PNC Bank, N.A.                      201 898 4894 Fax
Corporate Banking Department
22 South Street
Morristown, NJ 07960






August 26, 1997
                                                                   PNCBANK



Richard  Greenberg, Managing Member
Environmental Waste Management Associates, L.L.C.
100 Misty Lane
Parsippany, NJ 07054

Re:  $1,000,000.00 Committed Line of Credit

Dear Richard:

We are pleased to inform you that PNC Bank,  National  Association  (the "Bank")
has approved your request for a committed line of credit to Environmental  Waste
Management Associates, L.L.C. (the "Borrower"), which committed line is intended
as a renewal of the existing  committed line to  Environmental  Waste Management
Associates,  Inc.,  and not a novation.  We look forward to this  opportunity to
help you meet the  financing  needs of your  business.  As your primary bank, we
want to supply all your banking needs.

All the details  regarding  your loan are outlined in the following  sections of
this letter. If these terms are satisfactory, please follow the instructions for
proceeding with your loan provided at the end of this letter.


1,       Type of Facility  and Use of  Proceeds.  This is a committed  revolving
         line of credit  under  which the  Borrower  may  request  and the Bank,
         subject to the terms and conditions of this letter,  will make advances
         to the  Borrower  from time to time until the  Expiration  Date,  in an
         amount  in  the  aggregate  at  any  time  outstanding  not  to  exceed
         $1,000,000.00 (the "Line of Credit").  The "Expiration Date" means July
         31,  1998,  or such  later  date as may be  designated  by the  Bank by
         written  notice  to the  Borrower.  Advances  may be used  for  working
         capital or other general business purposes of the Borrower.


2.       Interest rate.  Interest on the unpaid balance of the Line of Credit
         advances will be charged at a rate per annum  which is at all  times
         equal to the sum of the rate of interest publicly  announced by the
         Bank from time to time as its prime rate (the "Prime Rate") plus one
         quarter percent (1/4%).

3.       Repayment.  Subject to the terms and  conditions  of this  letter,  the
         Borrower may borrow,  repay and reborrow until the Expiration  Date, on
         which the  outstanding  principal  balance  and any  accrued but unpaid
         interest shall be due and payable.  Interest will be due and payable on
         a monthly  basis,  and will be  computed  on the basis of a year of 360
         days  and  paid on the  actual  number  of days  elapsed.  Prior to the
         original  Expiration  Date,  and annually  thereafter if the Expiration
         date is extended, the Borrower must repay the Line of Credit in full so
         that there is no outstanding principal balance for a period of at least
         thirty (30) consecutive days.








                                                 Form 7A - Multistate Rev. 3/95


<PAGE>


PNCBANK
Richard Greenberg
Environmental Waste Management
Associates L.L.C.
August 26, 1997
Page 2






4.       Note.  The  obligation of the Borrower to repay loans under the Line of
         Credit shall be evidenced by a promissory note (the "Note") in form and
         content satisfactory to the Bank.

5.       Security.  The  Borrower  must cause the  following  to be executed and
         delivered to the Bank in form and content  satisfactory  to the Bank as
         security for the Line of Credit:

(x)               a guaranty  and  suretyship  agreement,  under  which  Richard
                  Greenberg,  Environmental Waste Management  Associates,  Inc.,
                  Integrated Analytical Laboratories, Inc. Integrated Analytical
                  Laboratories,    L.L.C.,    Environmental   Waste   Management
                  Associates of Maryland, Inc. and Construction  Remediation and
                  Maintenance,   L.L.C.   (individually  or  collectively,   the
                  "Guarantors")  will  unconditionally   jointly  and  severally
                  guarantee the due and punctual payment of all indebtedness
                  owed to the Bank by the Borrower.

(x)               a  security  agreement  granting  the  Bank a  first  priority
                  perfected lien on the Borrower's existing and future accounts,
                  inventory,  equipment,  general  intangibles,  chattel  paper,
                  documents and instruments.

(x)               The Bank Acknowledges that Greenberg Property,  L.L.C. intends
                  to  refinance  its first  commercial  mortgage  and its second
                  mortgage with a different financial institution.  Upon payment
                  in full of all obligations owed by Greenberg Property, L.L.C.,
                  in respect of the mortgage to PNC Bank,  the Bank will release
                  its mortgage claims on 100 Misty Lane, Parsippany,  NJ and any
                  guarantee of Greenberg  Property,  L.L.C. will be released and
                  returned.

         If the Line of  Credit  is  secured  by  inventory,  equipment  or real
         property, hazard insurance must be maintained on such property, in such
         amounts  and  with  such  coverages  as are  acceptable  to  the  Bank,
         containing a standard lender loss payable or mortgagee  clause in favor
         of the Bank.

6.       Covenants.  Unless compliance is waived in writing by the Bank or until
         payment in full and termination of the Line of Credit:

(a)               The Borrower will promptly submit to the Bank such information
                  relating to the Borrower's affairs   (including  but  not
                  limited  to  annual  financial statements and tax returns for
                  the Borrower and any guarantor)or any  security  for  the
                  Line of  Credit  as the  Bank  may reasonably request.

