------------------------------ OMB APPROVAL OMB Number 3235-0145 Expires: October 31, 2002 Estimated average burden hours per response . . . 14.90 ------------------------------ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL SCHEDULE 13G Under the Securities Exchange Act of 1934 Clean Harbors Inc -------------------------------------------------------------------------------- (Name of Issuer) Common Stock -------------------------------------------------------------------------------- (Title of Class of Securities) 184496107 -------------------------------------------------------------------------------- (CUSIP Number) December 31, 2001 -------------------------------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [ X ] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in 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 ("Act") 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). PAGE 1 OF 7 PAGES ----------------------------------------- -------------------------------------- CUSIP No. 184496107 13G Page 2 of 7 Pages ----------------------------------------- -------------------------------------- ---------- ----------------------------------------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only). John Hancock Financial Services, Inc. I.R.S. No. 04-3483032 ---------- ----------------------------------------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |_| N/A ---------- ----------------------------------------------------------------------------------------------------------------- 3 SEC USE ONLY ---------- ----------------------------------------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware ---------- ----------------------------------------------------------------------------------------------------------------- 5 SOLE VOTING POWER Number of Shares -0- -------- ------------------------------------------------------------------------------------------- Beneficially 6 SHARED VOTING POWER Owned by Each -0- -------- ------------------------------------------------------------------------------------------- Reporting 7 SOLE DISPOSITIVE POWER Person With -0- -------- ------------------------------------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER -0- ---------- ----------------------------------------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON None, except through its direct, wholly-owned subsidiary, John Hancock Life Insurance Company. ---------- ----------------------------------------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* N/A ---------- ----------------------------------------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 See line 9, above. ---------- ----------------------------------------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* HC ---------- ----------------------------------------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! PAGE 2 OF 7 PAGES ----------------------------------------- -------------------------------------- CUSIP No. 184496107 13G Page 3 of 7 Pages ----------------------------------------- -------------------------------------- ---------- ----------------------------------------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only). John Hancock Life Insurance Company I.R.S. No. 04-1414660 ---------- ----------------------------------------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |_| N/A ---------- ----------------------------------------------------------------------------------------------------------------- 3 SEC USE ONLY ---------- ----------------------------------------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Commonwealth of Massachusetts ---------- ----------------------------------------------------------------------------------------------------------------- 5 SOLE VOTING POWER Number of Shares 954,812 -------- ------------------------------------------------------------------------------------------- Beneficially 6 SHARED VOTING POWER Owned by Each -0- -------- ------------------------------------------------------------------------------------------- Reporting 7 SOLE DISPOSITIVE POWER Person With 954,812 -------- ------------------------------------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER -0- ---------- ----------------------------------------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 954,812 ---------- ----------------------------------------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* N/A ---------- ----------------------------------------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 7.7% ---------- ----------------------------------------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* IC, IA ---------- ----------------------------------------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! PAGE 3 OF 7 PAGES The original statement shall be signed by each person on whose behalf the statement is filed or his authorized representative. If the statement is signed on behalf of a person by his authorized representative other than an executive officer or general partner of the filing person, evidence of the representative's authority to sign on behalf of such person shall be filed with the statement, provided, however, that a power of attorney for this purpose which is already on file with the Commission may be incorporated by reference. The name and any title of each person who signs the statement shall be typed or printed beneath his signature. Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Sec. 240.13d-7 for other parties for whom copies are to be sent. Attention: Intentional misstatements or omissions of fact constitute Federal criminal violations (See 18 U.S.C. 1001) Item 1(a) Name of Issuer: -------------- Clean Harbors Inc Item 1(b) Address of Issuer's Principal Executive Offices: ----------------------------------------------- 1501 Washington Street Braintree, MA 02184 Item 2(a) Name of Person Filing: --------------------- This filing is made on behalf of John Hancock Financial Services, Inc. ("JHFS"), and JHFS's direct, wholly-owned subsidiary, John Hancock Life Insurance Company ("JHLICO"). Item 2(b) Address of the Principal Offices: -------------------------------- The principal business offices of JHFS and JHLICO is located at John Hancock Place, P.O. Box 111, Boston, MA 02117. Item 2(c) Citizenship: ----------- JHLICO is organized and exists under the laws of the Commonwealth of Massachusetts. JHFS is organized and exists under the laws of the State of Delaware. Item 2(d) Title of Class of Securities: ---------------------------- Common Stock Item 2(e) CUSIP Number: ------------ 184496107 Item 3 If the Statement is being filed pursuant to Rule ------------------------------------------------ 13d-1(b), or 13d-2(b), check whether the person filing is a: ----------------------------------------------------------- JHFS (g) (X) Parent Holding Company, in accordance with ss.240.13d-1(b)(ii)(G). JHLICO: (c) (X) Insurance Company as defined inss.3(a)(19) of the Act. (e) (X) Investment Adviser registered under ss.203 of the Investment Advisers Act of 1940. PAGE 4 OF 7 PAGES Item 4 Ownership: --------- (a) Amount Beneficially Owned: JHLICO has direct beneficial ownership of 954,812 Warrants for Common Stock, exercisable immediately. (b) Percent of Class: 7.7% ---------------- (c) (i) sole power to vote or to direct the vote: JHLICO has sole power to vote or to direct the vote of the 954,812 shares as discussed in Item 4(a) above. (ii) shared power to vote or to direct the vote: -0- (iii) sole power to dispose or to direct the disposition of: JHLICO has sole power to dispose or to direct the disposition of the 954,812 shares as discussed in Item 4(a) above. (iv) shared power to dispose or to direct the disposition of: -0- Item 5 Ownership of Five Percent or Less of a Class: -------------------------------------------- Not applicable Item 6 Ownership of More than Five Percent on Behalf of Another Person: --------------------------------------------------------------- Not applicable. Item 7 Identification and Classification of the Subsidiary which Acquired ------------------------------------------------------------------ the Security Being Reported on by the Parent Holding Company: ------------------------------------------------------------- Not applicable. Item 8 Identification and Classification of Members of the Group: --------------------------------------------------------- Not applicable. Item 9 Notice of Dissolution of a Group: -------------------------------- Not applicable. Item 10 Certification: ------------- By signing below the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were acquired in the ordinary course of business and were not acquired for the purpose of and do not have the effect of changing or influencing the control of the issuer of such securities and were not acquired in connection with or as a participant in any transaction having such purpose or effect. PAGE 5 OF 7 PAGES SIGNATURE After reasonable inquiry and to the best of its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct. John Hancock Financial Services, Inc. By: /s/Barry J. Rubenstein ---------------------- Name: Barry J. Rubenstein Dated: May 1, 2002 Title: Vice President, Counsel & Secretary John Hancock Life Insurance Company By: /s/Barry E. Welch ----------------- Name: Barry E. Welch Dated: May 1, 2002 Title: Senior Managing Director PAGE 6 OF 7 PAGES EXHIBIT A JOINT FILING AGREEMENT ---------------------- John Hancock Financial Services, Inc. and John Hancock Life Insurance Company agree that the Initial Schedule 13G, to which this Agreement is attached, relating to the Common Stock of Clean Harbors Inc is filed on behalf of each of them. John Hancock Financial Services, Inc. By: /s/Barry J. Rubenstein ---------------------- Name: Barry J. Rubenstein Dated: May 1, 2002 Title: Vice President, Counsel & Secretary John Hancock Life Insurance Company By: /s/Barry E. Welch ----------------- Name: Barry E. Welch Dated: May 1, 2002 Title: Senior Managing Director PAGE 7 OF 7 PAGES