FOURTH  AMENDMENT,  AGREEMENT  AND  WAIVER, dated as of April 30, 2001
(this  "Amendment"),  to  the  Amended  and Restated Debtor in Possession Credit
        ---------
Agreement,  initially  dated as of June 11,2000, amended and restated as of July
19,  2000 (as amended, supplemented or otherwise modified from time to time, the
"Credit  Agreement")  among  SAFETY-KLEEN SERVICES, INC., a Delaware corporation
 ------  ----------
(the  "Borrower"),  the  financial  institutions  or  entities from time to time
parties  to  this  Agreement (the "Lenders"), THE TORONTO-DOMINION BANK, HOUSTON
AGENCY,  as  letter  of  credit  issuing  bank  (the  "Issuing Lender"), TORONTO
 -                                                     ----------------
DOMINION  (TEXAS),  INC.,  as  administrative agent (the "General Administrative
                                                          ------- --------------
Agent"),  and  THE  CIT GROUP/BUSINESS CREDIT, INC. ("CIT"), as collateral agent
------
and  underwriter  (the  "Collateral  Agent";  collectively  with  the  General
                         ------------------
Administrative  Agent,  the  "Underwriters").
 -                            --------------


                              W I T N E S S E T H:
                              --------------------

          WHEREAS,  the  Borrower  has requested that the General Administrative
Agent  and the Lenders agree to amend certain provisions of the Credit Agreement
upon  the  terms  and  subject  to  the  conditions  set  forth  herein;  and

          WHEREAS,  the General Administrative Agent and the Lenders have agreed
to  such  amendments only upon the terms and subject to the conditions set forth
herein.

          NOW,  THEREFORE,  in  consideration  of  the  premises  and the mutual
covenants  contained  herein  and  in  the  Credit Agreement, the parties hereto
hereby  agree  as  follows:

          1.     Defined Terms. Unless otherwise defined herein, all capitalized
                 -------------
terms used herein shall have the meanings given to them in the Credit Agreement.

          2.     Amendment  of  Section 1.1. Section 1.1 of the Credit Agreement
                 -------------  -----------
is  hereby  amended  by

          (a)  inserting  the  following  new  definition  in  its  appropriate
               alphabetical  order:

               "Marketing  Book":  a marketing book for the sale of the Debtors'
                ---------------
          chemical  services  segment  (as  such  segment  is  more  thoroughly
          described  in the Debtors' presentation to the Lenders on December 20,
          2000), prepared by the Debtors' financial advisors and satisfactory in
          form and substance to the Underwriters in their reasonable discretion.


          (b)  replacing  the  definitions  of "Business  Plan" and "Termination
                                                --------------       -----------
               Date"  in  their  entireties,  respectively,  as  follows:
               ----

               "Business  Plan":  a  business  plan and related financial models
                --------------
          with  respect to the Debtors' branch sales and service business (i.e.,
          the  route-based  business),  prepared  by the Debtors with reasonable
          consultation  with  the  official  committee  of  unsecured  creditors
          appointed  in  the  Cases, to be satisfactory in form and substance to
          the  Underwriters  in  their  reasonable discretion including, without


<PAGE>
          limitation,  in  respect  of the areas identified by the Underwriters'
          financial advisors from time to time; provided, that the Business Plan
          need  not  include  a  valuation  of  the  Debtors'  businesses.


               "Penalty  Fee":  as  defined  in  Section  4.15.
               -------  ----

               "Termination Date": the earlier to occur of (a) January 31, 2002;
                ----------------
          (b)  the  effective  date  of  a  Plan  of Reorganization; and (c) the
          earlier  termination of the Revolving Credit Commitments in accordance
          with  the  terms  hereof.


          3.     Amendment  of  Section  4. Section 4 of the Credit Agreement is
                 ------------------------
hereby  amended  by  adding  the  following  new  Section  4.15:

               "4.15  Penalty  Fee. If the Debtors fail to timely deliver any of
                      ------------
          the  financial  statements  or  other  documents  required by Sections
          7.1(d),  7.11  or  7.12,  the  Borrower  agrees to pay, to the General
          Administrative  Agent,  for  the ratable benefit of the Lenders, a fee
          equal  to  $1,000,000  (the  "Penalty  Fee"). The Penalty Fee shall be
                                        ------------
          payable  irrespective  of  whether  the  General  Administrative Agent
          delivers  a  notice  of Default or Event of Default in respect of such
          failure,  and  acceptance  by  the General Administrative Agent of the
          Penalty  Fee shall not operate as a waiver of any right, remedy, power
          or  privilege  hereunder  or  under  the  Loan  Documents."