(b)               The Borrower  will not make or permit any change in the nature
                  of its business as carried on as of the date of this letter or
                  in its senior management or equity ownership.









<PAGE>

                                                 Form 7A - Multistate Rev. 3/95


PNCBANK
Richard Greenberg
Environmental Waste Management
Associates L.L.C.
August 26, 1997
Page 3





         (c)      The Borrower and the Guarantors will comply with the financial
                  and other covenants included in Exhibit "A" hereto.

7.       Representations  and Warranties.  To induce the Bank to extend the Line
         of Credit  and upon the  making of any  advance  to the  Borrower,  the
         Borrower represents and warrants as follows:

(a)               The Borrower's  latest  financial  statements  provided to the
                  Bank are true,  complete and accurate in all material respects
                  and  fairly  present  the  financial  condition,   assets  and
                  liabilities,   whether   accrued,   absolute,   contingent  or
                  otherwise and the results of the Borrower's operations for the
                  period specified therein.  The Borrower's financial statements
                  have been  prepared  in  accordance  with  generally  accepted
                  accounting  principles  consistently  applied  from  period to
                  period  subject  in the case of interim  statements  to normal
                  year-end  adjustments.  Since the date of the latest financial
                  statements provided to the Bank, the Borrower has not suffered
                  any damage, destruction or loss which has materially adversely
                  affected its business, assets, operations, financial condition
                  or results of operations.

(b)               There  are no  actions,  suits,  proceedings  or  governmental
                  investigations  pending or, to the  knowledge of the Borrower,
                  threatened  against  the  Borrower  which  could  result  in a
                  material adverse change in its business,  assets,  operations,
                  financial  condition or results of operations  and there is no
                  basis known to the  Borrower  or its  officers,  directors  or
                  shareholders  for  any  such  action,  suit,   proceedings  or
                  investigation.

(c)               The  Borrower  has  filed all  returns  and  reports  that are
                  required  to be filed by it in  connection  with any  federal,
                  state or local tax, duty or charge levied, assessed or imposed
                  upon the  Borrower or its  property,  including  unemployment,
                  social  security and similar  taxes and all of such taxes have
                  been either paid of adequate  reserve or other  provision  has
                  been made therefor.

(d)               If not a  natural  person,  the  Borrower  is duly  organized,
                  validly  existing and in good  standing  under the laws of the
                  state of its  incorporation  or organization and has the power
                  and authority to own and operate its assets and to conduct its
                  business  as now or  proposed  to be  carried  on, and is duly
                  qualified, licensed and in good standing to do business in all
                  jurisdictions where its ownership of property or the nature of
                  its business requires such qualification or licensing.

(e)               The  Borrower  has full power and  authority to enter into the
                  transactions  provided  for in this Letter  Agreement  and has
                  been duly authorized to do so by all necessary and appropriate
                  action and when executed and  delivered by the Borrower,  this
                  Letter  Agreement  and the other loan  documents  executed and
                  delivered pursuant hereto will constitute the legal, valid and
                  binding obligations of the Borrower  enforceable in accordance
                  with their terms.







                                                 Form 7A - Multistate Rev. 3/95
<PAGE>


PNCBANK
Richard Greenberg
Environmental Waste Management
Associates L.L.C.
August 26, 1997
Page 4






         (f)      There does not exist any default or  violation by the Borrower
                  of or under any of the terms,  conditions or  obligations  of:
                  (i)  its   organizational   documents;   (ii)  any  indenture,
                  mortgage,   deed  of  trust,  franchise,   permit,   contract,
                  agreement,  or other  instrument  to which it is a party or by
                  which it is  bound;  or (iii)  any  law,  regulation,  ruling,
                  order,  injunction,  decree  condition  or  other  requirement
                  applicable  to or imposed  upon the  Borrower by any law or by
                  any governmental authority, court or agency.


8.                Fees.  The Borrower will reimburse the Bank for the Bank's out
                  of pocket  expenses  incurred or to be incurred in  conducting
                  UCC, title and other public record searches, and in filing and
                  recording  documents  in the public  records  to  perfect  the
                  Bank's liens and security  interests.  The Borrower shall also
                  reimburse  the Bank for the  Bank's  expenses  (including  the
                  reasonable  fees  and  expenses  of  the  Bank's  outside  and
                  in-house  counsel) in documenting and closing this transaction
                  and in connection with any amendments, modifications, renewals
                  or enforcement actions relating to the Line of Credit.

9.                Depository.  The Borrower  will  establish and maintain at the
                  Bank the Borrower's primary depository accounts.


