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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
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                                 SCHEDULE 14D-9
 
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                 SOLICITATION/RECOMMENDATION STATEMENT PURSUANT
                           TO SECTION 14(D)(4) OF THE
                        SECURITIES EXCHANGE ACT OF 1934
 
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                               SAFETY-KLEEN CORP.
                           (NAME OF SUBJECT COMPANY)
 
                               SAFETY-KLEEN CORP.
                     (NAMES OF PERSON(S) FILING STATEMENT)
 
                    COMMON STOCK, PAR VALUE $0.10 PER SHARE
            (INCLUDING THE ASSOCIATED COMMON SHARE PURCHASE RIGHTS)
                         (TITLE OF CLASS OF SECURITIES)
 
                                   786484105
                     (CUSIP NUMBER OF CLASS OF SECURITIES)
 
                              DONALD W. BRINCKMAN
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                               ONE BRINCKMAN WAY
                           ELGIN, ILLINOIS 60123-7857
                                 (847) 697-8460
 
                 (NAME, ADDRESS AND TELEPHONE NUMBER OF PERSON
                AUTHORIZED TO RECEIVE NOTICES AND COMMUNICATIONS
                  ON BEHALF OF THE PERSON(S) FILING STATEMENT)
 
                               ----------------
 
                                WITH A COPY TO:
                             DENNIS N. NEWMAN, ESQ.
                         SONNENSCHEIN NATH & ROSENTHAL
                                  SEARS TOWER
                            CHICAGO, ILLINOIS 60606
                                 (312) 876-8000
 
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  ITEM 1. SECURITY AND SUBJECT COMPANY.
 
  The name of the subject company is Safety-Kleen Corp., a Wisconsin
corporation ("Safety-Kleen"). The address of the principal executive offices
of Safety-Kleen is One Brinckman Way, Elgin, Illinois 60123. The title of the
class of equity securities to which this Statement relates is the common
stock, par value $0.10 per share (the "Common Stock"), of Safety-Kleen,
including the associated common share purchase rights (the "Rights") issued
pursuant to the Rights Agreement, dated as of November 9, 1988, as amended
(the "Rights Agreement"), between Safety-Kleen and The First National Bank of
Chicago, as Rights Agent. References herein to the "Shares" means shares of
the Common Stock and shall, unless the context requires otherwise, include the
Rights.
 
ITEM 2. TENDER OFFER OF THE BIDDER.
 
  This Statement relates to the offer made by LES Acquisition, Inc. (the
"Offeror"), a Delaware corporation and wholly-owned subsidiary of Laidlaw
Environmental Services, Inc., a Delaware corporation ("LLE"), to exchange
$15.00 net in cash (subject to reduction as described below, the "Cash
Consideration") and that number of shares of common stock, par value $1.00 per
share, of LLE (the "LLE Common Stock") equal to the Exchange Ratio (as defined
below) (the "Stock Consideration" and, together with the Cash Consideration,
the "LLE Offer Consideration"), for each outstanding Share, upon the terms and
subject to the conditions disclosed in Amendment No. 2 to the Registration
Statement on Form S-4 filed by LLE with the Securities and Exchange Commission
(the "Commission") on December 16, 1997 (the "LLE Registration Statement").
Neither the Offeror nor any of its affiliates are affiliated with Safety-Kleen
and the LLE Offer was not solicited by Safety-Kleen.
 
  According to the LLE Registration Statement, the Cash Consideration to be
paid pursuant to the LLE Offer shall be reduced by the quotient of (a) the
aggregate amount of (1) any termination fees or expenses paid or reimbursed
(or payable or reimbursable) by Safety-Kleen pursuant to the Agreement and
Plan of Merger, dated as of November 20, 1997 (the "Philip Merger Agreement"),
by and among SK Parent Corp. ("SK Parent"), SK Acquisition Corp. ("SK
Acquisition") and Safety-Kleen and (2) any incremental costs, including the
cost of new severance arrangements and other expenses Safety-Kleen may incur
in connection with the Philip Merger Agreement divided by (b) the number of
outstanding Shares (on a fully diluted basis) as of the expiration date of the
LLE Offer. LLE has estimated in solicitng materials filed with the Commission
that the portion of the deductions from the Cash Consideration for such
termination fees and expenses and such severance agreements is up to $2.14 per
Share.
 
  According to the LLE Registration Statement, the "Exchange Ratio" means the
quotient (rounded to the nearest 1/100,000) determined by dividing $15.00 by
the weighted average trading prices for LLE Common Stock (as reported on the
New York Stock Exchange Inc. (the "NYSE") Composite Transactions reporting
system as published in The Wall Street Journal or, if not published therein,
in another authoritative source) for ten NYSE trading days (each, a "Trading
Day") selected by lot from the twenty Trading Days ending three business days
immediately prior to the expiration date of the LLE Offer, provided, that the
Exchange Ratio shall not be less than 2.80 nor greater than 3.50.
 
  According to the LLE Registration Statement: (i) the purpose of the LLE
Offer is for LLE to obtain control of, and ultimately the entire equity
interest in, Safety-Kleen; (ii) LLE presently intends, as soon as practicable
after consummation of the LLE Offer, to propose and seek to have Safety-Kleen
effect a merger of the Offeror with and into Safety-Kleen; and (iii) the
consideration per Share in such merger would be identical to the LLE Offer
Consideration.
 
  Shareholders should be aware that if Safety-Kleen is a "resident domestic
corporation" for purposes of the Wisconsin Statutes (which Safety-Kleen
believes it is), then unless LLE acquires beneficial ownership of at least 90%
of the outstanding Shares, the subsequent merger of the Offeror into Safety-
Kleen would have to be approved by both (a) the holders of at least 80% of the
outstanding Shares and (b) the holders of 66 2/3% of the

 
outstanding Shares not held by LLE or its affiliates, unless certain fair price
standards are satisfied. There can be no assurance that LLE would obtain the
required shareholder approval or that the LLE Offer Consideration would satisfy
those fair price standards (see "Item 8. Additional Information To Be
Furnished--(c) State Takeover Statutes" below).
 
  LLE has filed proxy materials with the Commission relating to the
solicitation of proxies by LLE and the Offeror for use at a special meeting of
shareholders of Safety-Kleen to be held on January 9, 1998 to consider
shareholder approval of a proposal to authorize, in accordance with Section
180.1150 of the Wisconsin Statutes, the restoration of full voting power to any
and all Shares acquired by LLE and the Offeror (or one or more subsidiaries of
LLE). For a description of Section 180.1150 of the Wisconsin Statutes, see
"Item 8. Additional Information To Be Furnished--(c) State Takeover Statutes."
 
  According to the LLE Registration Statement, the address of the principal
executive offices of the Offeror and LLE is 1301 Gervais Street, Suite 300,
Columbia, South Carolina 29201.
 
  THIS SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9 DOES NOT
CONSTITUTE A SOLICITATION OF PROXIES FOR USE AT ANY MEETING OF SAFETY-KLEEN'S
SHAREHOLDERS OR OTHERWISE. ANY SUCH SOLICITATION WHICH SAFETY-KLEEN MAY MAKE
WILL BE MADE ONLY BY MEANS OF SEPARATE PROXY MATERIALS COMPLYING WITH THE
REQUIREMENTS OF SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934, AS
AMENDED, AND THE RULES AND REGULATIONS PROMULGATED THEREUNDER.
 
ITEM 3. IDENTITY AND BACKGROUND.
 
  (a) The name and business address of Safety-Kleen, which is the person filing
this Statement, are set forth in Item 1 above.
 
  (b)(1) General. Reference is made to the information contained under the
captions "DIRECTORS' COMMITTEES, MEETINGS AND COMPENSATION--Board
Compensation," "EXECUTIVE COMPENSATION--Summary Compensation Table," "--
Option/SAR Grants In Last Fiscal Year," "--Pension Plan," "--Employment
Contracts And Severance Arrangements," "--Compensation Committee Report or
Executive Compensation" and "CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS" in
Safety-Kleen's Proxy Statement, dated March 28, 1997, relating to Safety-
Kleen's Annual Meeting of Shareholders. The relevant sections thereof are filed
as Exhibit 1 hereto and are incorporated herein by reference. The severance
agreements described under "--Employment Contracts and Severance Arrangements"
in Exhibit 1 have been replaced by new Change of Control Severance Agreements
described below. Reference is also made to the information under the caption
"SHARE OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT" filed herewith as
Exhibit 2 and incorporated herein by reference. Except as described herein or
incorporated herein by reference, to the knowledge of Safety-Kleen as of the
date hereof, there are no contracts, agreements, arrangements or understandings
or any actual or potential conflicts of interest between Safety-Kleen or its
affiliates and (i) Safety-Kleen, its executive officers, directors or
affiliates or (ii) LLE or the Offeror or their respective executive officers,
directors or affiliates.
 
  The Philip Merger. On November 20, 1997, Safety-Kleen signed the Philip
Merger Agreement, providing for the merger (the "Philip Merger") of SK
Acquisition with and into Safety-Kleen. SK Parent is a newly-formed company
owned equally by Philip Services Corp. ("Philip"), affiliates of Apollo
Management, L.P. ("Apollo") and affiliates of Blackstone Management Partners
III L.L.C. ("Blackstone").
 
  In the Philip Merger, each holder of a Share will receive $27.00 cash for
that Share. Upon completion of the Philip Merger, Safety-Kleen will be the
surviving corporation (the "Surviving Corporation") and will be a wholly-owned
subsidiary of SK Parent. Upon consummation of the Philip Merger, which is a
taxable transaction to shareholders, Safety-Kleen shareholders will no longer
have an interest in the Surviving Corporation.
 
  On December 22, 1997, Safety-Kleen announced that a special meeting of
shareholders of Safety-Kleen will be held on February 11, 1998 to vote on the
Philip Merger.
 
                                       2

 
  The Philip Merger is subject to certain conditions, including the approval
of Safety-Kleen's shareholders at a special meeting to be held as soon as
practicable, the expiration of antitrust regulatory waiting periods and the
funding of financing arrangements.
 
  The Philip Merger Agreement includes provisions prohibiting Safety-Kleen
from actively soliciting another purchaser, and provides for the payment of
certain fees and the reimbursement of certain expenses to SK Parent in the
event of a termination of the Philip Merger Agreement under certain
circumstances.
 
  The foregoing description of the Philip Merger Agreement does not purport to
be complete and is qualified in its entirety by reference to the Philip Merger
Agreement filed as Exhibit 3 hereto and incorporated herein by reference.
 
  (b)(2) Certain Executive Compensation and Other Employee-Related Matters in
Connection with a Change of Control of Safety-Kleen. The consummation of
either the Philip Merger or the LLE Offer will affect the compensation and
benefits to the directors and executive officers of Safety-Kleen as follows:
 
  Vesting of Stock Options. All of the outstanding stock options to purchase
Shares granted by Safety-Kleen (including stock options related to limited
stock appreciation rights) immediately vest and become exercisable upon a
"change of control", which would occur upon consummation of either the Philip
Merger or the LLE Offer. In addition, within three days of a "change of
control" of Safety-Kleen, holders of options related to limited stock
appreciation rights may receive for each Share subject to such option, an
amount in cash equal to the excess, if any, of the change of control value
(generally, the highest price at which the Shares trade in the 180 days prior
to such change of control) over the per Share exercise price of such option,
reduced by the amount of withholding or other taxes required by law to be
withheld. As of December 19, 1997, directors and executive officers held in
the aggregate options to purchase 2,446,265 Shares (including 2,251,265
options related to limited stock appreciation rights).
 
  Change of Control Severance Agreements. In August, 1997, Safety-Kleen
entered into Change of Control Severance Agreements with its 14 executive
officers and five other employees of Safety-Kleen who are not executive
officers. The Board of Directors of Safety-Kleen approved the Change of
Control Severance Agreements in order to close the gap between the prior
change of control agreements adopted by Safety-Kleen in 1990 and current
competitive practices for change of control agreements. Each Change of Control
Severance Agreement provides for, among other things: (a) a three-year
employment period, beginning on the date of a Change of Control (as defined in
such agreements; a Change of Control would occur upon consummation of either
the Philip Merger or the LLE Offer) at a guaranteed annual base salary equal
to at least 12 times the highest base monthly salary payable during the 12-
month period immediately preceding the Change of Control, with increases
consistent with increases in base salary awarded to other peer executives of
Safety-Kleen; (b) a guaranteed bonus for each bonus plan performance period
(under each bonus arrangement) ending within such three year employment
period; (c) continued participation in the incentive, savings, retirement,
welfare and other fringe benefit plans sponsored by Safety-Kleen; (d) full
vesting on the date of the Change of Control of all stock options (or a lump
sum payment of the spread of all non-vested, forfeited options); and (e) full
payment on the date of the Change of Control, of the value of the executive's
accrued benefits under Safety-Kleen's excess benefit and supplemental
retirement plans.
 
  If, during the three year employment period, the executive's employment is
terminated by Safety-Kleen (other than for Cause (as defined in such
agreements) or by reason of the executive's death or disability), or if the
executive terminates employment for Good Reason (as defined in such
agreements), the executive will receive: (i) guaranteed annual base salary,
guaranteed bonus and accrued vacation pay through the date of termination;
(ii) previously deferred and unpaid compensation; (iii) an amount equal to
three times the sum of the executive's guaranteed base salary and guaranteed
bonus in the year in which the termination occurs; (iv) the value of the
unvested portion of the executive's accounts under qualified Safety-Kleen
plans, (v) reimbursement for unpaid benefits which would have accrued if the
executive had remained employed by Safety-Kleen until three years after the
Change of Control under Safety-Kleen's excess benefit and supplemental plans;
and (vi) continuation of all medical, life insurance and other welfare
benefits for a period of three years from termination. The sum of the amounts
referred to in clauses (i) and (ii) is referred to as the "Accrued
Obligations".
 
                                       3

 
  If, during the three year employment period, the executive's employment is
terminated (i) by Safety-Kleen for Cause, as defined, the executive is entitled
only to his guaranteed base salary through the date of termination, plus any
deferred compensation and accrued vacation pay not previously paid; (ii) by the
executive other than for Good Reason, the executive is entitled only to the
Accrued Obligations; (iii) by Safety-Kleen for disability, the executive is
entitled to receive the Accrued Obligations and disability and other benefits
at least equal to the greater of those provided to peer executives by Safety-
Kleen immediately prior to the executive's termination and those provided to
peer executives by Safety-Kleen at any time during the 90 day period
immediately preceding a Change of Control; and (iv) by the executive's death,
his estate is entitled to the Accrued Obligations and benefits at least equal
to the most favorable benefits provided by the Surviving Corporation to
survivors of peer executives, and at least as favorable in the aggregate as the
most favorable provided to the executive during the 90 days preceding a Change
of Control.
 
  Each of the Change of Control Severance Agreements provides that if it is
determined that benefits received by the executive thereunder (or otherwise)
are subject to any excise tax under Section 4999 of the Internal Revenue Code
or any similar excise taxes, then Safety-Kleen will also pay the executive an
amount (the "Gross-up Payment") such that, after the payment of all income and
excise taxes, the executive will be in the same after-tax position that he
would have been in had no excise tax been imposed.
 
  Each Change of Control Severance Agreement contains a non-compete provision
that during the period of the executive's employment and for one year
thereafter, prohibits the executive from certain participation in the business
of any company engaged in business that directly or materially competes with
Safety-Kleen, and certain other competitive activity. Each such agreement also
obligates the executive to maintain the confidentiality of Safety-Kleen's
Confidential Information (as defined in such agreement).
 
