<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                            CECO ENVIRONMENTAL CORP.
             (Exact name of registrant as specified in its charter)

         New York                                     13-2566064
(State or other jurisdiction                       (I.R.S. Employer
of incorporation)                                Identification Number)

505 University Avenue,                                          M5G 1X3
Toronto, Ontario CANADA                                        (Zip Code)
(Address of Principal Executive Office)

                            CECO Environmental Corp.
                      1998 CECO Environmental Purchase Plan
                            (Full Title of the Plan)

                              Leslie J. Weiss, Esq.
                          Sugar, Friedberg & Felsenthal
                       30 North LaSalle Street, Suite 2600
                             Chicago, Illinois 60602
                     (Name and address of agent for service)

                                 (312) 704-9400
          (Telephone number, including area code, of agent for service)

Approximate date of commencement of proposed sale to the public: As soon as
Practicable After Registration Statement Becomes Effective.

                               Page 1 of 18 Pages
                         Exhibit Index Begins on Page 8

<PAGE>




                         CALCULATION OF REGISTRATION FEE

                                                Proposed         Proposed
 Title of                                       Maximum           Maximum
Securities        Amount       Offering         Aggregate        Amount of
 to be            to be       Price Per         Offering        Registration
Registered      Registered      Share           Price (1)         Fee(1)

Common            250,000       $1.625           $406,250         $119.85
Shares par
value
$0.01 per
share

Total             250,000       $1.625           $406,250         $119.85



(1) Based upon the closing price as reported by NASDAQ on September 14, 1998,
and estimated in the manner specified by Rule 457(c)under the Securities Act of
1933, solely for purposes of calculating the amount of registration fee.

<PAGE>



                                     PART I

                INFORMATION REQUIRED IN SECTION 10(A) PROSPECTUS

Item 1.  Plan Information.

                  The document(s) containing the information specified in part I
of Form S-8 will be sent or given to the employees as specified by Rule
428(b)(1) of the Securities Act of 1933, as amended (the "Security Act"). Such
documents are not required to be and are not being filed with the SEC or
included in this Form S-8 (by incorporation by reference or otherwise) in
accordance with the rules and regulations of the Securities and Exchange
Commission (the "SEC"). These documents and the documents incorporated by
reference into this Registration Statement pursuant to Item 3 of Part II of this
Registration Statement, taken together, constitute a prospectus that meets the
requirements of Section 10(a) of the Securities Act.

Item 2.           Registrant Information and Employee Plan Annual Information.

                  Upon written or oral request, any of the documents
incorporated by reference in Item 3 of Part II of this Registration Statement
(which documents are incorporated by reference in this Section 10(a)
Prospectus), other documents required to be delivered to eligible employees
pursuant to Rule 428(b) or additional information about the CECO Environmental
Corp. 1998 Employee Stock Purchase Plan and its administrators are available
without charge by contacting:

                                 Gloria Joaquin
                                   Controller
                               CECO Filters, Inc.
                             1029 Conshohocken Road
                             Conshohocken, PA 19428
                                 (610) 825-6495

                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 3.  Incorporation of Documents by Reference.

                  The following documents filed with the Commission pursuant to
the Securities Exchange Act of 1934 are incorporated by reference into this
Registration Statement.


<PAGE>


         a. The Company's Annual Report on Form 10-KSB for the fiscal year ended
December 31, 1997.

         b. The description of the Company's Common Stock, $0.01 par value,
contained in the Company's registration statement on Form 10 filed pursuant to
Section 12(g) of the Securities Exchange Act of 1934 on April 27, 1973, which
was declared effective on September 28, 1973, including any subsequent amendment
or any report or other filing with the Securities and Exchange Commission
updating such description.

         c. All reports subsequently filed by the Registrant pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934 since
the end of the fiscal year covered by the Company's document referred to in (a)
above, shall be deemed to be incorporated by reference in the Registration
Statement and to be part thereof from the date of filing of such documents.

