EXHIBIT 10.6

                            STOCK PURCHASE AGREEMENT

                                  By and Among

                          AMERICAN TOWER SYSTEMS, INC.,

                                OPM - USA - INC.

                                       and

                                THE STOCKHOLDERS

                                       of

                                OPM - USA - INC.

                                   Dated as of

                               September 30, 1997









<PAGE>





<TABLE>
<CAPTION>
                                TABLE OF CONTENTS

<S>               <C>                                                                                            <C>
ARTICLE 1         DEFINED TERMS...................................................................................1

ARTICLE 2         SALE AND PURCHASE OF STOCK......................................................................1
                  2.1      Agreement to Sell and Buy the Subject Stock............................................2
                  2.2      Closing Purchase Price; Tax Allocation Schedule........................................4
                  2.3      OPM Disclosure Schedule................................................................4

ARTICLE 3         REPRESENTATIONS AND WARRANTIES OF THE STOCKHOLDERS .............................................4
                  3.1      Organization and Business; Power and Authority; Effect of Transaction..................5
                  3.2      Financial and Other Information.  .....................................................5
                  3.3      Changes in Condition...................................................................5
                  3.4      Materiality............................................................................5
                  3.5      Title to Properties; Leases............................................................7
                  3.6      Compliance with Private Authorizations.................................................7
                  3.7      Compliance with Governmental Authorizations and Applicable Law.........................8
                  3.8      Intangible Assets......................................................................8
                  3.9      Related Transactions...................................................................8
                  3.10     Insurance..............................................................................8
                  3.11     Tax Matters.  .........................................................................9
                  3.12     Employee Retirement Income Security Act of 1974.......................................11
                  3.13     Absence of Sensitive Payments.........................................................11
                  3.14     Inapplicability of Specified Statutes.................................................11
                  3.15     Employment Arrangements...............................................................11
                  3.16     Material Agreements...................................................................12
                  3.17     Ordinary Course of Business...........................................................13
                  3.18     Material and Adverse Restrictions.....................................................13
                  3.19     Broker or Finder......................................................................13
                  3.20     Solvency..............................................................................13
                  3.21     Environmental Matters.................................................................14
                  3.22     Capital Stock.........................................................................14
                  3.23     Bank Accounts, Etc....................................................................15

ARTICLE 4         REPRESENTATIONS AND WARRANTIES OF THE STOCKHOLDERS
                  RELATING TO THE SUBJECT STOCK..................................................................15
                  4.1      Enforceability........................................................................15
                  4.2      Title to Shares.......................................................................15
                  4.3      No Conflict; Required Filings and Consents............................................15

ARTICLE 5         REPRESENTATIONS AND WARRANTIES OF ATS..........................................................16
                  5.1      Organization and Business; Power and Authority; Effect of Transaction.................16
                  5.2      Broker or Finder......................................................................16
                  5.3      ATS Financing.........................................................................16
                  5.4      Financial Information. ...............................................................17
                  5.5      Changes in Condition..................................................................17
                  5.6      No Legal Action.......................................................................17

ARTICLE 6         COVENANTS......................................................................................17
                  6.1      Access to Information; Confidentiality................................................18

                                        

<PAGE>



                  6.2      Agreement to Cooperate.  .............................................................19
                  6.3      Public Announcements..................................................................19
                  6.4      Notification of Certain Matters.......................................................19
                  6.5      No Solicitation.......................................................................20
                  6.6      Conduct of Business by OPM Pending the Closing........................................20
                  6.7      Preliminary Title Reports.............................................................21
                  6.8      Environmental Site Assessments........................................................21
                  6.9      Certain Tax Matters...................................................................22
                  6.10     ATS Post-Closing Covenants.  .........................................................23

ARTICLE 7         CLOSING CONDITIONS.............................................................................23
                  7.1      Conditions to Obligations of Each Party...............................................24
                  7.2      Conditions to Obligations of ATS......................................................26
                  7.3      Conditions to Obligations of the Stockholders.........................................27

ARTICLE 8         TERMINATION, AMENDMENT AND WAIVER..............................................................27
                  8.1      Termination...........................................................................28
                  8.2      Effect of Termination.................................................................28

ARTICLE 9         INDEMNIFICATION................................................................................28
                  9.1      Survival..............................................................................28
                  9.2      Indemnification.......................................................................29
                  9.3      Limitation of Liability...............................................................29
                  9.4      Notice of Claims......................................................................30
                  9.5      Defense of Third Party Claims.........................................................30
                  9.6      Exclusive Remedy......................................................................30

ARTICLE 10        GENERAL PROVISIONS.............................................................................30
                  10.1     Waivers; Amendments...................................................................31
                  10.2     Fees, Expenses and Other Payments.....................................................31
                  10.3     Notices...............................................................................32
                  10.4     Specific Performance; Other Rights and Remedies.......................................32
                  10.5     Severability..........................................................................33
                  10.6     Counterparts..........................................................................33
                  10.7     Section Headings......................................................................33
                  10.8     Governing Law.........................................................................33
                  10.9     Further Acts..........................................................................33
                  10.10    Entire Agreement......................................................................33
                  10.11    Assignment............................................................................33
                  10.12    Parties in Interest...................................................................33
                  10.13    Appointment of Representative. .......................................................33
</TABLE>

APPENDIX A:                Definitions

SCHEDULES:

         OPM Disclosure Schedule


                                       ii

<PAGE>



EXHIBITS:

         EXHIBIT A   Form of Noncompetition Agreement  (Section  7.2(i))  (to be
                     agreed upon)  
         EXHIBIT B   Form of Indemnity  scrow  Agreement (Section 9.3(b)) (to be
                     agreed upon)  
         EXHIBIT C   OPM Master Plan  (Section  6.10) 
         EXHIBIT D   Form of Employment Agreement (Section 7.2(p)) (to be agreed
                     upon) 
         EXHIBIT E:  Executive summary of financial Terms (Section 2.2(b).





                                       iii

<PAGE>




                            STOCK PURCHASE AGREEMENT

         This  Stock  Purchase  Agreement  (this  "Agreement")  is  dated  as of
September  30,  1997 by and among  American  Tower  Systems,  Inc.,  a  Delaware
corporation  ("ATS"),  OPM - USA - INC., a Florida corporation  ("OPM"), and the
undersigned stockholders  (individually,  a "Stockholder" and collectively,  the
"Stockholders") of OPM.

         WHEREAS, the Stockholders hold in the aggregate ninety (90) shares (the
"Subject  Stock") of common stock of OPM, which constitute all of the issued and
outstanding capital stock of OPM;

         WHEREAS, the Buyer desires to purchase, and the Sellers desire to sell,
the Subject Stock upon the terms and subject to the conditions set forth herein;
and

         WHEREAS,  OPM owns and leases and operates  communication towers and is
engaged in the business of managing  communication  sites for third parties (the
"OPM Business");

         NOW,  THEREFORE,  in  consideration  of  the  above  premises  and  the
covenants and agreements contained herein, the parties,  intending to be legally
bound, do hereby covenant and agree as follows:


                                    ARTICLE 1

                                  DEFINED TERMS

         As used  herein,  unless  the  context  otherwise  requires,  the terms
defined in  Appendix A shall have the  respective  meanings  set forth  therein.
Terms defined in the singular  shall have a comparable  meaning when used in the
plural,  and vice  versa,  and the  reference  to any gender  shall be deemed to
include all genders.  Unless otherwise  defined or the context otherwise clearly
requires,  terms for which  meanings are provided in this  Agreement  shall have
such  meanings  when used in the OPM  Disclosure  Schedule  and each  Collateral
Document  executed  or required  to be  executed  pursuant  hereto or thereto or
otherwise delivered,  from time to time, pursuant hereto or thereto.  References
to "hereof", "herein" or similar terms are intended to refer to the Agreement as
a whole and not a  particular  Section,  and  references  to "this  Section" are
intended to refer to the entire Section and not a particular subsection thereof.
The term "any party" shall, unless the context otherwise requires, refer to OPM,
the Stockholders and ATS.


                                    ARTICLE 2

                           SALE AND PURCHASE OF STOCK

         2.1  Agreement  to Sell and Buy the Subject  Stock.  Upon the terms and
subject to the conditions set forth in this Agreement,  each of the Stockholders
agrees to sell,  assign,  and  transfer  and  deliver to ATS,  and ATS agrees to
purchase and accept the assignment, transfer and delivery of, the Subject Stock,
in  consideration  of the  payment to the  Stockholders  of the  Purchase  Price
specified in Section 2.2.



                                                      


<PAGE>



         2.2      Closing Purchase Price; Tax Allocation Schedule.

         (a) The closing of the transaction  (the "Closing") shall take place at
Sullivan & Worcester LLP, One Post Office Square,  Boston,  Massachusetts 02109,
at 10:00 a.m.,  local time, on January 6, 1998 or such other date,  prior to the
Termination Date, as the parties may agree (the "Closing Date"). At the Closing,
(A) the Stockholders will deliver original certificates  representing all of the
Subject Stock, duly endorsed (or accompanied by duly executed stock powers), for
transfer  to  ATS,  and (B)  ATS  will  make or  cause  to be made  the  initial
installment of the purchase price (the "Initial  Installment")  in the amount of
eleven  (11) times the  forward  looking  twelve  (12)  months  Cash Flow of OPM
Communication  Towers  beginning  December  31, 1997 as  reflected in the Master
Plan. The purchase  Price for the Subject Stock (the "Purchase  Price") shall be
an amount equal to (i)  $105,000,000,  less (ii) the amount of  liabilities  and
obligations with respect to all Indebtedness of Money Borrowed or Purchase Money
Indebtedness  (other than  Indebtedness  owed to ATS or incurred  subsequent  of
October 6, 1997 with the prior written consent of ATS) and all Liens (other than
Permitted  Liens)  on any of the OPM  Assets  or the  OPM  Business  (the  "Debt
Reduction"),  all but the Initial  Installment  being payable in accordance with
the provisions of, and subject to  satisfaction  of the conditions set forth in,
Section  2.2(b).  The  Purchase  Price  shall be  payable  by wire  transfer  of
immediately  available  funds to the  Stockholders,  in  accordance  with  their
respective  holdings of the Subject  Stock for the Initial  Installment  to such
account (or accounts) as the Stockholders shall designate (including accounts of
individuals  other than the Stockholders in order to satisfy  obligations of OPM
pursuant to employment agreements with such individuals) in written instructions
to ATS delivered not less than two (2) business days prior to the Closing.

         Anything in this  agreement to the contrary  notwithstanding,  ATS will
make quarterly  installment  payments to the Stockholders for the balance of the
Purchase Price to in accordance with the following schedule:

<TABLE>
<CAPTION>
         Payment Date                       Date of Record                      Amount Due

<S>      <C>                                <C>                                 <C>   
         April 30,1998                      March 31, 1998                      See "Formula" below
         July 30, 1998                      June 30, 1998                               "
         October 30, 1998                   September 30, 1998                          "
         January 31, 1998                   December 31, 1998                           "
         April 30, 1999                     March 31, 1999                              "
         August 31, 1999                    June 30, 1999                               "
</TABLE>

For the purposes of the above calculations the "Formula" is the following:

         "Amount Due" is equal to:

                  The  Cash  Flow  as  of  the  "Date  of  Record"   divided  by
                  $9,600,000.   This   percentage  is  then  averaged  with  the
                  percentage of permits of the total number of permits required,
                  the denominator of this percentage  calculation is 250 and the
                  percentage  of  towers  completed,  the  denominator  of  this
                  percentage  calculation  is 200. The  resultant  amount is the
                  amount from which the previous  payments are  subtracted.  The
                  balance after  deducting an amount equal to the Debt Reduction
                  (in the case of the April 30, 1998 Payment  Date) and the Debt
                  Reduction  not  previously   deducted  (in  the  case  of  all
                  subsequent Payment Dates) is the "Amount Due".


                                       -2-


<PAGE>



         For example:

                  Assume as of March 31, 1998:
                           "Cash Flow" is $8,000,000
                           125 towers are permitted
                           133 towers are completed

                           $8,000,000     /      $9,600,000        =       83%
                           125 permits    /      250 permits       =       50%
                           133 towers     /      200 towers        =       66.5%

                           The average of the completions are      66.5%
                           The "Purchase Price" is               x $105,000,000
                                                                   ------------

                           The amount earned is                     $69,825,000
                           Less previous payments                   $30,000,000
                                                                   ------------

                           The amount due April 30, 1998      =     $39,825,000

         (b) For the purposes of  determining  the Initial  Installment  and the
quarterly amount due, "Cash Flow" shall be determined for the twelve (12) months
beginning immediately  subsequent to the determination  thereof, and shall mean,
the gross lease revenues  attributable to the OPM Communications  Towers,  minus
the annual  taxes on the site,  the  utility  expense on the site,  repairs  and
maintenance  to the site,  insurance  on the site and the lease  payments on the
site. Sales taxes collected by OPM are not included in the revenue.

         Cash Flow  shall be  determined  jointly  by ATS with the  Stockholders
Representative based on the above formula. In the event of disagreement, ATS and
the Stockholders Representative shall negotiate to resolve the disagreement and,
in the event they are unable to resolve  their  disagreement  within thirty (30)
days,  the matter shall be referred to a  recognized  national  accounting  firm
which  does not  serve as such for  ATS,  reasonably  acceptable  to ATS and the
Stockholders Representative, whose determination of cash flow in accordance with
the above formula shall be final,  determinative,  nonappealable  and binding on
ATS and the Stockholders,  and whose fees and expenses shall be borne equally by
ATS, on the one hand, and the  Stockholders,  on the other.  ATS shall cause any
payment  required to be made  pursuant to the  provisions  of this Section to be
made promptly to the  Stockholders  after agreement of ATS and the  Stockholders
Representative or the determination of the accounting firm, as the case may be.

         (c) The parties  hereto have  heretofore  agreed that (i) the aggregate
value  of all  Real  Property  of OPM  (including  without  limitation  the  OPM
Communication  Towers  constructed  as of the date  hereof or  between  the date
hereof and the Closing  Date) does not exceed 150% of the original cost thereof,
and (ii) on the basis thereof,  BIA Consulting,  Inc. shall promptly  conduct an
appraisal of the OPM Assets which shall be the basis for an allocation  schedule
(the "Tax  Allocation  Schedule")  pursuant to which the Purchase  Price and the
liabilities of OPM shall be allocated among the OPM Assets as follows: initially
to the  Real  Property  and  tangible  Personal  Property  and  the  balance  to
intangible   Personal  Property   (including  without  limitation   Governmental
Authorizations,  Private  Authorizations,  Leases (pursuant to which OPM acts as
lessor) and other Contracts,  collectively Section 197 assets of the Code). Each
of OPM,  the  Stockholders  and ATS shall  report the  purchase  and sale of the
Subject Stock and the other  Transactions  in accordance with the Tax Allocation
Schedule  for purposes of all  federal,  state and local Tax Returns  (including
amended  returns and claims for refund)  and  information  reports and shall not
take, and shall cause their respective Affiliates,  representatives,  successors
and assigns not to take, any position on any federal,  state or local Tax Return
or

                                       -3-


<PAGE>



report,  inconsistent with such reporting position. Each of the Stockholders and
ATS shall promptly give the other notice of any  disallowance of or challenge to
such reporting by any Taxing Authority.

         2.3 OPM Disclosure  Schedule.  The Stockholders will deliver to ATS, on
or before thirty (30) days from the  execution  and delivery of this  Agreement,
the OPM Disclosure  Schedule and all related documents  required to be delivered
by OPM or the  Stockholders  pursuant  to the  provisions  of  Article 3 of this
Agreement.  ATS  shall be  permitted,  for a period  of ten (10)  business  days
commencing upon its receipt of the completed OPM Disclosure Schedule and related
documents  to  terminate  this  Agreement,  if (a) the OPM  Disclosure  Schedule
reveals any  condition of which ATS is unaware as of the date of this  Agreement
and/or any breaches of the Stockholders' representations,  warranties, covenants
and  agreements  hereunder  (without  regard  to  matters  set  forth in the OPM
Disclosure Schedule),  which unknown conditions and/or breaches in the aggregate
would have a material  adverse effect on OPM or on ability of OPM to continue to
operate or ATS to operate the OPM Business as it is currently being operated, or
(b) the parties are unable to agree upon which Private Authorizations,  Material
Agreements  and  Leases  with  respect  to which a  third-party  consent  to the
consummation of the Transactions or modifications thereof will be a condition to
Closing.  In the event ATS terminates this Agreement  pursuant to the provisions
of this Section,  none of the parties shall have any further rights or remedies,
except as provided in Sections 6.1 (with  respect to  confidentiality),  6.3 and
10.3.


                                    ARTICLE 3

               REPRESENTATIONS AND WARRANTIES OF THE STOCKHOLDERS

         Each of the  Stockholders,  jointly and severally,  hereby  represents,
warrants and covenants to, and agrees with, ATS as follows:

         3.1  Organization  and  Business;   Power  and  Authority;   Effect  of
Transaction.

         (a) OPM is a corporation  duly organized,  validly existing and in good
standing under the laws of its jurisdiction of  organization,  has all requisite
power  and  authority  (corporate  and  other)  to own or hold  under  lease its
properties and to conduct its business as now conducted.

         (b) OPM has all requisite power and authority (corporate and other) and
has in full  force  and  effect  all  Governmental  Authorizations  and  Private
Authorizations necessary to enable it to execute and deliver, and to perform its
obligations  under,  this  Agreement and each  Collateral  Document  executed or
required to be executed by it pursuant  hereto or thereto or to  consummate  the
Transactions;  and the execution, delivery and performance of this Agreement and
each  Collateral  Document  executed  or  required to be executed by it pursuant
hereto or thereto have been duly authorized by all requisite  corporate or other
action on the part of OPM.  This  Agreement has been duly executed and delivered
by OPM and constitutes,  and each Collateral Document executed or required to be
executed by it pursuant hereto or thereto or to consummate the Transactions when
executed  and  delivered  by OPM  will  constitute,  legal,  valid  and  binding
obligations  of OPM,  enforceable  in accordance  with their  respective  terms,
except  as  such  enforceability  may  be  limited  by  bankruptcy,  moratorium,
insolvency  and similar laws  affecting the rights and remedies of creditors and
obligations of debtors generally and by general principles of equity.

         (c)  Except  as set  forth  in  Section  3.1(c)  of the OPM  Disclosure
Schedule,  neither the  execution  and delivery by OPM of this  Agreement or any
Collateral Document executed or required to be executed by it pursuant hereto or
thereto,  nor the  consummation  of the  Transactions,  nor compliance  with the
terms, conditions and provisions hereof or thereof by OPM:

                                       -4-


<PAGE>




                  (i) will conflict with, or result in a breach or violation of,
         or  constitute  a default  under,  any  Organic  Document of OPM or any
         Applicable  Law,  or will  conflict  with,  or  result  in a breach  or
         violation of, or constitute a default under, or permit the acceleration
         of any obligation or liability in, or but for any requirement of giving
         of notice or passage of time or both would  constitute  such a conflict
         with,  breach or  violation  of, or default  under,  or permit any such
         acceleration in, any Contractual Obligation of OPM; or

                  (ii)  will  require  OPM to make or  obtain  any  Governmental
         Authorization,  Governmental Filing or Private Authorization  including
         without limitation under the FCA.