10.               Additional Provisions. Before the first advance under the Line
                  of Credit, the Borrower agrees to sign and deliver to the Bank
                  the  Note  and  other   required   documents  and  such  other
                  instruments and documents as the Bank may reasonably  request,
                  such as  certified  resolutions,  incumbency  certificates  or
                  other evidence of authority. The Bank will not be obligated to
                  make any  advance  under  the Line of  Credit  if any Event of
                  Default  (as  defined  in the  Note) or event  which  with the
                  passage of time,  provision of notice or both would constitute
                  an Event of Default  under the Note shall have occurred and be
                  continuing.


Prior to execution of the final documents, the Bank may terminate this letter if
a material  adverse  change occurs with respect to the Borrower,  any guarantor,
any collateral for the Line of Credit or any other person or entity connected in
any way with the Line of Credit,  or if the Borrower fails to comply with any of
the terms and conditions of this letter,  or if the Bank  reasonably  determines
that any of the conditions cannot be met.

This letter is governed by the Laws of New Jersey.  No modification or waiver of
any of the terms of this letter will be valid and  binding  unless  agreed to in
writing  by the  Bank.  When  accepted,  this  letter  and the  other  documents
described herein will constitute the entire  agreement  between the Bank and the
Borrower   concerning   the  Line  of  Credit,   and  shall  replace  all  prior
understandings,  statements,  negotiations and written material  relating to the
Line of Credit.







                                                 Form 7A - Multistate Rev. 3/95

<PAGE>



PNCBANK
Richard Greenberg
Environmental Waste Management
Associates L.L.C.
August 26, 1997
Page 5






To accept these terms, please sign the enclosed copy of this letter as set forth
below and return it to the Bank within 15 days from the date of this letter.  If
accepted,  the final  documents must be executed within 30 days from the date of
this  letter,  or this letter may be  terminated  at the Bank's  option  without
liability or further obligation of the Bank.

Thank you for giving PNC Bank,  National  Association  this  opportunity to work
with your business.  We look forward to other ways in which we may be of service
to your business or to you personally.


Very truly yours,



PNC Bank, National Association



By:      /s/ Donna L. Keenan
             Donna L. Keenan

Title:     Vice President












                                                 Form 7A - Multistate Rev. 3/95



<PAGE>




PNCBANK
Richard Greenberg
Environmental Waste Management
Associates L.L.C.
August 26, 1997
Page 6




                                   ACCEPTANCE


With the intent to be legally bound hereby,  the above terms and  conditions are
hereby agreed to and accepted this 28th day of August 1997.

BORROWER:


Environmental Waste Management Associates, L.L.C.



By:      /s/ Richard Greenberg
         Richard Greenberg
                                                                   (SEAL)
Title:     Managing Member




GUARANTORS:

By: /s/ Richard Greenberg              Integrated Analytical Laboratories, Inc.
    Richard Greenberg, Individually

                                       By:   /s/  Michael Leftin
                                              Michael Leftin, President
Environmental Waste Management Associates, Inc.


By: /s/ Richard Greenberg
    Richard Greenberg, President
                                    Integrated Analytical Laboratories, L.L.C.


                                      By:    /s/  Michael Leftin
                                              Michael Leftin, Managing Member
Environmental Waste Management Associates
of Maryland, Inc.


By: /s/ Jeff K. Burks


Construction Remediation and Maintenance L.L.C.


By  /s/ Jeff K. Burks

                                               Form 7A -Multistate Rev. 3/95

<PAGE>


PNCBANK

                                    EXHIBIT A



FINANCIAL REPORTING COVENANTS:

(x)  The Borrower will deliver to the Bank:

(x)  Financial  Statements for its fiscal year, within 90 days after fiscal year
     end,  prepared  on a  reviewed  basis  by  a  certified  public  accountant
     acceptable to the Bank.

(x)  Financial  Statements for each fiscal  quarter  except the fourth  quarter,
     within 45 days after the quarter end.

(x)  The Borrower will deliver to the Bank within 45 days following the close of
     each  fiscal  quarter,   the  Borrower's   detailed  schedule  of  accounts
     receivable aging report.


(x)      The Guarantors will deliver to the Bank:


(x)  Personal  financial  statements  and  federal  income  tax  return for each
     calendar year within 90 days after year end.

(x)  Financial  statements for its fiscal year, within 90 days after fiscal year
     end,  prepared  on a  reviewed  basis  by  a  certified  public  accountant
     acceptable to the Bank.

(x)  Financial  Statements for each fiscal  quarter  except the fourth  quarter,
     within 45 days after the quarter end.

(x)  The Guarantors  will deliver to the Bank within 45 days following the close
     of each fiscal  quarter,  their  detailed  schedule of accounts  receivable
     aging report.


         FINANCIAL COVENANTS:

(x)  The Borrower  will  maintain at all times a debt to capital  funds ratio of
     1.0x or less. Debt will be defined as total liabilities, less any liability
     subordinated to the Bank (if applicable).  Capital funds will be defined as
     corporate net worth, less intangible  assets,  including but not limited to
     loans to stockholders and affiliates.








                                                 Form 7A - Multistate Rev. 3/95