  Payments that would be made to the persons who are parties to the Change of
Control Severance Agreements in the event they are all terminated during the
three year employment period after a Change of Control (other than for Cause or
by reason of the executive's death or disability) are approximately $46,036,306
for all officers with Change of Control Severance Agreements, including
approximately $3,845,937 for Mr. Brinckman.
 
  The foregoing description of the Change of Control Severance Agreements does
not purport to be complete and is qualified in its entirety by reference to the
Change of Control Severance Agreement filed as Exhibit 4 hereto and
incorporated herein by reference.
 
  Investment Banking Fees. Mr. Jannotta, a director of Safety-Kleen, is a
Senior Director of William Blair & Company L.L.C. ("William Blair"). William
Blair will receive a fee from Safety-Kleen upon consummation of the Philip
Merger or the LLE Offer. See "Item 5. Persons Retained, Employed Or To Be
Compensated."
 
  (b)(3) Certain Executive Compensation and Other Employee-Related Matters in
Connection with the Philip Merger.
 
  Indemnification and Insurance. Pursuant to the Philip Merger Agreement, SK
Parent has agreed that for a period of six years after the effective time of
the Philip Merger, the Surviving Corporation's articles of incorporation and
bylaws shall contain the provisions with respect to indemnification contained
in Safety-Kleen's articles of incorporation and by-laws on the date of the
Philip Merger Agreement, and that the Surviving Corporation's articles of
incorporation and by-laws shall not be amended in any manner that would
adversely affect the rights of persons who at any time prior to the effective
time of the Philip Merger was an employee, agent, director or officer of
Safety-Kleen or its subsidiaries ("Indemnified Parties") in respect of actions
or omissions occurring at or prior to the effective time of the Philip Merger.
SK Parent also agreed, subject to certain limitations, to cause to be
maintained in effect for not less than six years after the effective time of
the Philip Merger the current policies of directors' and officers' liability
insurance maintained by Safety-Kleen and its subsidiaries with respect to
matters occurring prior to the effective time of the Philip Merger. In
addition, the Philip Merger Agreement provides that, without limiting the
foregoing, in the event any Indemnified Party becomes involved in any capacity
in any action, proceeding or investigation based in whole or in part on, or
 
                                       4

 
arising in whole or in part out of, any matter, including the transactions
contemplated by the Philip Merger Agreement, existing or occurring at or prior
to the effective time of the Philip Merger, then to the extent permitted by
law, SK Parent will cause Safety-Kleen (or the Surviving Corporation if after
the effective time of the Philip Merger) to, and Safety-Kleen (or the
Surviving Corporation if after the effective time of the Philip Merger) shall,
periodically advance to such Indemnified Party its legal and other expenses
(including the cost of any investigation and preparation incurred in
connection therewith), subject to the provisions by such Indemnified Party of
an undertaking to reimburse the amounts so advanced in the event of a final
determination by a court of competent jurisdiction that such Indemnified Party
is not entitled thereto. The Philip Merger Agreement also provides that SK
Parent must cause Safety-Kleen (or the Surviving Corporation if after the
effective time of the Philip Merger) will, pay all expenses, including
attorneys' fees, that may be incurred by any Indemnified Party in enforcing
such indemnity and other obligations provided for in the Philip Merger
Agreement.
 
  SK Parent Letter. By letter dated November 19, 1997, SK Parent advised
Safety-Kleen's Board of Directors that, among other things, it looked forward
to discussing participation by current management of Safety-Kleen in the
equity of Safety-Kleen through stock option or similar plans and the potential
investment by members of management in SK Parent. However, there have been no
such discussions of these topics and it is not expected that there will be any
such discussion until after the effective time of the Philip Merger.
 
  Philip Merger Agreement Provisions Relating to Benefit Plans. In accordance
with the Philip Merger Agreement, upon consummation of the Philip Merger, the
holders of outstanding stock options to purchase Shares will receive from
Safety-Kleen for each Share subject to an option, cash in an amount equal to
the excess of $27.00 over the exercise price of the option, reduced by the
amount of withholding or other taxes required by law to be withheld. However,
as required by the terms of Safety-Kleen's outstanding stock options, holders
of options related to limited stock appreciation rights will receive for each
Share subject to such option, an amount in cash equal to the excess, if any,
of the change of control value (generally, the highest price at which the
Shares trade in the 180 days prior to shareholder approval of the Philip
Merger) over the per Share exercise price of such option, reduced by the
amount of withholding or other taxes required by law to be withheld.
 
  As of December 19, 1997, directors and executive officers held in the
aggregate options to purchase 2,446,265 Shares (including 2,251,265 options
related to limited stock appreciation rights), including options that will
vest upon consummation of the Philip Merger. Upon consummation of the Philip
Merger, (i) the directors who are not officers of Safety-Kleen who hold such
options would be entitled to receive approximately the following amounts:
Richard T. Farmer, $158,760, Russell A. Gwillim, $158,760, Edgar D. Jannotta,
$158,760, Karl G. Otzen, $158,760, Paul D. Schrage, $158,760, Marcia E.
Williams, $166,875, and W. Gordon Wood, $158,760; and (ii) assuming that the
Shares do not trade at a price in excess of $29 prior to shareholder approval
of the Philip Merger, all directors and executive officers who served at any
time since the beginning of Safety-Kleen's last fiscal year as a group would
collectively be entitled to receive approximately $25,690,713, including
approximately $5,371,445 for Mr. Brinckman.
 
  The Philip Merger Agreement provides that for a period of two years
following the effective time of the Philip Merger, SK Parent intends to cause
the Surviving Corporation to provide employee benefit plans and programs for
the benefit of employees of the Surviving Corporation and its subsidiaries
that are in the aggregate no less favorable to such employees than the
employee benefit plans of Safety-Kleen and its affiliates existing on the date
of the Philip Merger Agreement. All service credited to each employee by
Safety-Kleen through the effective time of the Philip Merger shall be
recognized by SK Parent or the Surviving Corporation for purposes of
eligibility and vesting under any employee benefit plan provided directly or
indirectly by SK Parent or the Surviving Corporation for the benefit of the
employees and in which the respective employees participate. SK Parent has
expressed its present intention to continue management of Safety-Kleen in the
same positions as management of the Surviving Corporation, subject to joint
review by management of SK Parent and Safety-Kleen after the effective time of
the Philip Merger, but intends not to continue Mr. Brinckman as an officer or
employee of the Surviving Corporation. Safety-Kleen currently expects that
there will be no significant change in the level of management benefit plans
after the effective time of the Philip Merger.
 
                                       5

 
  The Philip Merger Agreement also provides that SK Parent shall cause the
Surviving Corporation: (i) to honor (without modification) and assume the
written employment agreements, severance agreements and other agreements
listed on the disclosure schedule to the Philip Merger Agreement, all as in
effect on the date of the Philip Merger Agreement; and (ii) not to terminate
or adversely amend in any manner Safety-Kleen's 1997 and 1998 Management
Incentive Plans which adversely affects the benefits that participants in such
plans are entitled to thereunder with respect to any periods prior to and
including the effective time of the Philip Merger. The Philip Merger Agreement
also states that SK Parent intends to cause the Surviving Corporation to
continue to maintain its principal offices in Elgin, Illinois and to maintain
its charitable commitments and community involvement.
 
  (b)(4) Arrangements with LLE, its Executive Officers, Directors or
Affiliates.
 
  Other than existing and present business relationships (e.g., providing
services to each other or considering the purchase or sale of discrete assets
or operations or alliances) in the ordinary course of business not material to
Safety-Kleen or its affiliates and LLE or its affiliates or to the
relationship between them and the sale of certain assets of a LLE subsidiary
to Safety-Kleen in February 1996 and the accompanying cooperative services
agreement which is in the process of being terminated, as of the date hereof
there are no contracts, agreements, arrangements or understandings or actual
or potential conflicts of interest between Safety-Kleen or its affiliates and
LLE, the Offeror or their respective executive officers, directors or
affiliates that are required to be disclosed pursuant to the rules and
regulations of the Commission.
 
ITEM 4. THE SOLICITATION OR RECOMMENDATION.
 
  (a) Recommendation Of The Board Of Directors.
 
  THE BOARD OF DIRECTORS OF SAFETY-KLEEN (THE "BOARD") CONTINUES TO BELIEVE
THAT THE PHILIP MERGER IS IN THE BEST INTERESTS OF SAFETY-KLEEN AND ITS
SHAREHOLDERS AND, THEREFORE, THE BOARD (WITH ONE DIRECTOR ABSENT DUE TO
ILLNESS) UNANIMOUSLY RECOMMENDS THAT ALL SHAREHOLDERS OF SAFETY-KLEEN REJECT
THE LLE OFFER AND NOT TENDER THEIR SHARES PURSUANT TO THE LLE OFFER.
 
  The Board's determination, which was reached at a meeting held on December
20, 1997, was based on the Board's review and consideration of the interests
of Safety-Kleen and its shareholders. At the same meeting, the Board
unanimously (with one director absent due to illness) reaffirmed its
determination that the terms of the Philip Merger Agreement are in the best
interests of Safety-Kleen and its shareholders. The Board set February 11,
1998 as the date for a special meeting of shareholders to consider and approve
the Philip Merger Agreement. The record date for determination of shareholders
entitled to notice of and to vote at the special meeting was fixed as January
5, 1998.
 
  A copy of the letter to Safety-Kleen's shareholders communicating the
Board's recommendation and the press release relating thereto are filed as
Exhibits 5 and 6, respectively, to this Schedule 14D-9 and are incorporated
herein by reference.
 
  The LLE Offer is conditioned upon, among other things, the Board having
redeemed the Rights or amended the Rights Agreement so that the Rights are
inapplicable to the acquisition of Shares pursuant to the LLE Offer, or LLE
being otherwise satisfied in its sole discretion that the Rights are invalid
or are not applicable to the acquisition of Shares pursuant to the LLE Offer
and the proposed subsequent merger of the Offeror into Safety-Kleen. In light
of its decision discussed above, the Board determined not to take any action
to redeem the Rights in response to the LLE Offer. As more fully described
under "Item 8. Additional Information To Be Furnished--(a) Rights Agreement,"
the Board has adopted a resolution to delay the "Distribution Date" under the
Rights Agreement.
 
  The LLE Offer is also conditioned upon LLE being satisfied, in its sole
discretion, either that the provisions of Section 180.1141 of the Wisconsin
Statutes are inapplicable to LLE, the Offeror and the transactions
contemplated by the LLE Registration Statement, or that the Wisconsin Statutes
will not prohibit for any period
 
                                       6

 
of time the consummation of the proposed merger or any other "Business
Combination" (as defined in such Statutes) involving Safety-Kleen and LLE or
the Offeror, or any of their respective affiliates. In light of its decision
discussed above, the Board has determined not to take any action that would
render Section 180.1141 of the Wisconsin Statutes so inapplicable.
 
  (b)(1) Background.
 
  On June 10, 1997, the Executive Committee of the Board, which consists of
Messrs. Donald W. Brinckman, Russell A. Gwillim and Edgar D. Jannotta (the
"Executive Committee"), met to discuss certain general expressions of interest
received by Safety-Kleen regarding possible business combinations with Safety-
Kleen. The Executive Committee instructed management to discuss the
expressions of interest with Safety-Kleen's legal advisor, Sonnenschein Nath &
Rosenthal, and with Safety-Kleen's financial advisor, William Blair, in
preparation for an Executive Committee meeting on June 24th.
 
  At the Executive Committee meeting on June 24, 1997, after a presentation by
Safety-Kleen's legal advisors with respect to the legal framework for the
Board's deliberations, William Blair orally presented its preliminary view
that the per Share consideration Safety-Kleen could achieve in a sale
transaction was between $23 and $25. William Blair also discussed with the
directors financial and strategic buyers that might be interested in Safety-
Kleen if the Board were to decide to explore a possible sale transaction. The
Executive Committee determined to hold a special Board meeting on July 7th.
 
  At the July 7th Board meeting, management presented to the Board Safety-
Kleen's recent financial results for the second quarter of fiscal 1997 and
Safety-Kleen's forecasted financial performance. The directors discussed with
management Safety-Kleen's past stock price performance and potential
difficulties in achieving Safety-Kleen's forecasted financial performance.
Safety-Kleen's legal advisors and William Blair then made the presentations
concerning the expressions of interest in Safety-Kleen and orally presented
its view on the valuation of Safety-Kleen. According to William Blair: (i) its
preliminary analysis of selected recent merger or acquisition transactions in
the environmental services industry indicated a valuation of the equity of
Safety-Kleen of between $19.46 and $22.48 per Share; and (ii) its preliminary
discounted cash flow analysis indicated a valuation of the equity of Safety-
Kleen of between $25.71 and $26.80 per Share. Based on the foregoing, William
Blair's preliminary judgment of the per Share consideration that Safety-Kleen
could achieve in a sale transaction was between $23 and $25. After extensive
discussions, the Board asked management, with the assistance of Safety-Kleen's
legal and financial advisors, to prepare and present further information to
the Board relating to various strategies to enhance shareholder value.
 
  At the regularly scheduled August 8th Board meeting, the Board, management
and William Blair discussed the advisability of exploring strategic
alternatives, including a possible sale of Safety-Kleen. The Board, management
and William Blair also discussed other possible strategic alternatives such as
a stock buy-back program, acquisitions and/or operating the business in
accordance with Safety-Kleen's long range plan. William Blair orally presented
its view of the valuation of Safety-Kleen in a sale transaction and a
theoretical stock price analysis assuming that Safety-Kleen continues to
operate as an independent company. William Blair's view of the valuation of
Safety-Kleen was substantially the same as the view it presented to the Board
on July 7th except that, based on management revisions to its forecast of
Safety-Kleen's performance, William Blair's discounted cash flow analysis
indicated a valuation of the equity of Safety-Kleen of between $27.83 and
$29.01 per Share. Based on the foregoing and taking into account its view of
generally improved market conditions, William Blair's judgment of the per
Share consideration that Safety-Kleen could achieve in a sale transaction was
between $24 and $26. William Blair also discussed possible steps to be taken
by the Board in exploring strategic alternatives.
 
  After extensive discussions of William Blair's valuation analysis, the Board
directed management to explore, with the assistance of Safety-Kleen's
advisors, strategic alternatives for enhancing shareholder value. The Board
also instructed management to retain William Blair to render financial
advisory and investment banking services to Safety-Kleen in connection with
the evaluation of strategic alternatives and, as part of the exploration of
strategic alternatives, authorized management and William Blair to contact
third parties that might be interested in acquiring all or a part of Safety-
Kleen to determine whether they would be interested in
 
                                       7

 
participating in the process by executing confidentiality and standstill
agreements in order to receive confidential information with respect to Safety-
Kleen and its subsidiaries.
 
  On August 8, 1997, Safety-Kleen issued a press release stating that it had
engaged the services of William Blair to act as advisor to Safety-Kleen and
manage the process of exploring strategic options for enhancing shareholder
value. Safety-Kleen also announced the resignation of John G. Johnson, Jr.,
President and Chief Executive Officer of Safety-Kleen. Donald W. Brinckman,
Chairman of Safety-Kleen's Board of Directors, who had previously served as
Safety-Kleen's Chief Executive Officer from 1968 until December 31, 1994, was
appointed Chief Executive Officer. Mr. Joseph Chalhoub, President--Operations
of Safety-Kleen, was appointed President and Chief Operating Officer.
 
