PERSONAL AND CONFIDENTIAL

October 2, 1996


Mr. David R. Krache
c/o National Service Cleaning Corp.
3575 West 12th Street
Houston, TX  77008


         Re:      Employment Security Agreement


Dear Dave:


     In light of the recent developments at NSC Corporation  ("NSC"), NSC wishes
to offer you this  Employment  Security  Agreement in  appreciation of your past
dedicated service and to provide you with peace of mind.


     In consideration of the payments and other security listed below, you agree
to continue  your  employment  with NSC and provide  your full  cooperation  and
assistance to NSC.


     1. Term. The Term of the Agreement shall be for a period  commencing on the
date hereof and ending on December 31, 1998.

     2. Base Salary.  Your  current  base salary will not be reduced  during the
Term and will be  subject to normal  increases  which are in the  discretion  of
management.

     3.  Execution  Bonus.  Upon the execution and delivery of this agreement by
you, NSC shall pay to you, in one single lump sum, a one-time execution bonus in
the amount of Twenty Thousand ($20,000.00) Dollars.


     4.  Supplemental  Bonus and Guaranteed  Minimum Bonus.  With respect to any
bonus payable to you under any incentive  compensation  plan provided by NSC for
its senior  personnel  ("Plan"),  (i) if you remain  employed  with NSC  through
December 31, 1997, NSC agrees to pay you a supplemental bonus in an amount equal
to thirty-five (35%) percent of any bonus payable to you under the 1997 Plan and
(ii) if you remain  employed with NSC through the end of the Term, NSC agrees to
pay you a supplemental  bonus in an amount equal to thirty-five (35%) percent of
any  bonus  payable  to you  under  the  1998  Plan;  provided,  however,  that,
regardless  of the amount of any bonuses  payable to you under the 1997 and 1998
Plans, the amount of each  supplemental  bonus to be paid to you by NSC for each
such year shall in no event be less than Fifteen Thousand  ($15,000.00) Dollars,
or  Thirty  Thousand  ($30,000.00)  in  the  aggregate  for  both  years  (  the
"Guaranteed Minimum Bonus").

                                  Page 67 of 88
<PAGE>

    5.  Transaction  Bonus. In the event of a sale of NSC during the term to an
entity unrelated to NSC or its major shareholders, Rust International,  Inc. and
OHM  Corporation,  if you remain  employed  with NSC  through the closing of the
sale,  NSC will pay you a transaction  bonus equal to two (2) times your monthly
base salary for your assistance and  cooperation in facilitating  the closing of
the  sale.  NSC  will pay said  transaction  bonus to you as soon as  reasonably
practicable  following  the date of the  closing.  Payment of such bonus will be
subject to normal withholding.

     6. Stock Options.  Any otherwise  exercisable  stock options will remain in
effect,  in accordance  with the terms of the stock option plan under which they
were issued,  during any period of employment with NSC and any subsequent period
during  which you may be receiving  severance  pay.  However,  in the event of a
transaction  involving NSC, which under the terms of the stock option plan would
cause the options to terminate, NSC will use its reasonable efforts to cause the
exercisability of the options to be accelerated.

     7. (a)  Termination  Without  Cause.  If you are  terminated by NSC without
Cause prior to the end of the Term,  NSC will pay you (i) an amount equal to the
greater of (a) the amount of the base  salary  remaining  to be paid  during the
Term,  or (b) one year of continued  base salary  (payable in the same manner as
regular  salary),  measured  by your  base  salary in effect on the date of your
termination and (ii) the Guaranteed Minimum Bonus payment(s) (as provided for in
paragraph  4) for the  balance of the Term.  NSC will also  provide you with one
year's  continued  coverage  under NSC's  medical  and dental  plans at the rate
applicable to active  employees.  (The foregoing  period of continued salary and
benefits is hereinafter referred to as the "Severance Period.")  Notwithstanding
the foregoing, your payments under this paragraph 7(a) can, at your election, be
paid in a single lump sum.

