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                                                                     EXHIBIT 4.4

                                    AMENDMENT

                            CECO ENVIRONMENTAL CORP.
                             1997 STOCK OPTION PLAN
                            ------------------------

This Amendment of the CECO Environmental Corp. 1997 Stock Option Plan ("Plan")
is entered into as of January 20, 2000 by CECO Environmental Corp. (the
"Company"), effective the date hereof ("Effective Date").

                                    RECITALS

A. The Company adopted the Plan on October 1, 1997, effective the date thereof,
as an incentive stock option plan within the meaning of Section 422 of the
Internal Revenue Code ("Code").

B. The Company has determined it appropriate to amend the Plan to provide for
Company discretion to terminate or otherwise modify options issued pursuant to
the Plan, on or after the Effective Date, in the event of the sale, merger,
recapitalization, dissolution or other similar capital event as set forth
herein.

                                    AMENDMENT

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

         2.       Effective  January  20,  2000,  Section 11 of the Plan is
deleted in its  entirety  and  replaced as follows:

                                   "SECTION 11

           ADJUSTMENTS UPON CHANGES IN CAPITALIZATION; SALE OF COMPANY

         (a)      For all  stock options issued prior to January 20, 2000:

         A pro rata adjustment for an increase or decrease in the number of
         shares of Common Stock of the Company subject to the Plan or that may
         be awarded to any individual in any year shall be made to give effect
         to any consolidation of shares, the equivalent value in stock of cash
         dividends, stock dividends, stock splits, stock combinations,
         recapitalization and other similar changes in the capital structure of
         the Company. Pro rata adjustment shall be made in the number, kind and
         price of shares of Common Stock of the Company covered by any
         outstanding stock option hereunder to give effect to any consolidation
         of shares, stock dividends, stock spits, stock combinations,
         recapitalization and similar changes in the capital structure in the
         Company, or a merger or dissolution or reorganization of the Company,
         after the date the Option is granted so that the Optionee is treated in
         a manner equivalent to that of holders of the underlying Common Stock.

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         (b) For all stock options issued on or after January 20, 2000
         ("Effective Date") and on or before the last day for the duration of
         the Plan provided under Section 7 of the Plan:

         (i) In the event that the outstanding shares of Common Stock of the
         Company are changed into or exchanged for a different number or kind of
         shares or other securities of the Company or of another corporation by
         reason of any reorganization, merger, consolidation, recapitalization,
         reclassification, change in par value, stock split-up, combination of
         shares or dividend payable in capital stock, the Company shall make
         adjustments to such outstanding stock options (including, by way of
         example and not by way of limitation, the grant of substitute options
         under the Plan or under the plan of such other corporation) as the
         Administrator may determine to be appropriate under the circumstances
         in the sole discretion of the Administrator, and, in addition,
         appropriate adjustments shall be made in the number and kind of shares
         and in the option price per share subject to outstanding options under
         the Plan or under the plan of such successor corporation. No such
         adjustment shall be made which shall, within the meaning of Section 424
         of the Code, constitute such a modification, extension, or renewal of
         an option as to cause the adjustment to be considered as the grant of a
         new option.

                  (ii)  Notwithstanding anything herein to the contrary, the
         Company may, in its sole discretion:

                           (A) accelerate the timing of the exercise provisions
                  of any stock option in the event of (1) the adoption of a plan
                  of merger or consolidation under which all the shares of
                  Common Stock of the Company would be eliminated, or (2) a sale
                  of all or substantially all of the Company's assets or shares
                  of Common Stock; (B) cancel any or all stock options granted
                  hereunder (on or after the Effective Date) upon any of the
                  foregoing events and provide for the payment to Optionees in
                  cash of an amount equal to the difference between the option
                  price and the price of a share of Common Stock, as determined
                  in good faith by the Administrator, at the close of business
                  on the date of such event, multiplied by the number of such
                  shares of Option Stock so canceled; or (C) accelerate the
                  timing of the exercise provisions of any stock option if (1)
                  any such business combination is to be accounted for as a
                  pooling-of-interests under APB Opinion 16 (or any successor
                  opinion) and (2) the timing of such acceleration does not
                  prevent such pooling-of-interests treatment; provided, that if
                  any provision of the Plan would disqualify the combination
                  from pooling-of-interests accounting treatment, then the Plan
                  shall be interpreted to preserve such accounting treatment or,
                  if necessary, the applicable provision shall be null and void.
                  All determinations to be made in connection with the preceding
                  sentence shall be made by the independent accounting firm
                  whose opinion with respect to the pooling-of-interests
                  treatment is required as a condition to the Company's
                  consummation of such combination.

