EXHIBIT 10.6.4
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          Merrill Lynch                                  Ref. No. 582-07596
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                                UNCONDITIONAL GUARANTY

          FOR VALUE RECEIVED, and in order to induce MERRILL LYNCH BUSINESS
          FINANCIAL  SERVICES INC. ("MLBFS") to advance moneys or extend or
          continue  to  extend credit  to or  for  the benefit  of AMERICAN
          ECO/SP CORPORATION,  a corporation  organized and  existing under
          the  laws  of  the  State  of  Delaware  (with  any  successor-in
          interest, including, without limitation,  any successor by merger
          or  by  operation  of law,  herein  collectively  referred  to as
          "Customer") under (a)  that certain WCMA NOTE,  LOAN AND SECURITY
          AGREEMENT  NO. 582-7596  between  MLBFS and  Customer (the  "Loan
          Agreement"),  (b) any  "Additional Agreements",  as that  term is
          defined in the  Loan Agreement,  and (c) all  present and  future
          amendments  and other  evidences  of any  extensions,  increases,
          renewals  and  other  changes of  or  to  the  Loan Agreement  or
          Additional Agreements (collectively, the "Guaranteed Documents"),
          the undersigned hereby  unconditionally guarantees to MLBFS:  (i)
          the  prompt  and  full  payment  when  due,  by  acceleration  or
          otherwise,  of  all  sums now  or  any  time  hereafter due  from
          Customer  to  MLBFS  under  the Guaranteed  Documents;  (ii)  the
          prompt, full  and faithful performance and  discharge by Customer
          of each and  every other  covenant and warranty  of Customer  set
          forth  in the Guaranteed Documents, and (iii) the prompt and full
          payment and performance  of all  other indebtedness,  liabilities
          and  obligations  of  Customer  to MLBFS,  howsoever  created  or
          evidenced,   and  whether  now   existing  or  hereafter  arising
          (collectively,  the  "Obligations").    The  undersigned  further
          agrees to pay  all reasonable costs and  expenses (including, but
          not limited to, court costs and  reasonable attorneys' fees) paid
          or  incurred  by  MLBFS  in  endeavoring  to  collect or  enforce
          performance of  any  of the  Obligations,  or in  enforcing  this
          Guaranty.

          This Guaranty is absolute, unconditional and continuing and shall
          remain in effect  until all  of the Obligations  shall have  been
          fully paid,  performed and discharged.   Upon the  occurrence and
          during  the  continuance  of  any  Event  of  Default  under  the
          Guaranteed  Documents,  any or  all  of  the indebtedness  hereby
          guaranteed then  existing shall, at  the option of  MLBFS, become
          immediately   due    and    payable   from    the    undersigned.
          Notwithstanding the  occurrence of any such  event, this Guaranty
          shall continue and remain in full force and effect.

          The liability of the  undersigned hereunder shall in no  event be
          affected or impaired by any of the following, any of which may be
          done or  omitted by MLBFS from time to time, without notice to or
          the  consent of  the undersigned:  (a) any  renewals, amendments,
          modifications  or supplements  of  or to  any  of the  Guaranteed
          Documents,  or  any  extensions,  forbearances,   compromises  or
          releases of any  of the Obligations or any of MLBFS' rights under
          any of the Guaranteed  Documents; (b) any acceptance by  MLBFS of
          any  collateral or security for,  or other guarantors  of, any of
          the Obligations; (c) any failure, neglect or omission on the part
          of MLBFS  to realize upon or  protect any of  the Obligations, or
          any collateral or security therefor, or to exercise any lien upon
          or right of appropriation  of any moneys, credits or  property of
          Customer or  any  other  guarantor,  possessed by  or  under  the
          control of MLBFS or any of its affiliates, toward the liquidation
          or reduction of  the Obligations; (d) any application of payments
          or credits by MLBFS; (e) the granting of credit from time to time
          by  MLBFS to Customer  in excess of  the amount set  forth in the
          Guaranteed  Documents;  or (f)  any  other act  of  commission or
          omission of any kind or at any time upon the part of MLBFS or any
          of  its affiliates or any of their respective employees or agents
          with  respect to  any  matter whatsoever.    MLBFS shall  not  be
          required  at  any  time,  as  a  condition  of the  undersigned's
          obligations  hereunder, to  resort  to payment  from Customer  or
          other persons or  entities whatsoever, or any of their properties
          or estates, or resort to any collateral or pursue or  exhaust any
          other rights or remedies whatsoever.