     (b)  Severance.  If you are  terminated  by NSC  without  Cause  after  the
expiration  of the Term of this  Agreement,  you shall be  entitled  to  receive
severance pay for a period of one (1) year from the date of your  termination at
your annual  base  salary then in effect,  payable in the same manner as regular
salary,  together  with one year's  continued  coverage  under NSC's medical and
dental plans at the rate applicable to active employees.

     (c) Cause.  For  purposes  of this  Agreement,  Cause shall mean any act of
dishonesty  or  theft,  willful  misconduct,  acts of gross  negligence,  or the
willful and continued  failure or your refusal to perform assigned duties (other
than caused by a  disability,  which for purposes of this  Agreement  shall mean
your total and permanent  incapacity  to perform the duties you were  performing
immediately prior to the onset of such disability).

     8.  Survivor's  Benefit.  In the event of your death  before the end of the
Term, or during the course of any applicable  Severance Period,  your spouse, if
any,  shall  receive the full (or, if your death  occurs  during any  applicable
Severance  Period,  the  remainder of the) period of  continued  base salary and
medical and dental coverage set forth in paragraph 6 or 7 above.  Further,  your
spouse,  if any, shall receive the Guaranteed  Minimum Bonus due with respect to
the year of your death under paragraph 4 above.

                                 Page 68 of 88
<PAGE>

    9.  Affirmation.  As  further  consideration  for the  payments  and  other
security set forth above,  by signing  this  Agreement  you agree to continue to
abide by the covenants and agreements set forth in Exhibit A attached hereto.


     10.  Assignment.  You may not assign your rights or obligations  hereunder.
The rights and  obligations  of NSC hereunder  shall inure to the benefit of and
shall be binding upon its respective  successors and assigns.  NSC shall use its
reasonable  efforts to ensure that any  purchaser  of the business of NSC offers
the same or substantially  equivalent plans as the medical,  dental, and vehicle
allowance plans currently offered by NSC.

     11.       General Provisions.


     (a) This  Agreement  shall be  subject to and  governed  by the laws of the
Commonwealth of Massachusetts without regard to its choice of law principles.

     (b) Failure to insist upon strict  compliance with any provision(s)  hereof
shall not be deemed a waiver of such provision(s) or any other provision hereof.
If all or any part of this  Agreement  is declared by any court or  governmental
authority to be unlawful or invalid,  such  unlawfulness or invalidity shall not
serve to invalidate any portion of this Agreement not declared to be unlawful or
invalid.  Any  paragraph  or a part of a paragraph so declared to be unlawful or
invalid shall,  if possible,  be construed in a manner which will give effect to
the  terms  of such  paragraph  or part of a  paragraph  to the  fullest  extent
possible while remaining lawful and valid.

     (c) This Agreement  shall not be altered,  amended,  or modified  except by
written  instrument  executed  by NSC and you.  A waiver of any term,  covenant,
agreement, or condition contained in this Agreement shall not be deemed a waiver
of any other term,  covenant,  agreement,  or  condition,  and any waiver of any
default in any such term, covenant,  agreement, or condition shall not be deemed
a waiver of any later default thereof or of any other term, covenant, agreement,
or condition.

     (d) For  purposes  of this  Agreement  and  each of the  Exhibits  attached
hereto,  the term "NSC" shall mean and include NSC  Corporation  and each of its
subsidiaries,  including,  but not limited to, National Surface Cleaning,  Inc.,
National Service Cleaning Corp., Olshan Demolishing Management, Inc., NSC Energy
Services, Inc. and NSC Specialty Coatings, Inc.


     (e)  NSC's  obligation  to  pay  amounts   hereunder  are  subject  to  its
withholding obligations under applicable federal, state, and local laws.

                                 Page 69 of 88
<PAGE>


                                                     NSC CORPORATION


                              By:  /s/ VICTOR J. BARNHART
                                   Victor J. Barnhart,
                                   Acting President and Chief Executive Officer


                                                ACCEPTANCE
Agreed to and accepted this ____ day of ____________, 1996.