         (d)      OPM does not have any Subsidiaries.

         3.2 Financial and Other  Information.  OPM has heretofore  furnished to
ATS copies of the  financial  statements of OPM listed in Section 3.2 of the OPM
Disclosure  Schedule  (the  "OPM  Financial  Statements").   The  OPM  Financial
Statements,  including  in each case the notes  thereto,  have been  prepared in
accordance  with GAAP  applied on a  consistent  basis  throughout  the  periods
covered  thereby,  except as otherwise  noted therein or as set forth in Section
3.2 of the OPM  Disclosure  Schedule,  are true,  accurate  and  complete in all
material  respects,  do not contain any untrue  statement of a material  fact or
omit to state a material fact required by GAAP to be stated therein or necessary
in order to make the statements  contained  therein not  misleading,  and fairly
present the financial  condition and the results of operations  and cash flow of
OPM, on the bases therein stated,  as of the respective  dates thereof,  and for
the  respective  periods  covered  thereby  subject,  in the  case of  unaudited
financial  statements,  to normal  nonmaterial  year-end audit  adjustments  and
accruals.  Without  limiting the generality of the  foregoing,  all accounts and
notes receivable  reflected on the OPM Financial Statements and all accounts and
notes  receivable  arising  subsequent  to the  issuance  of the  OPM  Financial
Statements  have or  will  have  arisen  in the  ordinary  course  of  business,
represent or will represent  valid  obligations to OPM, and will be collected in
the aggregate  amounts thereof  recorded on the books of OPM, net of the reserve
for bad debts reflected on the most recent OPM Financial Statements.

         3.3 Changes in Condition.  Since the date of the most recent  financial
statements  constituting a part of the OPM Financial  Statements,  except to the
extent  specifically  described in Section 3.3 of the OPM  Disclosure  Schedule,
there has been no material adverse change in OPM. There is no Event known to OPM
which  materially  adversely  affects,  or (so  far as OPM  can  now  reasonably
foresee) is likely to materially  adversely  affect,  OPM,  except to the extent
specifically described in Section 3.3 of the OPM Disclosure Schedule.

         3.4 Materiality.  The  representations and warranties set forth in this
Article would in the aggregate be true and correct even without the  materiality
exceptions  or  qualifications  contained  therein  or  set  forth  in  the  OPM
Disclosure  Schedule,  except for such exceptions and  qualifications  including
without limitation those set forth in the OPM Disclosure  Schedule which, in the
aggregate for all such  representations  and  warranties,  are not and could not
reasonably be expected to be materially adverse to OPM.

         3.5      Title to Properties; Leases.

         (a)  Section  3.5(a) of the OPM  Disclosure  Schedule  contains a true,
accurate and complete description of all real property owned by OPM that is part
of the OPM Assets. OPM has, to the Stockholders'  knowledge,  good indefeasible,
marketable and insurable  title to all real property  (other than leasehold real
property)  and good  indefeasible  and  merchantable  title to all other  assets
(other than real property), tangible and intangible,  constituting a part of the
OPM Assets; all of such real property and other assets is so owned,

                                       -5-


<PAGE>



in each case,  free and clear of all Liens,  except (i)  Permitted  Liens,  (ii)
Liens  set forth on  Section  3.5(a) of the OPM  Disclosure  Schedule  and (iii)
Approved Title  Conditions.  Except for financing  statements  evidencing  Liens
referred to in the  preceding  sentence (a true,  accurate and complete list and
description  of  which is set  forth in  Section  3.5(a)  of the OPM  Disclosure
Schedule),  no financing  statements  under the Uniform  Commercial  Code and no
other  filing which names OPM as debtor or which covers or purports to cover any
of the OPM Assets is on file in any state or other jurisdiction, and OPM has not
signed or agreed to sign any such financing statement or filing or any agreement
authorizing any secured party thereunder to file any such financing statement or
filing.  Except as disclosed in Section 3.5(a) of the OPM  Disclosure  Schedule,
all  improvements  on the real  property  owned  or  leased  by OPM are,  to the
Stockholders' knowledge, in compliance with applicable zoning, wetlands and land
use laws, ordinances and regulations and applicable title covenants, conditions,
restrictions  and  reservations  in  all  respects   necessary  to  conduct  the
operations as presently  conducted,  except for any instances of  non-compliance
which do not and will not in the aggregate have a material adverse effect on the
owner or lessee, as the case may be, of such real property.  Except as disclosed
in Section 3.5(a) of the OPM Disclosure Statement,  all such improvements comply
in all material  aspects with all Applicable Laws,  Governmental  Authorizations
and Private  Authorizations.  Except as disclosed  in Section  3.5(a) of the OPM
Disclosure  Statement,  all of the  transmitting  towers,  ground  radials,  guy
anchors,  transmitting  buildings and related  improvements  located on the real
property  owned or leased by OPM are  located  entirely  on such real  property.
There is no pending and, to Stockholders' knowledge,  threatened or contemplated
action to take by eminent  domain or  otherwise  to condemn any part of any real
property  owned or leased by OPM.  Except as set forth in Section  3.5(a) of the
OPM Disclosure Schedule,  such real property (other than land), fixtures,  fixed
assets and other material items of personal property, including equipment, have,
in OPM's reasonable  business  judgment,  been maintained in a manner consistent
with generally  accepted  standards of sound engineering  practice and currently
permit the OPM  Business to be operated in all material  respects in  accordance
with  the  terms  and   conditions   of  all   Applicable   Laws,   Governmental
Authorizations and Private Authorizations.

         (b)  Section  3.5(b) of the OPM  Disclosure  Schedule  contains a true,
accurate and complete  description  of all Leases under which any real  property
used in the OPM Business is leased.  Except as  otherwise  set forth in Schedule
3.5(b) of the OPM Disclosure  Schedule,  each Lease or other  occupancy or other
agreement under which OPM holds real or personal property constituting a part of
the OPM Assets has been duly  authorized,  executed and delivered by OPM and, to
Stockholders'  knowledge,  each of the other  parties  thereto,  and is a legal,
valid and binding  obligation of OPM, and, to Stockholders'  knowledge,  each of
the other parties thereto,  enforceable in accordance with its terms,  except as
such  enforceability  may be limited by bankruptcy,  moratorium,  insolvency and
similar laws  affecting the rights and remedies of creditors and  obligations of
debtors generally and by general principles of equity. OPM has a valid leasehold
interest in and enjoys  peaceful  and  undisturbed  possession  under all Leases
pursuant to which it holds any such real property or tangible personal property.
All of such  Leases  are  valid and  subsisting  and in full  force and  effect;
neither OPM nor, to  Stockholders'  knowledge,  any other party  thereto,  is in
material  default  in  the   performance,   observance  or  fulfillment  of  any
obligation, covenant or condition contained in any such Lease. None of the fixed
assets or equipment  comprising a part of the OPM Assets is subject to contracts
of sale, and none is held by OPM as lessee or as conditional  sales vendee under
any  Lease or  conditional  sales  contract  and none is  subject  to any  title
retention agreement, except as set forth in Section 3.5(b) of the OPM Disclosure
Schedule.

         (c)  Section  3.5(c) of the OPM  Disclosure  Schedule  contains a true,
accurate  and  complete  description  of all  material  items  of  OPM  Personal
Property.  OPM  owns  and has  good  and  merchantable  title  to all of the OPM
Personal Property (the "OPM Personal Property"), in each case, free and clear of
all Liens, except (i) Permitted Liens and (ii) Liens set forth on Section 3.5(c)
of the OPM Disclosure Schedule (which Liens shall be released prior to Closing).
Except as set forth in Section 3.5(c) of the OPM Disclosure Schedule, all of the
OPM  Personal  Property is in a state of good repair and  maintenance  and is in
good

                                       -6-


<PAGE>



operating  condition,  normal wear and tear excepted,  has been  maintained in a
manner consistent with generally accepted standards of good engineering practice
and  currently  permits the OPM Business to be operated in  accordance  with the
terms and conditions of all Applicable Laws.

         3.6  Compliance  with  Private  Authorizations.  Section 3.6 of the OPM
Disclosure   Schedule  sets  forth  a  true,  accurate  and  complete  list  and
description of each Private  Authorization which individually is material to the
OPM Assets or the OPM  Business.  OPM has  obtained  all Private  Authorizations
which are  necessary  for the  ownership  or  operation of the OPM Assets or the
conduct of the OPM  Business  which,  if not  obtained  and  maintained,  could,
individually or in the aggregate,  materially  adversely affect OPM. All of such
Private  Authorizations are valid and in good standing and are in full force and
effect.  OPM is not in breach or violation of, or in default in the performance,
observance  or  fulfillment  of, any such  Private  Authorization,  and no Event
exists or has occurred, which constitutes,  or but for any requirement of giving
of notice or passage of time or both would constitute,  such a breach, violation
or default,  under any such  Private  Authorization,  except for such  defaults,
breaches or violations as do not and will not have in the aggregate any material
adverse  effect on OPM.  No such  Private  Authorization  is the  subject of any
pending  or,  to  Stockholders'  knowledge,  threatened  attack,  revocation  or
termination.

         3.7 Compliance with Governmental Authorizations and Applicable Law.

         (a)  Section  3.7(a) of the OPM  Disclosure  Schedule  contains a true,
complete and accurate  description of each Governmental  Authorization  required
under  Applicable  Laws (i) to own and operate the OPM  Business,  as  currently
conducted or proposed to be conducted  on or prior to the Closing  Date,  all of
which are in full  force and effect or (ii) that is  necessary  to permit OPM to
execute and deliver this Agreement and to perform its obligations hereunder. OPM
has  obtained  all  Governmental  Authorizations  which  are  necessary  for the
ownership  or  operation of the OPM Assets or the conduct of the OPM Business as
now conducted and which, if not obtained and maintained,  would, individually or
in the  aggregate,  have  any  material  adverse  effect  on  OPM.  None  of the
Governmental  Authorizations  listed in  Section  3.7(a)  of the OPM  Disclosure
Schedule is subject to any  restriction  or  condition  which would limit in any
material respect the ownership or operations of the OPM Assets or the conduct of
the OPM Business as currently conducted,  except for restrictions and conditions
generally   applicable  to  Governmental   Authorizations   of  such  type.  The
Governmental  Authorizations  listed in  Section  3.7(a)  of the OPM  Disclosure
Schedule  are valid and in good  standing,  are in full force and effect and are
not  impaired  in any  material  respect  by any act or  omission  of OPM or its
officers, directors,  employees or agents, and the ownership or operation of the
OPM Assets or the conduct of the OPM Business are in  accordance in all material
respects with the Governmental  Authorizations.  All material reports, forms and
statements  required to be filed by OPM with all Authorities with respect to the
OPM Business have been filed and are true, complete and accurate in all material
respects.  No such Governmental  Authorization is the subject of any pending or,
to  Stockholders'  knowledge,  threatened  challenge or  proceeding to revoke or
terminate any such Governmental Authorization. OPM has no reason to believe that
any such Governmental  Authorization  would not be renewed in the name of OPM by
the granting Authority in the ordinary course.

         (b) Except as otherwise specifically described in Section 3.7(b) of the
OPM  Disclosure  Schedule,  neither OPM nor any director or officer  thereof (in
connection  with  ownership or operation of the OPM Assets or the conduct of the
OPM  Business) is in or is charged by any  Authority  with or, to  Stockholders'
knowledge,  at any time since May 1, 1995 has been in or has been charged by any
Authority  with,  or,  to  Stockholders'   knowledge,  is  threatened  or  under
investigation  by any  Authority  with respect to,  breach or  violation  of, or
default in the  performance,  observance  or  fulfillment  of, any  Governmental
Authorization  or any  Applicable Law relating to the ownership and operation of
the OPM Assets or the conduct of the OPM Business.  In  particular,  but without
limiting the generality of the foregoing, there are no applications,  complaints
or Legal Actions pending or, to Stockholders' knowledge, threatened before or by
any Authority

                                       -7-


<PAGE>



(x)  relating to the  ownership or operation of the OPM Assets or the conduct of
the OPM Business which,  individually or in the aggregate, are reasonably likely
to result in the revocation or termination of any Governmental  Authorization or
the imposition of any restriction of such a nature as would adversely affect the
ownership or operation of the OPM Assets or the conduct of the OPM Business; (y)
involving  charges of illegal  discrimination  by OPM under any federal or state
employment Laws, or (z) involving  Environmental  Laws or zoning laws, except as
otherwise  specifically  described  in  Section  3.7(b)  of the  OPM  Disclosure
Schedule.

         (c) Except as otherwise specifically described in Section 3.7(c) of the
OPM  Disclosure   Schedule,   no  Event  exists  or  has  occurred,   which,  to
Stockholders'  knowledge,  constitutes,  or but for any requirement of giving of
notice or passage of time or both would constitute,  such a breach, violation or
default, under (i) any Governmental  Authorization or any Applicable Law, except
for  such  breaches,  violations  or  defaults  as do not  and  will  not  have,
individually or in the aggregate, any material adverse effect on OPM or (ii) any
material  requirement of any insurance  carrier,  applicable to the ownership or
operations of the OPM Assets or the conduct of the OPM Business.

         (d) With respect to matters, if any, of a nature referred to in Section
3.7(a),  3.7(b) or 3.7(c) of the OPM  Disclosure  Schedule,  except as otherwise
specifically  described in Section  3.7(d) of the OPM Disclosure  Schedule,  all
such  information  and  matters  set forth in the OPM  Disclosure  Schedule,  if
adversely  determined  against OPM, will not,  individually or in the aggregate,
have a materially adversely effect on OPM.

         3.8 Intangible Assets.  Section 3.8 of the OPM Disclosure Schedule sets
forth a true, accurate and complete  description of all Intangible Assets (other
than Governmental  Authorizations  and Private  Authorizations)  relating to the
ownership  and  operation  of the OPM Assets or the conduct of the OPM  Business
held or used by OPM,  including without  limitation the nature of OPM's interest
in each and the  extent  to which the same  have  been  duly  registered  in the
offices as  indicated  therein.  Except as set forth in  Section  3.8 of the OPM
Disclosure Schedule,  no Intangible Assets (except Governmental  Authorizations,
Private Authorizations, and the Intangible Assets so set forth) are required for
the  ownership or operation of the OPM Assets or the conduct of the OPM Business
as currently owned, operated and conducted or proposed to be owned, operated and
conducted  on or prior to the  Closing  Date.  OPM does not,  to its  knowledge,
wrongfully  infringe  upon or  unlawfully  use any  Intangible  Assets  owned or
claimed  by  another,  and OPM has not  received  any  notice  of any  claim  or
infringement relating to any such Intangible Asset.

         3.9  Related  Transactions.  OPM  is  not a  party  or  subject  to any
Contractual  Obligation relating to the ownership or operation of the OPM Assets
or the  conduct  of the  OPM  Business  between  OPM  and  any of its  officers,
directors, stockholders, employees or, to the knowledge of OPM, any Affiliate of
any thereof,  including without limitation any Contractual  Obligation providing
for the furnishing of services to or by, providing for rental of property, real,
personal or mixed,  to or from,  or  providing  for the lending or  borrowing of
money to or from or otherwise  requiring  payments to or from,  any such Person,
other than (i)  Employment  Arrangements  listed or described in Section 3.15 of
the OPM Disclosure Schedule, (ii) Contractual Obligations between OPM and any of
its directors, stockholders,  officers, employees or Affiliates of OPM or any of
the foregoing,  which will be terminated, at no cost or expense to OPM, prior to
the  Closing,  or (iii) as  specifically  set  forth in  Section  3.9 of the OPM
Disclosure Schedule.

         3.10 Insurance.  OPM maintains,  with respect to the OPM Assets and the
OPM Business, policies of fire and extended coverage and casualty, liability and
other forms of  insurance  in such  amounts and against such risks and losses as
are set forth in Section 3.10 of the OPM Disclosure Schedule.

         3.11     Tax Matters.

                                       -8-


<PAGE>




         (a) OPM has in  accordance  with  all  Applicable  Laws  filed  all Tax
Returns which are required to be filed, and has paid, or made adequate provision
for the payment of, all Taxes which have or may become due and payable  pursuant
to said Tax Returns and all other governmental  charges and assessments received
to date other than those Taxes being  contested in good faith for which adequate
provision  has been made on the most recent  balance  sheet  forming part of OPM
Financial Statements.  The Tax Returns of OPM have been prepared in all material
respects  in  accordance  with  all  Applicable  Laws  and  generally   accepted
principles  applicable to taxation  consistently applied. All Taxes which OPM is
required by law to withhold and collect have been duly  withheld and  collected,
and have been paid over, in a timely  manner,  to the proper  Authorities to the
extent due and payable.  OPM has not executed any waiver to extend, or otherwise
taken or failed to take any action that would have the effect of extending,  the
applicable  statute of limitations in respect of any Tax  liabilities of OPM for
the fiscal years prior to and including  the most recent  fiscal year.  Adequate
provision  has been made on the most recent  balance  sheet  forming part of OPM
Financial  Statements  for all Taxes  accrued  through the date of such  balance
sheet of any kind, including interest and penalties in respect thereof,  whether
disputed or not, and whether  past,  current or deferred,  accrued or unaccrued,
fixed, contingent, absolute or other, and there are, to Stockholders' knowledge,
no past  transactions  or matters  which could result in  additional  Taxes of a
material  nature to OPM for which an adequate  reserve has not been  provided on
such balance sheet. OPM is not a "consenting  corporation" within the meaning of
Section  341(f) of the Code. OPM has at all times been taxable as a Subchapter S
corporation  under the Code,  and has  never  been a member of any  consolidated
group for Tax purposes,  except as otherwise set forth in Section 3.11(a) of the
OPM Disclosure Schedule.

         (b) The information  shown on the federal income Tax Returns of OPM for
each of the most recent two tax years (true and  complete  copies of which have,
to the extent requested by ATS, been furnished by OPM to ATS) is true,  accurate
and complete in all material  respects  and fairly and  accurately  reflects the
information  purported to be shown.  Federal and state income Tax Returns of OPM
have not been examined by the IRS or applicable state Authority, and OPM has not
been notified of any proposed examination, except as shown in Section 3.11(b) of
the OPM Disclosure Schedule.

         (c) OPM is not a party to any tax sharing agreement or arrangement.