  On August 19, 1997, Safety-Kleen retained Credit Suisse First Boston
Corporation ("CSFB") to perform certain financial advisory services in
connection with Safety-Kleen's exploration of strategic alternatives. CSFB
performed a preliminary review of Safety-Kleen's analyses of the strategic
alternatives to remaining independent. In addition, it assisted Safety-Kleen by
identifying certain potential buyers that were subsequently contacted by
William Blair and by discussing with management some of the possible strategies
which might be used to enhance shareholder value were Safety-Kleen to remain
independent. It was available to the Board for discussion of these strategies,
but did not furnish any reports or opinions to the Board, nor did it make any
presentation to the Board.
 
  William Blair contacted, or as a result of the August 8th press release was
contacted by, 94 parties interested in considering the potential acquisition of
all or part of Safety-Kleen. Confidentiality and standstill agreements were
entered into with 50 potential buyers (including Philip and affiliates of
Apollo and Blackstone) and, beginning on September 5, 1997, copies of a
Confidential Memorandum describing Safety-Kleen and its operations were sent to
such potential buyers. Each potential buyer also received a letter setting
forth the deadline for submissions of preliminary indications of interest in
Safety-Kleen and other bidding requirements. Pursuant to the standstill
provisions of the confidentiality and standstill agreements entered into by
potential buyers, such buyers agreed not to make any unsolicited offer to
acquire Safety-Kleen or to take certain other actions, including purchasing any
Shares, for a period of from 18 to 24 months. Because Safety-Kleen was
considering various strategic alternatives, including the continued operation
of Safety-Kleen as an independent company, the Board felt it was important to
require that any potential buyer not only enter into a confidentiality
agreement, but also agree to the standstill provisions in order to prevent such
person from using Safety-Kleen's confidential non-public information to make an
unsolicited offer at a later date. Further, the Board believed that the
confidentiality and standstill agreements were necessary to create a stable,
orderly and cooperative process in which all potential buyers would be provided
information regarding Safety-Kleen on a level playing field.
 
  One of the potential buyers which contacted William Blair shortly after the
August 8th announcement was LLE. LLE refused to execute the confidentiality and
standstill agreement that was signed by all of the other potential buyers in
the process and therefore did not receive a Confidential Memorandum. On
September 24, 1997, LLE delivered a letter to Safety-Kleen proposing a reverse
merger in which Safety-Kleen would issue one Share for three shares of LLE
Common Stock. A copy of the LLE letter is filed herewith as Exhibit 7 and is
incorporated herein by reference and the foregoing description is qualified in
its entirety by such exhibit. William Blair responded to LLE by repeating
Safety-Kleen's request that LLE execute the confidentiality and standstill
agreement and participate in the process like other potential buyers.
 
  By early October 1997, Safety-Kleen had received 10 indications of interest
from potential buyers, nine of which expressed interest in acquiring Safety-
Kleen as a whole. At an Executive Committee meeting held on October 13, 1997,
the Executive Committee, with the assistance of William Blair and Safety-
Kleen's legal advisors, evaluated each indication of interest and selected four
potential buyers to proceed to the second stage of the process. On October 16,
1997, those four potential buyers received a second letter requesting that they
submit their best and highest written offer, including the price per share,
proposed transaction structure and amounts and sources of funds, by November
14, 1997. The potential buyers also received a draft merger agreement and were
instructed to submit their comments thereon with their written offer. Safety-
Kleen's letter stated that the certainty and timing of financing would be among
the factors considered in selecting a prospective purchaser.
 
                                       8

 
  Shortly after the October 13th Executive Committee meeting, another
potential buyer which had previously executed a confidentiality and standstill
agreement submitted a preliminary indication of interest in Safety-Kleen.
Members of the Executive Committee, with the assistance of Safety-Kleen's
advisors, determined to invite this potential buyer to join the second stage
of the process.
 
  The five potential buyers in the second stage of the process received access
to a special "Data Room" set up by Safety-Kleen, had the opportunity to meet
with management of Safety-Kleen and were able to visit various of Safety-
Kleen's facilities. From October 23rd through November 11, 1997, three of the
five potential buyers conducted meetings with management and visited selected
facilities. The remaining two potential buyers elected not to proceed further.
 
  On November 3, 1997, Mr. James R. Bullock, Chairman of LLE, delivered to Mr.
Brinckman a letter which disclosed that the LLE's Board of Directors had
authorized and directed senior management of LLE to pursue the acquisition of
all the outstanding shares of Safety-Kleen for a per Share consideration of
$14.00 in cash and 2.4 shares of LLE Common Stock. The letter stated that LLE
was willing to execute a confidentiality agreement provided such agreement did
not contain a standstill provision. The text of the letter was included in a
press release that was issued by LLE on November 4, 1997. A copy of the LLE
letter is filed herewith as Exhibit 8 and is incorporated herein by reference
and the foregoing description is qualified in its entirety by such exhibit.
 
  On November 3, 1997, after receipt of Mr. Bullock's letter, Mr. Brinckman
delivered a letter to Mr. Bullock requesting that LLE execute a
confidentiality and standstill agreement and informing Mr. Bullock that
Safety-Kleen's Board of Directors would fully consider the LLE proposal along
with others received by Safety-Kleen. In addition, Mr. Brinckman stated that
representatives of Safety-Kleen, together with its financial advisors, would
meet with representatives of LLE, together with its financial advisors, to
discuss information concerning LLE and its estimate of cost savings and
synergies.
 
  On November 5, 1997, Mr. Bullock and a representative of the LLE financial
advisor met with Mr. Chalhoub, Roy D. Bullinger, Senior Vice President--
Business Management and Marketing, Andrew A. Campbell, Senior Vice President--
Finance, F. Henry Habicht II, Senior Vice President--Corporate Development and
Environment, John Lucks, Vice President--Industrial Marketing and Business
Management, and representatives of William Blair to discuss plans for Safety-
Kleen, including LLE's view of potential synergies that could be achieved
through a combination of the two companies. Mr. Brinckman and Mr. Chalhoub
stated that a substantial portion of those proposed synergies could not be
achieved. This statement was based on Mr. Brinckman's and Mr. Chalhoub's
belief that: (i) LLE's estimate of between $30 to $45 million of annual
savings from the consolidation of sales and service centers was significantly
overstated because, although some Safety-Kleen branches may be closed and
related facility costs and some branch management personnel expenses saved,
service representatives and trucks of those branches would continue to be
needed to service such customers. Furthermore, because these service personnel
and trucks would be forced to work out of branch facilities located further
from their customers, the savings from such closures would be partially offset
by the additional expense of transporting materials longer distances to and
from customers; (ii) LLE's estimate of between $14 to $24 million of annual
savings from the internalization of Safety-Kleen waste into LLE facilities was
inconsistent with the fact that Safety-Kleen spends only approximately $4
million annually on hazardous waste incineration. Most hazardous waste
materials collected by Safety-Kleen are blended into fuel that is reclaimed in
cement kilms at a significant lower cost than incineration; and (iii) LLE's
estimate of approximately $30 million of annual savings from reduction of
corporate and head office functions was aggressive since many of those
functions are essential to support Safety-Kleen's branch sales and service
infrastructure.
 
  At the November 5th meeting, Mr. Bullock stated that LLE was prepared to
sign a mutual confidentiality agreement that did not contain a standstill
provision. Safety-Kleen again repeated its request that LLE, like every other
potential buyer in the process, sign a confidentiality and standstill
agreement.
 
  On November 7th and 11th, respectively, Philip and one of the two other
remaining potential buyers informed William Blair that instead of submitting
an offer by the November 14th deadline, they desired to negotiate exclusively
with Safety-Kleen. Philip indicated that it was prepared to negotiate on this
basis for the acquisition of all Safety-Kleen's Shares at a price of at least
$26 per share (most of which would be payable in cash, with the remainder in
Philip stock) while the other potential buyer indicated a range of between
$24-$25 in cash in a leveraged recapitalization transaction. William Blair
told these two potential buyers that the Board of Directors would consider
their request at the November 14, 1997 Board meeting. This preference
reflected a
 
                                       9

 
Board view that, with the price of the Shares at an all-time high, it was
desirable to capture the certain value represented by cash for the shareholders
and allow them to redeploy their investment, rather than assuming the
uncertainties of investment in a continuing enterprise. On November 12, 1997,
the other remaining potential buyer elected not to proceed further.
 
  At an Executive Committee meeting on November 10, 1997, the Executive
Committee received a progress report on the process and discussed the proposed
LLE offer. Management, with the assistance of William Blair, also discussed
strategic alternatives such as a possible stock buy-back program and pursing
Safety-Kleen's long-term business plan, including new business developments and
certain acquisitions and/or dispositions of assets.
 
  On November 13, 1997, LLE announced that it had filed a registration
statement on Form S-4 with the Commission relating to its previously announced
intention to offer to acquire all outstanding Shares of Safety-Kleen. LLE also
delivered a notice to Safety-Kleen requesting that a special meeting of
shareholders under Wisconsin law be convened in order to negate the effect of a
Wisconsin statute providing that, under certain circumstances, a person
acquiring more than 20% of a corporation's stock can cast only 10% of the votes
to which shares in excess of 20% ownership would otherwise be entitled. A copy
of a LLE letter dated November 13, 1997 sent to Mr. Brinckman is filed herewith
as Exhibit 9 and is incorporated herein by reference, and the foregoing
description is qualified in its entirety by such exhibit. On November 17, 1997,
Safety-Kleen filed a lawsuit in Federal District Court for the Northern
District of Illinois against LLE seeking a declaratory judgment that LLE
violated the "gun-jumping" prohibitions of federal securities law by certain of
its public announcements made before the effectiveness of the registration
statement with the Commission relating to the shares of LLE Common Stock it
proposes to use in its offer for Safety-Kleen. The suit also challenged LLE's
asserted right under Wisconsin law to demand such a shareholders' meeting at
that time. A copy of Safety-Kleen's complaint is attached hereto as Exhibit 10
and is incorporated herein by reference, and the foregoing summary description
is qualified in its entirety by such exhibit.
 
  On November 14, 1997, the Board of Directors of Safety-Kleen received a
progress report on the process and an analysis of strategic alternatives such
as a possible stock buy-back program and pursing Safety-Kleen's long-term
business plan, including new business developments and certain acquisitions
and/or dispositions of assets. William Blair informed the Board of the request
made earlier in the week by Philip and the other remaining bidder to negotiate
exclusively with Safety-Kleen. Based on subsequent conversations with Philip
and such other bidder, William Blair had been informed that Philip would
increase its consideration to $26.50 per share, payable all in cash, if Safety-
Kleen were to negotiate exclusively with Philip, and although the other bidder
might pay $25 per share, it would not increase its consideration any further.
 
  The Board also discussed its concerns with respect to the proposed LLE offer.
Those concerns included: the lower per share consideration in such offer
(which, based on the closing price of the LLE Common Stock on November 13,
1997, was approximately $25.71); the substantial amount of LLE Common Stock
which was part of that offer and the absence of any downside protection for
Safety-Kleen shareholders if the market value of such stock decreased;
questions as to the liquidity of that stock in the marketplace given that a
very small percentage of the outstanding shares of LLE Common Stock trade
daily; the business and financial prospects for the ongoing company in which
Safety-Kleen shareholders would have a very large continuing interest,
including management's views that LLE would not be able to achieve the
synergies it had outlined in the November 5th meeting for the reasons discussed
above; the conditional nature of the financing for the proposed offer,
including the execution of definitive agreements relating to a merger and the
satisfactory completion of due diligence investigations; and LLE's intention
not to continue Safety-Kleen as a separate ongoing business, to move Safety-
Kleen's Elgin headquarters (which currently employs approximately 650 persons)
and thus reduce the number of Safety-Kleen employees.
 
  The Board, with the assistance of management and Blair, determined that
management should negotiate exclusively with Philip provided that Philip
increased its per share price to $27 in cash. Philip informed William Blair
shortly after the Board meeting that it was prepared to negotiate a transaction
at $27 in cash provided that the definitive agreement provided for a
termination fee under certain circumstances.
 
                                       10

 
  Negotiations with Philip began on November 15th and continued until November
20th. Early in the negotiations, Philip told Safety-Kleen that it desired to
have Apollo and Blackstone and participate in the proposed acquisition. On
November 17th, Mr. Brinckman, Mr. Chalhoub and representatives of William Blair
met with representatives of Apollo and Blackstone and of financial institutions
invited by Philip to consider providing a portion of the funds necessary to
effectuate the proposed acquisition of Safety-Kleen. Safety-Kleen and its
representatives were informed that Philip, Apollo and Blackstone proposed to
form a new entity namely, SK Parent, for the purpose of acquiring Safety-Kleen.
 
  The parties extensively negotiated the proposed Merger Agreement, including
the conditions to the Merger and the provisions regarding termination events
and termination fees that would be contained in the Merger Agreement. During
the negotiations, on November 18 and 19, 1997, special meetings of the Board of
Directors were held to report on the status of the negotiations with Philip.
 
  At a special meeting of the Board of Directors on November 20, 1997, William
Blair and Safety-Kleen's legal advisors advised the Board of the progress of
the negotiations with Philip. The Board, management and William Blair
extensively discussed the proposed Philip transaction, including its structure,
the participation of Apollo and Blackstone and the financing commitments. Mr.
Allen Fracassi, President and Chief Executive Officer of Philip, who had asked
to address the Board, summarized his expectations for the proposed Philip
Merger and confirmed SK Parent's intention, stated in the Merger Agreement, to
maintain Safety-Kleen's principal offices in Elgin, Illinois and to maintain
Safety-Kleen's charitable commitments and community relations. He also informed
the directors that SK Parent intended to maintain Safety-Kleen as an ongoing
business and not to absorb its operations into Philip.
 
  Legal counsel reviewed the applicable legal principles and the form of the
Philip Merger Agreement presented for Board approval. The Board and its
advisors also discussed the terms of the commitment letter from the financial
institutions contacted by Philip to provide the necessary financing, as well as
the equity commitment letter executed by Philip, Apollo and Blackstone and
including the qualifications and conditions of such commitments. Copies of the
latest draft of the Philip Merger Agreement and letters evidencing such
commitments, and related term sheets, had previously been distributed to the
Board. William Blair then rendered to the Board its oral opinion (which opinion
was subsequently confirmed by delivery of a written opinion dated November 20,
1997) to the effect that, as of such date and based upon and subject to certain
matters stated in such opinion, the consideration to be received by the holders
of Shares in the Philip Merger is fair to such holders from a financial point
of view, and reviewed with the Board the financial analyses performed by it in
connection with its opinion (see "--(3) Opinions of Financial Advisor--November
20, 1997 Opinion"). The Board also considered the fact that SK Parent had
advised the Board that it looked forward to beginning discussions regarding the
participation by current management in the equity of the Surviving Corporation
through stock option or similar plans and the potential investment by Safety-
Kleen management in SK Parent. The Board's consideration of such possible
participation was part of its consideration of the effects of the Philip Merger
Agreement on Safety-Kleen's employees. Under Wisconsin law, directors, in
discharging their duties to the corporation and in determining what they
believe to be in its best interests, in addition to considering the interests
of shareholders, may consider, among other factors, the effects of proposed
actions on employees. In addition, the Board considered the fact that Mr.
Jannotta, a director of Safety-Kleen, is a Senior Director of William Blair.
 
