July 25, 2005


By facsimile to (617) 523-6215 and U.S. Mail


Mr. Alan S. McKim
Chairman, President, and Chief Executive Officer
Clean Harbors, Inc.
1501 Washington Street
Braintree, MA 02184-7535

Re:	Clean Harbors, Inc.
	Registration Statement on Form S-3
	Filed June 29, 2005
File No. 333-126205

Dear Mr. McKim:

	We reviewed the filing and have the comments below.

	Where indicated, we think that you should revise the document
in
response to the comments.  If you disagree, we will consider your
explanation why a comment is inapplicable or a revision is
unnecessary.  Be as detailed as necessary in your explanation.  To
understand better your disclosure, we may ask you in some comments
to
provide us supplemental information.  We may raise additional
comments after reviewing this information.

	Our review`s purpose is to assist you in your compliance with
applicable disclosure requirements and to enhance the overall
disclosure in your document.  We look forward to working with you
to
achieve these objectives.  We welcome any questions that you may
have
about comments or any other aspect of our review.  You may call us
at
the telephone numbers listed at the end of this letter.

1. If applicable, comments on the S-4 filed by Clean Harbors, Inc.
or
Clean Harbors on June 28, 2005 and the 10-K filed by Clean Harbors
on
March 31, 2005 and subsequent Exchange Act reports are comments on
the S-3 and vice versa.

2. We note that you intend to file by amendment the legality
opinion.
Allow us sufficient time to review the opinion before requesting
acceleration of the registration statement`s effectiveness.

3. We are not making any determination whether the disclosure,
including, for example, cautionary language or the disclosure`s
placement, satisfies the sections` requirements if the
registration
statement states that it:

* includes forward-looking statements within the meaning of
section
27A of the Securities Act and section 21E of the Exchange Act,

* otherwise makes reference to those provisions, or

* makes reference to the Private Litigation Reform Act of 1995
generally.

Selling Shareholders, page 14

4. For a beneficial owner that is not a natural person, indicate
by
footnote or otherwise whether the beneficial owner is a:

* reporting company under the Exchange Act,

* majority owned subsidiary of a reporting company under the
Exchange
Act, or

* registered investment fund under the 1940 Act.

5. For a beneficial owner that is not a natural person and that is
not one of the entities specified in the preceding comment, Clean
Harbors must identify by footnote or otherwise the natural person
or
persons having sole or shared voting and investment control over
the
securities held by the beneficial owner.  Refer to telephone
interpretation 4S. in the Regulation S-K section of the March 1999
supplement to our "Manual of Publicly Available Telephone
Interpretations" that is available on the Commission`s website at
http://www.sec.gov., and, if applicable, revise.

6. Confirm that none of the selling shareholders is a broker-
dealer
or a broker-dealer`s affiliate.

7. For a selling shareholder that is a broker-dealer, tell us
whether
the selling shareholder acquired its securities as compensation
for
underwriting activities.  Unless a broker-dealer acquired the
securities as compensation for underwriting activities, Clean
Harbors
must identify the broker-dealer as an underwriter in the
prospectus.
Language such as "may be deemed to be" an underwriter is
unacceptable
if the selling shareholder is a broker-dealer.

Plan of Distribution, page 17

8. We note the disclosure that the selling shareholders acquired
their securities in the ordinary course of business and have not
entered into any agreements, understandings, or arrangements with
any
underwriters or broker-dealers for the sale of their shares of
common
stock.  If a selling shareholder is a broker-dealer`s affiliate,
revise to clarify that the selling shareholder had no agreements
or
understandings, directly or indirectly, with any person to
distribute
the securities at the time of their purchase.  If Clean Harbors is
unable to make the representation, Clean Harbors must state in the
prospectus that the selling shareholder is an underwriter.
Language
such as "may be deemed to be" an underwriter is unacceptable if
the
selling shareholder is an affiliate of an underwriter that cannot
make the representation.

9. We note the disclosure that "If we are notified by any Selling
Shareholder that any material arrangement has been entered into
with
a broker-dealer for the sale of shares of common stock, if
required,
we will file a supplement to this prospectus."  Revise the
disclosure
to indicate that upon being notified by a selling shareholder that
any material arrangement has been entered into with any broker-
dealer
for the sale of shares of common stock, Clean Harbors will file a
supplement to this prospectus that includes to the extent
applicable
the amount of shares of common stock to be sold, the terms of the
sale, any plan of distribution, the names of any underwriters,
brokers, dealers, or agents, any discounts, commissions,
concessions,
or other items constituting compensation from the selling
shareholders, or any other information as may be required under
the
Securities Act.

10. State that you will file a prospectus supplement to name
successors to any selling shareholders who are able to use this
prospectus to resell the securities.

Closing

	File an amendment to the S-3 in response to the comments.  To
expedite our review, Clean Harbors may wish to provide us three
marked courtesy copies of the amendment.  Include with the filing
any
supplemental information requested and a cover letter tagged as
correspondence that keys the responses to the comments.  If Clean
Harbors thinks that compliance with any of the comments is
inappropriate, provide the basis in the letter.  We may have
additional comments after review of the amendment, the responses
to
the comments, and any supplemental information.

	We urge all persons responsible for the accuracy and adequacy
of
the disclosure in the registration statement reviewed by us to
ensure
that they have provided all information investors require for an
informed decision.  Since Clean Harbors and its management are in
possession of all facts relating to the disclosure in the
registration statement, they are responsible for the adequacy and
accuracy of the disclosures that they have made.

      If Clean Harbors requests acceleration of the registration
statement`s effectiveness, Clean Harbors should furnish a letter
at
the time of the request, acknowledging that:

* Should the Commission or the staff acting by delegated authority
declare the registration statement effective, it does not
foreclose
the Commission from taking any action on the filing.

* The action of the Commission or the staff acting by delegated
authority in declaring the registration statement effective does
not
relieve Clean Harbors from its full responsibility for the
adequacy
and accuracy of the disclosure in the registration statement.

* Clean Harbors may not assert our comments and the declaration of
the registration statement`s effectiveness as a defense in any
proceedings initiated by the Commission or any person under the
United States` federal securities laws.

	The Commission`s Division of Enforcement has access to all
information that Clean Harbors provides us in our review of the
registration statement or in response to our comments on the
registration statement.

	We will consider a written request for acceleration of the
registration statement`s effectiveness under Rule 461 of
Regulation C
under the Securities Act as confirmation that those requesting
acceleration are aware of their responsibilities under the
Securities
Act and the Exchange Act as they relate to the proposed public
offering of the securities specified in the registration
statement.
We will act on the request and by delegated authority grant
acceleration of the registration statement`s effectiveness.

	You may direct questions on accounting comments to Gustavo A.
Rodriguez, Staff Accountant, at (202) 551-3752 or Nudrat S. Salik,
Senior Staff Accountant, at (202) 551-3692.

You may direct questions on other comments and disclosure issues
to
Edward M. Kelly, Senior Counsel, at (202) 551-3728 or Christopher
B.
Edwards, Special Counsel, at (202) 551-3742.

Very truly yours,





Pamela A. Long

Assistant Director

cc:	C. Michael Malm, Esq.
	Davis, Malm & D`Agostine, P.C.
	1 Boston Place
	Boston, MA 02108



Mr. Alan S. McKim
July 25, 2005
Page 1








UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

         DIVISION OF
CORPORATION FINANCE