         3.12     Employee Retirement Income Security Act of 1974.

         (a) OPM (which for  purposes of this  Section  shall  include any ERISA
Affiliate) is not making any  contribution to or sponsoring,  and has not at any
time since its organization  made any contribution to or sponsored,  any Plan or
Benefit  Arrangement,  except  as set  forth  in  Section  3.12(a)  of  the  OPM
Disclosure Schedule.  As to all Plans and Benefit Arrangements listed in Section
3.12(a) of the OPM Disclosure Schedule:

                  (i) all such Plans and  Benefit  Arrangements  comply and have
         been  administered in form and in operation with all Applicable Laws in
         all  material  respects,  and OPM has not  received any notice from any
         Authority questioning or challenging such compliance;

                  (ii) all such Plans maintained or previously maintained by OPM
         that are or were  intended to comply with  Sections  401 and 501 of the
         Code comply and complied in form and in operation  with all  applicable
         requirements of such sections,  and no event has occurred which will or
         could  give  rise to  disqualification  of any  such  Plan  under  such
         sections or to a tax under Section 511 of the Code;

                  (iii)  none of the  assets  of any such Plan are  invested  in
         employer securities or employer real property;

                                       -9-


<PAGE>




                  (iv)  there  have  been  no  "prohibited   transactions"   (as
         described  in Section  406 of ERISA or  Section  4975 of the Code) with
         respect  to any such  Plan  and OPM has not  otherwise  engaged  in any
         prohibited transaction;

                  (v) there  have been no acts or  omissions  by OPM which  have
         given rise to or may give rise to any material fines, penalties,  taxes
         or related  charges under Sections  502(c),  502(i) or 4071 or ERISA or
         Chapter 43 of the Code for which OPM may be liable;

                  (vi)  there are no  Claims  (other  than  routine  claims  for
         benefits  or  actions  seeking  qualified  domestic  relations  orders)
         pending or threatened involving such Plans or the assets of such Plans,
         and, to Stockholders'  knowledge,  no facts exist which could give rise
         to any such Claims  (other than routine  claims for benefits or actions
         seeking qualified domestic relations orders);

                  (vii) no such Plan is  subject  to Title IV of  ERISA,  or, if
         subject,  there have been no "report  able  events"  (as  described  in
         Section 4043 of ERISA),  and no steps have been taken to terminate  any
         such Plan;

                  (viii) all group  health  Plans of OPM have been  operated  in
         compliance  in  all  material  respects  with  the  group  health  plan
         continuation coverage requirements of COBRA;

                  (ix) actuarially  adequate  accruals for all obligations under
         the Plans are  reflected in the most recent  balance sheet forming part
         of the OPM Financial Statements and such obligations include a pro rata
         amount of the  contributions  which would  otherwise  have been made in
         accordance  with past  practices  for the Plan years which  include the
         Closing Date;

                  (x) neither OPM nor any of its respective directors, officers,
         employees or any other  fiduciary has committed any breach of fiduciary
         responsibility  imposed  by ERISA or any  similar  Applicable  Law that
         would  subject  OPM or any of its  respective  directors,  officers  or
         employees to material  liability under ERISA or any similar  Applicable
         Law;

                  (xi) no such Plan which is subject to Part 3 of  Subtitle B of
         Title I of ERISA or Section 412 of the Code had an accumulated  funding
         deficiency  (as  defined in Section 302 of ERISA and Section 412 of the
         Code),  whether or not  waived,  as of the last day of the most  recent
         fiscal  year of such Plan to which  Part 3 of  Subtitle B of Title I of
         ERISA  or  Section  412 of the  Code  applied,  nor  would  have had an
         accumulated funding deficiency on such date if such year were the first
         year of such Plan to which Part 3 of  Subtitle B of Title I of ERISA or
         Section 412 of the Code applied;

                  (xii)  no  material  liability  to the  PBGC  has  been  or is
         expected  by OPM to be incurred  by OPM with  respect to any Plan,  and
         there has been no event or condition  which presents a material risk of
         termination of any Plan by the PBGC;

                  (xiii)  OPM  is  not  and  never  has  been  a  party  to  any
         Multiemployer Plan or made contributions to any such Plan;

                  (xiv) except as set forth in Section  3.12(a)(xiv)  of the OPM
         Disclosure  Schedule  (which entry,  if applicable,  shall indicate the
         present value of accumulated  plan  liabilities  calculated in a manner
         consistent with FAS 106 and actual annual expense for such benefits for
         each of the last two (2)  years)  and  pursuant  to the  provisions  of
         COBRA, OPM does not maintain any Plan that provides

                                      -10-


<PAGE>



         benefits  described in Section 3(1) of ERISA,  except as the provisions
         of COBRA may apply, to any former employees or retirees of OPM; and

                  (xv)  OPM has  made  available  to ATS a copy of the two  most
         recently filed Federal Form 5500 series and  accountant's  opinion,  if
         applicable,  for each Plan (and the two most recent actuarial valuation
         reports for each Plan,  if any,  that is subject to Title IV of ERISA),
         and all  information  provided by OPM to any actuary in connection with
         the  preparation  of any such  actuarial  valuation  report  was  true,
         accurate and complete in all material respects.

         (b) The  execution,  delivery and  performance by OPM of this Agreement
and the Collateral Documents executed or required to be executed pursuant hereto
and thereto will not involve any  prohibited  transaction  within the meaning of
ERISA or Section 4975 of the Code.

         3.13 Absence of Sensitive  Payments.  Neither OPM nor, to Stockholders'
knowledge,  any  of  its  officers,   directors,   employees,  agents  or  other
representatives, has with respect to the OPM Assets or the OPM Business (a) made
any  contributions,  payments  or  gifts  to or  for  the  private  use  of  any
governmental official, employee or agent where either the payment or the purpose
of such  contribution,  payment or gift is illegal  under the laws of the United
States or the  jurisdiction  in which made or (b)  established or maintained any
unrecorded fund or asset for any purpose or made any false or artificial entries
on its books.

         3.14  Inapplicability  of  Specified  Statutes.  OPM is not a  "holding
company", or a "subsidiary company" or an "affiliate" of a "holding company", as
such terms are defined in the Public  Utility  Holding  Company Act of 1935,  as
amended,  or an "investment  company" or a company  "controlled" by or acting on
behalf of an "investment  company",  as defined in the Investment Company Act of
1940, as amended, or a "carrier" or a person which is in control of a "carrier",
as defined in section 11301 of Title 49, U.S.C.

         3.15  Employment  Arrangements.  Section  3.15  of the  OPM  Disclosure
Schedule  contains a true,  accurate and complete list of all OPM employees (the
"OPM  Employees"),  together with each such employee's  title or the capacity in
which he or she is employed and the basis for each such employee's compensation.
OPM has no obligation or liability,  contingent or other,  under any  Employment
Arrangement  with any OPM  Employee,  other than those  listed or  described  in
Section 3.15 of the OPM Disclosure Schedule. Except as described in Section 3.15
of the OPM Disclosure  Schedule,  (a) none of the OPM Employees is now, or since
May 1,  1995  has  been,  represented  by any  labor  union  or  other  employee
collective bargaining organization,  and OPM is not, and never has been, a party
to any labor or other collective bargaining agreement with respect to any of the
OPM Employees,  (b) there are no pending  grievances,  disputes or controversies
with any union or any other employee or collective  bargaining  organization  of
such  employees,  or threats of strikes,  work  stoppages  or  slowdowns  or any
pending   demands  for  collective   bargaining  by  any  such  union  or  other
organization, (c) neither OPM nor any of such employees is now, or has since May
1,  1995  been,  subject  to or  involved  in or,  to  Stockholders'  knowledge,
threatened   with,   any  union   elections,   petitions   therefore   or  other
organizational  or recruiting  activities,  in each case with respect to the OPM
Employees,  and (d) none of the OPM  Employees  has  notified OPM that he or she
does not intend to  continue  employment  with OPM until the Closing or with ATS
following  the  Closing.   OPM  has  performed  in  all  material  respects  all
obligations  required to be performed under all Employment  Arrangements  and is
not in material  breach or violation of or in material  default or arrears under
any of the terms, provisions or conditions thereof.

         3.16 Material Agreements.  Listed on Section 3.16 of the OPM Disclosure
Schedule are all Material  Agreements  relating to the ownership or operation of
the OPM Assets or the conduct of the  business  of the OPM  Business or to which
OPM is a party  or to  which it is  bound  or  which  any of the OPM  Assets  is
subject.  True, accurate and complete copies of each of such Material Agreements
have been made available

                                      -11-


<PAGE>



by OPM to ATS and OPM has provided  ATS with  photocopies  of all such  Material
Agreements requested by ATS (or true, accurate and complete descriptions thereof
have been set forth in Section 3.16 of the OPM Disclosure Schedule, with respect
to Material Agreements comprised of site leases and site licenses granted by OPM
to third parties and with respect to Material  Agreements that are oral). All of
such Material Agreements are valid, binding and legally enforceable  obligations
of OPM and, to Stockholders'  knowledge,  all other parties  thereto,  except as
such  enforceability  may be limited by bankruptcy,  moratorium,  insolvency and
similar laws  affecting the rights and remedies of creditors and  obligations of
debtors  generally and by general  principles  of equity.  OPM has duly complied
with all of the material  terms and  conditions of each such Material  Agreement
and has not done or  performed,  or failed  to do or  perform  (and  there is no
pending or, to the  knowledge of OPM,  Claim  threatened in writing that OPM has
not so complied,  done and  performed or failed to do and perform) any act which
would  invalidate  or provide  grounds for the other party  thereto to terminate
(with or without  notice,  passage of time or both) such  Material  Agreement or
impair the rights or benefits,  or increase the costs,  of OPM under any of such
Material Agreements in any material respect.

         3.17 Ordinary Course of Business.  OPM, from the end of its most recent
fiscal  quarter to the date  hereof,  except (i) as may be  described on Section
3.17 of the OPM  Disclosure  Schedule,  or (ii) as may be required or  expressly
contemplated by the terms of this Agreement,  with respect to the OPM Assets and
the OPM Business:

                  (a) has operated its business in all material  respects in the
         normal,  usual and customary  manner in the ordinary and regular course
         of business, consistent with prior practice;

                  (b) except in each case in the  ordinary  course of  business,
consistent with prior practice:

                           (i) has not  incurred  any  obligation  or  liability
                  (fixed,  contingent or other)  individually  having a value in
                  excess of $20,000;

                           (ii)  has  not  sold  or  otherwise  disposed  of  or
                  contracted  to  sell  or  otherwise  dispose  of  any  of  its
                  properties or assets having a value in excess of $20,000;

                           (iii) has not entered into any individual  commitment
                  having a value in excess of $20,000; and

                           (iv)  has not canceled any debts or claims;

                  (c) has not created or permitted to be created any Lien on any
         of its property;

                  (d) has not made or  committed  to make any  additions  to its
         property or any purchases of equipment,  except in the ordinary  course
         of business consistent with past practice or for normal maintenance and
         replacements;

                  (e) has not  increased the  compensation  payable or to become
         payable to any of the OPM Employees other than nonmaterial increases in
         the ordinary  course of  business,  or  otherwise  materially  altered,
         modified or changed the terms of their employment;

                  (f) has not suffered any material damage,  destruction or loss
         (whether or not covered by insurance) or any  acquisition  or taking of
         property by any Authority;

                  (g) has not waived any rights of material  value  without fair
         and adequate consideration;

                                      -12-


<PAGE>




                  (h) has not experienced any work stoppage;

                  (i) except in the ordinary course of business, has not entered
         into,  amended or  terminated  any Lease,  Governmental  Authorization,
         Private Authorization, Material Agreement or Employment Arrangement, or
         any  transaction,  agreement or arrangement  with any Affiliate of OPM,
         except for OPM Nonassumed Obligations; and

                  (j) has not made, paid or declared any Distribution; and

                  (k) has not entered  into any other  transaction  or series of
         related transactions which individually or in the aggregate is material
         to the OPM Assets or the OPM Business.

         3.18  Material  and  Adverse  Restrictions.  OPM is not a  party  to or
subject  to,  nor is any of the OPM  Assets  subject  to,  any  Applicable  Law,
Governmental  Authorization,  Contractual  Obligation,  Employment  Arrangement,
Material  Agreement  or  Private  Authorization,  or  any  other  obligation  or
restriction  of any kind or  character,  which now has or, as far as OPM can now
reasonably foresee, at any time in the future, individually or in the aggregate,
is likely to have, any material  adverse  effect on OPM,  except as set forth in
Section 3.18 of the OPM Disclosure Schedule.

         3.19  Broker or Finder.  No Person  assisted  in or  brought  about the
negotiation  of this  Agreement or the  Transactions  in the capacity of broker,
agent or finder or in any similar capacity on behalf of OPM.

         3.20 Solvency. As of the execution and delivery of this Agreement,  OPM
is, and immediately  prior to and after giving effect to the consummation of the
Transactions will be, solvent.

         3.21 Environmental Matters.  Except as set forth in Section 3.21 of the
OPM Disclosure Schedule, with respect to the OPM Assets and the OPM Assets, OPM:

                  (a) has not been notified that it is potentially liable under,
         has not received any request for  information  or other  correspondence
         concerning its potential liability with respect to any site or facility
         under,  and,  to  Stockholders'   knowledge,   is  not  a  "potentially
         responsible  party" under, the  Comprehensive  Environmental  Response,
         Compensation  and  Liability  Act of 1980,  as  amended,  the  Resource
         Conservation Recovery Act, as amended, or any similar state law;

                  (b) has not  entered  into or  received  any  consent  decree,
         compliance  order  or  administrative  order  issued  pursuant  to  any
         Environmental Law;

                  (c) is  not a  party  in  interest  or in  default  under  any
         judgment,  order, writ,  injunction or decree of any Final Order issued
         pursuant to any Environmental Law;

                  (d) has  obtained all  Environmental  Permits  required  under
         Environmental  Laws, and has filed all applications,  notices and other
         documents  required to be filed prior to the date of this  Agreement to
         effect the timely renewal or issuance of all Environmental  Permits for
         the continued conduct of its business in the manner now conducted;

                  (e)  is in  compliance  in  all  material  respects  with  all
         Environmental  Laws, and is not the subject of or, to the Stockholders'
         knowledge,  threatened  with any Legal  Action  involving  a demand for
         damages or other potential liability,  including any Lien, with respect
         to violations or breaches of any Environmental Law;

                                      -13-


<PAGE>




                  (f) has not conducted or received any site  assessment,  audit
         or other  investigation  as to  material  environmental  matters at any
         property currently owned, leased, operated or occupied by OPM;

                  (g) has not installed or used any above ground or  underground
         storage  tanks,  friable  asbestos,  polychlorinated  biphenyls or urea
         formaldehyde foam insulation on any property currently owned, leased or
         operated by OPM and, to the Stockholders' knowledge, there are no above
         ground or underground storage tanks, friable asbestos,  polychlorinated
         biphenyls  or  urea   formaldehyde  foam  insulation  or  any  property
         currently owned, leased or operated by OPM;

                  (h) there has been no  disposal,  release,  spill or burial of
         any Hazardous  Materials by OPM (or any Person acting on its behalf) in
         violation  of  Environmental  Laws on any  property or facility  owned,
         leased,  operated or occupied by OPM or to the Stockholders'  knowledge
         at any facility or site to which Hazardous  Materials from or generated
         by OPM may have been taken at any time in the past;

                  (i)  to  the  Stockholders'  knowledge,   there  has  been  no
         disposal,  release,  spill or burial of any Hazardous  Materials by OPM
         (or any  Person  acting on its  behalf)  on any  property  which  could
         reasonably be expected to result or has resulted in contamination which
         requires  investigation,  remediation or other response  activity on or
         beneath any properties or facilities currently owned, leased,  operated
         or occupied by OPM; and

                  (j) has no knowledge of any past or present  Event  related to
         OPM's properties,  operations or business, which Event, individually or
         in the  aggregate,  may interfere  with or prevent  continued  material
         compliance with all  Environmental  Laws, or which,  individually or in
         the aggregate,  may form the basis of any material Claim for or arising
         out of the release or threatened  release into the  environment  of any
         Hazardous Material.

Section 3.21 of the Disclosure Schedule lists all off-site locations, including,
without   limitation,   commercial  waste  disposal   facilities  and  municipal
landfills,  to which OPM has  directed  the  transport  of  Hazardous  Materials
originating  from OPM or OPM's business  during the three (3) years prior to the
date hereof.

         3.22 Capital Stock. The authorized and outstanding capital stock of OPM
is as set forth in  Section  3.22 of the OPM  Disclosure  Schedule.  All of such
outstanding  capital stock has been duly authorized and validly issued, is fully
paid and  nonassessable  and is not subject to any preemptive or similar rights.
Except as described in Section 3.22 of the OPM Disclosure Schedule,  OPM has not
granted  or  issued,  nor has OPM  agreed to grant or issue,  any  shares of its
capital stock or any Option Security or Convertible  Security,  and OPM is not a
party to or bound by any  agreement,  put or commitment  pursuant to which it is
obligated to purchase,  redeem or otherwise  acquire any shares of capital stock
or any Option Security or Convertible Security.

         3.23 Bank Accounts,  Etc.  Section 3.23 of the OPM Disclosure  Schedule
contains a true,  accurate  and  complete  list of the date hereof of all banks,
trust companies,  savings and loan associations and brokerage firms in which OPM
has an account or a safe deposit box and the names of all Persons  authorized to
draw thereon, to have access thereto, or to authorize  transactions therein, the
names of all Persons,  if any,  holding valid and subsisting  powers of attorney
from OPM and a summary statement as to the terms thereof.  OPM agrees that prior
to the Closing  Date it will not make or permit to be made any change  affecting
any bank, trust company,  savings and loan  association,  brokerage firm or safe
deposit box or in the names of the Persons  authorized to draw thereon,  to have
access thereto or to authorize transactions therein or in such powers of

                                      -14-


<PAGE>



attorney,  or open any  additional  accounts  or boxes or grant  any  additional
powers of attorney, without in each case first notifying ATS in writing.


                                    ARTICLE 4

               REPRESENTATIONS AND WARRANTIES OF THE STOCKHOLDERS
                          RELATING TO THE SUBJECT STOCK

         Each  of the  Stockholders,  severally  and  not  jointly,  represents,
warrants and covenants to, and agrees with, ATS as follows:

         4.1 Enforceability. This Agreement has been duly executed and delivered
by such Stockholder and constitutes,  and each Collateral  Document  executed or
required to be  executed by such  Stockholder  pursuant  hereto or thereto  when
executed and delivered by such  Stockholder will  constitute,  legal,  valid and
binding  obligations of such  Stockholder,  enforceable in accordance with their
respective terms,  except as such  enforceability  may be subject to bankruptcy,
moratorium,  insolvency,   reorganization,   arrangement,  voidable  preference,
fraudulent conveyance and other similar laws relating to or affecting the rights
of  creditors  and  except as the same may be  subject  to the effect of general
principles of equity.

         4.2 Title to Shares.  Such Stockholder owns the Subject Stock set forth
opposite his name in Section 3.22 of the OPM Disclosure Schedule.  Except as set
forth in Section 3.22 of the OPM Disclosure Schedule,  such Stockholder owns and
has good and merchantable  title to such Subject Stock as so set forth, free and
clear of all Liens.