  For the reasons summarized above and taking into consideration the factors
listed below in this paragraph, and on the basis of the advice of William Blair
and its legal counsel, the Board voted unanimously to accept the offer from SK
Parent on the grounds that it was fair to, and in the best interests of,
Safety-Kleen's shareholders and was the best offer available at the end of a
comprehensive process of exploring strategic alternatives. In the course of
reaching its decision to approve the Philip Merger Agreement and the Philip
Merger, the Board consulted with Safety-Kleen's legal counsel and William Blair
and, applying the Board's familiarity with Safety-Kleen's business, financial
condition, prospects, current business strategy and opportunities and Safety-
Kleen's position in its industries, considered a number of factors, including,
among others, the following:
 
    (i) presentations by Safety-Kleen's management relating to Safety-Kleen's
  financial performance and future opportunities and prospects, including a
  review of current financial performance, a preliminary report
 
                                       11

 
  on a possible acquisition, possible writeoffs, progress in new businesses
  such as comprehensive services involving treatment and recycling of aqueous
  cleaning solutions and metal working and other fluids, and provision of
  services through its Total Environmental Activity Management approach;
 
    (ii) the presentation of William Blair at the November 20, 1997 Board
  meeting and the written opinion of William Blair dated November 20, 1997
  that, based upon and subject to the matters set forth therein and as of the
  date thereof, the cash consideration to be received by Safety-Kleen's
  shareholders in the Philip Merger is fair to Safety-Kleen's shareholders
  from a financial point of view; the full text of the November 20, 1997
  opinion of William Blair is included as Exhibit 11 hereto and should be
  read in its entirety (see "--(3) Opinions of Financial Advisor--November
  20, 1997 Opinion" below);
 
    (iii) the fact that William Blair contacted a substantial number of
  potential bidders over an extended period of time in a process designed to
  elicit third party proposals to acquire Safety-Kleen and enhance
  shareholder value and that participants in such process had been afforded
  sufficient time and information to submit such a proposal had they wished
  to do so;
 
    (iv) the Board's review, based in part on presentations by Safety-Kleen's
  management and financial advisors, of alternatives to the Philip Merger,
  including a stock buy-back program, acquisitions and dispositions, and the
  fact that none of such alternatives, even if successfully carried to
  completion, would have resulted in a per share consideration payable to the
  holders of Shares as high as the consideration payable in the Philip
  Merger;
 
    (v) the lower proposed cash and stock offer by LLE in the stated amount
  of $26 per Share, and the Board's concerns with respect to that offer
  discussed above;
 
    (vi) historical market prices and trading information for Safety-Kleen's
  Shares, including the fact that the $27.00 cash price represents a premium
  of approximately 52% over the closing price of $17.81 per Share on August
  7, 1997, the last trading day prior to the public announcement that Safety-
  Kleen was considering strategic alternatives and had retained William
  Blair;
 
    (vii) the terms and conditions of the Philip Merger Agreement, including
  (i) those relating to the fee of $50.0 million and/or expense
  reimbursements (for documented out of pocket expenses and fees incurred in
  connection with the Philip Merger up to a maximum of $25.0 million) to SK
  Parent payable upon termination of the Agreement as a result of, among
  other things, Safety-Kleen accepting a competing offer that is more
  favorable to Safety-Kleen's shareholders; and (ii) those relating to the
  ability of the Board to consider unsolicited offers from third parties
  prior to the effectiveness of the Philip Merger; and
 
    (viii) the interest of SK Parent in enhancing all of Safety-Kleen's
  businesses, its knowledge of Safety-Kleen's markets and customers and its
  intent to continue Safety-Kleen as an ongoing business and not absorb its
  operations into Philip, to maintain Safety-Kleen's principal office in
  Elgin; and SK Parent's intent to preserve Safety-Kleen's relationship with
  its employees and to maintain Safety-Kleen's charitable commitments and
  community investment.
 
  Immediately following the November 20th Board meeting, Safety-Kleen, SK
Parent and SK Acquisition entered into the Philip Merger Agreement. Safety-
Kleen and Philip also issued press releases announcing the Philip Merger.
 
  Later that day, Mr. Bullock of LLE delivered a letter to Safety-Kleen
advising Safety-Kleen of the LLE Offer. The letter disclosed that: (i) the $15
per share cash portion would be reduced by any incremental costs, such as
break-up fees, new severance arrangements and other expenses Safety-Kleen
might have incurred in connection with its agreement with Philip and others;
and (ii) the stock portion would be equal to $15 divided by the weighted
average trading price for shares of LLE Common Stock for 10 days selected by
lot from the 20 trading days ending three business days immediately prior to
the closing, provided that such number of shares shall not be less than 2.8
nor greater than 3.5. The text of the letter was included in a press release
that was issued by LLE on November 20, 1997. A copy of the LLE letter is filed
herewith as Exhibit 12 and is incorporated herein by reference, and the
foregoing description is qualified in its entirety by such exhibit. On
November 21, 1997, Safety-Kleen confirmed in a press release that it would
respond, in due course, to the LLE amended proposed offer to acquire Safety-
Kleen.
 
                                      12

 
  At a November 24, 1997 special meeting of the Board of Directors, the Board,
with the assistance of William Blair and its legal counsel, reviewed the
November 20, 1997 letter from Mr. Bullock regarding the LLE Offer. The Board
noted that LLE had improved its proposal to what it stated to be a $30 per
share offer. In its preliminary evaluation of that revised offer, the Board
and its advisors discussed, among other things: (i) anticipated deductions
from the cash portion of that purchase price; (ii) factors reducing the value
of the LLE Common Stock, including, among other things: (a) the sustainability
of LLE's present market multiple and the impact on that multiple of the LLE
proposed combination with Safety-Kleen; (b) the effects both in terms of
dilution and market impact of the issuance of approximately 162 million to 202
million shares of LLE Common Stock in connection with its proposed combination
with Safety-Kleen; and (c) Safety-Kleen management's views, based on the
explanation given to Safety-Kleen's management by Mr. Bullock at the November
5th meeting between them, that LLE would not be able to achieve a significant
portion of the $100 to $130 million synergies it outlined in the LLE Offer;
and (iii) the conditional nature of the financing for the LLE Offer. The Board
also again noted the impact that LLE's stated intention to move Safety-Kleen's
Elgin headquarters (which currently employs approximately 650 persons) to
South Carolina would have on Safety-Kleen's employees and the surrounding
communities.
 
  During the Board's review, a letter dated November 24, 1997 was received
from SK Parent expressing its views on the LLE Offer. That letter stated that
SK Parent does not believe the LLE Offer constitutes a Superior Proposal (as
that term is defined in the Philip Merger Agreement), or provided any
indication that LLE is reasonably likely to make a Superior Proposal. Parent
concluded in such letter that it would not be appropriate for Safety-Kleen to
engage in discussions or negotiations with LLE. SK Parent's interest in
acquiring Safety-Kleen pursuant to the Philip Merger Agreement (and its
interest in avoiding termination of the Philip Merger Agreement in favor of
the LLE Offer) is different from the interests of Safety-Kleen shareholders as
sellers of their Shares pursuant to the Philip Merger Agreement.
 
  The Board determined to meet again to further discuss the LLE Offer and
authorized William Blair to continue its analysis of such offer and to report
on such analysis at the next Board meeting.
 
  On November 24, 1997, LLE answered the complaint filed by Safety-Kleen on
November 17th with the United States District Court for the Northern District
of Illinois, denying liability and asserting several defenses. In addition,
LLE and its subsidiary filed counterclaims against Safety-Kleen and its
directors. The counterclaims seek a declaratory judgment that Safety-Kleen is
required to hold a special meeting under Wisconsin law, and assert claims
against Safety-Kleen for violation of certain Wisconsin statutes pertaining to
furnishing of shareholder lists and takeovers, and against the directors for
breach of fiduciary duty in failing to negotiate with LLE, and for failure to
amend the Rights Agreement, and a derivative claim for corporate waste.
Safety-Kleen believes that the LLE counterclaim is without merit and intends
to contest such action vigorously on behalf of Safety-Kleen and the Board of
Directors. A copy of LLE's answer and counterclaim is attached hereto as
Exhibit 13 and is incorporated herein by reference, and the foregoing summary
description is qualified in its entirety by such exhibit.
 
  On November 26, 1997, Safety-Kleen filed preliminary proxy materials with
the Commission relating to the solicitation of proxies by Safety-Kleen for use
at a special meeting of shareholders of Safety-Kleen to consider shareholder
approval of the Philip Merger Agreement and the Philip Merger.
 
  On December 4, 1997, the Federal District Court for the Northern District of
Illinois ruled that LLE can seek the approval of Safety-Kleen shareholders at
a special meeting to restore voting power to Shares that LLE may acquire in
excess of 20% of the outstanding Shares. The Court has also scheduled a
preliminary hearing for January 28, 1998 on LLE's request that the Rights
Agreement be amended to make it inapplicable to the LLE Offer and that the
Court void the termination fee and certain other provisions of the Philip
Merger Agreement.
 
  On December 8, 1997, at a special meeting of the Board of Directors, the
Board set January 9, 1998 as the date for a special meeting of its
shareholders to consider and vote upon a proposal by LLE to restore full
voting power to any Shares that LLE may acquire in excess of 20% of the
outstanding Shares. The Board also determined to take no position concerning
the vote on such restoration of voting power and not to solicit proxies in
connection with such vote. The record date for determination of shareholders
entitled to notice of and to vote at the special meeting was fixed as December
19, 1997.
 
                                      13

 
  On December 20, 1997, the Board met to consider the LLE Offer and took
actions referred to in this Item 4.
 
  (2) Reasons For The Recommendation.
 
  In reaching the conclusions with respect to the LLE Offer referred to in
Item 4(a), the Board considered numerous factors, including, but not limited
to:
 
 
    (i) the review by Safety-Kleen's legal counsel of the provisions of the
  Philip Merger Agreement relating to the ability of Safety-Kleen to furnish
  information to, and participate in discussions or negotiations with, a
  person making an unsolicited offer for Safety-Kleen if (x) the Board shall
  conclude in good faith, after consultation with its financial advisor, that
  such person has made or is reasonably likely to make a bona fide
  acquisition proposal for a transaction more favorable to Safety-Kleen's
  shareholders from a financial point of view than the transactions
  contemplated by the Philip Merger Agreement, and (y) in the opinion of the
  Board, only after receipt of advice from independent legal counsel to
  Safety-Kleen, the failure to provide such information or access or to
  engage in such discussions or negotiations would cause the Board to violate
  its fiduciary duties to Safety-Kleen's shareholders under applicable law,
  and, related to that review:
 
      (a) the presentation by William Blair concerning Safety-Kleen, LLE
    and the financial aspects of the LLE Offer and the written opinion of
    William Blair to the effect that, as of December 20, 1997, William
    Blair does not have a basis for concluding that the LLE Offer is
    superior to the Philip Merger from a financial point of view (such
    opinion having been expressed after review of the other factors
    referred to herein and various financial criteria used in assessing the
    LLE Offer, and having been based on various assumptions and subject to
    various limitations reviewed for the Board as part of William Blair's
    presentation). See "--(3) Opinions of Financial Advisor--December 20,
    1997 Opinion" below; and
 
      (b) the advice of Safety-Kleen's legal counsel that, in light of the
    presentation by William Blair and the other factors considered by the
    Board, failure to provide information or access to, or participate in
    discussions or negotiations with LLE, would not cause the Board to
    violate its fiduciary duties to Safety-Kleen's shareholders under
    applicable law;
 
    (ii) the presentation by Safety-Kleen's legal counsel of the Board's
  fiduciary duties under applicable law, summarizing previous such
  presentations that the Board had received in the course of its process of
  considering Safety-Kleen's strategic alternatives, and the written opinion
  of Safety-Kleen's special Wisconsin counsel that, subject to the
  limitations and qualifications expressed therein, Safety-Kleen's directors
  may take into account how a proposed transaction will affect other
  constituencies, in addition to the shareholders of Safety-Kleen, in
  carrying out their fiduciary duties; and that Wisconsin's business judgment
  rule would be applicable to their judgment;
 
    (iii) the fact that the value of the cash portion of the LLE Offer is
  significantly less than $15 per Share due to the stated but unfixed
  deductions for certain termination fees and expenses, new severance
  agreements and certain other expenses, and that as to the portion of such
  deductions for such termination fees and expenses and such severance
  agreements, LLE had filed soliciting material with the Commission
  estimating such deductions at from $1.28 to $2.14 per Share; and the advice
  of Safety-Kleen's legal counsel that the provisions of the Philip Merger
  Agreement relating to termination fees and expenses, the new severance
  agreements and other expenses are valid and binding on Safety-Kleen;
 
    (iv) the fact that the value of the stock portion of the LLE Offer could
  be materially and adversely affected by, among other things: (a) the
  pricing collar on the Exchange Ratio under which shareholders of Safety-
  Kleen would have no downside protection in the event that the average price
  of the LLE Common Stock used in determining the Exchange Ratio is less than
  $4.29 per share (particularly given the fact that the LLE Common Stock
  closed below $4.29 on December 10th, 11th, 17th and 18th); and (b) the
  absence of any assurance that the LLE Common Stock, when ultimately
  received by holders of Shares, would have a market value of, or could be
  sold for the price of, the LLE Common Stock used in determining the
  Exchange Ratio;
 
                                      14

 
    (v) the uncertain value of the LLE Common Stock, including uncertainties
  resulting from:
 
      (a) the views of Safety-Kleen's management, based on the explanation
    given to Safety-Kleen's management by Mr. Bullock at the November 5th
    meeting between them, that LLE would not be able to achieve a
    significant portion of the $100 million to $130 million of synergies it
    outlined in the LLE Offer, and the dilutive impact to LLE's earnings
    per share that would result from the inability to achieve those
    synergies;
 
      (b) the risks related to the ability of LLE, which was formed through
    the purchase by Rollins Environmental Services, Inc. of all of Laidlaw
    Inc.'s hazardous and industrial waste operations on May 15, 1997, to
    assimilate the operations of Safety-Kleen and to integrate the
    departments, systems and procedures of Safety-Kleen;
 
      (c) the fact that the LLE Common Stock has, in the past, traded at a
    premium to relevant multiples of "comparable" companies, and there is
    no assurance that this trading range can be maintained for shares of
    the LLE Common Stock that would be received by Safety-Kleen's
    shareholders in the LLE Offer;
 
      (d) the fact that the LLE Offer would result in an entity that has
    significantly more debt than does LLE currently, which would make
    Laidlaw Environmental particularly susceptible to adverse changes in
    its industry, the economy and the financial markets generally; and
 
      (e) the risks of material adverse impact on the value of the LLE
    Common Stock resulting from the issuance of approximately 162 million
    to 202 million shares of the LLE Common Stock in connection with the
    LLE Exchange Offer, as well as the substantial overhang from the 121
    million shares of the LLE Common Stock owned by Laidlaw Inc. and the
    $350 million 5% convertible debenture due 2009 (the "Laidlaw
    Convertible Debenture") issued by LLE that may be converted at the
    option of Laidlaw Inc. into the LLE Common Stock at a conversion price
    of $3.75 per share beginning in 2002;
 
    (vi) the fact that LLE's commitment letter with respect to the financing
  of the LLE Offer is subject to numerous conditions, including the execution
  of definitive agreements relating to a merger and its exchange offer and
  the satisfactory completion of due diligence examinations and a comparison
  of those conditions to the conditions of the Philip Merger Agreement;
 
    (vii) the fact that LLE's Pro Forma Financial Information disclosed in
  the LLE Registration Statement, does not fairly allocate the purchase price
  so as to comply with generally accepted accounting principles. A review of
  LLE's allocation discloses that:
 
      (a) LLE's Pro Forma Financial Information reflects an adjustment of
    $1.3 billion, writing up "certain Safety-Kleen property, plant and
    equipment to fair value," stated to be allocated "primarily [to]
    buildings, land, improvements and processing equipment". This write-up
    increases Safety-Kleen's net property, plant and equipment from
    $629,561,000 to $1,925,205,000 and records related depreciation expense
    of $32,392,000, using a 40 year estimated life for the entire write-up.
    It appears to make little, if any, allocation to machinery and
    equipment, autos and trucks, and leasehold improvements; and
 
      (b) LLE's Pro Forma Combined Balance Sheet reflects no purchase price
    allocation to identifiable intangible assets, notwithstanding the fact
    that Safety-Kleen has significant identifiable intangible assets
    including a publicly disclosed total of 400,000 customers, and
    software.
 