          4.     Amendment  of  Section 7.1. Section 7.1 of the Credit Agreement
                 --------------------------
is  hereby  amended  by

          (a)     replacing the  phrase  "commencing  on the  Audited  Financial
Statements  Delivery  Date"  with the phrase "commencing with the fiscal quarter
ending  November  30,  2001"  in  Section  7.1(c);  and

          (b)     deleting  Section 7.1(d) in its entirety and replacing it with
the  following  new  Section  7.1(d):

               "(d) (i) as soon as available, but in any event by June 30, 2001,
          copies  of the audited consolidated balance sheets of Holdings and its
          consolidated  subsidiaries  and the related consolidated statements of
          income  and  retained  earnings  and  cash  flows  of Holdings and its
          consolidated subsidiaries, for the years ended August 31, 1997, August
          31,  1998,  August  31,  1999  and  August  31, 2000, setting forth in
          comparative  form  in each case (other than with respect to the fiscal
          year  ending  August  31,  1997)  the  figures  for the previous year,
          reported  on  without  a qualification arising out of the scope of the
          audit,  by  Arthur  Andersen  or  other  independent  certified public
          accountants  of  nationally  recognized  standing,  and  consolidating
          schedules  and  supporting  analysis  in form and substance reasonably
          satisfactory to the Underwriters (collectively, the "Audited Financial
                                                               -----------------
          Statements")  and  (ii)  (A) as soon as available, but in any event by
          ----------
          August  22,2001,  preliminary  drafts  of  the  unaudited consolidated
          statements  of  income  and  retained  earnings  and  of cash flows of
          Holdings  and  its  consolidated  subsidiaries for the fiscal quarters
          ending  November  30, 2000, February 28, 2001 and May 31, 2001 and (B)
          as  soon  as  available, but in any event by September 15, 2001, final
          versions  of  the  unaudited  consolidated  statements  of  income and
          retained  earnings  and of cash flows of Holdings and its consolidated
          subsidiaries  for  the  fiscal  quarters  ending  November  30,  2000,


<PAGE>
          February  28,  2001  and  May  31, 2001, in each case setting forth in
          comparative  form  the  figures  for  the  previous year to the extent
          available, and consolidating schedules and supporting analysis in form
          and  substance  satisfactory  to  the  Underwriters,  certified  by  a
          Responsible  Officer  as  being fairly stated in all material respects
          (subject  to  normal  year-end  audit  adjustments);".

          5.     Amendment  of  Section  7.2(d).  Section  7.2(d)  of the Credit
                 ---------  --  -------
Agreement is hereby amended by replacing Section 7.2(d) in its entirety with the
following  new  Section  7.2(d);

               "(d)  as  soon  as  available,  but  no  later than the twentieth
          Business  Day  of  each fiscal month, commencing on October 26,2001, a
          report setting forth the calculations demonstrating compliance (or the
          failure  to comply) with the covenants established pursuant to Section
          7.11  for the immediately preceding fiscal month, in a form reasonably
          satisfactory  to  the  General  Administrative  Agent;"


          6.     Amendment  of  Section  7.11.  replacing  Section  7.11  in its
                 -------------  -------------
entirety  as  follows:

               "7.11  Financial  Condition  Covenants.  On  or before August 15,
                      -------------------------------
          2001,  the Borrower shall provide each Lender with a copy of the final
          Business  Plan and the revised business plan for the chemical services
          segment.  The  Borrower  shall afford the General Administrative Agent
          and  the  Underwriters  full  opportunity  to conduct due diligence in
          respect thereof. The General Administrative Agent and the Underwriters
          shall  negotiate  in  good  faith  such financial covenants (including
          capital expenditure limitations) as they may deem appropriate in their
          sole  discretion.  On or before September 15, 2001, the Borrower shall
          execute  and  deliver to the General Administrative Agent an amendment
          in form and substance satisfactory to the General Administrative Agent
          and  the  Underwriters,  containing  the  above-referenced  financial
          covenants."

          7.     Amendment  of  Section  7. Section 7 of the Credit Agreement is
                 ---------  --  ----------
hereby  amended  by  adding  the  following  new  Section  7.12:

               "7.12  Marketing  Book.  On or before August 31,2001, the Debtors
                      ---------------
          shall  deliver  to  the  Underwriters a copy of the Marketing Book and
          commence distribution to the potential acquirers or strategic partners
          recommended  by  the  Debtors'  financial  advisors."

          8.     Amendment  of  Section  9. Section 9 of the Credit Agreement is
                 -------------  -------  -
hereby  amended  by

         (a)     replacing  Section  9(p)  and  9(q)  in  their  entireties,
respectively, as  follows:


<PAGE>
               "(p)  the  Borrower  shall  have  failed  to  (i)  deliver to the
          Underwriters  by  August  31,2001, the Marketing Book, (ii) deliver to
          the  Underwriters  by  August 15,2001, the final Business Plan and the
          revised  business  plan  for  the  chemical  services segment or (iii)
          deliver to the Underwriters, by August 31, 2001, a preliminary Plan of
          Reorganization;  or"