          No  release  or discharge  in  whole  or  in  part of  any  other
          guarantor  of  the Obligations  shall  release  or discharge  the
          undersigned or any other  guarantor, unless and until all  of the
          Obligations  shall have  been  fully paid  and  discharged.   The
          undersigned expressly waives presentment, protest, demand, notice
          of dishonor or  default, notice of  acceptance of this  Guaranty,
          notice of advancement of funds under the Guaranteed Documents and
          all  other  notices  and  formalities to  which  Customer  or the
          undersigned might  be entitled, by statute or  otherwise, and, so
          long as there are any Obligations or MLBFS is committed to extend
          credit  to Customer, waives any right to revoke or terminate this
          Guaranty without the express written consent of MLBFS.

          So long as there  are any Obligations, the undersigned  shall not
          have any  claim, remedy  or right of  subrogation, reimbursement,
          exoneration, contribution, indemnification,  or participation  in
          any  claim, right,  or remedy  of MLBFS  against Customer  or any
          security which MLBFS  now has or  hereafter acquires, whether  or
          not such claim, right or remedy arises in equity, under contract,
          by statute, under common law, or otherwise.

          MLBFS  is hereby irrevocably authorized by  Guarantor at any time
          during  the continuance  of an  Event of  Default under  the Loan
          Agreement  or any other of the Guaranteed Documents or in respect
          of any of  the Obligations,  in its sole  discretion and  without
          demand or notice  of any kind, to appropriate,  hold, set off and
          apply toward the  payment of  any amount due  hereunder, in  such
          order  of application  as  MLBFS may  elect,  all cash,  credits,
          deposits,  accounts, securities  and  any other  property of  the
          undersigned  which is in transit to or in the possession, custody
          or  control of  MLBFS or  Merrill Lynch,  Pierce, Fenner  & Smith
          Incorporated  ("MLPF&S"),  or  any  of  their  respective agents,
          bailees  or  affiliates,   including,  without  limitation,   all
          securities  accounts  with MLPF&S  and  all  cash and  securities
          therein  or controlled thereby,  and all  proceeds thereof.   The
          undersigned  hereby collaterally  assigns and  grants to  MLBFS a
          security interest in all such property as additional security for
          the Obligations.  Upon the  occurrence and during the continuance
          of  an Event  of Default,  MLBFS shall  have all  rights in  such
          property available to  collateral assignees  and secured  parties
          under  all applicable  laws, including,  without  limitation, the
          UCC.

          The  undersigned  agrees  to  furnish  to  MLBFS  such  financial
          information concerning the undersigned as may be required by  any
          of the Guaranteed Documents  or as MLBFS may otherwise  from time
          to  time  reasonably request.    The  undersigned further  hereby
          irrevocably  authorizes  MLBFS  and   each  of  its   affiliates,
          including  without limitation MLPF&S, to at  any time (whether or
          not  an Event  of Default  shall have  occurred) obtain  from and
          disclose   to  each  other  any   and  all  financial  and  other
          information about the undersigned.

          No  delay on the part  of MLBFS in  the exercise of  any right or
          remedy under any agreement  (including, but not limited to,  this
          Guaranty)  shall  operate  as  a  waiver  thereof,  and,  without
          limiting  the  foregoing,  no delay  in  the  enforcement of  any
          security  interest, and no single or partial exercise by MLBFS of
          any  right or remedy shall preclude any other or further exercise
          thereof  or the  exercise of  any other  right or  remedy.   This
          Guaranty may be executed  in any number of counterparts,  each of
          which counterparts,  once they are executed  and delivered, shall
          be deemed to be an original and all of which  counterparts, taken
          together, shall constitute but  one and the same Guaranty.   This
          Guaranty  shall   be  binding   upon  the  undersigned   and  the
          undersigned's heirs and personal representatives, and shall inure
          to the benefit of MLBFS and its successors and assigns.  If there
          is  more  than  one guarantor  of  the  Obligations,  all of  the
          obligations  and  agreements of  the  undersigned  are joint  and
          several.

