loan Document or constitute a waiver of any of the
Agent's or the Banks' other rights or remedies.
<PAGE>

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

                          CECO GROUP, INC.

                          By: /s/ Marshall J. Morris
                          Name: /s/ Marshall J. Morris
                          Title: /s/  CFO

                          CECO FILTERS, INC.

                          By: /s/ Marshall J. Morris
                          Name: /s/ Marshall J. Morris
                          Title: /s/ Secretary

                          AIR PURATOR CORPORATION

                          By: /s/ Marshall J. Morris
                          Name: /s/ Marshall J. Morris
                          Title: /s/ Secretary

                          NEW BUSCH CO., INC.

                          By: /s/ Marshall J. Morris
                          Name: /s/ Marshall J. Morris
                          Title: /s/ Secretary

                          THE KIRK & BLUM MANUFACTURING COMPANY

                          By: /s/ David D. Blum
                          Name: /s/ David D. Blum
                          Title: /s/ VP
<PAGE>

                          KBD/TECHNIC, INC.

                          By: /s/ Marshall J. Morris
                          Name: /s/ Marshall J. Morris
                          Title: /s/ Assist. Secretary

                          PNC BANK, NATIONAL ASSOCIATION,
                          as Agent and as a Bank

                          By: /s/ John G. Siegrist
                          Title: /s/ Vice President

                          FIFTH THIRD BANK, as a Bank

                          By: /s/ David Alexander
                          Title: /s/ Fifth Third Bank - Assistant Vice President

                          BANK ONE, N.A., as a Bank

                          By: /s/ Mark Palazzo
                          Title: /s/ 1st Vice President
<PAGE>

                               GUARANTOR'S CONSENT

         By Corporate Guaranty, dated December 7, 2000 (the "Guaranty"), the
undersigned (the "Guarantor") guaranteed to the Agent and the Banks, subject to
the terms and conditions set forth therein, the prompt payment and performance
of all of the Obligations (as defined therein). The Guarantor consents to the
Borrowers' execution of the foregoing Second Amendment to Credit Agreement. The
Guarantor hereby acknowledges and agrees that the Guaranty remains unaltered and
in full force and effect and is hereby ratified and confirmed in all respects.

                               CECO ENVIRONMENTAL CORP.

                               By: /s/ Marshall J. Morris
                               Title: /s/ CFO
<PAGE>

                         SUBORDINATED CREDITOR'S CONSENT

         The undersigned (the "Subordinated Creditor") is a party to the
Subordination Agreement with the Agent and the Banks and other subordinated
creditors, dated December 7, 2000 (the "Subordination Agreement"). The
Subordinated Creditor consents to the Borrowers' execution of the foregoing
Second Amendment to Credit Agreement. The Subordinated Creditor agrees that
Section 3 of the foregoing Second Amendment to Credit Agreement applies to it
and that such Subordinated Creditor is bound thereby. The Subordinated Creditor
hereby acknowledges and agrees that, except as provided in Section 3 of the
foregoing Second Amendment to Credit Agreement, the Subordination Agreement
remains unaltered and in full force and effect and is hereby ratified and
confirmed in all respects.

                               GREEN DIAMOND OIL CORP.

                               By: /s/ Phillip DeZwirek
                               Title: /s/ President<PAGE>

                                                                   EXHIBIT 10.32

                              STOCK OPTION AGREEMENT

                            CECO ENVIRONMENTAL CORP.
                             1997 STOCK OPTION PLAN

THIS AGREEMENT is dated and made effective as of September 18, 2000 ("Effective
Date") by and between CECO ENVIRONMENTAL CORP. a New York corporation (the
"Company"), and DONALD WRIGHT ("Optionee").

                                   WITNESSETH:

WHEREAS, Optionee on the date hereof is an officer of the Company or one of its
Subsidiaries; and

WHEREAS, the Company desires to grant a non-qualified stock option to Optionee
to purchase shares of the Company's Common Stock pursuant to the Company's 1997
Stock Option Plan, as amended (the "Plan"); and

WHEREAS, the Board of Directors of the Company has authorized the grant of a
non-qualified stock option to Optionee and has determined that, on the Effective
Date, the Fair Market Value of Option Stock of the Company is $2.0625 per share.