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                  (iii) Upon a business combination by the Company or any
         Subsidiary with any corporation or other entity through the adoption of
         a plan of merger or consolidation or a share exchange or through the
         purchase of all or substantially all of the capital stock or assets of
         such other corporation or entity, the Board of Directors or the
         Committee may, in its sole discretion, grant stock options to all or
         any persons who, on the effective date of such transaction, hold
         outstanding options to purchase securities of such other corporation or
         entity and who, on and after the effective date of such transaction,
         will become employees of the Company or any Subsidiary. The number of
         shares of Option Stock subject to such substitute stock options shall
         be determined in accordance with the terms of the transaction by which
         the business combination is effected. Notwithstanding the other
         provisions of this Plan, the other terms of such substitute stock
         options shall be substantially the same as or economically equivalent
         to the terms of the options for which such stock options are
         substituted, all as determined by the Administrator. Upon the grant of
         substitute stock options pursuant hereto, the options to purchase
         securities of such other corporation or entity for which such stock
         options are substituted shall be canceled immediately.

                  (iv) Upon the dissolution or liquidation of the Company other
         than in connection with a transaction to which the preceding
         subparagraphs (i), (ii) or (iii) of this Section 11(b) is applicable,
         all stock options granted hereunder shall terminate and become null and
         void; provided, however, that if the rights of an Optionee under the
         applicable options have not otherwise terminated and expired, the
         Optionee shall have the right immediately prior to such dissolution or
         liquidation to exercise any stock option granted hereunder to the
         extent that the right to purchase shares thereunder has become
         exercisable as of the date immediately prior to such dissolution or
         liquidation."

         3.       The Plan is hereby ratified, confirmed and approved as amended
hereby.<PAGE>

                                                                   EXHIBIT 10.30

                                                                        PNC BANK

September 28, 2000

Marshall Morris, Chief Financial Officer
CECO Group, Inc.
3120 Forrer Road
Cincinnati, OH   45209

         Re:      Credit Agreement dated as of October 7, 1999
                  --------------------------------------------

Gentlemen:

         We refer to Section 6.3 of the Credit Agreement, dated as of December
7, 2000 (as amended, the "Agreement"), among CECO Group, Inc. and its
subsidiaries party thereto (collectively, the "Borrowers"), PNC Bank, National
Association, as agent (the "Agent") for the banks and other financial
institutions party thereto (the "Banks"), and the Banks. Capitalized terms used
herein without definition have the meanings given in the Agreement. In
connection with the delivery of Bonds by unaffiliated sureties for the
Borrowers, such sureties have requested and may from time to time require that
the Borrowers and/or their affiliates enter into indemnity agreements of the
type set forth as Exhibit A hereto (the "Indemnity Agreements"). As used herein,
"Bonds" means surety bonds, performance bonds or other instruments or agreements
of guarantee issued in connection with the fulfillment of obligations by the
Borrowers.

         The Borrowers have requested that the Banks consent to the execution
and delivery of the Indemnity Agreement and the execution and delivery by the
Borrowers from time to time of other Permitted Agreements.

         In reliance upon the Borrowers' representations and warranties and
subject to the terms and conditions herein set forth, the Banks agree as
follows:

         1. Consent. The Banks hereby consent to the execution, delivery and
performance of the Indemnity Agreement. The Banks hereby agree that the
execution, delivery and performance of Permitted Agreements in the ordinary
course of business do not and will not violate the provisions of Section 6.3 of
the Agreement.

         2. Limitation of Consent. Except as expressly described above, this
letter shall not constitute (a) a modification or an alteration of the terms,
conditions or covenants of the Agreement or any other Loan Document or (b) a
waiver, release or limitation upon the Agent's or the Banks' exercise of any of
their rights and remedies thereunder, which are herby

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expressly reserved. This letter shall not relieve or release the Borrowers in
any way from any of their duties, obligations, covenants or agreements under the
Agreement or the other Loan Documents or from the consequences of any Event of
Default thereunder, except as expressly described above. This letter shall not
obligate the Banks, or be construed to require the Banks, to waive any other
Events of Default or defaults, whether now existing or which may occur after the
date hereof.

         3. Execution in Counterparts.This letter agreement may be executed in
multiple counterparts, and by the parties hereto on separate counterparts, each
of which shall constitute an original, but all such counterparts shall
constitute but one and the same instrument.

         Please execute the enclosed extra copy of this letter in the space
provided below and return the fully executed document to the undersigned for
this letter to be effective.

                                                  Very truly yours,

                                                  PNC BANK, NATIONAL ASSOCIATION
                                                           as Agent

                                                  By: /s/ John G. Siegrist
                                                      --------------------------
                                                          John G. Siegrist

Accepted and agreed to, as of the date written above:

CECO GROUP, INC., as Borrowers'
 Representative

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

<PAGE>

                                                                   EXHIBIT 10.30

                                    EXHIBIT A

                           FORM OF INDEMNITY AGREEMENT

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