         4.3 No Conflict;  Required Filings and Consents. Except for consents as
set forth in Section 4.3 of the Disclosure  Schedule,  neither the execution and
delivery  by such  Stockholder  of this  Agreement  or any  Collateral  Document
executed  or required to be  executed  by such  Stockholder  pursuant  hereto or
thereto,  nor the  consummation  of the  Transactions,  nor compliance  with the
terms, conditions and provisions hereof or thereof by such Stockholder:

                  (i) will conflict with, or result in a breach or violation of,
         or constitute a default  under,  any  Applicable  Law, or will conflict
         with,  or result in a breach or violation  of, or  constitute a default
         under, or permit the acceleration of any obligation or liability in, or
         but for any  requirement  of the giving of notice or passage of time or
         both would constitute such a conflict with,  breach or violation of, or
         default  under,  or  permit  any   acceleration   in,  any  Contractual
         Obligation of such  Stockholder,  except for such conflicts,  breaches,
         defaults,  violations or accelerations that would not,  individually or
         in the aggregate, have a Material Adverse Effect;

                  (ii) will result in or permit the  creation or  imposition  of
         any Lien upon any property or asset of such Stockholder; or

                  (iii)  will   require  any   Governmental   Authorization   or
         Governmental Filing or Private Authorization of such Stockholder.


                                    ARTICLE 5

                      REPRESENTATIONS AND WARRANTIES OF ATS


                                      -15-


<PAGE>



         ATS  represents,  warrants  and  covenants  to,  and agrees  with,  the
Stockholders as follows:

         5.1  Organization  and  Business;   Power  and  Authority;   Effect  of
Transaction.

         (a) ATS is a corporation  duly organized,  validly existing and in good
standing  under  the  laws  of its  jurisdiction  of  incorporation  and has all
requisite  power and authority  (corporate and other) to own or hold under lease
its properties and to conduct its business as now conducted.

         (b) ATS has all  requisite  corporate  power  and  corporate  authority
necessary  to enable it to execute and deliver,  and to perform its  obligations
under,  this Agreement and each Collateral  Document  executed or required to be
executed by it pursuant hereto or thereto or to consummate the Transactions; and
the execution,  delivery and  performance of this Agreement and each  Collateral
Document  executed or  required to be executed by it pursuant  hereto or thereto
have been duly authorized by all requisite corporate or other action on the part
of  ATS.  This  Agreement  has  been  duly  executed  and  delivered  by ATS and
constitutes, and each Collateral Document executed or required to be executed by
it pursuant  hereto or thereto or to consummate the  Transactions  when executed
and delivered by ATS will constitute,  legal,  valid and binding  obligations of
ATS,  enforceable  in accordance  with their  respective  terms,  except as such
enforceability may be limited by bankruptcy,  moratorium, insolvency and similar
laws  affecting  the rights and remedies of  creditors  and the  obligations  of
debtors generally and by general principles of equity.

         (c) Except for matters which would have not material  adverse effect on
ATS, as of the Closing  Date,  neither the execution and delivery by ATS of this
Agreement or any Collateral  Document  executed or required to be executed by it
pursuant hereto or thereto, nor the consummation by ATS of the Transactions, nor
compliance with the terms, conditions and provisions hereof or thereof by ATS:

                  (i) will conflict with, or result in a breach or violation of,
         or  constitute  a default  under,  any  Organic  Document of ATS or any
         Applicable  Law on the part of ATS, or will conflict with, or result in
         a breach or violation of, or constitute a default under,  or permit the
         acceleration  of  any  obligation  or  liability  in,  or but  for  any
         requirement  of  giving  of notice  or  passage  of time or both  would
         constitute  such a conflict  with,  breach or violation  of, or default
         under, or permit any such  acceleration in, any Contractual  Obligation
         of ATS; or

                  (ii)  will  require  ATS to make or  obtain  any  Governmental
         Authorization,  Governmental Filing or Private Authorization  including
         without  limitation  under  the  FCA,  except  for  filings  under  the
         Hart-Scott-Rodino Act.

         5.2  Broker or  Finder.  No Person  assisted  in or  brought  about the
negotiation  of this  Agreement or the  Transactions  in the capacity of broker,
agent or finder or in any similar capacity on behalf of ATS.

         5.3 ATS  Financing.  ATS has and will,  at all times that the  Purchase
Price remains unpaid in full, have  sufficient  funds available to it to pay the
Purchase Price when due in accordance  with the provisions of this Agreement and
all transaction  related fees and expenses payable by ATS in connection with the
consummation of the Transactions.

         5.4  Financial  Information.   ATS  has  heretofore  furnished  to  the
Stockholders  copies of the audited  financial  statements of ATS for the fiscal
year ended December 31, 1996 and the unaudited  financial  statements of ATS for
the six  months  ended  June 30,  1997 (the  "ATS  Financial  Statements").  ATS
Financial  Statements,  including  in each  case the  notes  thereto,  have been
prepared in accordance  with GAAP applied on a consistent  basis  throughout the
periods covered thereby,  except as otherwise noted therein,  are true, accurate
and complete in all material respects,  do not contain any untrue statement of a
material fact or omit

                                      -16-


<PAGE>



to state a material fact  required by GAAP to be stated  therein or necessary in
order to make the  statements  contained  therein  not  misleading,  and  fairly
present the financial  condition and the results of operations  and cash flow of
ATS, on the bases therein stated,  as of the respective  dates thereof,  and for
the  respective  periods  covered  thereby  subject,  in the  case of  unaudited
financial  statements,  to normal  nonmaterial  year-end audit  adjustments  and
accruals.

         5.5 Changes in Condition.  Since the date of the most recent  financial
statements  constituting a part of the ATS Financial  Statements,  except to the
extent,  if any,  heretofore  specifically  disclosed  in  writing by ATS to the
Stockholders,  there has been no  material  adverse  change in ATS.  There is no
Event known to ATS which materially adversely affects, or (so far as ATS can now
reasonably foresee) is likely to materially adversely affect, ATS, except to the
extent,  if any,  heretofore  specifically  disclosed  in  writing by ATS to the
Stockholders.

         5.6 No Legal  Action.  There are no Legal  Actions  pending  or, to the
knowledge  of ATS,  threatened  against ATS or any of its  Affiliated  Entities,
officers  or  directors,  that  question  or may  affect  the  validity  of this
Agreement  or  the  right  or  ability  of ATS to  consummate  the  transactions
contemplated hereunder.


                                    ARTICLE 6

                                    COVENANTS

         6.1      Access to Information; Confidentiality.

         (a) OPM shall  afford  to ATS and its  accountants,  counsel,  lenders,
financial advisors and other representatives (the "Representatives") full access
during normal business hours  throughout the period prior to the Closing Date to
all of OPM's properties,  books,  contracts,  commitments and records (including
without  limitation Tax Returns) relating to the OPM Assets and the OPM Business
and, during such period,  shall furnish promptly upon request (i) a copy of each
report, schedule and other document filed or received by any of them pursuant to
the  requirements  of any  Applicable  Law or filed by it with any  Authority in
connection with the  Transactions or which may have an adverse effect on the OPM
Assets or the OPM Business or the businesses, operations, properties, prospects,
personnel,  condition  (financial or other),  or results of operations  thereof,
(ii) all financial records,  ledgers, work papers and other sources of financial
information  possessed and controlled by OPM or its accountants deemed by ATS or
its  Representatives  necessary or useful for the purpose of performing an audit
of the OPM Assets and the OPM Business and certifying  financial  statements and
financial  information,  and (iii) such other  information  in the possession or
control of OPM or its  accountants  concerning any of the foregoing as ATS shall
reasonably request; provided,  however, that OPM shall not be required to permit
any such access (x) to the extent same would  unreasonably  interfere with OPM's
normal business operations or (y) to any document,  the delivery of which would,
in the opinion of OPM's counsel,  have the effect of waiving any attorney-client
privilege enjoyed by OPM. All non-public  information relating to the OPM Assets
or the OPM  Business  furnished  prior  to the  execution,  or  pursuant  to the
provisions,  of this Agreement,  including without limitation this Section, will
be kept confidential and shall not, without the prior written consent of OPM, be
disclosed by ATS in any manner whatsoever, in whole or in part, and shall not be
used for any purposes,  other than in connection  with the  Transactions.  In no
event  shall  ATS or any of its  Representatives  use  such  information  to the
detriment  of OPM.  ATS agrees to reveal such  information  only to those of its
Representatives  or other  Persons  who need to know  such  information  for the
purpose of evaluating  the  Transactions,  who are informed of the  confidential
nature of such information and who shall undertake to act in accordance with the
terms and conditions of this  Agreement.  From and after the Closing,  OPM shall
not, without the prior written consent of ATS, disclose any

                                      -17-


<PAGE>



information  with  respect  to the OPM Assets or the OPM  Business,  and no such
information  shall be used for any purposes,  other than in connection  with the
Transactions or to the extent required by Applicable Law.

         (b) Subject to the terms and  conditions  of Section  6.1(a),  ATS may,
subject to prior  consultation  with OPM and to the  reasonable  approval of OPM
with respect to disclosure of information,  disclose such  information as may be
necessary in connection with seeking all Governmental and Private Authorizations
or that is required by Applicable  Law to be  disclosed.  In the event that this
Agreement  is  terminated  for any  reason,  ATS shall  promptly  redeliver  all
non-public  written  material  provided  pursuant  to this  Section or any other
provision of this Agreement or otherwise in connection with the Transactions and
shall not retain any copies, extracts or other reproductions in whole or in part
of such written  material,  other than one copy thereof which shall be delivered
to independent counsel for ATS.

         (c)  Anything in this  Section or  elsewhere  in this  Agreement to the
contrary  notwithstanding,  any  party  may  disclose  information  received  or
retained by it in accordance  with the  provisions  of this  Agreement if it can
demonstrate  (i) such  information  is  generally  available  to or known by the
public from a source other than the party seeking to disclose  such  information
or (ii) was obtained by the party  seeking to disclose such  information  from a
source other than the other party,  provided that such source was not bound by a
duty of confidentiality to the other party or another party with respect to such
information.

         (d) No investigation pursuant to this Section or otherwise shall affect
any  representation  or  warranty  in  this  Agreement  of  either  ATS  or  the
Stockholders or any condition to the  obligations of the parties hereto,  except
as set forth in Section 9.3(e).

         6.2      Agreement to Cooperate.

         (a) Each of the parties  hereto shall use reasonable  business  efforts
(x) to take,  or cause to be taken,  all actions and to do, or cause to be done,
all things necessary, proper or advisable under Applicable Law to consummate the
Transactions,  and (y) to refrain from taking,  or cause to be taken, any action
and to refrain from doing or causing to be done, any thing which could impede or
impair the consummation of the Transactions,  including,  in all cases,  without
limitation  using its reasonable  business  efforts (i) to prepare and file with
the applicable  Authorities  as promptly as  practicable  after the execution of
this Agreement all requisite applications and amendments thereto,  together with
related information,  data and exhibits, necessary to request issuance of orders
approving the  Transactions  by all such applicable  Authorities,  each of which
must be obtained or become final to the extent provided in Section 7.1(a),  (ii)
to  obtain  all  necessary  or  appropriate  waivers,  consents  and  approvals,
including  without  limitation  those  referred to in Section  7.2(d),  (iii) to
effect all necessary  registrations,  filings and submissions (including without
limitation filings under the Hart-Scott-Rodino Act and all filings necessary for
ATS to own and operate the OPM Assets and  conduct  the OPM  Business),  (iv) to
lift any injunction or other legal bar to the  Transactions  (and, in such case,
to proceed with the  Transactions  as  expeditiously  as  possible),  and (v) to
obtain the  satisfaction  of the  conditions  specified in Article 6,  including
without  limitation the truth and  correctness as of the Closing Date as if made
on and as of the Closing  Date of the  representations  and  warranties  of such
party  and  the  performance  and  satisfaction  as of the  Closing  Date of all
agreements and conditions to be performed or satisfied by such party.

         (b) The parties  shall  cooperate  with one another  (including  by ATS
providing  access to the Stockholders to the books and records of OPM subsequent
to the  Closing  Date)  in the  preparation,  execution  and  filing  of all Tax
Returns,  questionnaires,  applications,  or other documents  regarding any real
property transfer or gains,  sales, use,  transfer,  value added, stock transfer
and stamp Taxes, any transfer,  recording,  registration and other fees, and any
similar Taxes which become payable in connection with the Transactions  that are
required or permitted to be filed on or before the Closing Date.

                                      -18-


<PAGE>




         (c) OPM shall  cooperate  and use its  reasonable  business  efforts to
cause its independent  accountants to reasonably cooperate with ATS, and at ATS'
expense,  in order to enable  ATS to have its  independent  accountants  prepare
audited financial  statements for the OPM Business  described in Section 7.2(g).
OPM represents and warrants that any such  financial  statements  will have been
prepared in accordance  with GAAP applied on a consistent  basis  throughout the
periods  covered  thereby,  will be true,  accurate and complete in all material
respects,  and will  fairly  present  the  financial  condition  and  results of
operation of the Company on the basis therein stated, as of the respective dates
thereof and for the respective  periods covered  thereby.  Without  limiting the
generality of the foregoing,  OPM agrees that after the Closing Date it will (x)
consent to the use of such  audited  financial  statements  in any  registration
statement  or other  document  filed by ATS or any  Affiliate  of ATS  under any
applicable  federal or state  securities  Law the Securities Act or the Exchange
Act and (y) execute and deliver, and cause its directors and officers to execute
and  deliver,  such  "representation"  letters as are  customarily  delivered in
connection  with  audits  and as ATS'  independent  accountants  may  reasonably
request under the circumstances.

         6.3  Public  Announcements.  Until  the  Closing,  or in the  event  of
termination of this  Agreement,  OPM and ATS shall consult with the other before
issuing any press release or otherwise making any public statements with respect
to this Agreement or the Transactions and shall not issue any such press release
or make any such  public  statement  without  the prior  consent  of the  other.
Notwithstanding  the foregoing,  each party acknowledges and agrees that OPM and
ATS may,  without  its prior  consent,  issue such press  releases  or make such
public  statements as may be required by  Applicable  Law, in which case, to the
extent  practicable,  the party  proposing to make such press  release or public
statement will consult with the other  regarding the nature,  extent and form of
such press release or public  statement.  In addition,  subject to the terms and
conditions  hereof,  ATS may  disclose the subject  matter of this  Agreement to
Persons with whom OPM has a business or contractual  relationship  in connection
with ATS' due diligence investigation of OPM.

         6.4  Notification  of Certain  Matters.  Each party  shall give  prompt
notice  to the  other,  of the  occurrence  or  non-occurrence  of any Event the
occurrence  or  non-occurrence  of  which  would  be  likely  to  cause  (i) any
representation  or warranty made by it contained in this  Agreement to be untrue
or inaccurate in any respect, or (ii) any covenant,  condition or agreement made
by it contained in this Agreement not to be complied with or satisfied, or (iii)
any change to be made in the OPM Disclosure Schedule in any respect, or (iv) any
failure  made by it to comply  with or  satisfy,  or be able to  comply  with or
satisfy,  any covenant,  condition or agreement to be complied with or satisfied
by it  hereunder,  in each  case in any  respect  such  that  one or more of the
conditions  of  Closing  might not be  satisfied;  provided,  however,  that the
delivery of any notice  pursuant to this  Section  shall not limit or  otherwise
affect the remedies available hereunder to the party receiving such notice.

         6.5 No  Solicitation.  OPM shall not, nor shall it knowingly permit any
of its Representatives  (including,  without limitation,  any investment banker,
broker, finder, attorney or accountant retained by it) to, initiate,  solicit or
facilitate,  directly or indirectly, any inquiries or the making of any proposal
with  respect  to any  Alternative  Transaction,  engage in any  discussions  or
negotiations concerning,  or provide to any other Person any information or data
relating to, it or any Subsidiary for the purposes of, or otherwise cooperate in
any way with or assist or  participate  in, or  facilitate  any inquiries or the
making of any proposal which constitutes,  or may reasonably be expected to lead
to, a proposal  to seek or effect any  Alternative  Transaction,  or agree to or
endorse  any  Alternative   Transaction.   "Alternative   Transaction"  means  a
transaction  or series of related  transactions  (other  than the  Transactions)
resulting  in or likely to result in (i) any change of control of OPM,  (ii) any
merger,  consolidation  or other  business  combination  of OPM,  regardless  of
whether  OPM is  the  surviving  Entity  unless  the  surviving  Entity  remains
obligated  under this  Agreement  to the same extent as it was,  (ii) any tender
offer or exchange offer for, or any acquisitions of, any securities of OPM, (iv)
any sale or other  disposition of all or any substantial  part of the OPM Assets
or the OPM Business, (v) any issue

                                      -19-


<PAGE>



or sale,  or any  agreement  to issue or sell,  any capital  stock,  Convertible
Securities  or Option  Securities  by OPM, or (vi) any sale,  transfer,  pledge,
assignment  or other  conveyance  or any  agreement to sell,  transfer,  pledge,
assign  or  otherwise  convey,   any  Subject  Stock.  If  OPM  or  any  of  its
Representatives  receives any inquiry with respect to an Alternative Transaction
while this Agreement is in effect,  OPM shall inform the inquiring party that it
is not  entitled  to enter  into  discussions  or  negotiations  relating  to an
Alternative Transaction.

         6.6 Conduct of Business by OPM Pending the Closing. Except as otherwise
contemplated by this  Agreement,  after the date hereof and prior to the Closing
Date or earlier termination of this Agreement,  unless ATS shall otherwise agree
in writing,  OPM shall,  to the extent  relating to the OPM  Business or the OPM
Assets:

                  (a) conduct its  business in the  ordinary and usual course of
         business  and  consistent   with  past  practice,   including   without
         limitation the performance of such maintenance, repairs or replacements
         with respect to communication  towers,  fixtures and Personal  Property
         comprising the OPM Assets as is consistent with past practice;

                  (b) use all reasonable business efforts to preserve intact its
         business organizations and goodwill, keep available the services of its
         present  key   employees,   and  preserve  the  goodwill  and  business
         relationships  with customers and others having business  relationships
         with it;

                  (c) confer, as and when reasonably requested, on a regular and
         frequent  basis  with  one or  more  representatives  of ATS to  report
         material   operational  matters  and  the  general  status  of  ongoing
         operations;

                  (d) maintain with financially  responsible insurance companies
         insurance  on its assets and its  business in such  amounts and against
         such risks and losses as are consistent with past practice;

                  (e) use  reasonable  business  efforts to (i)  operate the OPM
         Business in conformity in all material  respects with all  Governmental
         and Private  Authorizations,  Leases and Material Agreements on a basis
         consistent  with past  practice  and  Applicable  Law and the rules and
         regulations of any Authority with  jurisdiction  over the OPM Assets or
         the OPM  Business,  and (ii) maintain in full force and effect all such
         Governmental and Private Authorizations, Leases and Material Agreements
         relating to the OPM Business;

                  (f) not (i)  dispose of any of the OPM Assets  owned by OPM or
         used  in  the  operation  of the  OPM  Business  (other  than  for  the
         disposition  in the ordinary  course of business of  immaterial  assets
         that are of no  further  use to the OPM  Business)  or (ii)  modify  or
         change in any material respect,  or enter into, any Material  Agreement
         relating to the OPM Business; and

                  (g) not  voluntarily  take or permit  to be taken  any  action
         which if taken  between the end of its most recent  fiscal  quarter and
         prior to the date of this  Agreement  would  have been  required  to be
         noted as an exception on Section 3.17 of the OPM Disclosure Schedule.