NOW, THEREFORE, in consideration of the premises and of the mutual covenants
herein contained, the parties hereto agree as follows:

1. Grant of Option. The Company hereby grants to Optionee as of the Effective
Date the right and option (the "Option") to purchase up to five thousand (5,000)
shares of Option Stock ("Shares") at an exercise price of $2.0625 per share on
the terms and conditions set forth herein and subject to the terms and
conditions of the Plan.

All capitalized terms not defined in this Agreement shall have the meaning set
forth in the Plan.

2.  Duration and Exercisability.

a. Exercise Period. The Option shall become exercisable on March 18, 2001 six
months after the date of this grant agreement.

b. Expiration. The Option shall expire on September 18, 2010 ("Expiration Date")
and must be exercised, if at all, on or before the Expiration Date.

<PAGE>

c. Lapse Upon Expiration. To the extent that this Option is not exercised prior
to the Expiration Date, all rights of Optionee under this Option shall thereupon
be forfeited.

3.  Manner of Exercise.

a. General. The Option may be exercised only by Optionee (or other proper party
in the event of death or incapacity), subject to the conditions of the Plan and
this Agreement, and subject to such other administrative rules as the
Administrator deems advisable, by delivering written notice of exercise to the
Company at its principal office. The notice shall state the number of Shares
exercised and shall be accompanied by payment in full of the Option price for
all Shares exercised pursuant to the notice. Any exercise of the Option shall be
effective upon receipt of such notice by the Company together with payment that
complies with the terms of the Plan and this Agreement. The Option may be
exercised with respect to any number or all of the shares as to which it can
then be exercised and, if partially exercised, may be so exercised as to the
unexercised shares at any time and from time to time prior to expiration of the
Option as provided in this Agreement.

b. Form of Payment. Subject to approval by the Administrator, payment of the
Option price by Optionee shall be in the form of cash, personal check, certified
check, or where permitted by law and provided that a public market for the
Company's stock exists: (i) through a "same day sale" commitment from Optionee
and a broker-dealer that is a member of the National Association of Securities
Dealers (an "NASD Dealer") whereby Optionee irrevocably elects to exercise the
Option and to sell a portion of the Shares so purchased to pay for the exercise
price and whereby the NASD Dealer irrevocably commits upon receipt of such
Shares to forward the exercise price directly to the Company; (ii) through a
"margin" commitment from Optionee and a NASD Dealer whereby Optionee irrevocably
elects to exercise the Option and to pledge the Shares so purchased to the NASD
Dealer in a margin account as security for a loan from the NASD Dealer in the
amount of the exercise price, and whereby the NASD Dealer irrevocably commits
upon receipt of such Shares to forward the exercise price directly to the
Company; or (iii) by tender of shares of Common Stock of the Company having a
Fair Market Value on the date received by the Company equal to the exercise
price for the Shares exercised. Optionee shall be solely responsible for any
income or other tax consequences from any payment for Shares with Optionee's
Common Stock of the Company.

c. Stock Transfer Records. Provided that the notice of exercise and payment are
in form and substance satisfactory to counsel for the Company, as soon as
practicable after the effective exercise of all or any part of the Option,
Optionee shall be recorded on the stock transfer books of the Company as the
owner of the Shares purchased, and the Company shall deliver to Optionee, or to
the NASD Dealer, as the case may be, one or more duly issued stock certificates
evidencing such ownership. All requisite original issue or transfer documentary
stamp taxes shall be paid by the Company. Optionee shall pay all other costs of
the Company incurred to issue such Shares to such NASD Dealer.

<PAGE>

Shares purchased pursuant to exercise hereunder: (i) may be deposited with a
NASD Dealer designated by Optionee, in street name, if so provided in such
exercise notice accompanied by all applications and forms reasonably required by
the Administrator to effect such deposit, or (ii) may be issued to Optionee and
such other person, as joint owners with the right of survivorship, as is
specifically described in such exercise notice. Optionee shall be solely
responsible for any income or other tax consequences of such a designation of
ownership hereunder (or the severance thereof).