          This  Guaranty shall  be governed  by the  laws of  the State  of
          Illinois.   THE  UNDERSIGNED  AGREES THAT  THIS  GUARANTY MAY  BE
          ENFORCED BY MLBFS IN ANY JURISDICTION AND VENUE IN WHICH THE LOAN
          AGREEMENT MAY BE ENFORCED.  THE UNDERSIGNED AND MLBFS HEREBY EACH
          EXPRESSLY WAIVE  ANY AND  ALL RIGHTS  TO A TRIAL  BY JURY  IN ANY
          ACTION,  PROCEEDING OR COUNTERCLAIM BROUGHT BY ANY OF THE PARTIES
          AGAINST  ANY OTHER PARTY IN ANY WAY  RELATED TO OR ARISING OUT OF
          THIS  GUARANTY  OR  THE  OBLIGATIONS.    WHEREVER  POSSIBLE  EACH
          PROVISION OF THIS GUARANTY SHALL BE INTERPRETED IN SUCH MANNER AS
          TO  BE EFFECTIVE  AND  VALID UNDER  APPLICABLE  LAW, BUT  IF  ANY
          PROVISION OF  THIS GUARANTY  SHALL BE  PROHIBITED  BY OR  INVALID
          UNDER SUCH LAW, SUCH  PROVISION SHALL BE INEFFECTIVE ONLY  TO THE
          EXTENT  OF SUCH PROHIBITION  OR INVALIDITY,  WITHOUT INVALIDATING
          THE REMAINDER  OF SUCH PROVISION  OR THE REMAINING  PROVISIONS OF
          THIS  GUARANTY.    NO  MODIFICATION  OR  WAIVER  OF  ANY  OF  THE
          PROVISIONS OF THIS  GUARANTY SHALL BE EFFECTIVE UNLESS IN WRITING
          AND SIGNED BY THE UNDERSIGNED AND AN OFFICER OF MLBFS.

    <PAGE> 


          MERRILL LYNCH
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                               CERTIFICATE OF SECRETARY
                                (WCMA LINE OF CREDIT)

          THE UNDERSIGNED HEREBY CERTIFIES that the undersigned is the duly
          appointed  and  acting  Secretary  (or  Assistant  Secretary)  of
          AMERICAN  ECO/SP  CORPORATION,  a  corporation   duly  organized,
          validly existing and in good standing under the laws of the State
          of  Delaware,  and that  the following  is  a true,  accurate and
          compared  transcript of  resolutions  duly, validly  and lawfully
          adopted  on the ____ day of ________________,1996 by the Board of
          Directors of  said corporation acting in accordance with the laws
          of the state of incorporation and the charter and by-laws of said
          corporation:

               "RESOLVED, that it is advisable and in the best interests of
               this  Corporation that  in  connection with  Working Capital
               Management  Account No.  582-7596 that  this Corporation  is
               subscribing from  Merrill  Lynch,  Pierce,  Fenner  &  Smith
               Incorporated it obtain from MERRILL LYNCH BUSINESS FINANCIAL
               SERVICES INC.  ("MLBFS")a commercial line of credit referred
               to by MLBFS as a "WCMA Line of Credit;" and

               "FURTHER RESOLVED,  that the President,  any Vice President,
               Treasurer, Secretary  or other officer of  this Corporation,
               or any one  or more of them,  be and each of  them hereby is
               authorized  and   empowered  for  and  on   behalf  of  this
               Corporation to: (a) execute and deliver to MLBFS: (i) a WCMA
               Note, Loan and Security  Agreement and all other agreements,
               instruments and  documents required  by MLBFS  in connection
               with said Line  of Credit,  and (ii) any  present or  future
               extensions of and amendments to any of the foregoing; all in
               such  form as  such officer  shall approve,  as conclusively
               evidenced  by his signature thereon; (b) grant to MLBFS such
               liens  and security interests on  any of the  assets of this
               Corporation   as  collateral   therefor  and/or   the  other
               obligations of this Corporation to MLBFS as  may be required
               by MLBFS;  and (c) do and  perform all such acts  and things
               deemed by any such  officer to be necessary or  advisable to
               carry  out and  perform the  undertakings and  agreements of
               this Corporation in connection therewith; and all prior acts
               of  said officers in these premises  are hereby ratified and
               confirmed; and 

               "FURTHER RESOLVED, that MLBFS is authorized to rely upon the
               foregoing resolutions  until it  receives written  notice of
               any change  or revocation, which change  or revocation shall
               not in  any event affect the obligations of this Corporation
               with respect  to any  transaction committed  to by  MLBFS or
               having  its inception prior to the receipt of such notice by
               MLBFS."

          THE UNDERSIGNED FURTHER CERTIFIES  that the foregoing resolutions
          have  not been rescinded, modified or repealed in any manner, and
          are in  full force and effect as of the date of this Certificate,
          and that the following individuals are of the duly elected acting
          officers of said corporation: 

               President:  /s/ Michael E. McGinnis   Michael E. McGinnis
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               Vice President:   -------------------

               Secretary:  /s/ John D. Walker        John D. Walker
                           -----------------------

               Treasurer:                             
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          IN WITNESS WHEREOF, the undersigned has executed this Certificate
          and  has affixed the seal of said corporation hereto, pursuant to
          due authorization, all as of this 27th day of August, 1996.

          (CORPORATE SEAL)

                                    /s/ John D. Walker
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                                        Secretary

                                    /s/ John D. Walker          
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                                        Printed Name