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


                                    FORM 10-Q


       QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
                              EXCHANGE ACT OF 1934


                For the Quarterly Period Ended February 29, 2000


                         Commission File Number 1-8368


                               SAFETY-KLEEN CORP.
                               ------------------
             (Exact name of registrant as specified in its charter)


         Delaware                                                51-0228924
-------------------------------                               ------------------
(State or other jurisdiction of                              (I.R.S. Employer
 incorporation or organization)                              Identification No.)


1301 Gervais Street Columbia, Suite 300, South Carolina                 29201
-------------------------------------------------------               ----------
    (Address of principal executive offices)                          (Zip Code)

       (803) 933-4200 (Registrant's telephone number, including area code)
       --------------


    -------------------------------------------------------------------------
   (Former name, address and former fiscal year, if changed since last report)

         Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Sections 13 or 15(d) of the  Securities  Exchange Act of
1934  during  the  preceding  12 months  (or for such  shorter  period  that the
registrant was required to file such reports),  and (2) has been subject to such
filing requirements for the past 90 days.

                            Yes        No  X
                                ----      ----
         The number of shares of the  issuer's  common stock  outstanding  as of
April 6, 2000 was 100,783,596.


<PAGE>

                                     Page 2

                                                SAFETY-KLEEN CORP.


                                      INDEX

PART I FINANCIAL INFORMATION......................................... 3


PART II  OTHER INFORMATION

Item 1   Legal Proceedings........................................... 3

Item 2   Changes In Securities And Use Of Proceeds................... 9

Item 3   Defaults Upon Senior Securities.............................10

Item 5   Other Events................................................10

Item 6   Exhibits and Reports on Form 8K.............................10

Signatures...........................................................16

Exhibit Index........................................................17



                                     Page 2
<PAGE>



                         PART I - FINANCIAL INFORMATION

         Due to the ongoing  internal  investigation  of the Company's  reported
financial  results and certain of its  accounting  policies  and  practices,  as
announced  by the  Company  on March 6, 2000,  the  Company is unable to prepare
financial  statements  for the quarter ended February 29, 2000 at this time. The
Company will file amended reports as soon as practicable.

                           PART II - OTHER INFORMATION

ITEM 1.  LEGAL PROCEEDINGS.

GENERAL

         The business of the Company's  hazardous and industrial  waste services
is continuously  regulated by federal,  state,  provincial and local  provisions
that have been enacted or adopted,  regulating  the discharge of materials  into
the environment or primarily for the purpose of protecting the environment.  The
nature of the Company's businesses results in its frequently becoming a party to
judicial or  administrative  proceedings  involving  all levels of  governmental
authorities and other interested parties. The issues that are involved generally
relate to  applications  for  permits  and  licenses  by the  Company  and their
conformity with legal requirements and alleged technical  violations of existing
permits and  licenses.  The Company  does not believe  that these issues will be
material to the  Company's  operations or financial  condition.  At February 29,
2000,  subsidiaries  of the Company were  involved in three  proceedings  of the
latter type relating  primarily to activities  at waste  treatment,  storage and
disposal  facilities  where the  Company  believes  sanctions  involved  in each
instance may exceed $100,000. The Company believes that the ultimate disposition
of these issues will not have a  materially  adverse  effect upon the  Company's
consolidated financial position or results of operations.

         From time to time,  the  Company  is named as a  defendant  in  various
lawsuits  arising in the  ordinary  course of  business,  including  proceedings
wherein  persons  claim injury  resulting  from the use of the  Company's  parts
cleaner equipment and/or cleaning  products,  other matters  involving  personal
injury and property  damage claims and  employment-related  claims.  A number of
such legal proceedings are currently pending in various courts and jurisdictions
throughout North America.  Based on the Company's assessment of known claims and
its historical claims payment pattern, and discussions with internal and outside
legal counsel and risk management personnel,  the Company believes that there is
no proceeding  pending against the Company  relating to such matters arising out
of the ordinary course of business that, if resolved against the Company,  would
have a  materially  adverse  effect upon the  Company's  consolidated  financial
position or results of operations.

         In the United States, CERCLA imposes financial liability on persons who
are  responsible for the release of hazardous  substances into the  environment.
Present  and  past  owners  and  operators  of  sites  which  release  hazardous
substances,  as well as generators and  transporters of the waste material,  are
jointly and severally liable for remediation costs and environmental


                                     Page 3
<PAGE>

damage.  At February  29,  2000,  the Company  had been  notified  that it was a
potentially  responsible  party in connection with 49 locations in its hazardous
waste  management  and other  businesses.  The Company  continually  reviews its
status with respect to each location and the extent of its alleged  contribution
to the volume of waste at the location,  the available  evidence  connecting the
Company to that  location,  and the numbers  and  financial  soundness  of other
potentially responsible parties at the location.  Based upon presently available
information,  the Company does not believe that  potential  liabilities  arising
from its  involvement  with these  locations  will be material to the  Company's
operations or financial condition.

SAFETY-KLEEN (PINEWOOD), INC. FINANCIAL ASSURANCE

         The Company's  report on this matter  contained in the Company's Report
on Form 10-K for the twelve months ended August 31, 1999 is incorporated  herein
by  reference  thereto.  In its May 19, 1994 order DHEC  established  Pinewood's
permitted  capacity at 2250 acre feet and  determined  that from the date of the
order all wastes  disposed,  hazardous and  non-hazardous,  would be included in
determining  the  exhaustion  of  permitted  capacity  and  non-hazardous  waste
disposed  prior to the May 19,  1994  order  would  not be  counted  toward  the
hazardous waste capacity. In June 1995, DHEC promulgated, and the South Carolina
legislature  approved,   regulations  (the  "Regulations")  governing  financial
assurance for environmental  cleanup and restoration  giving  owner/operators of
hazardous  waste  facilities the right to choose from among several  options for
providing financial assurance.  The options included insurance, a bond, a letter
of credit, a cash trust fund and a corporate guaranty with a financial test.

         As  previously  reported  in the  Company's  report  on Form 8-K  dated
January 19,  2000,  the South  Carolina  Court of Appeals  ("Court of  Appeals")
issued a decision on January 17, 2000. The Court of Appeals declared:

         1.       The  Regulations  invalid due to  insufficient  public  notice
                  during the  promulgation  procedure  and ordering  Pinewood to
                  immediately   comply   with  the  cash   financial   assurance
                  requirements of the May 19, 1994 DHEC Order. This decision, if
                  upheld,  would require a present cash payment of approximately
                  $70 million.

         2.       That  non-hazardous  and hazardous  waste volume count against
                  Pinewood capacity beginning with  the site's initial  disposal
                  of waste.  The  practical effect of the decision would  render
                  Pinewood  at  approximately  500 acre feet over its  permitted
                  capacity at this time, notwithstanding the fact that under the
                  DHEC  Board  Order,   Pinewood  was  prohibited  from  seeking
                  additional  capacity  until  it  was  within  three  years  of
                  exhaustion of presently  permitted  capacity.  Pinewood had at
                  least  four years  operation  remaining  under its  previously
                  determined  permitted  capacity at the time of the January 17,
                  2000 decision.