4.  Miscellaneous.

a. Employment Rights as Shareholder. This Agreement shall not confer on Optionee
any right with respect to employment by the Company or any Subsidiary. Optionee
shall have no rights as a shareholder with respect to Shares subject to this
Option until such Shares are issued to Optionee upon the exercise of this
Option. No adjustment shall be made for dividends (ordinary or extra-ordinary,
whether in cash, securities or other property), distributions or other rights
for which the record date is prior to the date such shares are issued, except as
provided in Section 11 of the Plan.

b. Securities Law Compliance. The exercise of the Option and the issuance and
transfer of Shares shall be subject to compliance by the Company and Optionee
with all applicable requirements of federal and state securities laws and with
all applicable requirements of any stock exchange on which the Company's Common
Stock may be listed at the time of such issuance or transfer.

c. Mergers, Recapitalization, Stock Splits, Etc. The provisions of Section 11 of
the Plan, as amended effective the Effective Date, shall govern all Options in
the event of any reorganization, merger, consolidation, recapitalization,
reclassification, change in par value, stock split-up, combination of shares or
dividend payable in capital stock, or other such transaction described under
Section 11 of the Plan, and the Company reserves all discretion provided
therein.

d. Nontransferability. The Option may not be transferred in any manner other
than by will or by the laws of descent and distribution and may be exercised
during the lifetime of Participant only by Participant. The terms of the Option
shall be binding upon the executors, administrators, successors and assigns of
Participant.

e. 1997 Stock Option Plan. The Option evidenced by this Agreement is granted
pursuant to the Plan, as amended the Effective Date, a copy of which Plan has
been made available to Optionee and is hereby incorporated into this Agreement.
This Agreement shall be subject to and in all respects limited and conditioned
as provided in the Plan. The Plan governs this Option and, in the event of any
questions as to the construction of this Agreement or in the event of a conflict
between the Plan and this Agreement, the Plan shall govern, except as the Plan
otherwise provides.

<PAGE>

f. Accounting Compliance. Optionee agrees that, in the event of a transaction
subject to Section 11 of the Plan, treated as a "pooling of interests" under
generally accepted accounting principles, and Optionee is an affiliate of the
Company or any Subsidiary (as described in Section 11 of the Plan) at the time
of such change of control transaction, Optionee will comply with all
requirements of Rule 145 of the Securities Act of 1933, as amended, and the
requirements of such other legal or accounting principles, and will execute any
documents necessary to ensure such compliance.

g. Stock Legend. The Administrator may require that the certificates for any
Shares purchased by Optionee (or, in the case of death, Optionee's successors)
bear an appropriate legend to reflect the restrictions of Section 4(f), of this
Agreement.

h. Withholding. Optionee acknowledges that, upon exercise of all or any portion
of this Option, the Company shall have the right to require Optionee to pay to
the Company an amount equal to the amount the Company is required to withhold as
a result of such exercise federal and state income tax purposes.

i. Scope of Agreement. This Agreement shall bind and inure to the benefit of the
Company and its successors and assigns and Optionee and any successor or
successors of Optionee permitted Section 4(d) of this Agreement.

j. Interpretation. The Administrator shall have the sole discretion to interpret
and administer the Plan. Any determination made by the Administrator with
respect to any Option shall be final and binding on the Company and on all
persons having an interest in the Option granted under this Agreement and the
Plan.

k. Entire Option. The Plan, as amended, is incorporated herein by reference.
This Agreement and the Plan constitute the entire agreement and understanding of
the parties hereto with respect to the subject matter hereof and supersede all
prior understandings and agreements with respect to such subject matter.

l. Successors and Assigns. The Company may assign any of its rights under the
Option. The Option shall be binding upon and inure to the benefit of the
successors and assigns of the Company. Subject to the restrictions on transfer
set forth herein, the Option shall be binding upon Optionee and Optionee's
heirs, executors, administrators, legal representatives, successors and assigns.

m. Governing Law. The Option shall be governed by and construed in accordance
with the internal laws of the State of Ohio, without regard to that body of law
pertaining to choice of law or conflict of law.

<PAGE>

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed
on the day and year first above written.

CECO ENVIRONMENTAL CORP.                                OPTIONEE

By: /s/ Richard J. Blum                                 /s/ Donald Wright
   ---------------------------------                    ------------------------
Its:/s/ President                                           Donald Wright

The Grant set forth in this
Agreement has been approved by
Administrators of CECO
Environmental Corp.
1997 Stock Option Plan

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