    The Board was advised that a reasonable allocation using the assumptions
  set forth below produces a materially greater loss in combined continuing
  operations, both before and after tax, and has a material negative impact
  on pro forma combined tangible net worth. Such assumptions were:
 
      (1) original cost, disclosed in Safety-Kleen's 1996 Annual Financial
    Statements, for Safety-Kleen's property, plant and equipment and
    equipment at customers (on the assumption that appraisal would restore
    those depreciated assets to that level);
 
 
                                      15

 
      (2) a value of approximately $300 million (calculated at an
    approximate per customer purchase price derived from publicly available
    information on number of customers and price paid for customers in
    recent Safety-Kleen acquisitions); and
 
      (3) the following useful lives (derived as reasonable estimates from
    Safety-Kleen's publicly disclosed accounting policies (taking into
    account the fact that property, plant and equipment is used): equipment
    at customers--10 years, buildings and improvements--30 years, leasehold
    improvements--10 years, machinery and equipment--10 years, autos and
    trucks--4 years, goodwill--40 years, customer lists--6 years,
    software--10 years.
 
    (viii) the uncertainty as to the completion and timing of the LLE Offer
  and any subsequent merger of the Offeror into Safety-Kleen;
 
    (ix) the fact that Safety-Kleen's shareholders' exposure to the impact of
  environmental liabilities would increase if the LLE Offer were consummated
  because of differences between their respective environmental services
  businesses:
 
      (a) Safety-Kleen is in the reclamation and resource recovery part of
    the hazardous waste business--i.e., collection, storage and processing
    of hazardous wastes without underground storage;
 
      In contrast, LLE is in the landfills and incinerators part of the
    hazardous waste business--i.e., collection of hazardous waste for
    burning or burying in hazardous waste landfills; this sector presents
    greater long term liability risk since these landfills will contain
    hazardous waste in perpetuity;
 
      (b) For 230 facilities, Safety-Kleen provides financial assurance for
    closure and post-closure care of $76.1 million, most of which is
    covered on the strength of its balance sheet, and current reserves,
    based on its actual experience in closing its own sites, of $49.2
    million for remedial cleanup work, superfund site liability, and
    closure activities;
 
      In contrast, for 85 facilities, LLE, based on its 1997 Form 10-K, is
    required to provide financial assurance of more than $450 million,
    which it cannot satisfy on the strength of its balance sheet, and must
    satisfy based on letters of credit, purchased insurance or guarantees
    from its parent, Laidlaw Inc. Notwithstanding its financial assurance
    obligation and its financial statement disclosure that it expects to
    spend $280 million on environmental liabilities, LLE has reserved only
    $183.1 million for environmental liabilities; and
 
      (c) the statements in various analysts' reports reflecting Laidlaw
    Inc.'s management's stated goal of deconsolidating with LLE;
 
    (x) the fact that if the LLE Offer and the subsequent merger of the
  Offeror into Safety-Kleen were consummated, Laidlaw Inc. would own between
  32% and 36% of Laidlaw Environmental (without taking into account the
  Laidlaw Convertible Debenture) and, therefore, would be able to exercise
  significant influence over all matters requiring shareholder approval,
  including the election of directors and approval of significant corporation
  transactions; and
 
    (xi) the fact that LLE has stated its intention to move Safety-Kleen's
  Elgin headquarters to South Carolina and reduce Safety-Kleen's work force
  and the adverse impact that would have on Safety-Kleen's employees.
 
  The foregoing describes all material factors considered and given weight by
the Board in connection with its evaluation of the LLE Offer. In view of the
variety of factors considered in connection with its evaluation of the LLE
Offer, the Board did not find it practicable to and did not quantify or
otherwise assign relative weights to the specific factors considered in
reaching its determinations and recommendation. In addition, individual members
of the Board may have given different weight to different factors. The Board
viewed its position and recommendation as being based on the totality of the
information presented to and considered by it.
 
  (3) Opinions of Financial Advisor.
 
  General. Safety-Kleen retained William Blair to act as its financial advisor
in connection with Safety-Kleen's exploration of strategic alternatives for
enhancing shareholder value. No limitations were imposed by the Safety-Kleen
Board of Directors upon William Blair with respect to the investigations made
or the procedures
 
                                       16

 
followed by it in rendering its opinions to the Board. William Blair is a
nationally recognized firm and, as part of its investment banking activities,
is regularly engaged in the valuation of businesses and their securities in
connection with merger transactions and other types of strategic combinations
and acquisitions. Safety-Kleen retained William Blair as its financial advisor
on the basis of William Blair's experience and expertise in transactions
similar to the Merger, its reputation in the investment banking community and
its existing investment banking relationship with Safety-Kleen. Edgar D.
Jannotta, Sr., a Senior Director of William Blair, serves as a member of the
Board of Directors of Safety-Kleen.
 
  The summary set forth below does not purport to be a complete description of
the analyses performed by William Blair, but describes, in summary form, the
principal elements of the analyses made by William Blair in arriving at its
opinions. The preparation of a fairness opinion is a complex process and
involves various determinations as to the most appropriate and relevant
methods of financial analysis and the application of these methods to the
particular circumstances. Therefore, such an opinion is not readily
susceptible to summary description. The preparation of a fairness opinion does
not involve a mathematical evaluation or weighing of the results of the
individual analyses performed, but requires William Blair to exercise its
professional judgment, based on its experience and expertise in considering a
wide variety of analyses taken as a whole. Each of the analyses conducted by
William Blair was carried out in order to provide a different perspective on
the Philip Merger and add to the total mix of information available. William
Blair did not form a conclusion as to whether any individual analysis,
considered in isolation, supported or failed to support an opinion as to
fairness. Rather, in reaching its conclusion, William Blair considered the
results of the analyses in light of each other and ultimately reached its
opinion based on the results of all analyses taken as a whole. William Blair
did not place particular reliance or weight on any individual analysis, but
instead concluded that its analyses, taken as a whole, supported its
determination. Accordingly, notwithstanding the separate factors summarized
above, William Blair believes that its analyses must be considered as a whole
and that selecting portions of its analyses and the factors considered by it,
without considering all analyses and factors, may create an incomplete view of
the evaluation process underlying its opinions. In performing its analyses,
William Blair made numerous assumptions with respect to industry performance,
business and economic conditions and other matters. The analyses performed by
William Blair are not necessarily indicative of actual values or future
results, which may be significantly more or less favorable than suggested by
such analyses.
 
  November 20, 1997 Opinion. At the November 20, 1997 meeting of the Safety-
Kleen Board of Directors, William Blair rendered its oral opinion (which
opinion was subsequently confirmed by delivery of a written opinion dated
November 20, 1997) that, as of such date, and based upon and subject to the
factors and assumptions set forth in such opinion, the consideration to be
received by Safety-Kleen's shareholders in the Merger is fair to Safety-
Kleen's shareholders from a financial point of view. The full text of William
Blair's opinion to Safety-Kleen's Board of Directors dated as of November 20,
1997 is attached hereto as Exhibit 10 and is incorporated herein by reference
and should be read in its entirety in connection with this Statement. The
following summary of William Blair's opinion is qualified in its entirety by
reference to the full text of William Blair's opinion. William Blair's opinion
was addressed to the Safety-Kleen Board of Directors for the purposes of its
evaluation of the Philip Merger and does not constitute a recommendation to
any Safety-Kleen shareholder as to how such shareholder should vote at the
special meeting of shareholders to vote on the Philip Merger.
 
  In connection with its opinion, William Blair reviewed a final draft of the
Merger Agreement, as well as certain financial and other information that was
publicly available or furnished to William Blair by Safety-Kleen, Philip,
Apollo and Blackstone, including certain internal financial analyses,
financial forecasts, reports and other information prepared by the management
of Safety-Kleen. William Blair held discussions with members of management of
Safety-Kleen concerning Safety-Kleen's historical and current operations,
financial condition and prospects. In addition, William Blair (i) compared the
financial position and operating results of Safety-Kleen with those of
publicly traded companies William Blair deemed relevant for its opinion; (ii)
compared certain financial terms of the Merger to certain financial terms of
other selected business combinations William Blair deemed relevant for its
opinion; and (iii) conducted such other financial studies, analyses and
investigations and reviewed such other factors as William Blair deemed
appropriate for the purposes of rendering its opinion.
 
 
                                      17

 
  In rendering its opinion, William Blair relied upon and assumed the accuracy,
completeness and fairness of all of the financial and other information that
was available to it from public sources and that was provided to William Blair
by Safety-Kleen. With respect to the financial projections supplied to William
Blair, William Blair assumed that they were reasonably prepared and reflected
the best currently available estimates and judgments of the management of
Safety-Kleen as to the future operating and financial performance of Safety-
Kleen. William Blair's opinion relates to financial fairness only; no opinion
is expressed as to the appropriateness of the financial structure or as to the
soundness of the financial condition of Safety-Kleen subsequent to the
effective time of the Philip Merger. William Blair did not assume any
responsibility for making any independent evaluation of Safety-Kleen's assets
or liabilities or for making any independent verification of any of the
information reviewed by William Blair.
 
  William Blair's opinion was necessarily based on economic, market, financial
and other conditions as they existed on November 20, 1997, the date of William
Blair's opinion, and on the information made available to William Blair as of
such date. It should be understood that, although subsequent developments may
affect its opinion, William Blair does not have any obligation to update,
revise or reaffirm William Blair's opinion. The following is a summary of the
material factors considered and principal financial analyses performed by
William Blair to arrive at its opinion. William Blair performed certain
procedures, including each of the financial analyses described below, and
reviewed with the management of Safety-Kleen the assumptions upon which such
analyses were based, and other factors.
 
  Summaries of Valuation Analyses. In connection with its opinion and the
presentation of its opinion to the Board of Directors of Safety-Kleen, William
Blair performed certain valuation analyses, including: (i) a comparison with
comparable publicly traded companies, (ii) a discounted cash flow analysis,
(iii) an analysis of certain comparable acquisitions and (iv) a premium
analysis. Such analyses are summarized below.
 
  Analysis of Certain Publicly Traded Companies. William Blair reviewed and
compared certain financial information relating to Safety-Kleen to
corresponding financial information, ratios and public market multiples for ten
publicly traded companies in the environmental services industry. Six of these
companies are solid waste management companies (the "Solid Waste Comparables")
and four are in the industrial waste management industry (the "Industrial Waste
Comparables"). The Solid Waste Comparables are (i) Allied Waste Industries,
Inc., (ii) Browning-Ferris Industries, Inc., (iii) USA Waste Services, Inc.,
(iv) Waste Management, Inc., (v) Waste Management International plc and (vi)
Wheelabrator Technologies Inc. The Industrial Waste Comparables are (i) Clean
Harbors, Inc., (ii) Envirosource, Inc., (iii) Laidlaw Environmental and (iv)
Philip. William Blair selected these companies because they are publicly traded
companies which William Blair deemed most comparable to Safety-Kleen's
operations and financial condition. Although William Blair compared the trading
multiples of the selected companies at the date of William Blair's opinion to
the implied purchase multiples of Safety-Kleen, none of the selected companies
is identical to Safety-Kleen. The per Share price calculations based on such
multiples ranged from $21.61 to $29.07 per Share.
 
  Among the information considered were revenue, operating income ("EBIT"),
earnings before interest, taxes, depreciation and amortization ("EBITDA"), net
income, earnings per share ("EPS"), gross profit margins, EBIT margins and net
income margins, growth in revenues and net income, return on assets and equity,
and capital structure. The multiples and ratios for Safety-Kleen and the
comparable companies were based on the most recent publicly available financial
information and on EPS estimates for 1997 and 1998 from First Call Corporation,
and the closing share prices as of November 14, 1997.
 
  William Blair observed that the multiples of common stock share price
("Price") to EPS, as well as multiples of market value plus book value of total
debt (including minority interests and preferred stock) less cash and
equivalents ("Enterprise Value") to revenues, EBIT and EBITDA implied by the
terms of the Merger compared favorably, from Safety-Kleen's perspective, to the
median of the corresponding multiples of the comparable companies.
Specifically, the terms of the Merger implied 1.9x latest twelve month ("LTM")
revenues, 15.8x LTM EBIT and 9.4x LTM EBITDA. By comparison, the analysis of
selected environmental service companies resulted in a median multiple of 1.9x
for Enterprise Value to LTM revenues, 16.2x for Enterprise Value to LTM EBIT
and 7.7x for Enterprise Value to LTM EBITDA. The analysis of selected
 
                                       18

 
environmental service companies also resulted in a median multiple of 22.8x
for the Price to LTM EPS, 19.4x for Price to estimated calendar 1997 EPS and
16.7x for Price to estimated calendar 1998 EPS. The terms of the Philip Merger
implied 26.3x for Price to LTM EPS, 25.5x for Price to estimated fiscal 1997
EPS and 22.3x for Price to estimated fiscal 1998 EPS.
 
  Discounted Cash Flow Analysis. Using a discounted cash flow ("DCF")
analysis, William Blair estimated the net present value of the unleveraged
free cash flows that Safety-Kleen could produce on a stand-alone basis over a
five year period from 1998 to 2002. In estimating these cash flows the
management of Safety-Kleen made certain assumptions about the operating
performance of Safety-Kleen over the five year period. Such assumptions
included assumptions regarding unit growth and pricing in the markets in which
Safety-Kleen competes, drum volume for hazardous waste, lube oil pricing,
developments in the hazardous waste industry, and U.S. and international
economic conditions. Without limitation, these cash flow estimates assumed
that certain possible changes or developments in Safety-Kleen's business,
which could potentially favorably impact value, would not affect cash flow
during such period. In calculating the "terminal value", William Blair assumed
multiples of Enterprise Value to EBITDA ranging from 6.0x to 8.0x, which
multiples William Blair believed to be appropriate for such an analysis. The
annual and terminal free cash flows were discounted to determine a net present
value of the unleveraged equity value of Safety-Kleen. Discount rates in a
range of 10.0% to 12.0% were chosen based upon an analysis of the weighted
average cost of capital of the publicly traded comparable group of companies
described above. The DCF analysis indicated a valuation of the equity of
Safety-Kleen of between $1.5 billion to $1.8 billion, or $25.58 to $30.35 per
share. As a result, William Blair believes that the price to be paid on the
Philip Merger compares favorably, from Safety-Kleen's perspective, to the
values indicated by the DCF analysis.
 
  Comparable Acquisitions. William Blair performed an analysis of selected
recent merger or acquisition transactions in the environmental services
industry. The selected transactions were chosen based on William Blair's
judgment that they were generally comparable, in whole or in part, to the
proposed transaction. In total William Blair examined twenty transactions that
were announced between September 10, 1993 and June 19, 1997 involving certain
environmental services companies. The selected transactions were not intended
to be representative of the entire range of possible transactions in the
environmental services industry. Although William Blair compared the
transaction multiples of these companies to the implied purchase multiples of
Safety-Kleen, none of the selected companies is identical to Safety-Kleen.
 