         6.7  Preliminary  Title Reports.  As promptly as practicable  after the
execution of this Agreement, OPM shall, at its sole cost and expense, deliver or
cause to be  delivered  to ATS a standard  preliminary  title report (the "Title
Reports")  dated on or after the date of this  Agreement  issued  by such  title
company or companies as OPM and ATS shall mutually reasonably agree with respect
to those OPM Assets  comprised of the parcels of real property  owned by OPM, as
described in Section 6.7 of the OPM Disclosure Schedule.


                                      -20-


<PAGE>



         6.8 Environmental  Site  Assessments.  As promptly as practicable after
the execution of this Agreement, ATS may at its own cost and expense obtain, and
deliver  to OPM  full  and  complete  copies  of,  Phase  I  environmental  site
assessment reports (the "Environmental  Reports") on any or all of those certain
parcels  of  real  property  described  on  Section  6.8 of the  OPM  Disclosure
Schedule.   Site  assessments   shall  be  conducted  by  such  consultants  and
professionals as ATS and OPM shall mutually agree and shall be arranged at times
mutually  convenient  to the  parties.  Each of OPM and ATS shall be entitled to
have  representatives  present at the time such site  assessments are conducted,
and to have copies of all correspondence with the Environmental Company.

         6.9      Certain Tax Matters.

         (a) The  Stockholders  shall be  responsible,  at their  sole  cost and
expense,  for the  preparation  and filing of all federal  and state  income Tax
Returns of OPM for all taxable periods ending on or before the Closing Date (the
"Pass  Through  Returns")  and for the  payment  of all Taxes  shown on the Pass
Through Returns or otherwise payable with respect to all such periods.  The Pass
Through  Returns  shall be prepared in a manner  which is  consistent  with past
practices of OPM, except as otherwise required by Applicable Law. Income,  gain,
loss,  deduction  and credit of OPM shall be allocated  between the Pass Through
Returns and any succeeding taxable period on the basis of a closing of the books
of OPM at the  close of  business  on the date  preceding  the  Closing  Date in
accordance  with Section  1362(e)(6)(D)  of the Code.  The Buyer shall  promptly
notify the Stockholders  following  receipt by the Buyer of any notice of audit,
examination or other  proceeding (a "Tax  Proceeding")  with respect to any Pass
Through Return,  and the Stockholders shall retain the sole right to control any
such  Tax  Proceeding,  provided  that the  Buyer  may  participate  in such Tax
Proceeding at its own expense, and provided,  further,  that ATS may control any
aspects of any such Tax Proceeding  relating to any item for which ATS is or may
be liable. The Stockholders shall retain the sole right to file any amended Pass
Through Return.  Notwithstanding the foregoing,  the Stockholders may not settle
or otherwise  agree to the  resolution  of any Tax  Proceeding  or file any such
amended Pass Through  Return  without in each case  obtaining  the prior written
consent of ATS such consent will not be  unreasonably  conditioned  or withheld,
if, as a result  of such  settlement  or  resolution  or the  filing of any such
amended Pass Through Return, OPM's tax basis in any of its assets for any period
after the Closing Date would be reduced or OPM's tax position  after the Closing
Date would otherwise be adversely affected.

         (b) After the Closing Date, ATS shall cooperate with the  Stockholders,
and the  Stockholders  shall  cooperate  with ATS,  in  connection  with all Tax
matters that may affect the Stockholders or OPM for any taxable period that ends
on or before the Closing Date,  including without  limitation the preparation of
income tax returns and the conduct of any Tax  Proceedings  for any such taxable
period.

         (c)  Anything in this  Section or  elsewhere  in this  Agreement to the
contrary  notwithstanding,  the  Stockholders  shall  join with ATS in making an
election under Section  338(h)(10) of the Code (and any corresponding  elections
under  state,  local or foreign  Tax Law)  (collectively  a "Section  338(h)(10)
Election") with respect to the purchase and sale of the Subject Stock hereunder.
ATS and the  Stockholders  agree  to  comply  with all of the  requirements  and
conditions  of  Section  338(h)(10)  of the  Code and the  Treasury  Regulations
thereunder and all other applicable Code Sections and Treasury  Regulations (and
state,  local  and  foreign  Tax  Laws)  relating  thereto,   including  without
limitation the timely filing of Form 8023A entitled  "Corporate  Qualified Stock
Purchase  Election." ATS and the  Stockholders  also agree to take all necessary
steps to effectuate such election (and any corresponding state, local or foreign
elections).  None of the  Stockholders  or ATS will take any  action,  including
without  limitation any action in connection with the filing of federal,  state,
local or foreign Tax Returns,  which would be inconsistent with or prejudice the
election  under Section  338(h)(10) of the Code provided for  hereunder.  In the
event (i) ATS takes any action which has the effect of causing the  Stockholders
not to be able to report the  transactions  contemplated by this Agreement as an
installment  sale under the Code and (ii) the balance of the Purchase  Price has
not been paid

                                      -21-


<PAGE>



prior to April 10, 1999, ATS will advance to the Stockholders an amount equal to
the tax liability  for the taxable year ended  December 31, 1998 created by such
action.  Such advance will be credited against the balance of the Purchase Price
and  will  be  evidenced  by a  non-interest  bearing  promissory  note  of  the
Stockholders  secured by such  balance  and  maturing  on the earlier of (x) the
payment of the balance of the Purchase Price or (y) August 31, 1999.

         6.10     ATS Post-Closing Covenants.

         (a) ATS  acknowledges  that its  obligation to make payment of the full
purchase price to the  Stockholders  is materially  affected by the business and
financial  performance of OPM subsequent to the Closing Date. OPM has previously
provided to ATS its business plan (the "Master Plan")  regarding  acquisition of
tower sites and  construction  of proposed  towers,  including  estimates of the
financing  required to: (i) compete the  acquisition  and  development  of tower
sites and  towers,  and (ii) meet the  financial  projections  contained  in the
Master Plan. A copy of the Master Plan is attached  hereto as Exhibit C and made
a part hereof. ATS agreed that, except as hereinafter  expressly limited,  Mills
shall have the right,  after the Closing  Date, to continue to manage and direct
the OPM Business  substantially  in  accordance  with the Master  Plan,  in such
manner as he shall,  in his reasonable  business  judgment,  deems  appropriate,
including  without  limitation those matters  necessary or desirable to complete
the Master  Plan.  Notwithstanding  the  foregoing,  ATS shall have the right to
approve the terms and conditions of any  agreements  with, or purchases or sales
of materials from or to, or any other business  relationship with, any Affiliate
of any of the  Stockholders,  which  approval  shall be based  on,  among  other
things,  receipt of bids from  Persons  who are not  Affiliated  with any of the
Stockholders.  ATS  shall,  within  ten  (10)  days of  receipt  from OPM of any
proposal  from an Affiliate  and bids  covering the subject of the proposal from
three (3) Persons who are not  Affiliates of any of the  Stockholders  (at least
one of which has been selected by ATS),  provide OPM with written  notice of its
approval or disapproval of the proposed Affiliate transaction. In the event such
notice is not  received  by OPM within  such ten (10) day  period,  ATS shall be
deemed to have approved the proposed Affiliate  transaction.  ATS further agrees
that it is  essential  that ATS provide the  financing  necessary  to fund fully
completion of the Master Plan and its projections.  Accordingly, ATS agrees that
it will,  from time to time  following the Closing Date,  provide,  upon written
request  of Mills,  all funds  necessary  to fund  acquisition  of tower  sites,
construction of communications  towers and other  improvements  reflected in the
Master Plan; provided, however, that such funding shall not exceed the aggregate
amount of $28,000,000  plus the amount by which (i) $9,000,000  exceeds (ii) the
aggregate  principal  amount  borrowed by OPM from ATS prior to the Closing Date
and outstanding at such time. ATS agrees for itself,  its successors and assigns
that,  from and after  the  Closing  Date  until  payment  in full by ATS to the
Stockholders  of the balance of the Purchase Price as provided in Section 2.2(b)
of this  Agreement,  in the absence of conduct by Mills in the  operation of the
OPM  Business  which  constitutes  gross  negligence,   willful  or  intentional
misconduct,  or  violation  of any  Applicable  Law, it will not in any material
fashion  interfere  with the operation by Mills of the OPM Business,  so long as
such  operation  is  in  substantial   compliance  with  the  Master  Plan.  ATS
acknowledges  and agrees  that the members of the Board of  Directors  of OPM or
their successors in the event of any merger, consolidation or combination of OPM
or the sale or transfer of the OPM Business  shall have  satisfied  all of their
fiduciary  duties and  responsibilities  related to the OPM  Business and Mills'
operation  and  management  of the OPM  Business  if they  shall  adhere  to the
provisions  of this Section 6.10 and they need not take, or require to be taken,
any action in conflict with such provisions.  The  Stockholders  acknowledge and
agree that the rights of Mills are unique to Mills and that, in the event of the
death or disability  (mental or physical) of Mills,  or his gross  negligence or
willful  or  intentional  misconduct  in  the  operation  of  the  OPM  Business
substantially  in accordance  with the Master Plan, ATS shall not be required to
recognize as successor to him any individual nominated by the Stockholders,  but
shall, in such event,  use its reasonable  business efforts to effect the timely
and expeditious  implementation of the Master Plan, including without limitation
performance  of its  obligations  with  respect  to  funding  set  forth in this
Section. By executing this Agreement

                                      -22-


<PAGE>



in his capacity as a Stockholder, Mills agrees that he will devote his full time
and effort to the OPM Business.


         (b) The  Stockholders  understand  and  agree  that,  anything  in this
Section or elsewhere in this Agreement to the contrary  notwithstanding,  ATS is
under no obligation  whatsoever to finance the  acquisition  of any sites (other
than those reflected in the Master Plan) or the  construction  of  communication
towers and other improvements thereon by OPM (or any successor thereto), but may
do  so  independently  and  in  a  manner  such  that  the  operations  of  such
communication  towers are not included in determining  Cash Flow for purposes of
determining  the  Purchase  Price.  The  Stockholders  agree that OPM or the OPB
Business  may be merged,  consolidated  or  combined  with or sold or  otherwise
transferred to ATS or any Affiliate thereof,  but, in any such event, ATS agrees
to maintain or cause to be maintained  separate  financial  books and records of
OPM or the OPM  Business in such manner as to enable the  determination  of Cash
Flow to be made in accordance with the provisions of Section 2.2(b).

         (c) ATS will  provide  to the  Stockholders,  promptly  after  the same
become available,  unaudited quarterly (for each of the first three (3) calendar
quarters) and annual consolidated  financial  statements of ATS (and, so long as
it  exists,   consolidated  with  its  parent  American  Tower  Systems  Holding
Corporation).  The Stockholders  Representative  shall have the right to examine
the books and  records of ATS and to discuss  financial,  operational  and other
affairs of ATS with the  officers of ATS, at such times during  normal  business
hours as the Stockholders  Representative  shall, from time to time,  reasonably
request,  subject to the Stockholder  Representative  executing and delivering a
confidentiality  agreement embodying terms and conditions comparable to those of
Section 6.1.


                                    ARTICLE 7

                               CLOSING CONDITIONS

         7.1 Conditions to Obligations of Each Party. The respective obligations
of each party to effect the Transactions shall,  except as hereinafter  provided
in this Section,  be subject to the satisfaction at or prior to the Closing Date
of the following  conditions,  any or all of which may be waived, in whole or in
part, to the extent permitted by Applicable Law:

                  (a) As of the Closing  Date,  no Legal Action shall be pending
         before or  threatened  in writing by any  Authority  seeking to enjoin,
         restrain,  prohibit or make illegal or to impose any materially adverse
         conditions in connection with, the consummation of the Transactions, it
         being understood and agreed that a written request by any Authority for
         information with respect to the  Transactions,  which information could
         be used in connection  with such Legal  Action,  shall not in itself be
         deemed to be a threat of any such Legal Action; and

                  (b) All authorizations, consents, waivers, orders or approvals
         required  to  be  obtained  from  all  Authorities,  and  all  filings,
         submissions, registrations, notices or declarations required to be made
         by any of the parties with any Authority,  prior to the consummation of
         the  Transactions,  shall have been obtained  from,  and made with, all
         such Authorities,  except for such authorizations,  consents,  waivers,
         orders, approvals, filings,  registrations,  notices or declarations as
         are set forth in Section 7.1(b) of the OPM  Disclosure  Schedule or the
         failure  to  obtain  or make  would  not,  in the  reasonable  business
         judgment of ATS,  have a material  adverse  effect on the OPM Assets or
         the OPM Business.


                                      -23-


<PAGE>



         7.2  Conditions to  Obligations of ATS. The obligation of ATS to effect
the  Transactions  shall  be  subject  to  the  satisfaction  of  the  following
conditions,  any or all of which  may be  waived,  in  whole or in part,  to the
extent permitted by Applicable Law:

                  (a) All agreements, certificates, opinions and other documents
         required to be delivered  pursuant to the  provisions of this Agreement
         shall be reasonably  satisfactory  in form,  scope and substance to ATS
         and its  counsel,  and ATS and its  counsel  shall  have  received  all
         information and copies of all documents, including records of corporate
         proceedings, which they may reasonably request in connection therewith,
         such documents where appropriate to be certified by proper  Authorities
         or corporate officers;

                  (b) The  Stockholders  shall have  furnished  ATS and, at ATS'
         request,  any bank or other financial  institution  providing credit to
         ATS,  with a  favorable  opinion,  dated the  Closing  Date,  of Ruden,
         McClosky,  Smith,  Schuster & Russell,  P.A.,  counsel  for OPM and the
         Stockholders, with respect to the matters set forth in Sections 3.1(a),
         (b) and (c),  3.7(b),  3.14, 3.22 and Article 4, and such other matters
         arising  after  the  date  of  this   Agreement  and  incident  to  the
         Transactions,  as ATS or its  counsel  or its  counsel  may  reasonably
         request  or which  may be  reasonably  requested  by any  such  bank or
         financial institution or their respective counsel;  counsel for OPM and
         the Stockholders may, in furnishing such opinion,  rely on, among other
         things,  on the  representations  and warranties of the Stockholders in
         Section 3.7(b), 4.2 and 4.3;

                  (c) The  representations  and  warranties of the  Stockholders
         contained in this  Agreement  or otherwise  made in writing by it or on
         its behalf  pursuant  hereto or otherwise  made in connection  with the
         Transactions  shall be true and correct at and as of the  Closing  Date
         with the same  force and  effect as though  made on and as of such date
         except those which speak as of a certain  date which shall  continue to
         be true and  correct  as of such date on the  Closing  Date  (including
         without limitation giving effect to any later obtained knowledge of the
         Stockholders,  OPM or ATS,  except as otherwise  specifically  provided
         herein);  each and all of the agreements and conditions to be performed
         or satisfied by the  Stockholders  or OPM  hereunder at or prior to the
         Closing  Date  shall  have  been duly  performed  or  satisfied  in all
         material  respects;  and the Stockholders shall have furnished ATS with
         such  certificates  and other  documents  evidencing  the truth of such
         representations,   warranties,   covenants  and   agreements   and  the
         performance  of such  agreements  or  conditions  as ATS or its counsel
         shall have reasonably requested;

                  (d) Except to the extent,  if any,  specifically  set forth in
         Section  7.2(d) of the OPM  Disclosure  Schedule,  all  authorizations,
         consents,  waivers,  orders or approvals  required by the provisions of
         this Agreement to be obtained from all Persons (other than Authorities)
         prior  to the  consummation  of  the  Transactions,  including  without
         limitation  those  required  in order for OPM to continue to own all of
         the OPM Assets and  continue to operate the OPM  Business as  conducted
         immediately prior to the Closing (including without limitation,  at the
         cost and expense of OPM, all  modifications of Private  Authorizations,
         Leases and Material  Agreements  of OPM set forth in Section  7.2(d) of
         the OPM  Disclosure  Schedule)  shall have been  obtained,  without the
         imposition,  individually  or in the  aggregate,  of any  condition  or
         requirement which could adversely affect ATS or OPM;

                  (e) Between the date of this  Agreement  and the Closing Date,
         there shall not have  occurred and be continuing  any material  adverse
         change in OPM from that  reflected  in the most  recent  OPM  Financial
         Statements;  as of the Closing Date,  the  Governmental  Authorizations
         with  respect to the  ownership  or  operation of the OPM Assets or the
         conduct  of the  OPM  Business  shall  not  have  been  materially  and
         adversely affected by any act, or failure to act, of OPM;

                                      -24-


<PAGE>




                  (f) The  Stockholders and OPM shall have delivered or cause to
         be  delivered  to  ATS  all  of  the  Collateral  Documents  and  other
         agreements,  documents and instruments  required to be delivered by the
         Stockholders  or OPM to ATS at or prior to the Closing  pursuant to the
         terms of this Agreement;

                  (g) ATS shall have received from its  independent  accountants
         (i) an unqualified report (as to the scope of the audit,  access to the
         books and records and the  cooperation  of management) on the financial
         statements  (consisting  of balance sheets for each of the fiscal years
         ended  December 31, 1995 and 1996 and statements of operations and cash
         flow for each of the two years in the period  ended  December 31, 1996)
         of the OPM,  which  financial  statements  shall have been  prepared in
         conformity  with GAAP and Regulation  S-X under the Securities  Act, or
         (ii) such other  documentation  as shall be reasonably  satisfactory to
         ATS  indicating  that  such an  unqualified  report  could be issued if
         requested by ATS;

                  (h) As of the Closing  Date,  except as otherwise set forth in
         Section 3.7(a) of the OPM Disclosure Schedule, no Legal Action shall be
         pending  before or threatened in writing by any Authority  which might,
         in the  reasonable  business  judgment of ATS, based upon the advice of
         counsel, have a material adverse effect on the OPM, it being understood
         and agreed that a written request by any Authority for information with
         respect  to the  Transactions,  which  information  could  be  used  in
         connection  with such Legal Action,  shall not be deemed to be a threat
         of any such Legal Action;

                  (i) Each of the individuals  named therein shall have executed
         and  delivered to ATS an agreement  mutually  acceptable to the parties
         which  when so agreed  upon shall be  attached  as Exhibit A hereto and
         made a part hereof (the "ATS Noncompetition Agreements");

                  (j)  The  Stockholders  shall  have  delivered  to ATS all use
         permits,  consents  or  other  Governmental  Authorizations  of and all
         Leases  from the  United  States  Forest  Service  set forth in Section
         7.2(j) of the OPM Disclosure Schedule; and

                  (k)  The   Environmental   Reports   shall  not  disclose  any
         exception, and no Event or Events shall have occurred subsequent to the
         date hereof, which,  individually or in the aggregate,  would cause the
         representations and warranties of the Stockholders set forth in Section
         3.21  (without  regard to  knowledge) to be inaccurate or incomplete in
         any material respect;

                  (l) ATS shall have  received,  at its  expense,  a copy of the
         standard  ALTA  title  insurance  policy  insuring  OPM's fee simple or
         leasehold  interest,  as the case may be, in the land and  improvements
         located at each of the  locations  described  in Section 7.2 (l) of the
         OPM  Disclosure  Schedule and the Title  Reports shall not disclose any
         exception, and no Event or Events shall have occurred subsequent to the
         date hereof, which,  individually or in the aggregate,  would cause the
         representations and warranties of the Stockholders set forth in Section
         3.5 (without regard to knowledge) to be inaccurate or incomplete in any
         material respect;

                  (m) Each of the Stockholders shall have executed and delivered
         to  ATS a Form  8023A  entitled  "Corporate  Qualified  Stock  Purchase
         Election" with respect to the Section 338(h)(10) Election;


                                      -25-


<PAGE>



                  (n) All Convertible  Securities and Option  Securities of OPM,
         if any, outstanding  immediately prior to the Closing shall be canceled
         and,  from and  after the  Closing,  shall no longer be of any force or
         effect;

                  (o) Owen P. Mills, the chief executive  officer of OPM and one
         of the  Stockholders  and OPM, shall have executed and delivered to ATS
         an agreement  mutually  acceptable  to the parties which when so agreed
         upon shall be  attached as Exhibit D hereto and made a part hereof (the
         "Mills Employment Agreement");

                  (p) ATS shall  have  received  a  favorable  opinion of Ruden,
         McClosky, Smith, Schuster & Russell, P.A., dated the Closing Date, with
         respect to the validity of Section 6.10 under Florida law; and

                  (q) ATS shall have received the written resignations of all of
         the officers and directors of OPM and of all of the  trustees,  if any,
         under all Benefit Arrangements of OPM.