Item 4.  Description of Securities.

                  Not Applicable.

Item 5.  Interest of Named Experts and Counsel.

                  The validity of the Shares offered hereby will be passed upon
for the Company by Sugar, Friedberg & Felsenthal, 30 North LaSalle Street, Suite
2600, Chicago, Illinois 60602.

Item 6.  Indemnification of Officers and Directors.

                  The Company's By-laws provide that the Company shall indemnify
any person made, or threatened to be made, a party to an action or proceeding,
whether civil or criminal or investigative (a "proceeding"), including an action
by or in the right of the Company or any other corporation of any type or kind,
domestic or foreign, or any partnership, joint venture, trust, employee benefit
plan or other enterprise, which any director or officer of the Company served in
any capacity at the request of the Company, by reason of the fact that he, his
testator or interstate, was a director or officer of the Company, or served such
other corporation, partnership, joint venture, trust, employee benefit plan or
other enterprise in any capacity, against judgment, fines, amounts paid in
settlement and reasonable expenses, including attorney's fees actually and
necessarily incurred as a result of such proceeding, or any appeal therein, if
such director or officer acted, in good faith, for a purpose which he reasonably
believed to be in, or in the case of service for any other corporation or any
partnership, joint venture, trust, employee benefit plan or other enterprise,
not opposed to, the best interests of the Company and, in criminal proceedings,
in addition, had no reasonable cause to believe that his conduct was unlawful.


<PAGE>

         Any determination as to whether a person has met an applicable standard
of conduct shall be made in accordance with the provisions of the Business
Corporation Law of the State of New York.

         No indemnification shall be made to or on behalf of any person if a
judgment or other final adjudication adverse to such person establishes that his
acts were committed in bad faith or were the result of active and deliberate
dishonesty and were material to the cause of action so adjudicated, or that he
personally gained in fact a financial profit or other advantage to which he was
not legally entitled.

         The Company's indemnification provisions shall be enforced to the
fullest extent permitted under law.

Item 7.  Exemption from Registration Claimed.

                  Not Applicable.

Item 8.  Exhibits.

         Exhibit
         Number            Description
         ------            -----------
  
           4              CECO Environmental Corp. 1998 Stock Purchase Plan
           5              Opinion of Counsel regarding legality
          23.1            Consent of Independent Public Accountant
          23.2            Consent of Counsel (Included in Exhibit 5)
          24.             Power of Attorney (Contained within Signature Page)

Item 9.  Undertakings.

(1)               The undersigned Registrant hereby undertakes:

                           (a) To file, during any period in which offers or
sales are being made, a post-effective amendment to this Registration Statement:
To include any material information with respect to the plan of distribution not
previously disclosed in the Registration Statement or any material change to
such information in the Registration Statement;

                           (b) That, for the purpose of determining any
liability under the Securities Act of 1933, each such post-effective amendment
shall be deemed to be a new registration statement relating to the securities
offered therein, and the offering of such securities at that time shall be
deemed to be the initial bona fide offering thereof;
<PAGE>

                           (c) To remove from registration by means of a
post-effective amendment any of the securities being registered which remain
unsold at the termination of the offering.

(2) The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Registrant's annual report pursuant to Section 13(a) or 15(d) of the Securities
Exchange Act of 1934 that is incorporated by reference in the Registration
Statement shall be deemed to be a new registration statement relating to the
securities offered therein and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof.

(3) Insofar as indemnification for liabilities arising under the Securities Act
of 1933 may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Securities and Exchange Commission
such indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In the even that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred
or paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.


<PAGE>


                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be singed on its behalf by the undersigned, thereunto
duly authorized, in the City of Toronto, Province of Ontario, on this 17th day 
of September, 1998.


                                            CECO ENVIRONMENTAL CORP.