  William Blair reviewed the consideration paid in such transactions in terms
of the Enterprise Value of such transactions as a multiple of revenues, EBIT
and EBITDA for the latest twelve months prior to the announcement of such
transactions. Additionally, William Blair reviewed the consideration paid in
such transactions in terms of the price paid for the common stock ("Equity
Purchase Price") of such transactions as a multiple of net income for the
twelve months prior to the announcement of such transactions. William Blair
observed that the multiples of Equity Purchase Price to net income, as well as
multiples of Enterprise Value to revenues, EBIT and EBITDA implied by the
terms of the Philip Merger compared favorably, from Safety-Kleen's
perspective, to the median of the corresponding multiples of the comparable
acquisitions.
 
  Such analysis of the twenty acquisitions in the environmental services
industry resulted in a median multiple of 1.4x for Enterprise Value to LTM
revenues, 14.9x for Enterprise Value to LTM EBIT, 8.7x for Enterprise Value to
LTM EBITDA and 23.3x for Equity Purchase Price to LTM net income. In contrast,
the implied purchase multiples for Safety-Kleen were 1.9x for Enterprise Value
to LTM revenues, 15.8x for Enterprise Value to LTM EBIT, 9.4x for Enterprise
Value to LTM EBITDA and 26.3x for Equity Purchase Price to LTM net income.
 
  Premium Analysis. In addition to evaluating multiples paid in transactions
in the environmental services industry, William Blair considered, for twenty-
two industrial transactions which were announced from March 29, 1996 to
September 29, 1997 and whose Enterprise Value ranged from $790.7 million to
$2.8 billion, the premiums paid over each company's stock price prior to the
announcement of a transaction. The median premium paid in those transactions
was 45.7%, 42.8% and 28.7%, respectively, over each company's stock price one
month, one week and one day before each respective announcement. In contrast,
the premium paid over the
 
                                      19

 
price of the Shares on July 8, 1997, August 1, 1997 and August 7, 1997 or one
month, one week and one day, respectively, prior to the announcement that
Safety-Kleen was evaluating strategic alternatives, was 56.5%, 53.2% and
51.6%, respectively. As a result, William Blair believes that the premium paid
over the price of the Shares compares favorably, from Safety-Kleen's
perspective, to the values indicated by the premium analysis.
 
  December 20, 1997 Opinion. On December 20, 1997 the Safety-Kleen Board of
Directors requested William Blair's opinion as to the superiority, from a
financial point of view, of the consideration which would be received pursuant
to the terms of the LLE Offer as compared with the Philip Merger. Based on the
advice of Safety-Kleen's counsel, William Blair made that comparison based on
their respective anticipated values from a financial point of view as of
consummation.
 
  At the December 20, 1997 meeting of the Safety-Kleen Board of Directors,
William Blair rendered its oral opinion (which opinion was subsequently
confirmed by delivery of a written opinion dated as of December 20, 1997)
that, as of such date, and based upon and subject to the factors and
assumptions set forth in such written opinion, William Blair does not have a
basis for concluding that the LLE Offer is superior to the Philip Merger from
a financial point of view. The full text of William Blair's opinion to the
Safety-Kleen Board of Directors dated as of December 20, 1997 is attached
hereto as Exhibit 14 and is incorporated herein by reference and should be
read in its entirety in connection with this Statement. The following summary
of William Blair's opinion is qualified in its entirety by reference to the
full text of William Blair's opinion. William Blair's opinion was addressed to
the Safety-Kleen Board of Directors for the purposes of its evaluation of the
LLE Offer and does not constitute a recommendation to any Safety-Kleen
shareholder as to how such shareholder should vote at the special meeting to
vote on the Philip Merger.
 
  In connection with William Blair's review of the LLE Offer and the Philip
Merger and the preparation of its opinion, William Blair: (a) reviewed the
terms and conditions of the Philip Merger Agreement and the financial terms as
set forth in the Philip Merger Agreement and the Preliminary Proxy Statement
dated November 26, 1997 filed by Safety-Kleen with the Commission; (b)
reviewed the terms and conditions of the LLE Offer and the financial terms as
set forth in the LLE Registration Statement; (c) analyzed the historical
revenue, operating earnings, net income, dividend capacity and capitalization
of both LLE and certain other publicly held companies that William Blair
believes to be comparable to LLE; (d) analyzed certain publicly available
financial and other information relating to LLE and the unaudited pro forma
combined financial information in the LLE Offer and performed a sensitivity
analysis on such pro forma financial information based upon variable synergy
assumptions; (f) reviewed the historical market prices and trading volume of
the LLE Common Stock as well as its stock ownership and analyzed factors which
could influence the trading price of the LLE Common Stock on the anticipated
closing date for the LLE Offer; (g) together with Safety-Kleen's management
met with Mr. Bullock, Chairman of LLE; and (h) performed such other analyses
as William Blair deemed appropriate.
 
  William Blair's opinion with respect to the LLE Offer reflects only limited
access to LLE management and no access to internal LLE projections. Upon
consummation of either the Philip Merger or the LLE Offer, Safety-Kleen will
pay William Blair a transaction fee. The amount of such fee increases as the
consideration received by Safety-Kleen's shareholders increases.
 
  In rendering its opinion, William Blair assumed that the Philip Merger or
the LLE Offer would be consummated on the terms described in the Philip Merger
Agreement or the LLE Registration Statement, respectively, without any waiver
of any material terms or conditions by Safety-Kleen and that obtaining the
necessary regulatory approvals for the Philip Merger or the LLE Offer would
not have an adverse effect on Safety-Kleen.
 
  William Blair's opinion was necessarily based on economic, market, financial
and other conditions as they existed on December 20, 1997, the date of its
opinion, and on the information available to William Blair as of such date. It
should be understood that, although subsequent developments may affect its
opinion, William Blair does not have any obligation to update, revise or
reaffirm its opinion. The following is a summary of the material factors
considered and principal financial analyses performed by William Blair to
arrive at its opinion. William Blair performed certain procedures, including
each of the financial analyses described below, and reviewed with the Board of
Directors of Safety-Kleen the assumptions upon which such analyses were based.
 
                                      20

 
  Factors Considered and Summary of Analyses Performed. In connection with its
opinion and the presentation of its opinion to the Board of Directors of
Safety-Kleen, William Blair reviewed certain factors and performed certain
analyses, including: (i) a comparison of the current purported nominal value
of the LLE Offer with the $27.00 per share cash consideration in the Merger;
(ii) an assessment of the factors which could influence the trading price of
the LLE Common Stock between the time of announcement of a transaction with
LLE and closing; and (iii) a discounted cash flow analysis of the value of the
LLE Common Stock on a pro forma basis following an acquisition of Safety-
Kleen. Such factors and analyses are reviewed below.
 
  Summary of LLE Offer. William Blair reviewed the LLE Offer. Pursuant to its
terms, LLE and a subsidiary propose to exchange, for each outstanding Share,
cash in the amount of $15.00 less termination fees and expenses, new severance
agreements and other deal expenses plus that number of shares of LLE Common
Stock determined by the Exchange Ratio. In soliciting materials filed with the
Commission, LLE identified termination fees and expenses of $1.28 per share
and severance costs of $0.86 per share. The termination fees and expenses
would reduce the cash portion of the LLE Offer by $1.28, from $15.00 to $13.72
per share. Should the entire severance cost be deducted, the cash portion
would be further reduced by $0.86, from $13.72 to $12.86 per share. While LLE
has challenged these fees, William Blair assumed their validity for purposes
of rendering its opinion. William Blair noted that the Exchange Ratio provides
Safety-Kleen shareholders with LLE Common Stock with a market value of $15.00,
assuming that the LLE Common Stock price for randomly selected days among the
twenty trading days prior to closing of the LLE Offer averages between
$4.28571 and $5.35714 per share. Should the price of the LLE Common Stock as
selected for use in its Exchange Ratio be below $4.28571 at closing, the
Exchange Ratio would be fixed at 3.5 shares; should the price be above
$5.35714 the Exchange Ratio would be 2.8 shares. William Blair noted that on
December 19, 1997, the LLE Common Stock opened below the collar at $4.13 and
closed within the collar at $4.44 per share. In addition, William Blair noted
that the LLE Common Stock closed below the collar on December 10, December 11,
December 17 and December 18, 1997. An average stock price selected at the time
of closing for the Exchange Ratio of below $4.29 would result in the stock
portion of the consideration having a market value of less than $15.00 at that
time. Combining the cash portion of less than $13.72 and the stock portion of
$15.00, the nominal value would at most be $28.72. Assuming the termination
fees and expenses are deducted from the cash portion, LLE's average stock
price would have to decrease to $3.79 per share, or 14.6% below the closing
price on December 19, 1997 for the LLE Offer to have a market value equal to
the cash consideration of $27.00 per share in the Philip Merger; should the
entire severance cost be added to the deductions from the cash portion, LLE's
average share price would have to fall to $4.04 per share, or 9.0% from the
closing price on December 19, 1997 for the LLE Offer to have a market value
equal to the cash consideration of $27.00 per share in the Philip Merger.
 
  Factors which could affect LLE's share price prior to closing of the LLE
Offer. William Blair advised the Safety-Kleen Board of Directors that the
following factors could affect the price of the LLE Common Stock:
 
 1. Possible revision in financial analysts' estimates for accretion in LLE's
    fiscal 1998 EPS resulting from a combination of Safety-Kleen and LLE
 
  William Blair pointed out that research analysts as of December 17, 1997 are
of the view that a LLE acquisition of Safety-Kleen would result in substantial
accretion in its fiscal 1998 earnings per share ("EPS"). As of December 17,
1997, the mean estimate of nine research analysts for LLE's fiscal 1998 EPS is
$0.16. During a telephonic conference with institutional investors on November
4, 1997, following its announcement of a proposal to acquire all of the
outstanding Shares for a consideration per Share equal to $14 in cash and 2.4
shares of the LLE Common Stock, Mr. Bullock stated that the acquisition of
Safety-Kleen would be accretive and that one analyst's estimate of a combined
pro forma 1998 EPS of $0.28 was "in the ball park." This estimate indicated
accretion of approximately 75% to LLE resulting from the acquisition of
Safety-Kleen. The accretion was dependent on achieving annual synergies of
approximately $100 million. On November 5, 1997, a research analyst from
Merrill Lynch reported that the acquisition of Safety-Kleen would double his
estimate to $0.30 per share.
 
 
                                      21

 
  William Blair noted that revised expectations by research analysts
concerning LLE's synergy assumption would reduce their estimates for 1998
results. William Blair performed a sensitivity analysis to determine the
accretion or (dilution) to EPS which would result from various assumed levels
of synergies. The table below shows the results of such analysis.
 
                           EPS ACCRETION (DILUTION)
 


                                                      CALENDAR YEAR END
                                                      -----------------
             ANNUAL SYNERGIES ACHIEVED              1998                          1999
             -------------------------              ----                          ----
                                                                            
             $25 million                            (34.6)%                       (23.0)%
             $50 million                            (14.7)                         (9.3)
             $75 million                              5.2                           4.5
             $100 million                            25.1                          18.3

 
  William Blair described the discussions regarding synergy expectations that
took place on November 5, 1997 between Mr. Bullock, members of management of
Safety-Kleen and their respective representatives. During that meeting, Mr.
Bullock presented the components of LLE's synergy expectations as follows:
 
  . Internalization of Safety-Kleen waste into LLE's incineration
    facilities--$14 to $24 million
 
  . Closing of branch facilities--$37 million ($1.5 million annual savings
    per branch)
 
  . Closing of recycle centers--$12 to $15 million ($2 to $2.5 million annual
    savings per center)
 
  . Selling, general and administrative savings--the balance, which includes
    potential closing of Elgin facility (approximately $30 million)
 
  . Total synergies--$93 to $106 million
 
  During that meeting, Safety-Kleen management expressed significant doubt as
to LLE's ability to achieve these levels of synergies, in particular the
realization of cost savings through the internalization of waste streams and
the closing of branch locations with resulting employee reductions which would
negatively impact service to customers.
 
  Below are estimates prepared by Safety-Kleen management of synergies which
LLE might achieve, based solely on their knowledge of Safety-Kleen's business,
publicly available information regarding LLE and Safety-Kleen's meeting with
Mr. Bullock.
 
  . Internalization of Safety-Kleen waste ($4.1 million total cost less LLE
    process and transportation expense of approximately 50%)--approximately
    $2.0 million
 
  . Savings from consolidation with Safety-Kleen's operating facilities ($0.2
    million per branch facilities and recycling centers)--$10 million to $12
    million
 
  . Selling, general and administrative expense savings--$14.4 million
 
  . Total synergies--$26.4 to $28.4 million
 
  For the purposes of its assessment of factors which could affect LLE's stock
price, William Blair assumed, with the consent of the Board of Directors of
Safety-Kleen, total synergies of $50 million. In arriving at this number, in
addition to the aforementioned opinions of synergies, William Blair took into
account the November 5, 1997 meeting of LLE, its financial advisor, Safety-
Kleen management and William Blair. Because annual synergies of $50 million
are substantially below analysts' expectations and would result in a dilutive
transaction to LLE, a downward revision of analysts' expectations could have
the impact of reducing LLE's share price.
 
 2. Possible revision of pro forma financial statements
 
  The LLE Registration Statement contains unaudited pro forma combined
financial information. William Blair reviewed the basis of presentation of
these financial statements. Among other things, William Blair noted that LLE
(based on its estimate of fair value) has allocated $1.9 billion of the
proposed purchase price to
 
                                      22

 
property, plant and equipment carried on Safety-Kleen's books, net of
depreciation, at $629 million. For accounting presentation purposes, LLE
depreciates such assets over a 40 year period, resulting in an annual
depreciation charge of $32.3 million. William Blair noted that LLE depreciates
buildings over periods of between 20 and 40 years and machinery over periods
of between 5 and 30 years. If LLE had prepared its pro forma financial
statements on a basis consistent with its historical reporting methodologies,
and were to change the depreciation period from 40 to 20 years, pretax income
would decrease by $32.3 million. While William Blair noted this in its
presentation to the Board, it did not reflect this change in any of its
analyses.
 
 3. Possible price/earnings multiple contraction in LLE Common Stock prior to
 closing
 
  William Blair reviewed and compared certain financial information relating
to LLE and Safety-Kleen to corresponding financial information, ratios and
public market multiples for nine publicly traded companies in the
environmental services industry. Taken as a whole, this is the same group of
comparable companies listed under "--November 20, 1997 Opinion" above.
Although William Blair compared the trading multiples of the selected
companies as of December 17, 1997 to LLE, none of the selected companies is
identical to Safety-Kleen or the LLE Common Stock. William Blair observed the
LLE Common Stock currently trades at very high EPS and EBITDA multiples
relative to its peer group of comparable companies as well as its expected
earnings growth rate. At December 17, 1997, LLE's stock price is trading at
approximately 23.3x calendar 1998 EPS and 16.5x LTM EBITDA (the EBITDA figures
used for this calculation include the pro forma results of Rollins
Environmental Services) which represents a premium to the industry median of
approximately 38% for EPS, and 87% for LTM EBITDA. William Blair pointed out
that assuming $50 million of annual synergies, $1.28 of deductions from the
cash portion of the LLE Offer and a LLE share price within the collar, the
value of the LLE Offer applying the LLE multiple would be $28.72. But if
Safety-Kleen's multiple, the industry median multiple or the S&P 500 multiple
were used, the value to Safety-Kleen shareholders would be $22.41, $23.78 and
$26.39, respectively.
 
