Exhibit (4)(a)
                                        Ninth Amendment dated 1/14/02 to A&R DIP



                  NINTH WAIVER (this "WAIVER") dated as of January 14, 2002, 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 (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 waive 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  waiver  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. Waiver.  Section 4.3(a) of the Credit Agreement  provides that, if
at any time during the Commitment Period,  the sum of the aggregate  outstanding
Loans and L/C Obligations  exceeds the Borrowing Base, the Borrower shall pay to
the General  Administrative  Agent an amount equal to such  excess.  The General
Administrative  Agent and the Lenders  hereby waive such  requirement  until the
earlier of January 31, 2002 and the date, if any, the Borrowing Base falls below
$68,000,000,  provided  that,  as long as the sum of the  aggregate  outstanding
Loans and L/C  Obligations  exceeds the Borrowing  Base,  the Borrower  shall be
prohibited from requesting any additional  extensions of credit under the Credit
Agreement, except for a letter of credit in the approximate amount of $2,000,000
for the benefit of Blue  Cross/Blue  Shield which has previously  been discussed
with the General Administrative Agent.

           3. Conditions to Effectiveness. This Waiver shall become effective as
of the date first above  written  when each of the Required  Lenders  shall have
executed and delivered this Waiver.

           4. 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.



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           5. Fees and  Expenses.  The  Borrower  agrees to (i) pay the  General
Administrative  Agent for the account of each Lender a fee in the amount of .25%
of the  Revolving  Credit  Facility  and  (ii)  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 Waiver, including the reasonable fees and expenses of counsel.

           6.  Counterparts.  This  Waiver  may be  executed  on any  number  of
separate  counterparts  and all of said  counterparts  taken  together  shall be
deemed to constitute one and the same instrument.

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



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           IN WITNESS WHEREOF,  the parties hereto have caused this Waiver 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



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                                  TORONTO DOMINION (TEXAS), INC.,
                                    as General Administrative Agent, Underwriter
                                    and Lender


                                  By:
                                      ------------------------------
                                      Name:
                                      Title:


                                  THE TORONTO-DOMINION BANK,
                                  HOUSTON AGENCY
                                    as Issuing Lender


                                  By:
                                      -------------------------------
                                      Name:
                                      Title:

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


                                     By:
                                         ----------------------------------
                                          Name:
                                          Title:













                            Signature Page to Waiver

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<PAGE>

                                        GSCP RECOVERY, INC.


                                        By:
                                            --------------------------
                                             Name:
                                             Title:












                           Signature Page to Waiver

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                                   GSCP RECOVERY II, L.P.

                                   By:  GSC Recovery II GP, L.P.,
                                        its general partner

                                         By:  GSC RII, LLC, its general partner

                                              By: GSCP (NJ) Holdings, L.P.,
                                                  its sole member

                                                   By: GSCP (NJ), Inc.,
                                                       its general partner

                                                   By:
                                                      ------------------------
                                                       Name:
                                                       Title:














                           Signature Page to Waiver

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                                     BANK ONE, NA


                                     By:
                                        ---------------------------------
                                         Name:
                                         Title:











                           Signature Page to Waiver

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                                     GOLDMAN SACHS CREDIT PARTNERS, L.P.


                                     By:
                                         -----------------------------------
                                         Name:
                                         Title:











                           Signature Page to Waiver

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                                   SENIOR DEBT PORTFOLIO
                                   By Boston Management and Research, as Advisor


                                   By:
                                       ------------------------------------
                                       Name:
                                       Title:












                           Signature Page to Waiver

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