SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 SCHEDULE 13D/A

                                (Amendment No. 4)

                   Under the Securities Exchange Act of 1934*


                           Bennett Environmental Inc.
                           --------------------------
                                (Name of Issuer)


                                  Common Shares
                         ------------------------------
                         (Title of Class of Securities)


                                    081906109
                                 --------------
                                 (CUSIP Number)


                               Christine Morabito
                            Richards, Layton & Finger
                                One Rodney Square
                                   10th Floor
                              Tenth & King Streets
                           Wilmington, Delaware 19801
                            United States of America
                                 (302) 651-7700
            --------------------------------------------------------
            (Name, Address and Telephone Number of Person Authorized
                     to Receive Notices and Communications)


                                   May 2, 2006
             -------------------------------------------------------
             (Date of Event which Requires Filing of this Statement)


     If the filing person has previously filed a statement on Schedule
     13G to report the acquisition which is the subject of this
     Statement because of Rule 13d-1(b)(3) or (4), check the
     following: [ ]


     *  The information required on the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


                                 SCHEDULE 13D/A
CUSIP NO. 081906109
--------------------------------------------------------------------------------
1    NAMES OF REPORTING PERSONS S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE
     PERSONS

     Second City Capital Partners I, Limited Partnership
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                         (a) [ ]
                                                                         (b) [X]
--------------------------------------------------------------------------------
3    SEC USE ONLY
--------------------------------------------------------------------------------
4    SOURCE OF FUNDS

     OO
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) or 2(e)
                                                                             [ ]
--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION:

     Delaware
--------------------------------------------------------------------------------
Number of                         7    SOLE VOTING POWER           1,755,300
Shares Bene-                      ----------------------------------------------
ficially                          8    SHARED VOTING POWER         0
Owned by                          ----------------------------------------------
Reporting                         9    SOLE DISPOSITIVE POWER      1,755,300
Person With                       ----------------------------------------------
                                  10   SHARED DISPOSITIVE POWER    0
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     1,755,300
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 11 EXCLUDES CERTAIN
     SHARES
                                                                             [ ]
--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     8.0%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     PN
--------------------------------------------------------------------------------

                                       2


Item 1.  Security and Issuer.

         The class of securities to which this statement relates is Common
Shares(the "Common Shares") of Bennett Environmental Inc., a company federally
incorporated in Canada (the "Issuer"). The address of the principal executive
office of the Issuer is 1540 Cornwall Road, Suite 208 Oakville, Ontario L6J 7W5
Canada.

Item 2.  Identity and Background.

         Names of Person Filing:

         (a)      This statement is filed on behalf of Second City Capital I,
Limited Partnership, a Delaware limited partnership, as an amended statement on
Schedule 13D (the "Reporting Party"). The general partner of the Reporting Party
is Second City General Partner Inc., a Delaware corporation having the same
address as the Reporting Party (the "General Partner"). Actions of the General
Partner are made by majority vote of its three directors, Samuel Belzberg, a
Canadian citizen, and Strauss Zelnick and David Maron, each United States
citizens. Approximately 40 limited partners of the Reporting Party are the
ultimate beneficial owners of Common Shares, with the General Partner having a
carried interest in certain profits related thereto.

         (b)      The Reporting Party's business address is c/o Richards Layton
& Finger, One Rodney Square, 10th floor, Tenth & King Streets, Wilmington,
Delaware 19801.

         (c)      The Reporting Party is engaged principally in the investment
business.

         (d)      Neither the Reporting Party nor the General Partner nor any
director thereof has, during the five years prior to the date hereof, been
convicted in a criminal proceeding (excluding traffic violations or similar
misdemeanors).

         (e)      Neither the Reporting Party nor the General Partner nor any
director thereof has, during the five years prior to the date hereof, been party
to a civil proceeding of a judicial or administrative body of competent
jurisdiction, as a result of which he was or is subject to a judgment, decree or
final order enjoining future violations of, or prohibiting or mandating
activities subject to, federal or state securities laws or finding any violation
with respect to such laws.

         (f)      The Reporting Party is a Delaware limited partnership. The
General Partner is a Delaware corporation. Two directors of the General Partner
are United States citizens and one is a Canadian citizen.

Item 3.  Source and Amount of Funds or Other Consideration.

         The Reporting Party acquired the Common Shares held by it in open
market transactions.

Item 4.  Purpose of Transaction.