  Additionally, LLE's calendar 1998 P/E ratio is at 1.6x its expected EPS
long-term growth rate of 15%, compared to the industry's 1998 P/E ratio to
growth rate of 1.2x. William Blair noted that Safety-Kleen's operating
characteristics and growth prospects would be a major component of a pro forma
combined entity. As indicated in the unaudited pro forma combination analysis
for the year ended August 31, 1997 provided by LLE in the LLE Registration
Statement, Safety-Kleen's operations provided 51.9% of the combined revenue
and 102.7% of the combined operating income (before the restructuring charge
taken by LLE related to the acquisition of Rollins in the amount of $331.7
million). William Blair also noted that estimated growth in earnings per share
reported by First Call for the 1999 calendar year for LLE and Safety-Kleen
were 22.2% and 12.4%, respectively. William Blair pointed out that after a
potential combination with Safety-Kleen, it was unlikely that LLE would be
able to retain its multiples given the contribution of the growth
characteristics of Safety-Kleen's business to the combined entity.
 
 4. Trading Characteristics of the LLE Common Stock
 
  William Blair noted that for any Exchange Ratio for average LLE Common Stock
prices within the collar, Safety-Kleen shareholders would receive LLE Common
Stock with a value at closing of approximately $870 million. William Blair
compared this with the common stock's historical trading characteristics of
the LLE Common Stock. Between February 7, 1997 and December 17, 1997,
approximately 29.2 million shares traded representing approximately $117
million in total dollar volume as compared with the $870 million proposed to
be issued to Safety-Kleen shareholders. The weighted average trading price for
the LLE Common Stock during this period is $4.01 per share. During this same
period, LLE's daily stock trading volume was less than 135,000 shares, or $0.5
million in dollar volume. William Blair expressed concern as to the ability of
the market for the pro forma combined entity to absorb the shares that would
be issued to Safety-Kleen shareholders in the LLE Offer.
 
 
                                      23

 
  William Blair contrasted the $27.00 all cash offer of the Philip Merger with
the stock component of the LLE Offer and pointed out that the value of the LLE
Common Stock would be affected, up or down, by market conditions. On October
27, 1997, when the Dow Jones Industrial Average fell 554 points, or 7.2%. The
LLE Common Stock dropped 13.8%.
 
  Safety-Kleen shareholders are affected by a substantial overhang from the 121
million shares owned by Laidlaw Inc., constituting approximately 67.4% of LLE's
outstanding shares. In addition, Laidlaw Inc. holds a $350 million 5%
subordinated convertible pay-in-kind debenture which becomes convertible into
93 million shares of the LLE Common Stock in 2002. Laidlaw Inc. has been
divesting itself of environmental assets since Mr. Bullock became its Chief
Executive Officer in 1993. Laidlaw Inc. management has a stated goal of wanting
to deconsolidate LLE and make it easier to potentially exit its LLE investment
by increasing the float. The sale by Laidlaw Inc. of a sizable block of its
stock could be detrimental to the trading value of the LLE Common Stock.
 
  William Blair compared the institutional holdings of LLE and Safety-Kleen,
respectively. Based on Schedule 13-F filings, as of September 30, 1997, LLE's
25 largest institutional holders represented approximately 14% of its total
market capitalization (based on December 16, 1997 share prices), and
approximately 40% of LLE's total public float. This compares to 53% of Safety-
Kleen's total market capitalization which is held by its 25 largest
institutional holders as of September 30, 1997. William Blair also pointed out
during the December 20, 1997 Board meeting that there is little overlap in
institutional ownership for the LLE Common Stock in Safety-Kleen's common
stock. Safety-Kleen's institutional holders may assess ownership of the common
stock of the pro forma combined entity differently from ownership of Safety-
Kleen common stock, given their different investment characteristics, including
leverage, environmental risk, management, valuation and operations.
 
  William Blair compared certain differences in operating, financial and other
characteristics between the ownership in Safety-Kleen common stock and common
stock of the pro forma combined entity. William Blair pointed out that LLE has
substantial assets in hazardous waste and incineration operations and that
different environmental risk could be attached to such operations as contrasted
to Safety-Kleen's operations. William Blair noted that in contrast to Safety-
Kleen, LLE does not pay a dividend. Furthermore, upon closing, the pro forma
combined entity, would have debt of approximately $2.1 billion as opposed to
Safety-Kleen's $246.1 million. Total debt to total capitalization would
increase from 33.2% for Safety-Kleen to 64.0% for the pro forma combined
entity. The ratio of calendar 1998 EBITDA to interest expense for Safety-Kleen
is 12.2x compared to 2.9x for the pro forma combined entity assuming $50
million of synergies. These factors could lead current Safety-Kleen
shareholders to either (i) sell the LLE Common Stock received in a transaction,
potentially affecting the price of that stock around the time of closing, (ii)
short the LLE Common Stock in advance of closing in order to hedge their
prospective position in the LLE Common Stock; and/or (iii) convey a desire to
sell the LLE Common Stock after closing, and thereby create a potential market
overhang.
 
  Discounted Cash Flow Analysis. Using a discounted cash flow ("DCF") analysis,
William Blair estimated the net present value of the unleveraged free cash
flows that LLE and Safety-Kleen could produce on a combined basis over a five
year period from 1998 to 2002. From this analysis William Blair derived an
intrinsic value for the combined entity as of the anticipated closing date. The
cash flows were based on the aforementioned projections prepared by Safety-
Kleen's management for Safety-Kleen on a stand-alone basis combined with (i)
estimates for LLE's cash flow for fiscal 1998 and 1999 as contained in a
research report dated September 25, 1997 prepared by Raymond James & Associates
("Raymond James"), arithmetically adjusted by William Blair to approximate a
calendar year and (ii) estimates for LLE's cash flow for the calendar years
2000, 2001 and 2002 prepared by William Blair by applying growth, margin and
capital requirement assumptions contained in the Raymond James report for the
fiscal 1999 year. For the reasons previously described, William Blair assumed
annual synergies achieved of $50 million. In calculating the terminal value,
William Blair assumed multiples of enterprise value to EBITDA ranging from 6.0x
to 8.0x which multiples William Blair believed to be appropriate for such an
analysis. The annual free cash flows and terminal values were discounted to
determine a net present value of the unleveraged equity value of the pro forma
combined entity. Discount rates in a range of 10.0% to
 
                                       24

 
12.0% were chosen based upon an analysis of the weighted average cost of
capital of the publicly traded comparable group of companies described above.
The DCF analysis indicated an intrinsic value of the pro forma combined entity
of between $1.3 billion and $1.8 billion, or $3.29 to $4.65 per share. William
Blair pointed out that the intrinsic value as derived in a DCF analysis
represents a value which assumes 100% control of the cash flows. An owner of a
single share, or a minority position, of a publicly traded stock does not
control the cash flow of that entity. Given that public shareholder ownership
is a non-control position, the intrinsic value normally exceeds public prices
by an amount described by William Blair as a "control premium." William Blair
referred to its premium analysis as described above in "--November 20, 1997
Opinion", in which William Blair considered, for 22 industrial transactions
which were announced from March 29, 1996 to September 29, 1997 and whose
enterprise value ranged from $790.7 million to $2.8 billion, the premiums paid
in such transactions over each company's stock price prior to the announcement
of a transaction. The median premium paid in those transactions was 45.7%,
42.8% and 28.7%, respectively, over each company's stock price one month, one
week and one day before each respective announcement. In order to compare the
intrinsic value per share with the market price of the LLE Common Stock,
William Blair selected a control premium of 25%, which would be an appropriate
discount from the low and high intrinsic value per share of the pro forma
combined entity. William Blair compared these intrinsic values (as discounted
for such control premium) with the collar contained in the LLE Offer and with
the $3.79 to $4.04 range of values per share for the LLE Common Stock required
to cause the LLE transaction to be equivalent to the Philip Merger, from a
financial point of view.
 
ITEM 5. PERSONS RETAINED, EMPLOYED OR TO BE COMPENSATED.
 
  Safety-Kleen retained the services of William Blair pursuant to a letter
agreement (the "William Blair Letter Agreement") dated August 8, 1997, to
render certain financial advisory and investment banking services in
connection with Safety-Kleen's analysis of strategic options including a
possible business combination (through tender offer, merger, sale or exchange
of stock, sale of all or a substantial part of its assets or otherwise) of
Safety-Kleen with another party (the "Possible Transaction"). In exchange for
the services provided, Safety-Kleen agreed to pay William Blair a quarterly
retainer fee of $25,000, payable in advance (with the first installment due
upon execution of the William Blair Engagement Letter), and an opinion fee of
$300,000, payable in the event Blair renders a fairness opinion or advises the
Board of Directors that it is unable to render such an opinion. In addition,
Safety-Kleen agreed to pay William Blair an additional fee (subject to a
credit of the retainer fee and opinion fee) equal to 0.5% of the Total
Consideration (as defined in the William Blair Engagement Letter) received by
Safety-Kleen and its shareholders as a result of the consummation of any
Possible Transaction. The William Blair Engagement Letter also provides that
Safety-Kleen shall reimburse William Blair for all itemized out-of-pocket
expenses (including reasonable fees and expenses of William Blair's counsel
and any other independent experts retained by William Blair) reasonably
incurred by William Blair in connection with its engagement by Safety-Kleen.
Safety-Kleen and William Blair also entered into a separate letter agreement,
dated August 8, 1977, whereby Safety-Kleen agreed to indemnify William Blair
against certain liabilities in connection with William Blair's engagement
under the William Blair Engagement Letter.
 
  William Blair rendered a written opinion to the Board dated November 20,
1997 that, based upon and subject to the matters set forth therein and as of
the date thereof, the cash consideration to be received by Safety-Kleen's
shareholders in the Philip Merger was fair to Safety-Kleen's shareholders from
a financial point of view.
 
  William Blair has provided certain investment banking services to Safety-
Kleen from time to time which William Blair has received customary
compensation. Mr. Edgar D. Janotta, a director of Safety-Kleen, is a Senior
Director of William Blair. In the ordinary course of its business, William
Blair and its affiliates may actively trade the debt and equity securities of
both Safety-Kleen and LLE for their own accounts and for the accounts of
customers and, accordingly, may at any time hold a long or short position in
such securities.
 
  Pursuant to a letter agreement dated August 19, 1997 (the "CSFB Engagement
Letter"), between Credit Suisse First Boston Corporation ("CSFB") and Safety-
Kleen, Safety-Kleen retained CSFB to meet with the Board of Directors to
discuss its analysis of a potential Sale of Safety-Kleen (as defined in the
CSFB Engagement Letter) and the Sale process and to perform such other
financial advisory services in connection with a potential Sale as Safety-
Kleen may reasonably request. The CSFB Engagement Letter provides for the
payment to CSFB
 
                                      25

 
of a financial advisory fee of $250,000, payable upon the execution of the CSFB
Engagement Letter, and a transaction fee of $1,000,000, payable upon the
closing of a Sale of Safety-Kleen. Safety-Kleen also agreed to reimburse CSFB
for CSFB's reasonable out-of-pocket expenses, including the fees and expenses
of CSFB's legal counsel. In addition, Safety-Kleen agreed to indemnify CSFB
against certain liabilities, including liabilities arising under federal
securities laws.
 
  CSFB has provided certain investment banking services to Safety-Kleen from
time to time for which CSFB has received customary compensation. In the
ordinary course of its business, CSFB and its affiliates may actively trade the
debt and equity securities of both Safety-Kleen and LLE for their own accounts
and for the accounts of customers and, accordingly, may at any time hold a long
or short position in such securities.
 
  Safety-Kleen has retained Chase Mellon Shareholder Services to distribute
information (including this Statement on Schedule 14D-9) on behalf of Safety-
Kleen in connection with the LLE Offer and related matters. Safety-Kleen has
also retained Hill & Knowlton as public relations advisor in connection with
the LLE Offer and related matters. Such firms will receive customary
compensation for services rendered and also will be reimbursed for their out-
of-pocket expenses.
 
  Except as set forth above, neither Safety-Kleen nor any person acting on its
behalf has employed, retained or compensated any persons to make solicitations
or recommendations to shareholders with respect to the LLE Offer.
 
  ITEM 6. RECENT TRANSACTIONS AND INTENT WITH RESPECT TO SECURITIES.
 
  (a) To the best knowledge of Safety-Kleen, no transactions in the Common
Stock have been effected during the past 60 days by Safety-Kleen or any
executive officer, director, affiliate or subsidiary of Safety-Kleen.
 
  (b) To the best knowledge of Safety-Kleen, its executive officers, directors,
affiliates and subsidiaries do not presently intend to tender, pursuant to the
LLE Offer, any Shares which are held of record or are beneficially owned by
such persons or to otherwise sell any such Shares.
 
  ITEM 7. CERTAIN NEGOTIATIONS AND TRANSACTIONS BY THE SUBJECT COMPANY.
 
  (a) Other than as set forth or referenced in Items 3(b) or 4, no negotiation
is being undertaken or is underway by Safety-Kleen in response to the LLE Offer
which relates to or would result in:
 
    (1) an extraordinary transaction such as a merger or reorganization,
  involving Safety-Kleen or any subsidiary of Safety-Kleen;
 
    (2) a purchase, sale or transfer of a material amount of assets by
  Safety-Kleen or any subsidiary of Safety-Kleen;
 
    (3) a tender offer for or other acquisition of securities by or of
  Safety-Kleen; or
 
    (4) any material change in the present capitalization or dividend policy
  of Safety-Kleen.
 
  (b) Except as described above, in Item 3(b), there are no transactions, board
resolutions, agreements in principle or signed contracts in response to the LLE
Offer which relate or would result in one or more of the matters referred to in
Item 7(a).
 
  ITEM 8. ADDITIONAL INFORMATION TO BE FURNISHED.
 
  (a) Rights Agreement. Each Right issued pursuant to the Rights Agreement
initially entitles the registered holder thereof to purchase one Share at a
price of $73.00 per Share, subject to adjustment. On the earlier of (i) the
tenth day following public announcement that a person or group of affiliated or
associated persons have acquired beneficial ownership of 20% or more of the
outstanding Shares (an "Acquiring Person") or (ii) the tenth business day (or
such later date as may be determined by action of Safety-Kleen's Board of
Directors prior to the time any person becomes an Acquiring Person) after the
commencement of, or announcement of an intention to make, a tender offer or
exchange offer the consummation of which would result in the beneficial
ownership by a person or group of affiliated or associated persons of 20% or
more of such outstanding Shares
 
                                       26

 
(the earlier of such dates being the "Distribution Date"), the Rights become
exercisable and trade separately from the Shares. In the event that a person
becomes an Acquiring Person, each holder of a Right (other than Rights
beneficially owned by the Acquiring Person (which will be void), will
thereafter have the right to receive, upon exercise of a Right, that number of
Shares having a market value of two times the exercise price of the Right. In
addition, if Safety-Kleen is acquired in a merger or other business combination
transaction or 50% or more of its consolidated assets or earning power are
sold, proper provision will be made so that each holder of a Right will
thereafter have the right to receive, upon the exercise thereof at the then
current exercise price of the Right, that number of common stock of the
acquiring company which at the time of such transaction will have a market
value of two times the exercise price of the Right. The Rights may be redeemed
at a price of $.67 per Right at any time prior to a person or group becoming an
Acquiring Person.
 