Pinewood  petitioned for a rehearing which was denied by the Court of Appeals in
its order dated April 4, 2000.

         The Company will appeal the case to the South  Carolina  Supreme Court.
To address  the  possibility  that no relief will be achieved in the state court
system, a strategy has been devised


                                     Page 4
<PAGE>

and a complaint  prepared to challenge the decision in Federal  Court,  upon the
theory  that South  Carolina's  imposition  of a cash fund  requirement  and its
interpretation  with  respect to  permitted  capacity  violates the Federal laws
and/or the United States Constitution. As a fall back position, the Company will
pursue the  promulgation of new regulations  identical to those declared invalid
by the  Court of  Appeals  and will  seek  additional  capacity  through  permit
modification proceedings before DHEC.

         The Stock Purchase Agreement among Rollins Environmental Services, Inc.
(now Safety-Kleen Corp.) and Laidlaw Inc. and Laidlaw Transportation, Inc. dated
February 6, 1997,  provides  that Laidlaw  Inc.  shall  maintain,  solely at its
expense,  until the tenth  anniversary  of the Closing Date (May 15, 1997),  the
financial  mechanism as may be permitted by the relevant  environmental  laws to
provide the required financial assurance for potential environmental cleanup and
restoration at the Pinewood facility.

         If none of the  challenges  to the  decision of the Court of Appeals is
successful,  enforcement  of the decision  could have a material  adverse impact
upon the Company's financial position.

MATTERS RELATED TO INVESTIGATION OF FINANCIAL RESULTS

         As  previously  reported in the  Company's  Current  Report on Form 8-K
dated March 6, 2000,  the Company  announced  that it had  initiated an internal
investigation  of its  prior  reported  financial  results  and  certain  of its
accounting  policies and practices  following  receipt by the Company's Board of
Directors of information  alleging possible  accounting  irregularities that may
have affected the  previously  reported  financial  results of the Company since
fiscal year 1998. The Board has appointed a Special Committee, consisting solely
of four independent  outside  directors of the Company,  to conduct the internal
investigation, and has engaged the law firm Shaw Pittman and the accounting firm
Arthur  Andersen  LLP to assist with the  comprehensive  investigation  of these
matters.  Pending  the outcome of the  investigation,  the Board also has placed
Kenneth W. Winger, the Company's Chief Executive Officer and a Director, Michael
J. Bragagnolo,  Executive Vice President and Chief Operating Officer and Paul R.
Humphreys,   Sr.  Vice  President  of  Finance  and  Chief   Financial   Officer
(collectively  referred to as the "Individual  Defendants"),  on  administrative
leave.

         Between March 6 and 30, 2000, various Company  shareholders (the "Class
Members")  filed actions in the United States District Court for the District of
South Carolina,  on behalf of various  alleged  classes of Company  shareholders
(the "Federal Class Actions"), asserting federal securities fraud claims against
the  Company,  the  Individual   Defendants  (the  Company  and  the  Individual
Defendants  collectively  referred to as the "Defendants") and in one case James
R. Bullock, former Chairman of the Board of the Company ("Bullock"). The Federal
Class Actions are as follows:


                                     Page 5
<PAGE>
<TABLE>
<CAPTION>

   No.                     CASE NAME                         COURT             DOCKET #          DATE OF      CLASS PERIOD
                                                                                                 FILING

  <S>      <C>                                        <C>                   <C>                    <C>         <C>

   1.      Rachel Samet, Individually and on Behalf   United States         3:00-0739-10           3/7/00      7/7/98 - 3/6/00
           of all others Similarly Situated vs.       District Court
           Safety-Kleen Corp., Kenneth W. Winger,     (Columbia Division)
           Paul R. Humphreys and Michael Bragagnolo

   2.      Jack Forrest, on behalf of himself and     United States         3:00-736               3/7/00
           all other similarly situated vs.           District Court
           Safety-Kleen Corp., Kenneth W. Winger,     (Columbia Division)
           Michael J. Bragagnolo and Paul R.
           Humphreys

   3.      Kenneth Steiner, Individually and on       United States         3:00-0750-10           3/8/00      5/4/98 - 3/6/00
           Behalf of all others Similarly Situated    District Court
           vs. Safety-Kleen Corp., Kenneth W.         (Columbia Division)
           Winger, Paul R. Humphreys, Michael
           Bragagnolo and James R. Bullock

   4.      D. Scott Kelley, Individually and on       United States         3:00-0748-10           3/8/00      7/7/98 - 3/6/00
           Behalf of all others Similarly Situated    District Court
           vs. Safety-Kleen Corp., Kenneth W.         (Columbia Division)
           Winger, Paul R. Humphreys and Michael
           Bragagnolo

   5.      Izidor Klein, Individually and on Behalf   United States         3:00-749-17            3/8/00      7/7/98 - 3/6/00
           of all other Similarly Situated v.         District Court
           Safety-Kleen Corp., Kenneth W. Winger,     (Columbia Division)
           Michael Bragagnolo and Paul R. Humphreys

   6.      Michael Potts, Individually and on         United States         3:00-0769-17           3/9/00      7/7/98 - 3/6/00
           Behalf of all others Similarly Situated    District Court
           vs. Safety-Kleen Corp., Kenneth W.         (Columbia Division)
           Winger, Paul R. Humphreys and Michael
           Bragagnolo


                                     Page 6
<PAGE>


   No.                     CASE NAME                         COURT             DOCKET #          DATE OF      CLASS PERIOD
                                                                                                 FILING

   7.      Jerry Krim and Hirsch Weber,               United States         3:00-0768-17           3/9/00      7/7/98 - 3/6/00
           Individually and on Behalf of all others   District Court
           Similarly Situated vs. Safety-Kleen        (Columbia Division)
           Corp., Kenneth W. Winger, Paul R.
           Humphreys and Michael Bragagnolo

   8.      Faye Scher, Individually and on Behalf     United States         3:00-0791-17           3/13/00     7/7/98 - 3/6/00
           of all others Similarly Situated vs.       District Court
           Safety-Kleen Corp., Kenneth W. Winger,     (Columbia Division)
           Paul R. Humphreys and Michael Bragagnolo

   9.      Maurice Suede, Individually and on         United States         3:00-0792-17           3/13/00     10/6/98 - 3/3/00
           Behalf of all others Similarly Situated    District Court
           vs. Safety-Kleen Corp., Kenneth W.         (Columbia Division)
           Winger, Paul R. Humphreys and Michael
           Bragagnolo

   10.     Myron H. Smith, Individually and on        United States         3:00-0829-17           3/15/00     7/7/98 - 3/6/00
           Behalf of all others Similarly Situated    District Court
           vs. Safety-Kleen Corp., Kenneth W.         (Columbia Division)
           Winger, Paul R. Humphreys and Michael
           Bragagnolo

   11.     Frank A. Riccobono, Individually and on    United States         3:00-0866-17           3/20/00     7/7/98 - 3/3/00
           Behalf of all others Similarly Situated    District Court
           vs. Safety-Kleen Corp., Kenneth W.         (Columbia Division)
           Winger, Paul R. Humphreys and Michael
           Bragagnolo