         7.3 Conditions to Obligations  of the  Stockholders.  The obligation of
the Stockholders to effect the Transactions shall be subject to the satisfaction
of the following  conditions,  any or all of which may be waived, in whole or in
part, to the extent permitted by Applicable Law:

                  (a) All agreements, certificates, opinions and other documents
         required to be delivered  pursuant to the  provisions of this Agreement
         shall be reasonably  satisfactory  in form,  scope and substance to the
         Stockholders and their counsel,  and the Stockholders and their counsel
         shall  have  received  all  information  and  copies of all  documents,
         including records of corporate  proceedings,  which they may reasonably
         request in connection therewith, such documents where appropriate to be
         certified by proper Authorities or corporate officers;

                  (b) ATS shall have furnished the Stockholders,  with favorable
         opinions,  dated the Closing Date, of Sullivan & Worcester LLP, counsel
         for ATS,  with respect to the matters set forth in Section 5.1 and with
         respect to such other matters  arising after the date of this Agreement
         and incident to the Transactions,  as the Stockholders or their counsel
         may reasonably request;

                  (c) The  representations  and  warranties  of ATS contained in
         this  Agreement  or  otherwise  made in  writing by it or on its behalf
         pursuant hereto or otherwise made in connection  with the  Transactions
         shall be true and correct at and as of the  Closing  Date with the same
         force and  effect as though  made on and as of such date  except  those
         which speak as of a certain  date which  shall  continue to be true and
         correct  as of  such  date  on  the  Closing  Date  (including  without
         limitation  giving effect to any later  obtained  knowledge of OPM, the
         Stockholders or ATS, except as otherwise specifically provided herein);
         each  and all of the  agreements  and  conditions  to be  performed  or
         satisfied  by ATS  hereunder at or prior to the Closing Date shall have
         been duly  performed or satisfied  in all  material  respects;  and ATS
         shall have furnished the Stockholders  with such certificates and other
         documents  evidencing  the truth of such  representations,  warranties,
         covenants and  agreements  and the  performance  of such  agreements or
         conditions as the  Stockholders  or their counsel shall have reasonably
         requested;

                  (d) ATS shall have  delivered  or cause to be delivered to the
         Stockholders  all of the  Collateral  Documents  and other  agreements,
         documents  and  instruments  required  to be  delivered  by  ATS to the
         Stockholders  at or prior to the Closing  pursuant to the terms of this
         Agreement;


                                      -26-


<PAGE>



                  (e) Between the date of this  Agreement  and the Closing Date,
         there shall not have  occurred and be continuing  any material  adverse
         change in ATS from that  reflected  in the most  recent  ATS  Financial
         Statements;

                  (f) As of the Closing  Date,  no Legal Action shall be pending
         before or threatened in writing by any  Authority  which might,  in the
         reasonable business judgment of the Stockholders, based upon the advice
         of counsel,  have a material  adverse effect on ATS' ability to operate
         the OPM Assets and the OPM Business  subsequent to the Closing Date, it
         being understood and agreed that a written request by any Authority for
         information with respect to the  Transactions,  which information could
         be used in connection with such Legal Action, shall not be deemed to be
         a threat of any such Legal Action;

                  (g) OPM shall have executed and delivered to the  Stockholders
         the Mills Employment Agreement; and

                  (h) The Stockholders  shall have received a favorable opinion,
         dated the Closing Date, of Florida  counsel with respect to the binding
         effect on ATS of Section 6.10.


                                    ARTICLE 8

                        TERMINATION, AMENDMENT AND WAIVER

         8.1 Termination.  This Agreement may be terminated at any time prior to
the Closing Date:

                  (a)      by mutual consent of the Stockholders and ATS; or

                  (b)  by  either  ATS  or the  Stockholders  if  any  permanent
         injunction,   decree  or  judgment  by  any  Authority  preventing  the
         consummation   of  the   Transactions   shall  have  become  final  and
         nonappealable; or

                  (c) by the  Stockholders in the event (i) the Stockholders are
         not  in  material   breach  of  this   Agreement   and  none  of  their
         representations  or  warranties  shall have  become and  continue to be
         untrue in any material  respect,  and (ii) either (A) the  Transactions
         have not been consummated  prior to the Termination Date, or (B) ATS is
         in material breach of this Agreement or any of its  representations  or
         warranties  shall have become and continue to be untrue in any material
         respect,  and such a breach or  untruth  exists  and is not  capable of
         being  cured  by  and  will  prevent  or  delay   consummation  of  the
         Transactions by or beyond the Termination Date; or

                  (d) by ATS in the event (i) ATS is not in  material  breach of
         this Agreement and none of its representations or warranties shall have
         become and  continue  to be untrue in any  material  respect,  and (ii)
         either  (A) the  Transactions  have not been  consummated  prior to the
         Termination Date, or (B) OPM or the Stockholders are in material breach
         of  this  Agreement  or  any of the  Stockholders'  representations  or
         warranties  shall have become and continue to be untrue in any material
         respect,  and such a breach or  untruth  exists  and is not  capable of
         being  cured  by  and  will  prevent  or  delay   consummation  of  the
         Transactions by or beyond the Termination Date; or

                  (e) by ATS in the  event of a  failure  of the  condition  set
         forth in Section 7.2(k) or 7.2(l).


                                      -27-


<PAGE>



         The term "Termination Date" shall mean June 30, 1998 or such other date
as the parties may, from time to time, mutually agree.

         The right of ATS or OPM to terminate  this  Agreement  pursuant to this
Section shall remain  operative  and in full force and effect  regardless of any
investigation made by or on behalf of any party, any Person controlling any such
party or any of their respective  Representatives  whether prior to or after the
execution of this Agreement.

         8.2      Effect of Termination.

         (a)   Except  as   provided   in   Sections   6.1  (with   respect   to
confidentiality), 6.3 and 10.3 and this Section, in the event of the termination
of this  Agreement  pursuant to Section  8.1,  or in the event the  Transactions
shall not have been consummated  prior to the end of business on the Termination
Date, this Agreement shall forthwith become void, there shall be no liability on
the part of any party,  or any of their  respective  shareholders,  officers  or
directors, to the other and all rights and obligations of any party shall cease;
provided,  however,  that such  termination  shall not  relieve  any party  from
liability  for  any  misrepresentation  or  breach  of any  of  its  warranties,
covenants or agreements set forth in this Agreement.

         (b)  In  the  event  this  Agreement  is  terminated  pursuant  to  the
provisions of Section  8.1(a),  8.1(b) or 8.1(e),  except as provided in Section
8.2(a), none of the parties shall have any further rights or remedies.



                                    ARTICLE 9

                                 INDEMNIFICATION

         9.1  Survival.  The  representations  and  warranties  of  the  parties
contained in or made pursuant to this Agreement or any Collateral Document shall
survive the Closing and shall remain  operative and in full force and effect for
a period  of (a) two (2)  years  after the  Closing  Date or (b) the  applicable
statute  of  limitations  in the  case of  matters  of a nature  referred  to in
Sections 3.1, 3.11, 3.12, 3.21 and 3.22,  Article 4 and Section 4.1,  regardless
of any investigation or statement as to the results thereof made by or on behalf
of any party hereto. The covenants and agreements of the parties contained in or
made pursuant to this  Agreement or any  Collateral  Document  shall survive the
Closing and shall remain  operative and in full force and effect for the statute
of  limitations  applicable  to  contractual  obligations.  The term  "Indemnity
Period" shall mean the applicable period with respect to which a representation,
warranty,  covenant  or  agreement  survives  the  Closing as  provided  in this
Section.  No claim for  indemnification,  other  than with  respect  to fraud or
intentional and willful breach or  misrepresentation,  may be asserted after the
expiration  of the  Indemnity  Period.  Notwithstanding  anything  herein to the
contrary, any representation,  warranty, covenant and agreement which arises and
is the subject of a Claim which is asserted in writing  prior to the  expiration
of the applicable  Indemnity  Period shall survive with respect to such Claim or
any dispute with respect thereto until the final resolution thereof.

         9.2      Indemnification.

         (a) Each Stockholder,  jointly and severally,  agrees that on and after
the Closing he shall  indemnify and hold harmless OPM, ATS and their  respective
stockholders,  directors, officers, employees and representatives (collectively,
the "ATS  Indemnified  Parties")  from and against any and all damages,  claims,
losses,  expenses,  costs,  obligations,   and  liabilities  including,  without
limiting  the  generality  of the  foregoing,  liabilities  for  all  reasonable
attorneys',  accountants'  and experts'  fees and expenses  incurred,  including
those

                                      -28-


<PAGE>



incurred  to enforce  the terms of this  Agreement  or any  Collateral  Document
(collectively,  "Loss and Expense"),  suffered by the ATS Indemnified Parties by
reason of, or arising out of any breach of  representation  or warranty  made by
the  Stockholders  pursuant to this Agreement or any Collateral  Document or any
failure by the  Stockholders (or OPM prior to the Closing) to perform or fulfill
any of  their  covenants  or  agreements  set  forth  in this  Agreement  or any
Collateral Document.

         (b) ATS agrees to that on and after the Closing it will  indemnify each
of the Stockholders and hold each of them harmless from and against all Loss and
Expense suffered by any of them by reason of, or arising out of :

                  (i) any  breach  of  representation  or  warranty  made by ATS
         pursuant to this Agreement or any Collateral Document or any failure by
         ATS to perform or fulfill any of its covenants or agreements  set forth
         in this Agreement or any  Collateral  Document or any failure of OPM to
         perform or fulfill any of its covenants or agreements set forth in this
         Agreement or any Collateral Document required to be performed after the
         Closing; or

                  (ii) any  Legal  Action  or other  Claim  by any  third  party
         relating to ATS or the ownership or  operations  of OPM's  business and
         properties subsequent to the Closing,  including without limitation any
         and all obligations and liabilities under Governmental  Authorizations,
         Private  Authorizations,   Leases,   Material  Agreements,   Employment
         Arrangements, Plans, Benefit Arrangements and
         Contractual Obligations.

         (c)  Anything in this  Section or  elsewhere  in this  Agreement to the
contrary notwithstanding,  the parties agrees that the Stockholders shall not be
required  to  indemnify  ATS,  and  ATS  shall  be  required  to  indemnify  the
Stockholders,  if,  notwithstanding  the fact that OPM has not  agreed to be, or
made any election to be or be treated as, a "consenting  corporation" within the
meaning of Section 341(f) of the Code, the Internal Revenue Service or any other
Authority  shall have determined that OPM has tax liability under Section 341 of
the Code.

         9.3      Limitation of Liability.

         (a)  Notwithstanding  the provisions of Section 9.2, after the Closing,
except as otherwise provided in Section 9.6, the ATS Indemnified Parties, on the
one hand, and the Stockholders,  on the other hand, shall be entitled to recover
its  Loss and  Expense  in  respect  of any  Claim  only in the  event  that the
aggregate Loss and Expense for all Claims exceeds, in the aggregate, $50,000, in
which event the indemnified party shall be entitled to recover all such Loss and
Expense (including without limitation such $50,000).

         (b) In the case any event shall occur which would otherwise entitle any
party to assert a claim for indemnification hereunder, no Loss and Expense shall
be deemed to have been  sustained  by such party to the  extent of any  proceeds
received by such party from any insurance policies with respect thereto.

         9.4 Notice of Claims.  If an  indemnified  party  believes  that it has
suffered or incurred  any Loss and  Expense,  it shall  notify the  indemnifying
party promptly in writing,  and in any event within the  applicable  time period
specified in Section 9.1, describing such Loss and Expense,  all with reasonable
particularity  and containing a reference to the provisions of this Agreement in
respect of which such Loss and Expense shall have occurred.  If any Legal Action
is  instituted  by a third  party  with  respect to which an  indemnified  party
intends  to claim any  liability  or  expense  as Loss and  Expense  under  this
Article,  such indemnified party shall promptly notify the indemnifying party of
such Legal Action, but the failure to so notify the indemnifying party shall not
relieve such indemnifying party of its obligations under this Article, except to
the extent such failure to notify prejudices such  indemnifying  party's ability
to defend against such Claim.

                                      -29-


<PAGE>




         9.5 Defense of Third Party Claims.  The  indemnifying  party shall have
the right to  conduct  and  control,  through  counsel  of their  own  choosing,
reasonably  acceptable to the indemnified party, any third party Legal Action or
other Claim, but the indemnified party may, at its election,  participate in the
defense  thereof at its sole cost and expense;  provided,  however,  that if the
indemnifying  party shall fail to defend any such Legal  Action or other  Claim,
then the indemnified party may defend, through counsel of its own choosing, such
Legal Action or other Claim, and (so long as it gives the indemnifying  party at
least fifteen (15) days' notice of the terms of the proposed  settlement thereof
and permits the indemnifying party to then undertake the defense thereof) settle
such Legal Action or other Claim and to recover the amount of such settlement or
of any  judgment and the  reasonable  costs and  expenses of such  defense.  The
indemnifying party shall not compromise or settle any such Legal Action or other
Claim without the prior written consent of the indemnified  party, which consent
shall not  unreasonably  be withheld,  delayed or  conditioned  if the terms and
conditions of such compromise or settlement  proposed by the indemnifying  party
and agreed to in writing by the  claimant  in such Legal  Action or other  Claim
(the "Settlement  Proposal") (a) include a full release of the indemnified party
from the Legal  Action or other  Claim  which is the  subject of the  Settlement
Proposal,  and (b) if the indemnified party is an ATS Indemnified  Party, do not
include any term or condition  which would  restrict in any material  manner the
continued  ownership or  operations  of the OPM Assets or the conduct of the OPM
Business in substantially the manner then being theretofore owned,  operated and
conducted  by ATS or OPM (or any  successor  or  assign).  No matter  whether an
indemnifying  party defends or prosecutes any third party Legal Action or Claim,
the  indemnified  and  indemnifying  parties  shall  cooperate in the defense or
prosecution  thereof.  Such  cooperation  shall  include  access  during  normal
business hours afforded to the indemnifying  party to, and reasonable  retention
by the  indemnified  party of,  records  and  information  which are  reasonably
relevant  to such  third  party  Legal  Action or Claim,  and  making  employees
available on a mutually  convenient basis to provide additional  information and
explanation of any material provided hereunder, and the indemnifying party shall
reimburse the indemnified party for all its reasonable out-of-pocket expenses in
connection therewith.

         9.6  Exclusive  Remedy.   Except  for  fraud,  willful  or  intentional
misrepresentation  or willful or  intentional  breach of  warranty,  covenant or
agreement or as otherwise provided in Section 10.5, the indemnification provided
in this Article shall be the sole and exclusive post-Closing remedy available to
any party against the other party for any Claim under this Agreement.


                                   ARTICLE 10

                               GENERAL PROVISIONS


         10.1 Waivers; Amendments. Changes in or additions to this Agreement may
be made,  or compli  ance  with any  term,  covenant,  agreement,  condition  or
provision  set forth herein may be omitted or waived  (either  generally or in a
particular  instance and either  retroactively or prospectively)  with, but only
with,  the  consent in writing of the  parties  hereto.  No delay on the part of
either  party at any time or times in the  exercise of any right or remedy shall
operate as a waiver thereof. Any consent may be given subject to satisfaction of
conditions  stated therein.  The failure to insist upon the strict provisions of
any  covenant,  term,  condition  or other  provision  of this  Agreement  or to
exercise  any right or remedy  thereunder  shall not  constitute a waiver of any
such  covenant,  term,  condition  or other  provision  thereof  or  default  in
connection  therewith.  The waiver of any  covenant,  term,  condition  or other
provision thereof or default thereunder shall not affect or alter this Agreement
in any other  respect,  and each and every  covenant,  term,  condition or other
provision of this  Agreement  shall,  in such event,  continue in full force and
effect,  except as so waived,  and shall be operative  with respect to any other
then existing or subsequent default in connection therewith.

                                      -30-


<PAGE>




         10.2 Fees, Expenses and Other Payments.  All  Hart-Scott-Rodino  filing
fees shall be borne equally by the  Stockholders and ATS provided that the total
amount  to be borne by  Stockholders  shall  not  exceed  $25,000,  all costs of
preliminary  title  reports to a date  reasonably  proximate to the Closing Date
shall be borne by the Stockholders, and all costs of environmental studies shall
be borne by ATS.  All  costs  and  expenses,  incurred  in  connection  with any
transfer taxes,  sales taxes,  recording or documentary  taxes,  stamps or other
charges  levied by any  Authority  in  connection  with this  Agreement  and the
consummation of the  Transactions  shall be borne by ATS and all other costs and
expenses  incurred in connection with this Agreement and the consummation of the
Transactions,  including  without  limitation fees and disbursements of counsel,
financial  advisors and  accountants  incurred by the parties  hereto,  shall be
borne  solely  and  entirely  by the party  which has  incurred  such  costs and
expenses.