  At a meeting held on November 14, 1997, the Board resolved that, for purposes
of the LLE Offer, the Distribution Date shall not occur until the earlier of
(i) the "Close of Business" (as defined in the Rights Agreement) on the tenth
day after the Shares Acquisition Date (as defined in the Rights Agreement) and
(ii) the Close of Business on such date on or after November 19, 1997 as may be
determined by the Board of Directors of Safety-Kleen before any Person becomes
an Acquiring Person. As a result of such action, the commencement of the LLE
Offer will not, in and of itself, result in the occurrence of a Distribution
Date.
 
  On November 20, 1997, in connection with the execution and delivery of the
Philip Merger Agreement and the transactions contemplated thereby, the Board
authorized the execution and delivery of a Second Amendment, dated as of
November 20, 1997 (the "Second Amendment"), to the Rights Agreement. The Second
Amendment provides, among other things, that the execution, delivery and
performance of the Philip Merger Agreement will not (i) cause SK Parent, SK
Acquisition or any of their respective affiliates or associates to become an
Acquiring Person, (ii) give rise to a Distribution Date or (iii) trigger
certain other events specified in the Rights Agreement.
 
  The foregoing description of the Rights Agreement does not purport to be
complete and is qualified in its entirety by reference to the Rights Agreement
and the amendments thereto which are filed as exhibits to the Safety-Kleen's
Form 8-A dated December 28, 1988, Safety-Kleen's Form 8 dated as of August 10,
1990 and the Form 8-A/A dated November 20, 1997, each as filed with the
Commission.
 
  (b) Shareholder Litigation.
 
  Between November 4 and 12, 1997, and on December 5, 1997, putative class
actions were filed against Safety-Kleen and its directors in the Circuit Court
of Cook County, Illinois, entitled William Steiner V. Donald W. Brinckman, Et
Al., No. 97 Ch 14053; Josh Kaplan V. Donald W. Brinckman, Et Al., No. 97 Ch
14097; Robin Fernhoff V. Safety Kleen Corp., Et Al., No. 97 Ch 14195; Larry
Hanon V. Safety Kleen Corp., Et Al., No. 97 Ch 14113; Epstein Family Trust, Et
Al. V. Safety Kleen Corp., Et Al. No. 97 Ch 14379; Gershon Knoll V. Richard T.
Farmer, Et Al, No. 97 CH 14111; and David Steinberg, Et Al. V. Safety-Kleen
Corp., Et Al., No. 97 Ch 15551 (collectively, the "Shareholder Actions"). In
general, the complaints in the Shareholder Actions allege, among other things,
that the director defendants (i) have refused to seriously consider the LLE's
offer, and have failed to maximize stockholder value by entertaining offers to
purchase Safety-Kleen, (ii) have breached their fiduciary and other common law
duties due to plaintiff and other class members in that they have not
exercised, and are not exercising, independent business judgment and (iii) are
acting to entrench themselves in their offices and positions and maintain their
salaries and prerequisites, all at the expense and to the detriment of the
public shareholders of Safety-Kleen. As relief, the complaints seek, among
other things: (i) a declaration that the action be certified as a proper class
action; (ii) injunctive relief requiring that the director defendants carry out
their fiduciary duties to plaintiff and other members of the class by
announcing their intention to, among other things, cooperate fully with any
entity or person, including LLE, having a bona fide interest in proposing any
transaction that would maximize stockholder value; and (iii) damages, costs,
and attorneys' fees. Safety-Kleen believes that the allegations contained in
the complaints are without merit and, if the plaintiffs elect to proceed with
their actions, intends to contest the actions vigorously on behalf of itself
and the Board of Directors.
 
  On December 5, 1997, all of the Shareholder Actions, other than the action
filed on December 5th were consolidated into a single action.
 
                                       27

 
  Copies of each of the Shareholder Actions are filed as Exhibits 15 through 21
and incorporated herein by reference, and the foregoing is qualified in its
entirety by reference to such exhibits.
 
  (c) State Takeover Statutes. As a Wisconsin corporation, Safety-Kleen is
subject to the provisions of the Wisconsin Statutes affecting "business
combinations" (as defined in the Wisconsin Statutes) and other transactions
between corporations and their shareholders. In addition, Chapter 552 of the
Wisconsin Statutes provides further anti-takeover protection for certain
Wisconsin-based corporations.
 
  Business Combination Statutes. Sections 180.1140 to 180.1144 of the Wisconsin
Statutes (the "Wisconsin Business Combination Statute") regulate a broad range
of "business combinations" between a Wisconsin resident domestic corporation
(which Safety-Kleen believes it is) and an "interested stockholder" (which LLE
would be if it consummated the LLE Offer). The Wisconsin Business Combination
Statute defines a "business combination" to include a merger or share exchange,
sale, lease, exchange, mortgage, pledge, transfer or other disposition of
assets equal to at least 5%, 10% of its earning power, or issuance of stock or
rights to purchase stock with a market value equal to at least 5% of the
outstanding stock, adoption "interested stockholder." An "interested
stockholder" is defined as a person who beneficially owns, directly or
indirectly, 10% of the voting power of the outstanding voting stock of a
corporation or who is an affiliate or associate of the corporation and
beneficially owned 10% of the voting power of the then outstanding voting stock
within the last three years. The Wisconsin Business Combination Statute
prohibits a corporation from engaging in a business combination (other than a
business combination of a type specifically excluded from the coverage of the
statute) with an interested stockholder for a period of three years following
the date such person becomes an interested stockholder, unless the board of
directors approved the business combination or the acquisition of the stock
that resulted in a person becoming an interested stockholder before such
acquisition. Business combinations after the three-year period following the
stock acquisition date are permitted only if (i) the board of directors
approved the acquisition of the stock prior to the acquisition date; (ii) the
business combination is approved by a majority of the outstanding voting stock
not beneficially owned by the interested stockholder; or (iii) the
consideration to be received by shareholders meets certain requirements of the
statute with respect to form and amount.
 
  Fair Price Statute. Sections 180.1130 to 180.1132 of the Wisconsin Statutes
provide that certain mergers, share exchanges or sales, leases, exchanges or
other dispositions of assets in a transaction involving a "significant
shareholder" (which LLE would be if it consummated the LLE Offer) and a
resident domestic corporation (which Safety-Kleen believes it is) are subject
to a supermajority vote of shareholders (the "Wisconsin Fair Price Statute"),
in addition to any approval otherwise required. A "significant shareholder" is
defined as a person who beneficially owns, directly or indirectly, 10% or more
of the voting stock of a corporation or an affiliate of the corporation which
beneficially owned, directly or indirectly, 10% or more of the voting stock of
the corporation within the last two years. Such business combination must be
approved by 80% of the voting power of the corporation's stock and at least
two-thirds of the voting power of the corporation's stock not beneficially held
by the significant shareholder that is party to the relevant transaction or any
of its affiliates or associates, in each case voting together as a single
group, unless the following fair price standards have been met: (i) the
aggregate value of the per share consideration is equal to the higher of (a)
the highest price paid for any common shares of the corporation by the
significant shareholder in the transaction in which it became a significant
shareholder or within two years before the date of the business combination;
(b) the market value of the corporation's shares on the date of commencement of
any tender offer by the significant shareholder, the date on which the person
became a significant shareholder or the date of the first public announcement
of the proposed business combination, whichever is higher; or (c) the highest
liquidation or dissolution distribution to which holders of the shares would be
entitled; and (ii) either cash, or the form of consideration used by the
significant shareholder to acquire the largest number of shares, is offered.
 
  Control Share Statute. Under Section 180.1150 (the "Wisconsin Control Share
Statute") of the Wisconsin Statutes, the voting power of shares, including
shares issuable upon conversion of convertible securities or exercise of
options or warrants, of a "resident domestic corporation" held by any person or
persons acting as a group in excess of 20% of the voting power in the election
of directors is limited to 10% of the full voting power of those shares, unless
the articles of incorporation otherwise provide. This restriction does not
apply to shares
 
                                       28

 
acquired directly from the resident domestic corporation, in certain specified
transactions, or in a transaction in which the corporation's shareholders have
approved restoration of the full voting power of the otherwise restricted
shares.
 
  Defensive Action Statute. Section 180.1134 (the "Wisconsin Defensive Action
Restrictions") of the Wisconsin Statutes provides that in addition to the vote
otherwise required by law or the articles of incorporation of a resident
domestic corporation the approval of the holders of a majority of the shares
entitled to vote is required before such a corporation can take certain action
while a takeover offer is being made or after the takeover offer has been
publicly announced and before it is concluded. Under the Wisconsin Defensive
Action Restrictions, shareholder approval is required for the corporation to
(i) acquire more than 5% of the outstanding voting shares at a price above the
market price from any individual or organization that owns more than 3% of the
outstanding voting shares and has held such shares for less than two years,
unless an equal offer is made to acquire all voting shares; or (ii) sell or
option assets of the corporation which amount to at least 10% of the market
value of the corporation, unless in the case of this clause (ii) the
corporation has at least three independent directors and a majority of the
independent directors vote to opt out of this provision.
 
  Corporate Takeover Statute. In addition to the Wisconsin Corporation Law,
Chapter 552 of the Wisconsin Statutes (the "Wisconsin Corporate Takeover Law")
regulates a broad range of "takeover offers" (as defined in the Wisconsin
Corporate Takeover Law). The Wisconsin Corporate Takeover Law makes it unlawful
for any person to make a takeover offer involving a target company in
Wisconsin, or to acquire any equity securities of a target company pursuant to
the offer, unless a registration statement has been filed with the Wisconsin
commissioner of securities 10 days prior to the commencement of the takeover
offer or such takeover offer is exempted by rule or order of the commissioner.
However, the foregoing registration requirement applies only to a target
company that: (i) does not have any of its securities registered under Section
12 of the Securities Exchange Act of 1934, as amended; (ii) has at least 51% of
its registered securities held of record by residents of Wisconsin; or (iii)
has at least 33% of its registered securities held of record by residents of
Wisconsin, has its principal office in Wisconsin and its business or operations
have a substantial economic effect in Wisconsin. Although Safety-Kleen is a
"target company" for purposes of the Wisconsin Corporate Takeover Law, Safety-
Kleen does not satisfy the foregoing conditions. The Wisconsin Corporate
Takeover Law also imposes certain reporting and filing requirements on persons
making a takeover offer, imposes certain substantive requirements on the terms
of any takeover offer and makes unlawful certain fraudulent and deceptive
practices, all of which provisions may be applicable to the Offer.
 
  (d) Regulatory Filing. On December 11, 1997, Safety-Kleen filed its
Notification and Report Form with respect to the LLE Offer under the Hart-
Scott-Rodino Antitrust Improvements Act of 1976, as amended (the "HSR Act").
LLE filed a Notification and Report Form with respect to the LLE Offer on
November 26, 1997. Under the provisions of the HSR Act applicable to the LLE
Offer, the purchase of shares pursuant to the LLE Offer may not be consummated
until the expiration of a 30-calendar day waiting period following the LLE
filing under such HSR Act. Accordingly, assuming the filing made by LLE was not
deficient, the waiting period with respect to the LLE Offer will expire at
11:59 p.m., New York City time, on December 26, 1997, unless LLE receives a
request for additional information or documentary material or the Antitrust
Division and the Federal Trade Commission terminate the waiting period prior
thereto.
 
                                       29

 
ITEM 9. MATERIAL TO BE FILED AS EXHIBITS.
 
  The following Exhibits are filed herewith:
 


 EXHIBIT NO.                          DESCRIPTION
 ----------- ------------------------------------------------------------
                                                                      
 Exhibit 1   Excerpts from Safety-Kleen's Proxy Statement, dated March
             28, 1997, relating to Safety-Kleen's 1997 Annual Meeting of
             Shareholders.
 Exhibit 2   Share Ownership of Certain Beneficial Owners and Management.
 Exhibit 3   Agreement and Plan of Merger, dated as of November 20, 1997,
             by and among SK Parent Corp., SK Acquisition Corp. and
             Safety-Kleen Corp.
 Exhibit 4   Change of Control Severance Agreement.
 Exhibit 5*  Letter to Shareholders of Safety-Kleen, dated December 22,
             1997.
 Exhibit 6   Press Release issued by Safety-Kleen Corp., dated December
             22, 1997.
 Exhibit 7   Text of September 24, 1997 letter from Laidlaw Environmental
             Services, Inc.
 Exhibit 8   Text of November 4, 1997 letter from Laidlaw Environmental
             Services, Inc.
 Exhibit 9   Text of November 13, 1997 letter from Laidlaw Environmental
             Services, Inc.
 Exhibit 10  Complaint filed by Safety-Kleen Corp. v. Laidlaw
             Environmental Services, Inc. (dated November 17, 1997,
             United States District Court for the Northern District of
             Illinois Eastern Division).
 Exhibit 11* Opinion of William Blair & Company L.L.C., dated November
             20, 1997.
 Exhibit 12  Text of November 20, 1997 letter from Laidlaw Environmental
             Services, Inc.
 Exhibit 13  Verified Answer, Affirmative Defenses, and Counterclaim
             filed by Laidlaw Environmental Services, Inc. v. Safety-
             Kleen Corp., et al. (dated November 24, 1997, United States
             District Court for the Northern District of Illinois Eastern
             Division).
 Exhibit 14* Opinion of William Blair & Company L.L.C., dated December
             20, 1997.
 Exhibit 15  Complaint filed by William Steiner against Donald W.
             Brinckman, et al. (dated November 4, 1997, Circuit Court of
             Cook County, Illinois County Department, Chancery Division).
 Exhibit 16  Complaint filed by Josh Kaplan against Donald W. Brinckman,
             et al. (dated November 5, 1997, Circuit Court of Cook
             County, Illinois County Department, Chancery Division).
 Exhibit 17  Complaint filed by Gershon Knoll against Richard T. Farmer,
             et al. (dated November 5, 1997, Circuit Court of Cook
             County, Illinois County Department, Chancery Division).
 Exhibit 18  Complaint filed by Larry Hanon against Safety-Kleen Corp.,
             et al., (dated November 5, 1997, Circuit Court of Cook
             County, Illinois County Department, Chancery Division).
 Exhibit 19  Complaint filed by Robin Fernhoff against Safety-Kleen
             Corp., et al. (dated November 6, 1997, Circuit Court of Cook
             County, Illinois County Department, Chancery Division).
 Exhibit 20  Complaint filed by Epstein Family Trust against Safety-Kleen
             Corp., et al. (dated November 12, 1997, Circuit Court of
             Cook County, Illinois County Department, Chancery Division).
 Exhibit 21  Complaint filed by David Steinberg against Safety-Kleen
             Corp., et al. (dated December 5, 1997, Circuit Court of Cook
             County, Illinois County Department, Chancery Division).

- --------
  *Included in copies mailed to shareholders.
 
                                       30

 
                                   SIGNATURE
 
  AFTER REASONABLE INQUIRY AND TO THE BEST OF MY KNOWLEDGE AND BELIEF, I
CERTIFY THAT THE INFORMATION SET FORTH IN THIS STATEMENT IS TRUE, COMPLETE AND
CORRECT.
 
                                          Safety-Kleen Corp.
 
                                            /s/ Donald W. Brinckman
                                          By: _________________________________
                                            Name: Donald W. Brinckman
                                            Title: Chairman and Chief
                                             Executive Officer
 
Dated: December 21, 1997
 
                                       31