   12.     Michael Schmeling, on behalf of himself    United States         3:00-875               3/20/00     7/9/97 - 3/6/00
           and all other similarly situated vs.       District Court
           Safety-Kleen Corp., Kenneth W. Winger,     (Columbia Division)
           Michael J. Bragagnolo and Paul R.
           Humphreys


                                     Page 7
<PAGE>


   No.                     CASE NAME                         COURT             DOCKET #          DATE OF      CLASS PERIOD
                                                                                                 FILING

   13.     Joseph Lyons, on behalf of himself and     United States         3:00-996               3/29/00     7/7/98 - 3/6/00
           all other similarly situated vs.           District Court
           Safety-Kleen Corp., Kenneth W. Winger,     (Columbia Division)
           Michael J. Bragagnolo and Paul R.
           Humphreys

   14.     John Ulrich, on behalf of himself and      United States         3:00-1005              3/30/00     10/6/98 - 3/3/00
           all others similarly situated vs.          District Court
           Safety-Kleen Corp., Kenneth W. Winger,     (Columbia Division)
           Michael J. Bragagnolo and Paul R.
           Humphreys

</TABLE>


         The  significant  part of these  actions  brought  on behalf of various
putative  classes of  purchasers of Company  securities  between May 4, 1998 and
March 6,  2000 (the  "Class  Periods")  is the  allegation  that the  Defendants
disseminated  materially false and misleading information and failed to disclose
material  facts with respect to the Company's  financial  condition and business
prospects,  thereby  causing  the  market  price  of  Company  securities  to be
artificially  inflated  during  the Class  Periods  and that the  Class  Members
acquired Company  securities  during the Class Periods at artificially  inflated
prices and were damaged thereby.

         The Federal Class Actions assert various  violations of securities laws
including  violations of Sections 10(b) and 20(a) of the Securities Exchange Act
of 1934 and Rules 10b-5 and 14a-9  promulgated  under the Exchange Act, Sections
11,  12(a)(2) and 15 of the  Securities Act of 1933. The claims under Section 15
of the  Securities  Act of 1933 and 20(a) of the Exchange Act have been asserted
against the Individual Defendants, and in once case Bullock, but not against the
Company.  These actions seek to recover  damages in an unspecified  amount which
the Class  Members  allegedly  sustained by  purchasing  Company  securities  at
artificially  inflated prices,  as well as related relief.  As of April 7, 2000,
the Company had not received  copies of the  Complaints in cases  numbered 2, 12
and 13.  Allegations  and causes of action may be contained in these cases which
are not included in this disclosure.

         In addition to the above,  two  shareholder  derivative  lawsuits  were
filed in the Delaware  Court of Chancery for New Castle  County on behalf of the
Company,  against  certain of its directors and former  directors (the "Delaware
Derivative  Actions"):  (1) Civil Action No. 17923-NC on March 24, 2000, pending
under the caption Peter Frank, Plaintiff vs. Kenneth W. Winger, John W. Rollins,
James R. Bullock,  David E. Thomas,  Jr.,  Leslie W.  Haworth,  Henry B. Tippie,
James L. Wareham, John W. Rollins, Jr., Robert W. Luba and Grover C. Wren (sic),
Defendants  (the  "Director   Defendants")  and  Safety-Kleen   Corp.   (Nominal
Defendant) and (2) Civil Action No. 1974-NC on March 30, 2000, pending under the
caption Harbor Finance Partners,  derivatively on behalf of Safety-Kleen  Corp.,
Plaintiff against James R. Bullock,  John W. Rollins, Sr., David E. Thomas, Jr.,
Kenneth W. Winger, Leslie W. Haworth, Henry B. Tippie,


                                     Page 8
<PAGE>


James L. Wareham,  John W. Rollins,  Jr., Robert W. Luba, Peter N.T. Widdrington
and Grover C. Wrenn, Defendants and Safety-Kleen Corp. (Nominal Defendant).  The
Delaware  Derivative  Actions assert,  inter alia, that the Director  Defendants
breached  their  fiduciary  obligations to the Company and its  Shareholders  by
failing  to  adequately  supervise  the  Company  and to  monitor  its  internal
financial  administrative  policies,  procedures  and controls  over an extended
period of time,  thereby  exposing the Company to class action  lawsuits and the
loss of  goodwill  in the  investment  community,  resulting  in  damages to the
Company and its shareholders.  These claims seek to recover damages on behalf of
the Company against the Director  Defendants in an unspecified amount as well as
related relief.

         It is  anticipated  that  other  lawsuits  similar  in  nature  to  the
previously disclosed lawsuits may be filed.

         Shortly  after  the  Company's  March  6,  2000  announcement,  Company
representatives  met with officials of the  Securities  and Exchange  Commission
(the  "Commission")  and  advised  the  Commission  of  the  alleged  accounting
irregularities  and the  Company's  internal  investigation  with respect to the
allegations.  On March 10, 2000, the Company was advised that the Commission had
initiated a formal  investigation  of the Company.  Also on March 10, 2000,  the
Commission  issued a subpoena to the Company requiring the production of certain
financial  and  corporate  documents  relating  to the  preparation  of  Company
financial  statements,  reports and audits for Fiscal Years 1998,  1999 and 2000
and for other  various  documents  pertaining  to and  ancillary  to the alleged
accounting  irregularities.  The Company has obtained an indefinite extension of
time to respond to the Subpoena.

         On or about  March 22,  2000,  the  Company  was served with a subpoena
issued by a Grand  Jury  sitting  in the United  States  District  Court for the
Southern District of New York seeking production of the same documents described
in the Commission's  Subpoena.  The Company has obtained an indefinite extension
of time to respond to the Subpoena.

         The Company is cooperating with each of the investigations.

         Other than as herein reported there have been no additional significant
legal proceedings or any material changes in the legal proceedings  reported in
PART II, Item 3 of the Company's Report on Form 10-K for the twelve months ended
August 31, 1999.

ITEM 2.  CHANGES IN SECURITIES AND USE OF PROCEEDS.

         (c) On January 5, 1999 the Company issued 6014  unregistered  shares of
common stock,  par value $1.00 per share.  On January 4, 2000 the Company issued
5621 unregistered  shares of Common Stock, par value $1.00 per share. The shares
were issued under the Non-Employee  Director Stock Plan,  pursuant to which each
non-employee  director  receives  50% of his  annual  remuneration  in shares of
Company common stock.

         The  Company  believes  that the  issuance of these  securities  to the
directors was exempt from the registration requirements of the Securities Act of
1933, as amended,  pursuant to section 4(2) thereof by virtue of the recipients'
status as directors of the Company.


                                     Page 9
<PAGE>


ITEM 3.  DEFAULTS UPON SENIOR SECURITIES.

         As  previously  announced  by the  Company  in a Form 8-K  filed by the
Company on March 13,  2000,  the  Company  is in default of certain  obligations
under the Amended and Restated Credit  Agreement dated as of April 3, 1998 among
Safety-Kleen Services, Inc. (formerly known as LES, Inc.), Safety-Kleen Services
(Canada) Ltd. (formerly known as Laidlaw Environmental  Services (Canada) Ltd.),
the Lenders,  Toronto  Dominion  (Texas),  Inc.,  The Toronto  Dominion Bank, TD
Securities  (USA) Inc.,  The Bank of Nova Scotia,  NationsBank,  N.A., The First
National Bank of Chicago and Wachovia Bank N.A. (the "Credit Facility").