                                            By:  /s/ Phillip DeZwirek
                                            -----------------------------------
                                                 Phillip DeZwirek
                                                 Chief Executive Officer
                                                 Chief Financial Officer

                                POWER OF ATTORNEY

         KNOW ALL MEN BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Phillip DeZwirek, his or her
attorney-in-fact, for him or her in any and all capacities, to sign any
amendments to this Registration Statement, and to file the same, with exhibits
thereto, and other documents in connection therewith, with the Securities and
Exchange Commission, hereby ratifying and confirming all that said
attorney-in-fact, or his substitute, may do or cause to be done by virtue
hereof.

         Pursuant to the requirements of the Securities Act of 1933, as amended
this Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.




Date: September 17, 1998                    /s/ Phillip DeZwirek
                                            ------------------------
                                            Phillip DeZwirek
                                            Chief Executive Officer,
                                            Chief Financial Officer

Date: September 17, 1998                    /s/ Jason Louis DeZwirek
                                            ------------------------
                                            Jason Louis DeZwirek
                                            Director

Date: September 17, 1998                    /s/ Josephine Grivas
                                            --------------------
                                            Josephine Grivas
                                            Director

Date: September 17, 1998                    /s/ Donald Wright
                                            -----------------
                                            Donald Wright
                                            Director
<PAGE>



                                  EXHIBIT INDEX

         Exhibit                                                      Page
         Number            Document                                   Number
         ------            --------                                   ------


         4                 CECO Environmental Corp. 1998
                           Stock Purchase Plan                            9

         5                 Opinion of Counsel regarding legality         17

        23.1               Consent of Margolis & Company P.C.            18

        23.2               Consent of Counsel (Included in               17
                           Exhibit 5)

        24.                Power of Attorney (Contained with             7
                           Signature Page)
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 14712}]
{"company-data": {"conformed-name": "CECO ENVIRONMENTAL CORP", "cik": "0000003197", "assigned-sic": "3564", "irs-number": "132566064", "state-of-incorporation": "NY", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-63571", "film-number": "98710838"}, "business-address": {"street1": "505 UNIVERSITY AVE", "street2": "STE 1400", "city": "TORONTO ONTARIO MSG", "state": "A6", "phone": "4165936543"}, "mail-address": {"street1": "111 ELIZABETH STREET SUITE 600", "city": "TORONTO ONTARIO", "state": "A6"}, "former-company": [{"former-conformed-name": "API ENTERPRISES INC", "date-changed": "19920703"}, {"former-conformed-name": "ALARM PRODUCTS INTERNATIONAL INC", "date-changed": "19851210"}]}
SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                            CECO ENVIRONMENTAL CORP.
             (Exact name of registrant as specified in its charter)

         New York                                     13-2566064
(State or other jurisdiction                       (I.R.S. Employer
of incorporation)                                Identification Number)

505 University Avenue,                                          M5G 1X3
Toronto, Ontario CANADA                                        (Zip Code)
(Address of Principal Executive Office)

                            CECO Environmental Corp.
                      1998 CECO Environmental Purchase Plan
                            (Full Title of the Plan)

                              Leslie J. Weiss, Esq.
                          Sugar, Friedberg & Felsenthal
                       30 North LaSalle Street, Suite 2600
                             Chicago, Illinois 60602
                     (Name and address of agent for service)

                                 (312) 704-9400
          (Telephone number, including area code, of agent for service)

Approximate date of commencement of proposed sale to the public: As soon as
Practicable After Registration Statement Becomes Effective.

                               Page 1 of 18 Pages
                         Exhibit Index Begins on Page 8
CALCULATION OF REGISTRATION FEE

                                                Proposed         Proposed
 Title of                                       Maximum           Maximum
Securities        Amount       Offering         Aggregate        Amount of
 to be            to be       Price Per         Offering        Registration
Registered      Registered      Share           Price (1)         Fee(1)

Common            250,000       $1.625           $406,250         $119.85
Shares par
value
$0.01 per
share

Total             250,000       $1.625           $406,250         $119.85

(1) Based upon the closing price as reported by NASDAQ on September 14, 1998,
and estimated in the manner specified by Rule 457(c)under the Securities Act of
1933, solely for purposes of calculating the amount of registration fee.
PART I

                INFORMATION REQUIRED IN SECTION 10(A) PROSPECTUS

Item 1.  Plan Information.