By:      /s/ DAVID R. KRACHE
         David R. Krache


                                 Page 70 of 88
<PAGE>

                                    EXHIBIT A


     (A) I agree  that  while I am  employed  by NSC,  I will not,  directly  or
indirectly, compete with the business conducted by NSC.

     (B) I agree that for a period of twelve (12) months  after the  termination
of employment,  whether  voluntary or involuntary,  and regardless of the reason
for or manner of  termination,  I will not,  alone or with  others,  directly or
indirectly (as owner,  stockholder,  partner,  lender,  other investor director,
officer, employee, consultant or otherwise):

     (1)  Solicit,  perform  or engage in any  business  of the same or  similar
nature to the business of NSC, or which is competitive with the business of NSC,
anywhere within the Restricted Area as hereinafter defined; and

     (2) Sell,  attempt to sell,  provide or attempt to provide any  products or
services  (in  competition  with  those  products  or  services  which I sold or
provided on behalf of NSC) to, or solicit,  perform, engage in, divert or accept
any  business of the same or similar  nature to the  business  of NSC from,  any
person, firm or entity:

     (a) residing,  maintaining a principal  place of business or located within
the Restricted Area;

     (b) who was a customer  of NSC within the  Restricted  Area during the last
twenty-four (24) months of my employment; or


     (c) to whom I sold,  attempted  to sell,  provided or  attempted to provide
such  products  or  services  during  the last  twenty-four  (24)  months  of my
employment with NSC.

     (3)  Induce  or  attempt  to induce  any  customer  of NSC to  reduce  such
customer's  business  with NSC or divert such  customer's  business from NSC, by
direct advertising, solicitation or otherwise.


     (4)  Disclose the names of any  customers or potential  customers of NSC to
any other person, firm, corporation or other entity.


     I agree that I will  comply  with the most  restrictive  of the  provisions
specified in  subsections  (1),  (2)(a)  through (c), (3) and (4) above which is
allowed by applicable  state law. The parties agree that if  enforcement of this
Agreement is sought,  the  enforcing  court should  select the most  restrictive
provisions appropriate under applicable state law.

     (C) I agree that while I am employed by NSC and for a period of twelve (12)
months  after  termination  of  my  employment  for  any  reason,  voluntary  or
involuntary,  with or without Cause, I will not directly or indirectly  hire, or
attempt to hire any  employee of NSC nor will I encourage or induce any employee
of NSC to terminate employment with NSC.

     (D)  "Restricted  Area"  shall  mean and  include  each and every  state or
territory  in which NSC has  conducted  or  solicited  any  business  within the
twenty-four (24) months  immediately  preceding the termination of my employment
and up to and including the date of the termination of my employment. "Customer"
shall  mean any  person  firm or other  entity,  or any  parent,  subsidiary  or

                                 Page 71 of 88
<PAGE>
affiliate  thereof,  with which NSC has had a contract,  engaged in any business
with or for which NSC has performed  any services  within the  twenty-four  (24)
months  immediately  preceding the  termination  of my employment  and up to and
including the date of the  termination  of my employment.  "Potential  Customer"
shall  mean any  person  firm or other  entity,  or any  parent,  subsidiary  or
affiliate  thereof,  from which NSC has  solicited  or  attempted to solicit any
business,  or to which NSC has  submitted  any bid or written or oral  proposal,
within the twenty-four (24) months  immediately  preceding the termination of my
employment and up to and including the date of the termination of my employment.


     (E) I acknowledge  that during the term of my employment,  I will be making
use of,  acquiring,  or  adding  to NSC's  Classified  Information.  In order to
protect the Classified Information, I will not, during the term of my employment
with NSC or  thereafter,  in any way utilize any of the  Classified  Information
except in connection with my employment by NSC. I will not copy,  reproduce,  or
remove  from  NSC's  premises  the  original  or any  copies  of the  Classified
Information and I will not disclose any of the Classified Information to anyone.

                                 Page 72 of 88

<PAGE>