ITEM 5.  OTHER EVENTS

         On April 14, 2000, the Company issued the press release filed with this
Quarterly  Report on Form 10-Q as Exhibit  99.1.  The  information  contained in
Exhibit 99.1 is incorporated by reference herein.

ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K.

     (a)   Exhibits:

(3)(a) Restated  Certificate of  Incorporation of the Company dated May 13, 1997
and  Amendment  to  Certificate  of  Incorporation  dated May 15,  1997 filed as
Exhibit 3(a) to the  Company's  Form 10-Q for the Quarter ended May 31, 1997 and
incorporated herein by reference.

(3)(a)(i)  Certificate  of  Correction  Filed to Correct a Certain  Error in the
Restated and Amended  Certificate of  Incorporation of the Company dated October
15, 1997 filed as Exhibit  (3)(a)(i) to the Company's Form 10-K-405 for the Year
ended August 31, 1997, and incorporated herein by reference.

(3)(a)(ii) Certificate of Amendment to the Restated Certificate of Incorporation
of the  Company  dated  November  25, 1998 filed as Exhibit  (3)(a)(iii)  to the
Company's  Form 10-Q for the quarter  ended  November 30, 1998 and  incorporated
herein by reference.

(3)(a)(iii)   Certificate   of  Amendment  to  the   Restated   Certificate   of
Incorporation of the Company dated November 30, 1998 filed as Exhibit (3)(a)(iv)
to the  Company's  Form  10-Q  for the  quarter  ended  November  30,  1998  and
incorporated herein by reference.

(3)(b) Amended and Restated  Bylaws of the Company filed as Exhibit 4(ii) to the
Company's Current Report on Form 8-K dated July 29, 1997 and incorporated herein
by reference.

(4)(a) Indenture dated as of May 29, 1998 between LES, Inc. (a subsidiary of the
Company),  Company,  subsidiary  guarantors  of the Company and The Bank of Nova
Scotia  Trust  Company  of New York,  as trustee  filed as  Exhibit  4(b) to the
Company's Form S-4 Registration  Statement No. 333-57587 filed June 24, 1998 and
incorporated herein by reference.


                                    Page 10

<PAGE>


(4)(b)  First  Supplemental  Indenture  effective  as of November 15, 1998 among
Safety-Kleen  Services,  Inc., the Company, SK Europe, Inc. and The Bank of Nova
Scotia  Trust  Company of New York,  as trustee  filed as Exhibit  (4)(f) to the
Company's Form S-4 Registration  Statement No. 333-82689 filed July 12, 1999 and
incorporated herein by reference.

(4)(c)  Second  Supplemental  Indenture  effective  as  of  May  7,  1999  among
Safety-Kleen Services, Inc., the Company, SK Services, L.C., SK Services (East),
L.C. and The Bank of Nova Scotia Trust  Company of New York, as trustee filed as
Exhibit   (4)(d)  to  the  Company's  Form  10-K  filed  October  29,  1999  and
incorporated herein by reference.

(4)(d)  Indenture  dated as of May 17, 1999  between the Company and the Bank of
Nova Scotia Trust Company of New York, as trustee filed as Exhibit (4)(b) to the
Company's Form S-4 Registration  Statement No. 333-82689 filed July 12, 1999 and
incorporated herein by reference.

(4)(e)  Registration  Rights  Agreement  dated as of May 17,  1999  between  the
Company and TD  Securities,  NationsBanc  Montgomery  Securities LLC and Raymond
James &  Associates,  Inc.  filed as Exhibit  (4)(a) to the  Company's  Form S-4
Registration Statement No. 333-82689 filed July 12, 1999 and incorporated herein
by reference.

(4)(f) Amended and Restated  Credit  Agreement among Laidlaw  Chem-Waste,  Inc.,
Laidlaw Environmental Services (Canada) Ltd., Toronto Dominion (Texas) Inc., The
Toronto-Dominion  Bank,  TD  Securities  (USA)  Inc.,  The Bank of Nova  Scotia,
NationsBank,  N.A. and The First National Bank of Chicago and NationsBank,  N.A.
as  Syndication  Agent dated as of April 3, 1998,  filed as Exhibit  4(f) to the
Company's Form 10-Q for the quarter ended  February 28, 1999,  and  incorporated
herein by reference.

(4)(g)  Supplement to the Amended and Restated  Credit  Agreement  among Laidlaw
Chem-Waste, Inc., Laidlaw Environmental Services (Canada) Ltd., Toronto Dominion
(Texas) Inc., The  Toronto-Dominion  Bank, TD Securities (USA) Inc., The Bank of
Nova  Scotia,  NationsBank,  N.A.  and The First  National  Bank of Chicago  and
NationsBank,  N.A.  as  Syndication  Agent  dated as of April 3, 1998,  filed as
Exhibit 4(e) to a subsidiary of the Company's  Form S-4  Registration  Statement
No. 333-57587 filed June 24, 1998 and incorporated herein by reference.

(4)(h) Waiver and First Amendment to the Amended and Restated  Credit  Agreement
dated  as of May 15,  1998  among  LES,  Inc.,  Laidlaw  Environmental  Services
(Canada) Ltd., the Lenders, Toronto Dominion (Texas), Inc., The Toronto Dominion
Bank, TD Securities (USA) Inc., The Bank of Nova Scotia, NationsBank,  N.A., The
First  National  Bank of Chicago and  Wachovia  Bank filed as Exhibit  4(f) to a
subsidiary of the Company's Form S-4 Registration  Statement No. 333-57587 filed
June 24, 1998 and incorporated herein by reference.

(4)(i)  Commitment  to Increase  Supplement  to the Amended and Restated  Credit
Agreement  dated as of June 3,  1998  among  LES,  Inc.,  Laidlaw  Environmental
Services (Canada) Ltd., the Lenders, Toronto Dominion (Texas), Inc., The Toronto
Dominion Bank, TD Securities  (USA) Inc., The Bank of Nova Scotia,  NationsBank,
N.A., The First National Bank of Chicago and Wachovia Bank filed as Exhibit 4(g)
to a subsidiary of the Company's Form S-4  Registration  Statement No. 333-57587
filed June 24, 1998 and incorporated herein by reference.


                             Page 11
<PAGE>

(4)(j) Second Amendment to the Amended and Restated Credit Agreement dated as of
November 20, 1998 among  Safety-Kleen  Services,  Inc.  (formerly  known as LES,
Inc.),   Safety-Kleen   Services  (Canada)  Ltd.   (formerly  known  as  Laidlaw
Environmental  Services  (Canada) Ltd.), the Lenders,  Toronto Dominion (Texas),
Inc.,  The Toronto  Dominion  Bank, TD Securities  (USA) Inc.,  The Bank of Nova
Scotia, NationsBank,  N.A., The First National Bank of Chicago and Wachovia Bank
N.A.,  filed as Exhibit  (4)(j) to the Company's Form 10-Q for the quarter ended
February 28, 1999 and incorporated herein by reference.