               "(q)  the  Borrower  shall  have  failed  to (i) after reasonable
          consultation  with  the  General Administrative Agent and the Steering
          Committee's  advisors,  engage,  by June 21, 2001, an executive search
          firm reasonably acceptable to the General Administrative Agent and the
          Steering  Committee's  advisors  to assist the Borrower in identifying
          candidates  for  and  hiring a Chief Executive Officer of Safety-Kleen
          Corp.  (the  "Chief  Executive  Officer")  or  (ii)  after  reasonable
                        -------------------------
          consultation  with  the  General Administrative Agent and the Steering
          Committee's  advisors,  hire,  by  October 31, 2001, a Chief Executive
          Officer  reasonably acceptable to the General Administrative Agent and
          the  Steering  Committee's  advisors, provided, that this Section 9(q)
                                                --------
          shall  terminate  and  be  of  no  force and effect upon and after the
          hiring  of  a  Chief  Executive  Officer;  or"


          (b)     adding  the  following  new  Section  9(r):

               "(r)  all  conditions  precedent  to effectiveness of the Plan of
          Reorganization  shall  not  have  been  satisfied by January 31,2002;"


          9.     Waiver.  The Required Lenders hereby waive any Default or Event
                 ------
of  Default  that  occurred  by  virtue  of  the Debtors' failure to satisfy the
requirements  of(i)  Section  7.1  (d)(i) and (ii) Section 9(q) as such Sections
were  in  effect  prior  to  this  Amendment.

          10.     Representations  and  Warranties.  After giving effect to this
                  --------------------------------
Amendment,  the  Borrower  hereby  represents  and  warrants  that  all  of  the
representations  and  warranties  contained in the Credit Agreement are true and
correct  in all material respects as of the date hereof (unless stated to relate
to  a  specific  earlier date, in which case such representations and warranties
shall  be true and correct in all material respects as of such earlier date) and
that  no  Default  or  Event  of  Default  has  occurred  and  is  continuing.

          11.     Expenses. The Borrower agrees to pay and reimburse the General
                  --------
Administrative  Agent for all of its reasonable out-of-pocket costs and expenses
incurred  in  connection  with  the  negotiation,  preparation,  execution,  and
delivery  of  this  Amendment,  including  the  reasonable  fees and expenses of
counsel.

          12.     Effectiveness.  This  Amendment  shall become effective on the
                  -------------
date  upon  which  the  General  Administrative  Agent  shall  have  received
counterparts  hereof  duly  executed  by  the Borrower and the Required Lenders.

          13.     Continuing  Effects.  Except  as  expressly  waived or amended
                  ----------  -------
hereby, the Credit Agreement shall continue to be and shall remain in full force
and  effect  in  accordance  with  its  terms.


<PAGE>
          14.     Counterparts.  This  Amendment  may be executed by the parties
                  ------------
hereto on one or more counterparts, and all of such counterparts shall be deemed
to  constitute  one  and the same instrument. This Amendment may be delivered by
facsimile  transmission  of  the  relevant  signature  pages  hereof.

          15.     GOVERNING  LAW.  THIS  AMENDMENT  SHALL  BE  GOVERNED  BY, AND
                  ---------  ---
CONSTRUED  AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.


          IN  WITNESS  WHEREOF, the parties hereto have caused this Amendment to
be  duly  executed and delivered by their proper and duly authorized officers as
of  the  day  and  year  first  above  written.


                                    SAFETY-KLEEN  SERVICES,  INC.

                                    By:  /S/ Larry W.Singleton
                                    ----------------------------------------
                                    Name:  Larry W.Singleton
                                    Title: CFO
                                    Date: 06/22/2001


<PAGE>
                                  TORONTO  DOMINION  (TEXAS),  INC,
                                    as General Administrative Agent, Underwriter
                                    and  Lender

                                    By:  /S/ Jano Mott
                                    ----------------------------------------
                                    Name:  Jano Mott
                                    Title: Vice President



                                  THE  TORONTO-DOMINION  BANK,
                                  HOUSTON  AGENCY
                                    as  Issuing  Lender

                                    By:  /S/ Jano Mott
                                    ----------------------------------------
                                    Name:  Jano Mott
                                    Title: Mgr. Syndications & Credit Admin.



<PAGE>
                                  THE CIT GROUP/BUSINESS CREDIT, INC.
                                  as Collateral Agent, Underwriter and Lender

                                    By:  /S/ Mark J. Long
                                    ----------------------------------------
                                    Name:  Mark J. Long
                                    Title: Vice President


<PAGE>
                                  BANK ONE, NA


                                    By:  /S/ Richard Babcock
                                    ----------------------------------------
                                    Name:  Richard Babcock
                                    Title: First Vice President


<PAGE>
                                  BANK OF AMERICA, N.A.


                                    By:  /S/ William Crawford
                                    ----------------------------------------
                                    Name:  William Crawford
                                    Title: Managing Director


<PAGE>
                                  GOLDMAN SACHS CREDIT PARTNERS, L.P.


                                    By:  /S/ Kevin Ulrich
                                    ----------------------------------------
                                    Name:  Kevin Ulrich
                                    Title: Authorized Signatory


<PAGE>
                                  SENIOR DEBT PORTFOLIO
                                  By Boston Management and Research, as
                                  Investment Advisor


                                    By:  /S/ Payson F. Swaffield
                                    ----------------------------------------
                                    Name:  Payson F. Swaffield
                                    Title: Vice President


<PAGE>