         10.3  Notices.  All  notices  and  other  communications  which  by any
provision of this Agreement are required or permitted to be given shall be given
in  writing  and shall be  effective  (a) three (3) days after  being  mailed by
first-class  or  express  mail,  postage  prepaid,  (b) the next  day when  sent
overnight by recognized  courier  service,  (c) upon  confirmation  when sent by
telex,  telegram,  telecopy or other form of rapid  transmission,  confirmed  by
mailing (by first  class or express  mail,  postage  prepaid,  or by  recognized
courier  service) written  confirmation at  substantially  the same time as such
rapid  transmission,  or (d) upon  delivery  when  personally  delivered  to the
receiving party (which if other than an individual  shall be an officer or other
responsible party of the receiving party).  All such notices and  communications
shall be mailed, sent or delivered as follows:

         (a)      If to ATS (or OPM after the Closing):

                  116 Huntington Avenue
                  Boston, Massachusetts 02116
                  Attention:   Joseph B. Winn, Chief Financial Officer
                  Telecopier No.:  (617) 375-7575

                  with copies to:

                  American Tower Systems, Inc.
                  6400 North Congress Avenue, Suite 1750
                  Boca Raton, Florida  33487
                  Attention:  James S. Eisenstein
                  Telecopier No.:  (561) 998-2278

                               and

                  Sullivan & Worcester LLP
                  One Post Office Square
                  Boston, Massachusetts 02109
                  Attention:  Norman A. Bikales, Esq.
                  Telecopier No.:  (617) 338-2880


                                      -31-


<PAGE>



         (b) If to any Stockholder or OPM (prior to the Closing):

                  325 Interstate Boulevard
                  Sarasota, Florida 34240
                  Attention: Owen P. Mills, President
                  Telecopier No.:   (941) 379-4562

                  with a copy to:

                  Ruden, McClosky, Smith, Schuster & Russell, P.A.
                  1549 Ringling Boulevard, Suite 600
                  Sarasota, FL  34236
                  Attention:  John M. Dart, Esq.
                  Telecopier No.:  (941) 955-7590

or to such other person(s),  telex or facsimile  number(s) or address(es) as the
party to receive any such communication or notice may have designated by written
notice to the other party.

         10.4  Specific  Performance;  Other  Rights  and  Remedies.  Each party
recognizes and agrees that in the event the other party should refuse to perform
any of its  obligations  under this  Agreement or any Collateral  Document,  the
remedy at law would be inadequate and agrees that for breach of such provisions,
each party shall,  in addition to such other  remedies as may be available to it
at law or in equity or as  provided  in Article  9, be  entitled  to  injunctive
relief and to enforce its rights by an action for  specific  performance  to the
extent permitted by Applicable Law. Each party hereby waives any requirement for
security  or the post ing of any bond or other  surety  in  connection  with any
temporary or permanent award of injunctive, mandatory or other equitable relief.
Nothing  herein  contained  shall be  construed as  prohibiting  each party from
pursuing any other  remedies  available to it pursuant to the provisions of, and
subject to the  limitations  contained in, this  Agreement or Applicable Law for
such breach or threatened breach.  Anything in this Section or elsewhere in this
Agreement  to  the  contrary  notwithstanding,  if  an  Authority  of  competent
jurisdiction  shall have issued a Final Order that ATS is in material  breach of
this  Agreement,  ATS shall pay to the  Stockholders  an aggregate  amount to be
determined  as follows:  (a) the amount due as of such date in  accordance  with
Section 2.2(a); and (b) $5,000,000.

         10.5 Severability.  If any term or provision of this Agreement shall be
held or deemed  to be, or shall in fact be,  invalid,  inoperative,  illegal  or
unenforceable  as  applied  to  any  particular  case  in  any  jurisdiction  or
jurisdictions,  or in  all  jurisdictions  or  in  all  cases,  because  of  the
conflicting of any provision with any  constitution or statute or rule of public
policy or for any other reason,  such circumstance  shall not have the effect of
rendering the provision or provisions in question invalid, inoperative,  illegal
or unenforceable in any other  jurisdiction or in any other case or circumstance
or of rendering any other  provision or  provisions  herein  contained  invalid,
inoperative,  illegal or  unenforceable to the extent that such other provisions
are not themselves actually in conflict with such constitution,  statute or rule
of public policy, but this Agreement shall be reformed and construed in any such
jurisdiction or case as if such invalid,  inoperative,  illegal or unenforceable
provision had never been contained herein and such provision reformed so that it
would be valid,  operative and  enforceable to the maximum  extent  permitted in
such jurisdiction or in such case.  Notwithstanding the foregoing,  in the event
of any such  determination  the  effect  of which is to  affect  materially  and
adversely any party,  the parties  shall  negotiate in good faith to modify this
Agreement  so as to effect  the  original  intent of the  parties  as closely as
possible to the fullest  extent  permitted by  Applicable  Law in an  acceptable
manner to the end that the  Transactions  are fulfilled and  consummated  to the
maximum extent possible.


                                      -32-


<PAGE>



         10.6   Counterparts.   This   Agreement  may  be  executed  in  several
counterparts,  each of  which  shall be  deemed  an  original,  but all of which
together shall constitute one and the same  instrument,  binding upon all of the
parties. In pleading or proving any provision of this Agreement, it shall not be
necessary to produce more than one of such counterparts.

         10.7 Section Headings. The headings contained in this Agreement are for
reference  purposes  only  and  shall  not in any  way  affect  the  meaning  or
interpretation of this Agreement.

         10.8  Governing  Law. The validity,  interpretation,  construction  and
performance of this Agreement  shall be governed by, and construed in accordance
with,  the  applicable  laws of the United States of America and the laws of the
State of Florida  applicable to contracts  made and performed in such State and,
in any event,  without giving effect to any choice or conflict of laws provision
or rule that would cause the  application  of domestic  substantive  laws of any
other jurisdiction.  Anything in this Agreement to the contrary notwithstanding,
including  without  limitation  the provisions of Article 8, in the event of any
dispute  between the parties  which results in a Legal  Action,  the  prevailing
party shall be entitled to receive from the non-prevailing  party  reimbursement
for reasonable legal fees and expenses incurred by such prevailing party in such
Legal Action.

         10.9 Further Acts. Each party agrees that at any time, and from time to
time, before and after the consummation of the transactions contemplated by this
Agreement,  it  will do all  such  things  and  execute  and  deliver  all  such
Collateral  Documents  and other  assurances,  as any other party or its counsel
reasonably  deems  necessary  or  desirable  in order to carry out the terms and
conditions of this  Agreement  and the  transactions  contemplated  hereby or to
facilitate  the enjoyment of any of the rights  created  hereby or to be created
hereunder.

         10.10  Entire  Agreement.   This  Agreement   (together  with  the  OPM
Disclosure  Schedule and the other Collateral  Documents delivered in connection
herewith),  constitutes  the entire  agreement of the parties and supersedes all
prior agreements and undertakings,  both written and oral,  between the parties,
with respect to the subject matter hereof .

         10.11  Assignment.  This Agreement shall not be assignable by any party
and any such  assignment  shall be null and void,  except that it shall inure to
the benefit of and by binding  upon any  successor  to any party by operation of
law,  including by way of merger,  consolidation or sale of all or substantially
all of its assets,  and ATS may assign its rights and remedies  hereunder to any
bank or other financial institution which has loaned funds or otherwise extended
credit to it.

         10.12  Parties in Interest.  This  Agreement  shall be binding upon and
inure  solely to the  benefit of each  party,  and  nothing  in this  Agreement,
express or implied,  is  intended to or shall  confer upon any Person any right,
benefit or remedy of any nature whatsoever under or by reason of this Agreement,
except as otherwise provided in Section 10.11.

         10.13   Appointment  of   Representative.   Each   Stockholder   hereby
irrevocably  appoints and  authorizes  to act as its agent,  representative  and
attorney-in-fact hereunder (the "Stockholders Representative"). Each Stockholder
irrevocably  authorizes the Stockholders  Representative  to take such action on
behalf of such  Stockholder  and to exercise  all such  powers as are  expressly
delegated to the Stockholders Representative hereunder, together with such other
powers as are reasonably  incidental thereto including,  but not limited to, the
execution  and  delivery  of  certificates,   statements,   notices,  approvals,
extensions,  waivers,  undertakings and amendments to this Agreement required or
permitted to be made,  given or determined  hereunder or in connection  with the
transactions contemplated hereby. The holders of a majority of the Subject Stock
may, from time to time, remove the Representative and appoint a substitute or

                                      -33-


<PAGE>



successor   Stockholders   Representative.   Notice  of  any  such  removal  and
appointment   shall  be  given   immediately   to  ATS  and  the   Stockholders.
Simultaneously  with the execution of this Agreement,  each  Stockholder  (other
than  the  Stockholders   Representative)  has  delivered  to  the  Stockholders
Representative  certificates  representing  the  Subject  Stock  owned  by  such
Stockholder  duly endorsed (or  accompanies by duly endorsed stock powers).  The
appointment and agency created hereby is irrevocable and shall survive the death
or incompetency of any Stockholder.

         10.14  Mutual  Drafting.  This  Agreement  is the  result  of the joint
efforts of OPM and ATS, and each provision hereof has been subject to the mutual
consultation,  negotiation  and  agreement  of the parties and there shall be no
construction  against  any  party  based  on any  presumption  of  that  party's
involvement in the drafting thereof.













                      [SIGNATURES APPEAR ON FOLLOWING PAGE]


                                      -34-


<PAGE>



         IN  WITNESS  WHEREOF,  ATS and OPM have  caused  this  Agreement  to be
executed  as of the  date  first  written  above by  their  respective  officers
thereunto duly authorized.

                                  American Tower Systems, Inc.


                                  By:_____________________________________
                                      Name:
                                     Title:

                                  OPM - USA - INC.


                                  By:______________________________________
                                      Name:
                                     Title:


                                  Stockholders


                                  _________________________________________
                                        Owen B. Mills


                                 _________________________________________
                                        Sonja L. Mills



                                      -35-


<PAGE>



                                                                      APPENDIX A

                                   DEFINITIONS

         Acceptance Notice shall have the meaning given to it in Section 2.2(c).

         Accounts Receivable shall mean (a) any and all rights to the payment of
money or other forms of  consideration  of any kind at any time now or hereafter
owing or to be owing to OPM  attributable  to the  ownership or operation of the
OPM Business (whether  classified under the Uniform Commercial Code of any state
as accounts,  contract rights, chattel paper, general intangibles or otherwise),
including  without  limitation  accounts  receivable,  letters of credit and the
right to receive payment thereunder, chattel paper, insurance proceeds, contract
rights, notes, drafts, instruments, documents, acceptances, and all other debts,
obligations  and  liabilities  in whatever form now or hereafter  owing from any
other Person, all guarantees, security and Liens for the payment of any thereof,
and all of OPM's  rights  to  goods,  now  owned  or  hereafter  acquired,  sold
(delivered,  undelivered,  in  transit  or  returned)  which may be  represented
thereby; and (b) all proceeds of any of the foregoing.

         adverse,  adversely, when used alone or in conjunction with other terms
(including  without  limitation  "affect," "change" and "effect") shall mean any
Event which is reasonably likely, in the reasonable business judgment of ATS, to
be expected to (a)  adversely  affect the  validity  or  enforceability  of this
Agreement  or  the  likelihood  of  consummation  of  the  Transactions,  or (b)
adversely affect the business, operations,  management, properties or prospects,
or the  condition,  financial  or other,  or  results  of  operation  of the OPM
Business, or (c) impair OPM's ability to fulfill its obligations under the terms
of this Agreement,  or (d) adversely affect the aggregate rights and remedies of
ATS under this Agreement.  Notwithstanding  the foregoing,  and anything in this
Agreement to the contrary  notwithstanding,  any Event  generally  affecting the
economy or the tower  communications  business shall not be deemed to constitute
such a change, affect or effect.

         Affiliate,  Affiliated shall mean, with respect to any Person,  (a) any
other Person at the time  directly or indirectly  controlling,  controlled by or
under direct or indirect  common control with such Person,  (b) any other Person
of which such Person at the time owns, or has the right to acquire,  directly or
indirectly,  twenty  percent  (20%) or more of any class of the capital stock or
beneficial  interest,  (c) any other Person  which at the time owns,  or has the
right to acquire,  directly or  indirectly,  twenty percent (20%) or more of any
class of the  capital  stock or  beneficial  interest  of such  Person,  (d) any
executive  officer  or  director  of  such  Person,  (e)  with  respect  to  any
partnership,  joint venture or similar Entity, any general partner thereof,  and
(f) when used with respect to an  individual,  shall  include any member of such
individual's immediate family or a family trust.

         Agreement shall mean this Agreement as originally in effect, including,
unless the context  otherwise  specifically  requires,  this Appendix A, the OPM
Disclosure  Schedule  and all exhibits  hereto,  and as any of the same may from
time to time be supplemented, amended, modified or restated in the manner herein
or therein provided.

         Amount Due shall have the meaning given to it in Section 2.2(a).

         Applicable Law shall mean any Law of any Authority, whether domestic or
foreign,  including  without  limitation  the  FCA  and all  federal  and  state
securities and  Environmental  Laws, to which a Person is subject or by which it
or any of its business or operations is subject or any of its property or assets
is bound.


                                       A-1


<PAGE>



         Assets shall mean the business and the tangible and  intangible  assets
used in  connection  with the conduct of the business or  operations  of the OPM
Business,  which  business  and  assets  are  being  exchanged,  transferred  or
otherwise conveyed hereunder.

         ATS shall have the meaning given to it in the Preamble.

         ATS' Financial Statements shall have the meaning given to it in Section
5.2

         ATS' Indemnified  Parties shall have the meaning given to it in Section
9.2(a)

         ATS'  Noncompetition  Agreements  shall have the meaning given to it in
Section 7.2(i).

         Authority shall mean any governmental or quasi-governmental  authority,
whether  administrative,  executive,  judicial,  legislative  or  other,  or any
combination   thereof,   including  without   limitation  any  federal,   state,
territorial,   county,   municipal  or  other   government  or  governmental  or
quasi-governmental agency, arbitrator,  authority,  board, body, branch, bureau,
central bank or comparable  agency or Entity,  commission,  corporation,  court,
department,  instrumentality,  master, mediator, panel, referee, system or other
political unit or  subdivision or other Entity of any of the foregoing,  whether
domestic or foreign., including without limitation the FCC.

         Benefit Arrangement shall mean any material benefit arrangement that is
not a Plan,  including  (a)  any  employment  or  consulting  agreement  (b) any
arrangement providing for insurance coverage or workers' compensation  benefits,
(c) any  incentive  bonus or deferred  bonus  arrangement,  (d) any  arrangement
providing termination  allowance,  severance or similar benefits, (e) any equity
compensation plan, (f) any deferred  compensation plan, and (g) any compensation
policy and  practice,  but only to the  extent  that it covers or relates to any
officer, employee or other Person involved in the ownership and operation of the
Assets or the conduct of the business of the OPM Business.

         Cash Flow shall have the meaning given to it in Section 2.2(b).

         Claims shall mean any and all debts, liabilities,  obligations, losses,
damages,  deficiencies,  assessments  and  penalties,  together  with all  Legal
Actions, pending or threatened, claims and judgments of whatever kind and nature
relating  thereto,  and all fees, costs,  expenses and disbursements  (including
without  limitation  reasonable  attorneys'  and  other  legal  fees,  costs and
expenses) relating to any of the foregoing.

         Closing shall have the meaning given to it in Section 2.2.

         Closing Date shall have the meaning given to it in Section 2.2.

         COBRA shall mean the Consolidated Omnibus Budget  Reconciliation Act of
1985,  as  amended,  as set  forth  in  Section  4980B of the Code and Part 6 of
Subtitle B of Title I of ERISA.

         Code shall mean the Internal  Revenue  Code of 1986,  and the rules and
regulations  thereunder,  all as from time to time in effect,  or any  successor
law,  rules or  regulations,  and any  reference to any  statutory or regulatory
provision  shall be deemed  to be a  reference  to any  successor  statutory  or
regulatory provision.

         Collateral Documents shall mean the Indemnity Escrow Agreement, the ATS
Noncompetition  Agreements,  the  Mills  Employment  Agreement,  instruments  of
conveyance and assignment  sufficient to vest in ATS title to all of the Subject
Stock, and any other agreement, certificate, contract, instrument, notice,

                                       A-2


<PAGE>



opinion or other document delivered pursuant to the provisions of this Agreement
or any Collateral Document.

         Contract, Contractual Obligation shall mean any agreement, arrangement,
commitment,  contract, covenant,  indemnity,  undertaking or other obligation or
liability  which  involves  the  ownership or operation of the OPM Assets or the
conduct of the OPM Business.

         Control (including the terms  "controlled,"  "controlled by" and "under
common control with") means the possession, directly or indirectly or as trustee
or executor,  of the power to direct or cause the direction of the management or
policies of a Person,  or the disposition of such Person's assets or properties,
whether through the ownership of stock, equity or other ownership,  by contract,
arrangement or understanding,  or as trustee or executor,  by contract or credit
arrangement or otherwise.

         Debt Reduction shall have the meaning given to it in Section 2.2(a).

         Employment Arrangement shall mean, with respect to OPM, any employment,
consulting,   retainer,   severance  or  similar  contract,   agreement,   plan,
arrangement or policy  (exclusive of any which is terminable  within thirty (30)
days without liability, penalty or payment of any kind by OPM or any Affiliate),
or providing for severance,  termination payments, insurance coverage (including
any self-insured arrangements), workers compensation, disability benefits, life,
health, medical, dental or hospitalization  benefits,  supplemental unemployment
benefits, vacation or sick leave benefits, pension or retirement benefits or for
deferred compensation, profit-sharing, bonuses, stock options, stock purchase or
appreciation rights or other forms of incentive  compensation or post-retirement
insurance,  compensation or post-retirement insurance, compensation or benefits,
or any collective bargaining or other labor agreement, whether or not any of the
foregoing is subject to the provisions of ERISA,  but only to the extent that it
covers or relates to any  officer,  employee  or other  Person  involved  in the
ownership or operation of the OPM Assets or the conduct of the OPM Business.

         Encumber  shall  mean  to  suffer,  accept,  agree  to  or  permit  the
imposition of a Lien.

         Entity shall mean any corporation,  firm, unincorporated  organization,
association,  partnership,  limited  liability  company,  trust  (inter vivos or
testamentary),  estate of a deceased, insane or incompetent individual, business
trust,  joint stock  company,  joint  venture or other  organization,  entity or
business,  whether acting in an individual,  fiduciary or other capacity, or any
Authority.