(4)(k) Waiver and Third Amendment to the Amended and Restated  Credit  Agreement
dated as of May 6, 1999 among  Safety-Kleen  Services,  Inc.  (formerly known as
LES,  Inc.),  Safety-Kleen  Services  (Canada) Ltd.  (formerly  known as Laidlaw
Environmental  Services  (Canada) Ltd.), the Lenders,  Toronto Dominion (Texas),
Inc.,  The Toronto  Dominion  Bank, TD Securities  (USA) Inc.,  The Bank of Nova
Scotia, NationsBank,  N.A., The First National Bank of Chicago and Wachovia Bank
N.A. filed as Exhibit (4)(l) to the Company's  Form S-4  Registration  Statement
No. 333-82689 filed July 12, 1999 and incorporated herein by reference.

(4)(l)  Registration  Rights  Agreement  dated May 15,  1997 among the  Company,
Laidlaw  Transportation,  Inc. and Laidlaw Inc.,  the form of which was filed as
Exhibit B to Annex A to the  Company's  Definitive  Proxy  Statement on Form DEF
14A, filed on May 1, 1997 and incorporated herein by reference.

(4)(m)  Indenture  dated as of May 1, 1993  between the  Industrial  Development
Board  of  the   Metropolitan   Government  of  Nashville  and  Davidson  County
(Tennessee)  and  NationsBank of Tennessee,  N.A.,  filed as Exhibit 4(f) to the
Company's Form 10-Q for the Quarter ended May 31, 1997, and incorporated  herein
by reference.

(4)(n) Indenture of Trust dated as of August 1, 1995 between Tooele County, Utah
and West One Bank,  Utah, now known as U.S.  Bank, as Trustee,  filed as Exhibit
4(h) to the  Company's  form  10-Q  for the  Quarter  ended  May 31,  1997,  and
incorporated herein by reference.

(4)(o)  Indenture of Trust dated as of July 1, 1997 between Carbon County,  Utah
and U.S. Bank, a national banking association, as Trustee, filed as Exhibit 4(i)
to the Company's Form 10-Q for the Quarter ended May 31, 1997, and  incorporated
herein by reference.

(4)(p)  Indenture of Trust dated as of July 1, 1997 between Tooele County,  Utah
and U.S. Bank, a national banking association, as Trustee, filed as Exhibit 4(j)
to the Company's Form 10-Q for the Quarter ended May 31, 1997, and  incorporated
herein by reference.

(4)(q) Indenture of Trust dated as of July 1, 1997 between California  Pollution
Control Financing  Authority and U.S. Bank, a national banking  association,  as
Trustee,  filed as Exhibit 4(k) to the Company's Form 10-Q for the Quarter ended
May 31, 1997, and incorporated herein by reference.

(4)(r)  Promissory Note dated May 15, 1997 for  $60,000,000  from the Company to
Westinghouse Electric  Corporation,  filed as Exhibit 4(n) to the Company's Form
10-Q for the Quarter ended May 31, 1997, and incorporated herein by reference.


                                    Page 12
<PAGE>

(4)(s) Letter dated May 7, 1999 from Toronto-Dominion  (Texas) Inc. (as assignee
of Westinghouse  Electric  Corporation) and agreed to by the Company and Laidlaw
Inc. amending the terms of the Promissory Note dated May 15, 1997 (as referenced
in Exhibit (4)(r)) filed as Exhibit (4)(u) to theCompany's Form S-4 Registration
Statement  No.  333-82689  filed  July  12,  1999  and  incorporated  herein  by
reference.

(4)(t)  Guaranty  Agreement  dated May 15, 1997 by Laidlaw Inc. to  Westinghouse
Electric  Corporation  guaranteeing  Promissory  Note  dated  May 15,  1997  (as
referenced   in  Exhibit   (4)(s))   from  Company  to   Westinghouse   Electric
Corporation),  filed as Exhibit 4(o) to the Company's  Form 10-Q for the Quarter
ended May 31, 1997, and incorporated herein by reference.

(4)(u) Collateral Account Pledge and Security Agreement dated as of May 17, 1999
among the Company,  The Bank of Nova Scotia Trust Company of New York, as escrow
agent and The Bank of Nova Scotia Trust Company of New York,  as trustee,  filed
as Exhibit (4)(d) to the Company's Form S-4 Registration Statement No. 333-82689
filed July 12, 1999 and incorporated herein by reference.

(4)(v) Rights  Agreement dated as of October 15, 1999 between the
Company and EquiServe  Trust  Company,  N.A., as Rights Agent,  filed as Exhibit
(c)1 to the Company's  Current  Report on Form 8-K filed on October 15, 1999 and
incorporated herein by reference.

(4)(w) First Amendment to Rights Agreement,  dated as of March 17, 2000, between
Safety-Kleen  Corp. and Equiserve  Trust Company,  N.A. filed as Exhibit 99.1 to
the  Company's  Current  Report  on  Form  8-K  filed  on  March  17,  2000  and
incorporated herein by reference.

(4)(x) Letter Agreement,  dated October 12, 1999, between Safety-Kleen Corp. and
Laidlaw Inc.  filed as Exhibit 99.2 to the Company's  Current Report on Form 8-K
filed on March 17, 2000 and incorporated herein by reference.

(4)(y) Other instruments defining the rights of holders of nonregistered debt of
the Company  have been omitted from this exhibit list because the amount of debt
authorized  under any such instrument does not exceed 10% of the total assets of
the Company and its  subsidiaries.  The Company  agrees to furnish a copy of any
such instrument to the Commission upon request.

(10)(a) Agreement and Plan of Merger dated as of March 16, 1998 by and among the
Company,  LES Acquisition,  Inc., and Safety-Kleen Corp.  included as Annex A of
Safety-Kleen's  Revised Amended  Prospectus on Form 14D-9 filed as Exhibit 62 to
Safety-Kleen's  Amendment  No.  28 to  Schedule  14-9A on March  17,  1998,  and
incorporated herein by reference.

(10)(b) Stock  Purchase  Agreement  between  Westinghouse  Electric  Corporation
(Seller) and Rollins Environmental Services, Inc. (Buyer) for National Electric,
Inc.  dated March 7, 1995 filed as Exhibit 2 to the Company's  Current Report on
Form 8-K filed on June 13, 1995 and incorporated herein by reference.


                                    Page 13
<PAGE>


(10)(c) Second  Amendment to Stock Purchase  Agreement (as referenced in Exhibit
(10)(b)  above),  dated May 15, 1997 among  Westinghouse  Electric  Corporation,
Rollins Environmental  Services, Inc. and Laidlaw Inc., filed as Exhibit 4(m) to
the  Company's  Form 10-Q for the Quarter ended May 31, 1997,  and  incorporated
herein by reference.

(10)(d) Rollins  Environmental  Services,  Inc. 1982 Incentive Stock Option Plan
filed with Amendment No. 1 to the Company's  Registration  Statement No. 2-84139
on Form S-1 dated June 24, 1983 and incorporated herein by reference.

(10)(e) Rollins Environmental  Services,  Inc. 1993 Stock Option Plan filed with
the  Company's  Proxy  Statement  for the Annual  Meeting of  Shareholders  held
January 28, 1994 and incorporated herein by reference.