                  The document(s) containing the information specified in part I
of Form S-8 will be sent or given to the employees as specified by Rule
428(b)(1) of the Securities Act of 1933, as amended (the "Security Act"). Such
documents are not required to be and are not being filed with the SEC or
included in this Form S-8 (by incorporation by reference or otherwise) in
accordance with the rules and regulations of the Securities and Exchange
Commission (the "SEC"). These documents and the documents incorporated by
reference into this Registration Statement pursuant to Item 3 of Part II of this
Registration Statement, taken together, constitute a prospectus that meets the
requirements of Section 10(a) of the Securities Act.

Item 2.           Registrant Information and Employee Plan Annual Information.

                  Upon written or oral request, any of the documents
incorporated by reference in Item 3 of Part II of this Registration Statement
(which documents are incorporated by reference in this Section 10(a)
Prospectus), other documents required to be delivered to eligible employees
pursuant to Rule 428(b) or additional information about the CECO Environmental
Corp. 1998 Employee Stock Purchase Plan and its administrators are available
without charge by contacting:

                                 Gloria Joaquin
                                   Controller
                               CECO Filters, Inc.
                             1029 Conshohocken Road
                             Conshohocken, PA 19428
                                 (610) 825-6495

                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 3.  Incorporation of Documents by Reference.

                  The following documents filed with the Commission pursuant to
the Securities Exchange Act of 1934 are incorporated by reference into this
Registration Statement.
a. The Company's Annual Report on Form 10-KSB for the fiscal year ended
December 31, 1997.

         b. The description of the Company's Common Stock, $0.01 par value,
contained in the Company's registration statement on Form 10 filed pursuant to
Section 12(g) of the Securities Exchange Act of 1934 on April 27, 1973, which
was declared effective on September 28, 1973, including any subsequent amendment
or any report or other filing with the Securities and Exchange Commission
updating such description.

         c. All reports subsequently filed by the Registrant pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934 since
the end of the fiscal year covered by the Company's document referred to in (a)
above, shall be deemed to be incorporated by reference in the Registration
Statement and to be part thereof from the date of filing of such documents.

Item 4.  Description of Securities.

                  Not Applicable.

Item 5.  Interest of Named Experts and Counsel.

                  The validity of the Shares offered hereby will be passed upon
for the Company by Sugar, Friedberg & Felsenthal, 30 North LaSalle Street, Suite
2600, Chicago, Illinois 60602.

Item 6.  Indemnification of Officers and Directors.

                  The Company's By-laws provide that the Company shall indemnify
any person made, or threatened to be made, a party to an action or proceeding,
whether civil or criminal or investigative (a "proceeding"), including an action
by or in the right of the Company or any other corporation of any type or kind,
domestic or foreign, or any partnership, joint venture, trust, employee benefit
plan or other enterprise, which any director or officer of the Company served in
any capacity at the request of the Company, by reason of the fact that he, his
testator or interstate, was a director or officer of the Company, or served such
other corporation, partnership, joint venture, trust, employee benefit plan or
other enterprise in any capacity, against judgment, fines, amounts paid in
settlement and reasonable expenses, including attorney's fees actually and
necessarily incurred as a result of such proceeding, or any appeal therein, if
such director or officer acted, in good faith, for a purpose which he reasonably
believed to be in, or in the case of service for any other corporation or any
partnership, joint venture, trust, employee benefit plan or other enterprise,
not opposed to, the best interests of the Company and, in criminal proceedings,
in addition, had no reasonable cause to believe that his conduct was unlawful.
Any determination as to whether a person has met an applicable standard
of conduct shall be made in accordance with the provisions of the Business
Corporation Law of the State of New York.