         The Reporting Party acquired the Common Shares for investment purposes.
Except as indicated below and elsewhere in this Schedule 13D, the Reporting
Party currently has no plans or proposals that relate to or would result in any
of the matters described in subparagraphs (a) through (j) of Item 4 of Schedule
13D. On May 3, 2006 a representative of the Reporting Party signed a letter of
support with Broadmark Capital, LLC for replacing the board of directors of the
Company with certain replacement nominees, but the Reporting Party reserved its

                                       3


right to vote its shares of Common Stock in its discretion. A copy of the form
of support letter received and signed by the Reporting Party is attached as an
Exhibit to this Schedule 13D.

Item 5.  Interest in Securities of the Issuer.

         (a)      As of the above date, the Reporting Party beneficially owns,
1,755,300 shares, or 8.1%, of the outstanding Common Shares. Samuel Belzberg, a
director of the General Partner, additionally owns 10,000 Common Shares.

         (b)      The Reporting Party holds the power to vote or to direct the
vote and to dispose or to direct the disposition of all shares beneficially
owned by it.

         (c)      During the sixty days preceding the filing of this statement,
the Reporting Party purchased the following shares of Common Stock in the open
market:

                  None.

         (d)      Not applicable.

         (e)      Not applicable.

Item 6.  Contracts, Arrangements, Understandings or Relationships
         with respect to Securities of the Issuer

         Except as indicated below and elsewhere in this Schedule 13D and the
attached exhibits, there is no contract, arrangement, understanding or
relationship between the Reporting Party and any other person with respect to
any securities of the Company. On May 3, 2006 a representative of the Reporting
Party signed a letter of support with Broadmark Capital, LLC for replacing the
board of directors of the Company with certain replacement nominees, but the
Reporting Party reserved its right to vote its shares of Common Stock in its
discretion. On May 2, 2006, Broadmark Capital, LLC, was engaged by the Reporting
Party and John Bennett, another shareholder of the Issuer, to seek to
reconstitute the board of directors of the Issuer. This engagement did not
confer any authority with respect to the vote or sale of Common Stock of the
Issuer.

         Except as indicated in this Schedule 13d and the attached exhibits,
there is no contract, arrangement, understanding or relationship between the
Reporting Party and any other person with respect to any securities of the
Company.


Item 7.  Material to be Filed as Exhibits:

         Form of Support Letter


                                       4


                                   SIGNATURES

         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


Dated:   May 15, 2006
                                       /s/ JOHNNY CIAMPI
                                       -----------------------------------------
                                       Name: Johnny Ciampi
                                       Title: Vice President


                                       5


                                                   2800 One Union Square
                                                   600 University Street
                                                   Seattle, Washington 98101
                                                   (206) 623-1200
                                                   Facsimile: (206) 623-2213
                                                   E-mail: seattle@broadmark.com

                                                   Investment Bankers

                                                   May 2, 2006


[LOGO OMITTED]
BROADMARK CAPITAL, LLC

Christopher Wallace
Investment Principal
Second City Capital Partners
1075 West Georgia Street
Suite 2600
Vancouver, BC
Canada, V6E 3C9

Re:   Bennett Environmental Inc. (the "Company")
------------------------------------------------

Dear Mr. Wallace:

Further to our recent discussions, we are writing to confirm your support for
our initiative to replace the current board of directors of the Company with the
individuals listed in Schedule "A" attached to this letter or such other
individuals that are mutually acceptable to you and us (the "Replacement
Nominees").

We also confirm that your support for this initiative does not constitute an
agreement, commitment or understanding as to how you will exercise voting rights
attached to, or otherwise deal with, the common shares of the Company owned or
controlled by you.

Please confirm your agreement with the above by signing in the space provided
below and returning a copy of this letter to us by fax (ATTN: Joseph L.
Schocken, Fax: (206) 623-2213). We also ask that you confirm the number of
Company common shares that you currently directly or indirectly own or control
by completing the statement below your signature.


Thank you for your support.


Sincerely,

/s/ JOSEPH L. SCHOCKEN
------------------------------
Joseph L. Schocken
President
Broadmark Capital, LLC


Acknowledged and agreed this __day of__________, 2006.

___________________________________

I/We currently directly or indirectly own or control ___________________ common
shares of the Company.


                               NEW YORK - SEATTLE
                                MEMBER NASD/SIPC


                                  SCHEDULE "A"

                              Replacement Nominees


Christopher S. Wallace

Michael F. Blair

Michael P. Fleischer

Joseph L. Schocken