(10)(f)  Company's 1997 Stock Option Plan, filed as Exhibit 4.4 to the Company's
Registration  Statement  No.  333-41859 on Form S-8 dated  December 10, 1997 and
incorporated herein by reference.

(10)(g) First  Amendment to Company's  1997 Stock Option Plan,  filed as Exhibit
(10)(g) to the  Company's  Form 10-Q dated  January  14,  2000 and  incorporated
herein by reference.

(10)(h)  Company's  Director's  Stock Option  Plan,  filed as Exhibit 4.5 to the
Company's  Registration  Statement No.  333-41859 on Form S-8 dated December 10,
1997 and incorporated herein by reference.

(10)(i)  First  Amendment  to  Company's  Director's  Stock Option Plan filed as
Exhibit  (10)(i)  to  the  Company's  Form  10-Q  dated  January  14,  2000  and
incorporated herein by reference.

(10)(j)  Stock  Purchase  Agreement  dated  February 6, 1997 among the  Company,
Laidlaw Inc., and Laidlaw Transportation,  Inc. filed as Exhibit A to Annex A to
the  Definitive  Proxy  Statement  on Form  DEF 14A  filed  on May 1,  1997  and
incorporated herein by reference.

(10)(k)  Executive  Bonus Plan for fiscal  year 2000 filed as  Appendix C to the
Definitive  Proxy  Statement  on Form DEF 14A  filed  on  October  29,  1999 and
incorporated herein by reference.

(10)(l) Company's U.S.  Supplemental  Executive Retirement Plan filed as Exhibit
10(g) to the  Company's  10-Q for the  quarter  ended  November  30,  1997,  and
incorporated herein by reference.

(10)(m)   Form of Change of Control Agreement A-12-22.

(10)(n)    Form of Change of Control Agreement A1 RB 11 30.

(10)(o)    Form of Change of Control Agreement A2-12-22.

(10)(p)    Form of Change of Control Agreement AAMB0120.


                                    Page 14
<PAGE>


(10)(q)    Form of Change of Control Agreement B-12-22.

(10)(r)     Form of Change of Control Agreement C-12-22.

(10)(s)     Form of Change of Control Agreement D-12-22.

99.1        Press Release of April 14, 2000

     (b)      Reports on Form 8-K.

i.   The Company  filed a Current  Report on Form 8-K on January 7, 2000,  which
     contained Item 5 related to the Company  announcing  operating  results for
     the first  quarter  ended  November 30, 1999 and also  releasing  financial
     information as part of an analysts' call.

ii.  The  Company  filed a Current  Report on Form 8-K on January 19, 2000 which
     contained Item 5 related to the Company  announcing  that the Company would
     appeal a  decision  of the South  Carolina  Court of  Appeals  relating  to
     various  financial  assurance,  capacity and other issues at its  Pinewood,
     South Carolina facility.

iii. The  Company  filed a Current  Report on Form 8-K on January 26, 2000 which
     contained Item 5 related to the Company announcing the resignation of James
     R. Bullock as Chairman of the Board of  Directors  and as a Director of the
     Company.

iv.  The  Company  filed a Current  Report on Form 8-K on February 9, 2000 which
     contained Item 5 announcing that the appointment of Peter N.T.  Widdrington
     to the Board of Directors and as Chairman of the Board.

v.   The Company  filed a Current  Report on Form 8-K on February 11, 2000 which
     contained  Item 5  announcing  that the Board of  Directors  of the Company
     disbanded the Special Committee formed September 13, 1999.


                                    Page 15
<PAGE>

                                   SIGNATURES

         Pursuant to the  requirements  of the Securities  Exchange Act of 1934,
the  Company  has duly  caused  this  report to be  signed on its  behalf by the
undersigned thereunto duly authorized.

   DATE:  April 14, 2000                     SAFETY-KLEEN CORP.
                                             ------------------
                                                (Registrant)


                                           /s/ Henry H. Taylor
                                         ------------------------
                                              Henry H. Taylor
                               Vice President, General Counsel and Secretary

                                           /s/ John G. McGregor
                                         ------------------------
                                              John G. McGregor
                                      Interim Chief Financial Officer

                                    Page 16

<PAGE>

                                  EXHIBIT INDEX


(3)(a)           Restated Certificate of  Incorporation of the Company dated May
                 13, 1997 and Amendment  to Certificate of  Incorporation  dated
                 May 15, 1997 filed as Exhibit 3(a) to the  Company's  Form 10-Q
                 for the Quarter ended May 31, 1997 and  incorporated  herein by
                 reference.

(3)(a)(i)        Certificate  of Correction Filed to Correct  a Certain Error in
                 the Restated and  Amended Certificate of  Incorporation  of the
                 Company dated  October 15, 1997 filed  as Exhibit  (3)(a)(i) to
                 the Company's Form 10-K-405 for the Year ended August 31, 1997,
                 and incorporated herein by reference.

(3)(a)(ii)       Certificate  of  Amendment  to  the  Restated   Certificate  of
                 Incorporation  of the Company dated  November 25, 1998 filed as
                 Exhibit  (3)(a)(iii) to the Company's Form 10-Q for the quarter
                 ended November 30, 1998 and incorporated herein by reference.

(3)(a)(iii)      Certificate  of  Amendment  to  the  Restated   Certificate  of
                 Incorporation  of the Company dated  November 30, 1998 filed as
                 Exhibit  (3)(a)(iv) to the Company's  Form 10-Q for the quarter
                 ended November 30, 1998 and incorporated herein by reference.

(3)(b)           Amended and Restated  Bylaws of the  Company filed as Exhibit 4
                 (ii) to the Company's Current Report on Form 8-K dated July 29,
                 1997 and incorporated herein by reference.

(4)(a)           Indenture  dated  as of May  29,  1998  between  LES,  Inc.  (a
                 subsidiary of the Company),  the Company, subsidiary guarantors
                 of the Company and The Bank of Nova Scotia Trust Company of New
                 York, as trustee  filed as Exhibit 4(b) to the  Company's  Form
                 S-4  Registration  Statement No.  333-57587 filed June 24, 1998
                 and incorporated herein by reference.

(4)(b)           First Supplemental Indenture effective as of  November 15, 1998
                 among Safety-Kleen Services,  Inc. the Company, SK Europe, Inc.
                 and The Bank of Nova  Scotia  Trust  Company  of New  York,  as
                 trustee  filed as  Exhibit  (4)(f)  to the  Company's  Form S-4
                 Registration  Statement No.  333-82689  filed July 12, 1999 and
                 incorporated herein by reference.

(4)(c)           Second Supplemental Indenture effective as of May 7, 1999 among
                 Safety-Kleen Services, Inc., the Company, SK Services, L.C., SK
                 Services (East), L.C. and The Bank of Nova Scotia Trust Company
                 of  New  York,  as  trustee  filed  as  Exhibit  (4)(d)  to the
                 Company's  Form 10-K filed  October 29,  1999 and  incorporated
                 herein by reference.


                                    Page 17
<PAGE>


(4)(d)           Indenture  dated as of May 17, 1999 between the Company and the
                 Bank of Nova Scotia Trust Company of New York, as trustee filed
                 as Exhibit (4)(b) to the Company's Form S-4 Registration State-
                 ment No. 333-82689 filed July 12, 1999 and incorporated  herein
                 by reference.