         No indemnification shall be made to or on behalf of any person if a
judgment or other final adjudication adverse to such person establishes that his
acts were committed in bad faith or were the result of active and deliberate
dishonesty and were material to the cause of action so adjudicated, or that he
personally gained in fact a financial profit or other advantage to which he was
not legally entitled.

         The Company's indemnification provisions shall be enforced to the
fullest extent permitted under law.

Item 7.  Exemption from Registration Claimed.

                  Not Applicable.

Item 8.  Exhibits.

         Exhibit
         Number            Description
         ------            -----------
  
           4              CECO Environmental Corp. 1998 Stock Purchase Plan
           5              Opinion of Counsel regarding legality
          23.1            Consent of Independent Public Accountant
          23.2            Consent of Counsel (Included in Exhibit 5)
          24.             Power of Attorney (Contained within Signature Page)

Item 9.  Undertakings.

(1)               The undersigned Registrant hereby undertakes:

                           (a) To file, during any period in which offers or
sales are being made, a post-effective amendment to this Registration Statement:
To include any material information with respect to the plan of distribution not
previously disclosed in the Registration Statement or any material change to
such information in the Registration Statement;

                           (b) That, for the purpose of determining any
liability under the Securities Act of 1933, each such post-effective amendment
shall be deemed to be a new registration statement relating to the securities
offered therein, and the offering of such securities at that time shall be
deemed to be the initial bona fide offering thereof;
(c) To remove from registration by means of a
post-effective amendment any of the securities being registered which remain
unsold at the termination of the offering.

(2) The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Registrant's annual report pursuant to Section 13(a) or 15(d) of the Securities
Exchange Act of 1934 that is incorporated by reference in the Registration
Statement shall be deemed to be a new registration statement relating to the
securities offered therein and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof.

(3) Insofar as indemnification for liabilities arising under the Securities Act
of 1933 may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Securities and Exchange Commission
such indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In the even that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred
or paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.
SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be singed on its behalf by the undersigned, thereunto
duly authorized, in the City of Toronto, Province of Ontario, on this 17th day 
of September, 1998.

                                            CECO ENVIRONMENTAL CORP.

                                            By:  /s/ Phillip DeZwirek
                                            -----------------------------------
                                                 Phillip DeZwirek
                                                 Chief Executive Officer
                                                 Chief Financial Officer

                                POWER OF ATTORNEY

         KNOW ALL MEN BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Phillip DeZwirek, his or her
attorney-in-fact, for him or her in any and all capacities, to sign any
amendments to this Registration Statement, and to file the same, with exhibits
thereto, and other documents in connection therewith, with the Securities and
Exchange Commission, hereby ratifying and confirming all that said
attorney-in-fact, or his substitute, may do or cause to be done by virtue
hereof.

         Pursuant to the requirements of the Securities Act of 1933, as amended
this Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.

Date: September 17, 1998                    /s/ Phillip DeZwirek
                                            ------------------------
                                            Phillip DeZwirek
                                            Chief Executive Officer,
                                            Chief Financial Officer

Date: September 17, 1998                    /s/ Jason Louis DeZwirek
                                            ------------------------
                                            Jason Louis DeZwirek
                                            Director

Date: September 17, 1998                    /s/ Josephine Grivas
                                            --------------------
                                            Josephine Grivas
                                            Director

Date: September 17, 1998                    /s/ Donald Wright
                                            -----------------
                                            Donald Wright
                                            Director
EXHIBIT INDEX

         Exhibit                                                      Page
         Number            Document                                   Number
         ------            --------                                   ------

         4                 CECO Environmental Corp. 1998
                           Stock Purchase Plan                            9

         5                 Opinion of Counsel regarding legality         17

        23.1               Consent of Margolis & Company P.C.            18

        23.2               Consent of Counsel (Included in               17
                           Exhibit 5)

        24.                Power of Attorney (Contained with             7
                           Signature Page)