(4)(e)           Registration  Rights Agreement dated as of May 17, 1999 between
                 Company and TD Securities,  NationsBanc  Montgomery  Securities
                 LLC and  Raymond  James &  Associates,  Inc.  filed as  Exhibit
                 (4)(a) to the  Company's  Form S-4  Registration  Statement No.
                 333-82689  filed  July 12,  1999  and  incorporated  herein  by
                 reference.

(4)(f)           Amended and Restated Credit Agreement among Laidlaw Chem-Waste,
                 Inc.,  Laidlaw  Environmental  Services (Canada) Ltd.,  Toronto
                 Dominion (Texas) Inc., The Toronto-Dominion Bank, TD Securities
                 (USA) Inc., The Bank of Nova Scotia, NationsBank,  N.A. and The
                 First  National  Bank  of  Chicago  and  NationsBank,  N.A.  as
                 Syndication  Agent dated as of April 3, 1998,  filed as Exhibit
                 4(f) to the Company's  Form 10-Q for the quarter ended February
                 28,  1999,  and  incorporated   herein  by  reference.   (4)(g)
                 Supplement to the Amended and Restated  Credit  Agreement among
                 Laidlaw  Chem-Waste,   Inc.,  Laidlaw  Environmental   Services
                 (Canada)   Ltd.,    Toronto    Dominion   (Texas)   Inc.,   The
                 Toronto-Dominion  Bank, TD Securities  (USA) Inc.,  The Bank of
                 Nova Scotia,  NationsBank,  N.A. and The First National Bank of
                 Chicago and NationsBank,  N.A. as Syndication Agent dated as of
                 April 3, 1998,  filed as Exhibit  4(e) to a  subsidiary  of the
                 Company's Form S-4  Registration  Statement No. 333-57587 filed
                 June 24, 1998 and incorporated herein by reference.

(4)(h)           Waiver and First  Amendment to the Amended and Restated  Credit
                 Agreement  dated as of May 15,  1998 among LES,  Inc.,  Laidlaw
                 Environmental  Services  (Canada)  Ltd.,  the Lenders,  Toronto
                 Dominion   (Texas),   Inc.,  The  Toronto   Dominion  Bank,  TD
                 Securities  (USA) Inc.,  The Bank of Nova Scotia,  NationsBank,
                 N.A.,  The First  National  Bank of Chicago and  Wachovia  Bank
                 filed as Exhibit 4(f) to a subsidiary of the Company's Form S-4
                 Registration  Statement No.  333-57587  filed June 24, 1998 and
                 incorporated herein by reference.

(4)(i)           Commitment  to Increase  Supplement to the Amended and Restated
                 Credit  Agreement  dated as of June 3, 1998  among  LES,  Inc.,
                 Laidlaw  Environmental  Services  (Canada)  Ltd.,  the Lenders,
                 Toronto Dominion  (Texas),  Inc., The Toronto Dominion Bank, TD
                 Securities  (USA) Inc.,  The Bank of Nova Scotia,  NationsBank,
                 N.A.,  The First  National  Bank of Chicago and  Wachovia  Bank
                 filed as Exhibit 4(g) to a subsidiary of the Company's Form S-4
                 Registration  Statement No.  333-57587  filed June 24, 1998 and
                 incorporated herein by reference.


                                    Page 18

<PAGE>


(4)(j)           Second  Amendment to the Amended and Restated Credit  Agreement
                 dated as of November 20, 1998 among Safety-Kleen Services, Inc.
                 (formerly known as LES, Inc.),  Safety-Kleen  Services (Canada)
                 Ltd. (formerly known as Laidlaw Environmental Services (Canada)
                 Ltd.), the Lenders, Toronto Dominion (Texas), Inc., The Toronto
                 Dominion  Bank,  TD  Securities  (USA)  Inc.,  The Bank of Nova
                 Scotia,  NationsBank,  N.A., The First National Bank of Chicago
                 and  Wachovia  Bank  N.A.,  filed  as  Exhibit  (4)(j)  to  the
                 Company's Form 10-Q for the quarter ended February 28, 1999 and
                 incorporated herein by reference.

(4)(k)           Waiver and  Third Amendment  to the Amended and Restated Credit
                 Agreement dated as of May 6, 1999 among Safety-Kleen  Services,
                 Inc.  (formerly  known  as LES,  Inc.),  Safety-Kleen  Services
                 (Canada) Ltd. (formerly known as Laidlaw Environmental Services
                 (Canada) Ltd.), the Lenders,  Toronto Dominion  (Texas),  Inc.,
                 The Toronto  Dominion Bank, TD Securities  (USA) Inc., The Bank
                 of Nova Scotia,  NationsBank,  N.A., The First National Bank of
                 Chicago and Wachovia Bank N.A.  filed as Exhibit  (4)(l) to the
                 Company's Form S-4  Registration  Statement No. 333-82689 filed
                 July 12, 1999 and incorporated herein by reference.

(4)(l)           Registration Rights Agreement  dated  May  15,  1997  among the
                 Company, Laidlaw  Transportation, Inc.  and Laidlaw  Inc.,  the
                 form  of  which  was filed  as  Exhibit  B  to  Annex A  to the
                 Company's Definitive Proxy Statement on Form DEF 14A,  filed on
                 May 1, 1997 and incorporated herein by reference.

(4)(m)           Indenture  dated  as  of May 1,  1993  between  the  Industrial
                 Development  Board of the Metropolitan  Government of Nashville
                 and Davidson  County  (Tennessee) and NationsBank of Tennessee,
                 N.A.,  filed as Exhibit 4(f) to the Company's Form 10-Q for the
                 Quarter  ended  May  31,  1997,  and  incorporated   herein  by
                 reference.

(4)(n)           Indenture of Trust dated  as of August 1, 1995  between  Tooele
                 County,  Utah and West One Bank,  Utah, now known as U.S. Bank,
                 as Trustee,  filed as Exhibit 4(h) to the  Company's  form 10-Q
                 for the Quarter ended May 31, 1997, and incorporated  herein by
                 reference.

(4)(o)           Indenture  of Trust dated  as of  July 1, 1997  between  Carbon
                 County, Utah and U.S. Bank, a national banking association,  as
                 Trustee,  filed as Exhibit 4(i) to the Company's  Form 10-Q for
                 the Quarter  ended May 31,  1997,  and  incorporated  herein by
                 reference.

(4)(p)           Indenture  of Trust  dated  as of July 1, 1997  between  Tooele
                 County, Utah and U.S. Bank, a national banking association,  as
                 Trustee,  filed as Exhibit 4(j) to the Company's  Form 10-Q for
                 the Quarter  ended May 31,  1997,  and  incorporated  herein by
                 reference.

(4)(q)           Indenture of Trust dated as of July 1, 1997 between  California
                 Pollution Control Financing Authority and U.S. Bank, a national
                 banking association,  as Trustee,  filed as Exhibit 4(k) to the
                 Company's  Form 10-Q for the Quarter  ended May 31,  1997,  and
                 incorporated herein by reference.


                                    Page 19


<PAGE>


(4)(r)           Promissory Note dated  May 15, 1997 for  $60,000,000  from  the
                 Company to Westinghouse Electric Corporation,  filed as Exhibit
                 4(n) to the  Company's  Form 10-Q for the Quarter ended May 31,
                 1997, and incorporated herein by reference.

(4)(s)           Letter dated May 7, 1999 from Toronto-Dominion (Texas) Inc. (as
                 assignee of Westinghouse Electric Corporation) and agreed to by
                 the  Company  and  Laidlaw  Inc.  amending  the  terms  of  the
                 Promissory  Note dated May 15, 1997 (as  referenced  in Exhibit
                 (4)(r))  filed as  Exhibit  (4)(u)  to the  Company's  Form S-4
                 Registration  Statement No.  333-82689  filed July 12, 1999 and
                 incorporated herein by reference.

(4)(t)           Guaranty  Agreement dated  May  15, 1997  by  Laidlaw  Inc.  to
                 Westinghouse Electric Corporation  guaranteeing Promissory Note
                 dated May 15,  1997 (as  referenced  in  Exhibit  (4)(s))  from
                 Company to Westinghouse Electric Corporation), filed as Exhibit
                 4(o) to the  Company's  Form 10-Q for the Quarter ended May 31,
                 1997, and incorporated herein by reference.

(4)(u)           Collateral  Account Pledge and  Security Agreement dated  as of
                 May 17, 1999 among the  Company, The Bank  of Nova Scotia Trust
                 Company  of New  York,  as  escrow  agent  and The Bank of Nova
                 Scotia Trust Company of New York, as trustee,  filed as Exhibit
                 (4)(d) to the  Company's  Form S-4  Registration  Statement No.
                 333-82689  filed  July 12,  1999  and  incorporated  herein  by
                 reference.

(4)(v)           Rights  Agreement  dated  as of  October 15, 1999  between  the
                 Company and EquiServe  Trust  Company,  N.A., as  Rights Agent,
                 filed  as Exhibit (c)1 to the Company's  Current Report on Form
                 8-K  filed  on  October  15,  1999 and  incorporated  herein by
                 reference.

(4)(w)           First Amendment to Rights Agreement,dated as of March 17, 2000,
                 between  Safety-Kleen  Corp. and Equiserve Trust Company,  N.A.
                 filed as Exhibit 99.1 to the Company's  Current  Report on Form
                 8-K  filed  on  March  17,  2000  and  incorporated  herein  by
                 reference.

(4)(x)           Letter Agreement, dated October 12, 1999, between  Safety-Kleen
                 Corp.  and Laidlaw Inc.  filed as Exhibit 99.2 to the Company's
                 Current  Report  on Form  8-K  filed  on  March  17,  2000  and
                 incorporated herein by reference.

(4)(y)           Other   instruments   defining   the   rights  of   holders  of
                 nonregistered  debt of the Company  have been omitted from this
                 exhibit  list because the amount of debt  authorized  under any
                 such  instrument does not exceed 10% of the total assets of the
                 Company and its  subsidiaries.  The Company agrees to furnish a
                 copy of any such instrument to the Commission upon request.

(10)(a)          Agreement and Plan of Merger dated  as of March 16, 1998 by and
                 among  the  Company,  LES  Acquisition, Inc., and  Safety-Kleen
                 Corp. included  as  Annex A  of Safety-Kleen's  Revised Amended
                 Prospectus on Form 14D-9 filed as Exhibit 62 to  Safety-Kleen's
                 Amendment  No.  28 to  Schedule  14-9A on March 17,  1998,  and
                 incorporated herein by reference.


                                    Page 20
<PAGE>


(10)(b)          Stock   Purchase  Agreement   between   Westinghouse   Electric
                 Corporation (Seller) and Rollins Environmental  Services,  Inc.
                 (Buyer) for National  Electric,  Inc. dated March 7, 1995 filed
                 as Exhibit 2 to the Company's  Current Report on Form 8-K filed
                 on June 13, 1995 and incorporated herein by reference.

(10)(c)          Second Amendment to Stock Purchase  Agreement (as referenced in
                 Exhibit (10)(b) above),  dated May 15, 1997 among  Westinghouse
                 Electric Corporation,  Rollins Environmental Services, Inc. and
                 Laidlaw Inc.,  filed as Exhibit 4(m) to the Company's Form 10-Q
                 for the Quarter ended May 31, 1997, and incorporated  herein by
                 reference.

(10)(d)          Rollins  Environmental  Services,  Inc.  1982  Incentive  Stock
                 Option  Plan  filed  with  Amendment  No.  1 to  the  Company's
                 Registration  Statement No.  2-84139 on Form S-1 dated June 24,
                 1983 and incorporated herein by reference.

(10)(e)          Rollins  Environmental  Services, Inc. 1993  Stock Option  Plan
                 filed with the Company's Proxy Statement for the Annual Meeting
                 of Shareholders  held January 28, 1994 and incorporated  herein
                 by reference.

(10)(f)          Company's 1997 Stock  Option Plan, filed as Exhibit 4.4 to  the
                 Company's  Registration  Statement  No.  333-41859  on Form S-8
                 dated December 10, 1997 and incorporated herein by reference.

(10)(g)           First Amendment to Company's  1997 Stock Option Plan, filed as
                 Exhibit  (10)(g) to the  Company's  Form 10-Q dated January 14,
                 2000 and incorporated herein by reference.

(10)(h)          Company's  Director's  Stock  Option  Plan,  filed  as  Exhibit
                 4.5 to the Company's  Registration  Statement No.  333-41859 on
                 Form S-8 dated  December  10, 1997 and  incorporated  herein by
                 reference.

(10)(i)          First Amendment to Company's Director's Stock Option Plan filed
                 as Exhibit (10)(i) to the Company's Form 10-Q dated January 14,
                 2000 and incorporated herein by reference.


(10)(j)          Stock  Purchase  Agreement  dated  February 6, 1997  among  the
                 Company,  Laidlaw Inc., and Laidlaw Transportation,  Inc. filed
                 as Exhibit A to Annex A to the  Definitive  Proxy  Statement on
                 Form DEF 14A  filed on May 1, 1997 and  incorporated  herein by
                 reference.

(10)(k)          Executive Bonus  Plan for  fiscal year 2000 filed as Appendix C
                 to the  Definitive  Proxy  Statement  on Form DEF 14A  filed on
                 October 29, 1999 and incorporated herein by reference.


                                    Page 21
<PAGE>


(10)(l)          Company's U.S.  Supplemental Executive Retirement Plan filed as
                 Exhibit  10(g)  to the  Company's  10-Q for the  quarter  ended
                 November 30, 1997, and incorporated herein by reference.

(10)(m)          Form of Change of Control Agreement A-12-22.

(10)(n)          Form of Change of Control Agreement A1 RB 11 30.

(10)(o)          Form of Change of Control Agreement A2-12-22.

(10)(p)          Form of Change of Control Agreement AAMB0120.

(10)(q)          Form of Change of Control Agreement B-12-22.

(10)(r)          Form of Change of Control Agreement C-12-22.

(10)(s)          Form of Change of Control Agreement D-12-22.

99.1             Press Release of April 14, 2000


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