         Environmental Law shall mean any Law relating to or otherwise  imposing
liability or  standards of conduct  concerning  pollution or  protection  of the
environment,   including   without   limitation   Laws  relating  to  emissions,
discharges,  releases or  threatened  releases of  Hazardous  Materials or other
chemicals or  industrial  pollutants,  substances,  materials or wastes into the
environment (including,  without limitation,  ambient air, surface water, ground
water,  mining or reclamation or mined land, land surface or subsurface  strata)
or otherwise relating to the manufacture,  processing, generation, distribution,
use, treatment, storage, disposal, cleanup, transport or handling of pollutants,
contaminants,  chemicals or industrial, toxic or hazardous substances, materials
or wastes. Environmental Laws shall include without limitation the Comprehensive
Environmental  Response,  Compensation and Liability Act (42 U.S.C. Section 6901
et seq.), the Hazardous Material  Transportation Act (49 U.S.C.  Section 1801 et
seq.),  the Resource  Conservation  and Recovery Act (42 U.S.C.  Section 6901 et
seq.), the Federal Water Pollution Control Act (33 U.S.C. Section 1251 et seq.),
the Clean Air Act (42 U.S.C. Section 7401 et seq.), the Toxic Substances Control
Act (15 U.S.C. Section 2601 et seq.), the Occupational Safety and Health Act (29
U.S.C.  Section 651 et seq.), the Federal Insecticide  Fungicide and Rodenticide
Act (7  U.S.C.  Section  136 et  seq.),  and  the  Surface  Mining  Control  and
Reclamation  Act of 1977 (30 U.S.C.  Section  1201 et seq.),  and any  analogous
federal, state, local

                                       A-3


<PAGE>



or foreign,  Laws, and the rules and regulations  promulgated  thereunder all as
from time to time in effect,  and any  reference to any  statutory or regulatory
provision  shall be deemed  to be a  reference  to any  successor  statutory  or
regulatory provision.

         Environmental Permit shall mean any Governmental Authorization required
by or pursuant to any Environmental Law.

         Environmental  Reports  shall have the  meaning  given to it in Section
6.8.

         ERISA shall mean the Employee  Retirement  Income Security Act of 1974,
and the rules and regulations thereunder, all as from time to time in effect, or
any successor law, rules or  regulations,  and any reference to any statutory or
regulatory  provision  shall  be  deemed  to be a  reference  to  any  successor
statutory or regulatory provision.

         ERISA  Affiliate  shall  mean any  Person  that is  treated as a single
employer with OPM under Sections 414(b),  (c), (m) or (o) of the Code or Section
4001(b)(1) of ERISA.

         Event  shall  mean the  existence  or  occurrence  of any act,  action,
activity,  circumstance,  condition,  event,  fact,  failure  to act,  omission,
incident or practice, or any set or combination of any of the foregoing.

         Exchange Act shall mean the  Securities  Exchange Act of 1934,  and the
rules and  regulations  thereunder,  all as from time to time in effect,  or any
successor  law,  rules or  regulations,  and any  reference to any  statutory or
regulatory  provision  shall  be  deemed  to be a  reference  to  any  successor
statutory or regulatory provision.

         Executive Summary shall have the meaning given to it in Section 2.2(b).

         FCA  shall  mean the  Communication  Act of  1934,  and the  rules  and
regulations  thereunder,  all as from time to time in effect,  or any  successor
law,  rules or  regulations,  and any  reference to any  statutory or regulatory
provision  shall be deemed  to be a  reference  to any  successor  statutory  or
regulatory provision.

         FCC shall mean the Federal Communications  Commission and shall include
any successor Authority.

         Final  Order  shall  mean,  with  respect to any  Authority,  including
without  limitation  the FCC, one with respect to which no appeal,  no stay,  no
petition or application for rehearing, reconsideration,  review or stay, whether
on motion of the applicable Authority or other Person or otherwise, and no other
Legal Action contesting such consent or approval, is in effect or pending and as
to  which  the  time or  deadline  for  filing  any  such  appeal,  petition  or
application  or other Legal  Action has expired or, if filed,  has been  denied,
dismissed or  withdrawn,  and the time or deadline for  instituting  any further
Legal Action has expired.

         Formula shall have the meaning given to it in Section 2.2(a).

         GAAP shall mean means,  except to the extent that a deviation therefrom
is expressly  required by this Agreement and except that OPM maintains its books
on a modified cash-accrual basis, such principles applied on a consistent basis,
(i) as set forth in Opinions of the Accounting  Principles Board of the American
Institute of Certified Public Accountants  ("AICPA") and/or in statements of the
Financial Accounting Standards Board that are applicable in the circumstances as
of the date in  question,  (ii) when not  inconsistent  with such  opinions  and
statements, as set forth in other AICPA publications and guidelines and/or (iii)
that  otherwise  arise by custom for the  particular  industry,  all as the same
shall exist on the date of this Agreement.


                                       A-4


<PAGE>



         Governmental  Authorizations  shall  mean all  approvals,  concessions,
consents,   franchises,   licenses,  permits,  plans,  registrations  and  other
authorizations  of all  Authorities,  including  without  limitation  the United
States Forest  Service and the Federal  Aviation  Administration,  in connection
with the  ownership  or  operation  of the OPM Assets or the  conduct of the OPM
Business.

         Governmental  Filings shall mean all filings,  including  franchise and
similar Tax  filings,  and the payment of all fees,  assessments,  interest  and
penalties associated with such filings, with all Authorities.

         Hart-Scott-Rodino Act shall mean the Hart-Scott-Rodino  Improvement Act
of 1976, as from time to time in effect, or any successor law, and any reference
to any  statutory  provision  shall be deemed to be a reference to any successor
statutory provision.

         Hazardous  Materials  shall mean and include any  substance,  material,
waste, constituent, compound, chemical, natural or man-made element or force (in
whatever state of matter):  (a) the presence of which requires  investigation or
remediation under any Environmental  Law, or (b) that is defined as a "hazardous
waste" or  "hazardous  substance"  under any  Environmental  Law; or (c) that is
toxic, explosive,  corrosive,  etiologic,  flammable,  infectious,  radioactive,
carcinogenic,   mutagenic  or  otherwise  hazardous  and  is  regulated  by  any
applicable Authority or subject to any Environmental Law; or (d) the presence of
which on the real property owned or leased by such Person causes or threatens to
cause a nuisance upon any such real property or to adjacent  properties or poses
or threatens to pose a hazard to the health or safety of persons on or about any
such real property;  or (e) the presence of which on adjacent  properties  could
constitute a trespass by such Person; or (f) that contains gasoline, diesel fuel
or other  petroleum  hydrocarbons,  or any  by-products  or  fractions  thereof,
natural gas,  polychlorinated  biphenyls ("PCBs") and PCB-containing  equipment,
radon or other radioactive elements,  ionizing radiation,  electromagnetic field
radiation  and other  non-ionizing  radiation,  sonic  forces and other  natural
forces,  lead,  asbestos  or  asbestos-containing  materials  ("ACM"),  or  urea
formaldehyde foam insulation.

         Indebtedness  shall mean,  with  respect to any Person,  (a) all items,
except  items of  capital  stock or of  surplus  or of  general  contingency  or
deferred tax reserves or any minority  interest in any Subsidiary of such Person
to the extent such interest is treated as a liability with indeterminate term on
the  consolidated  balance sheet of such Person,  which in accordance  with GAAP
would be included in  determining  total  liabilities  as shown on the liability
side of a balance sheet of such Person, (b) all obligations  secured by any Lien
to which any property or asset owned or held by such Person is subject,  whether
or not the obligation  secured  thereby shall have been assumed,  and (c) to the
extent not  otherwise  included,  all  Contractual  Obligations  of such  Person
constituting  capitalized leases and all obligations of such Person with respect
to Leases constituting part of a sale and leaseback arrangement.

         Indebtedness  for Money Borrowed shall mean, with respect to OPM, money
borrowed  and  Indebtedness  represented  by notes  payable and drafts  accepted
representing   extensions  of  credit,  all  obligations   evidenced  by  bonds,
debentures,  notes or other similar instruments, the maximum amount currently or
at any time thereafter  available to be drawn under all  outstanding  letters of
credit  issued  for the  account of such  Person,  all  Indebtedness  upon which
interest  charges are  customarily  paid by such  Person,  and all  Indebtedness
(including  capitalized lease obligations)  issued or assumed as full or partial
payment  for  property  or  services,  whether  or not any such  notes,  drafts,
obligations or Indebtedness represent Indebtedness for money borrowed, but shall
not include (a) trade payables,  (b) expenses  accrued in the ordinary course of
business,  (c) customer advance payments and customer  deposits  received in the
ordinary course of business,  or (d) conditional sales agreements not prohibited
by the terms of this Agreement.

         Initial Installment shall have the meaning given to it in Section 2.2.


                                       A-5


<PAGE>



         Intangible  Assets shall mean all assets and property  lacking physical
properties the evidence of ownership of which must  customarily be maintained by
independent  registration,  documentation,  certification,  recordation or other
means,  and  shall  include,   without  limitation,   concessions,   copyrights,
franchises,  license, patents, permits, service marks, trademarks,  trade names,
and applications with respect to any of the foregoing, technology and know-how.

         Intellectual  Property  shall mean any and all  research,  information,
inventions,  designs,  procedures,  developments,   discoveries,   improvements,
patents and applications therefor, trademarks and applications therefor, service
marks, trade names, copyrights and applications therefor,  logos, trade secrets,
drawing, plans, systems,  methods,  specifications,  computer software programs,
tapes, discs and related data processing  software (including without limitation
object and source  codes)  owned by such Person or in which it has an  ownership
interest  and all other  manufacturing,  engineering,  technical,  research  and
development data and know-how made, conceived, developed and/or acquired by such
Person,  which  relate  to the  manufacture,  production  or  processing  of any
products  developed  or sold by such  Person or which are within the scope of or
usable in connection  with such Person's  business as it may, from time to time,
hereafter be conducted or proposed to be conducted.

         Law shall mean any (a) administrative,  judicial,  legislative or other
action,  code,  consent  decree,  constitution,  decree,  directive,  enactment,
finding, guideline, law, injunction, interpretation, judgment, order, ordinance,
policy statement,  proclamation,  promulgation,  regulation,  requirement, rule,
rule of law, rule of public policy,  settlement  agreement,  statute, or writ of
any  Authority,  domestic  or  foreign;  (b) the common  law,  or other legal or
quasi-legal  precedent;  or (c)  arbitrator's,  mediator's  or referee's  award,
decision,  finding or recommendation;  including, in each such case or instance,
any interpretation,  directive,  guideline or request, whether or not having the
force of law including, in all cases, without limitation any particular section,
part or provision thereof.

         Lease  shall mean any lease of  property,  whether  real,  personal  or
mixed, and all amendments thereto.

         Legal  Action  shall  mean,  with  respect to any  Person,  any and all
litigation   or   legal   or   other   actions,   arbitrations,   counterclaims,
investigations, proceedings, requests for material information by or pursuant to
the  order of any  Authority  or  suits,  at law or in  arbitration,  equity  or
admiralty,  whether or not  purported  to be  brought on behalf of such  Person,
affecting such Person or any of such Person's business, property or assets.

         Lien shall mean any of the  following:  mortgage;  lien  (statutory  or
other);  or other security  agreement,  arrangement or interest;  hypothecation,
pledge  or  other  deposit  arrangement;  assignment;  charge;  levy;  executory
seizure;   attachment;   garnishment;   encumbrance   (including  any  easement,
exception,  reservation or limitation,  right of way, and the like); conditional
sale,  title  retention  or other  similar  agreement,  arrangement,  device  or
restriction;   preemptive  or  similar  right;  any  financing  lease  involving
substantially  the same economic  effect as any of the foregoing;  the filing of
any financing  statement under the Uniform  Commercial Code or comparable law of
any  jurisdiction;  restriction on sale,  transfer,  assignment,  disposition or
other alienation; or any option, equity, claim or right of or obligation to, any
other Person, of whatever kind and character.

         Loss and Expense shall have the meaning given to it in Section 9.2(a).

         Master Plan shall have the meaning given to it in Section 6.10.


                                       A-6


<PAGE>



         material, materially or materiality for the purposes of this Agreement,
shall, unless specifically stated to the contrary,  be determined without regard
to the fact that various  provisions of this Agreement set forth specific dollar
amounts.

         Material  Agreement  shall mean,  with respect to OPM, any  Contractual
Obligation  which (a) was not entered into in the  ordinary  course of business,
(b) was entered into in the ordinary  course of business  which (i) involved the
purchase,  sale or lease  of  goods  or  materials,  or  purchase  of  services,
aggregating  more than $20,000  during any of the last three fiscal years,  (ii)
extends for more than three (3)  months,  or (iii) is not  terminable  on thirty
(30) days or less  notice  without  penalty  or other  payment,  (c)  involves a
capitalized  lease  obligation or  Indebtedness  for Money  Borrowed,  (d) is or
otherwise   constitutes   a   written   agency,   broker,    dealer,    license,
distributorship,   sales  representative  or  similar  written  agreement,   (e)
accounted  for more than three  percent (3%) of the revenues of the OPM Business
in any of the last  three  fiscal  years or is likely to  account  for more than
three  percent  (3%) of revenues of the OPM Business  during the current  fiscal
year,  (f) is with the United States Forest Service or any other  Authority,  or
(g)  involves  the  management  by OPM of any  communication  tower of any other
Person.

         Mills shall have the meaning given to it in Section 6.10.

         Mills  Employment  Agreement  shall  have  the  meaning  given to it in
Section 7.2(b).

         Multiemployer  Plan shall mean a Plan which is a  "multiemployer  plan"
within the meaning of Section 4001(a)3 of ERISA.

         Net Revenues shall have the meaning given to it in Section 2.2(b).

         Objection Notice shall have the meaning given it in the Section 6.10.

         OPM shall have the meaning given to it in the Preamble.

         OPM Assets shall mean all of the Assets of OPM.

         OPM  Business  shall have the meaning  given them in the third  Whereas
paragraph.

         OPM Communication Towers shall mean all of the communication towers and
other  property  associated  therewith  (including  without  limitation  storage
facilities,  generators and other property and equipment  needed to operate such
towers)  located on any real  property (i) owned or leased by OPM as of the date
of this Agreement,  or (ii) as to which valid and binding  agreements to acquire
or  lease  by OPM are in  effect  as of the  date of this  Agreement,  or  (iii)
acquired or leased, or agreed to be acquired or leased, by OPM subsequent to the
date of this  Agreement  and prior to the Closing with the express prior written
consent of ATS. A true,  complete and accurate list of all sites  referred to in
clauses (i) and (ii) of the  preceding  sentence is set forth as part of Section
3.5(a) or (b) of the OPM Disclosure Schedule.

         OPM Disclosure Schedule shall mean the OPM Disclosure Schedule dated as
of the date of this Agreement delivered by OPM to ATS.

         OPM Employees shall have the meaning given it in the Section 3.15.

         OPM Financial  Statements shall have the meaning given to it in Section
3.2..


                                       A-7


<PAGE>



         Organic  Document  shall  mean,  with  respect  to a Person  which is a
corporation,  its charter,  its by-laws and all shareholder  agreements,  voting
trusts and similar arrangements applicable to any of its capital stock and, with
respect to a Person which is a  partnership,  its agreement and  certificate  of
partnership,  any  agreements  among  partners,  and any  management and similar
agreements  between the partnership  and any general  partners (or any Affiliate
thereof).

         Pass Through Returns shall have the meaning given to it in Section 6.9.

         PBGC shall mean the Pension Benefit Guaranty Corporation and any Entity
succeeding to any or all of its functions under ERISA.

         Permitted  Liens shall mean (a) Liens for current taxes not yet due and
payable, (b) such imperfections of title, easements,  encumbrances and mortgages
or  other  Liens,  if  any,  as  are  not,  individually  or in  the  aggregate,
substantial in character,  amount or extent and do not  materially  detract from
the value, or materially interfere with the present use, of the property subject
thereto or affected thereby,  or otherwise  materially impair the conduct of the
OPM  Business,  and (c) such other Liens as are  permitted by the  provisions of
this Agreement to be in place on the Closing Date.

         Permitted Site shall mean that a site with respect to which notice from
all  applicable  Authorities  has been  received by OPM (or its  successors  and
assigns)  that  all  Governmental   Authorizations   necessary  to  construct  a
communication  tower on such site have been fully approved and are in full force
and effect.

         Person shall mean any natural individual or any Entity.

         Personal  Property shall mean all of the machinery,  equipment,  tools,
vehicles, furniture, leasehold improvements, office equipment, plant, inventory,
spare parts and other  tangible  personal  property which are owned or leased by
OPM and used or useful as of the date hereof in the  conduct of the  business or
operations  of the OPM  Business,  plus such  additions  thereto  and  deletions
therefrom arising in the ordinary course of business between the date hereof and
the Closing Date.

         Plan shall mean,  with respect to any Person and at a particular  time,
any employee benefit plan which is covered by ERISA and in respect of which such
Person or an ERISA  Affiliate is (or, if such plan were terminated at such time,
would under  Section 4069 of ERISA be deemed to be) an  "employer" as defined in
Section  3(5) of ERISA,  but only to the extent that it covers or relates to any
officer, employee or other Person involved in the ownership and operation of the
Assets or the conduct of the business of the OPM Business.

         Private Authorizations shall mean all approvals, concessions, consents,
franchises,  licenses,  permits,  and other authorizations of all Persons (other
than   Authorities)   including   without   limitation  those  with  respect  to
Intellectual Property.

         Purchase Price shall have the meaning given to it in Section 2.2.

         Real Property shall mean all of the fee estates and buildings and other
fixtures and improvements  thereon,  leasehold  interest,  easements,  licenses,
rights to access,  right-of-  way, and other real  property  interest  which are
owned  or  used  by OPM as of the  date  hereof,  in the  operations  of the OPM
Business,  plus such additions  thereto and deletions  therefrom  arising in the
ordinary course of business between the date hereof and the Closing Date.

         Regulations  shall mean the federal income tax regulations  promulgated
under  the Code,  as such  Regulations  may be  amended  from time to time.  All
references herein to specific sections of the Regulations

                                       A-8


<PAGE>



shall be deemed  also to refer to any  corresponding  provisions  of  succeeding
Regulations, and all references to temporary Regulations shall be deemed also to
refer to any corresponding provisions of final Regulations.

         Representatives shall have the meaning given to it in Section 6.1(a).

         Securities Act shall mean the Securities Act of 1933, and the rules and
regulations  thereunder,  all as from time to time in effect,  or any  successor
law,  rules or  regulations,  and any  reference to any  statutory or regulatory
provision  shall be deemed  to be a  reference  to any  successor  statutory  or
regulatory provision.

         Stockholders shall have the meaning given to it in the Preamble.

         Stockholders'  knowledge means the actual  knowledge of any Stockholder
or any OPM officer or senior  manager,  as such knowledge  exists on the date of
this Agreement and no later date,  after  reasonable  review of appropriate  OPM
records.

         Stockholders  Representative  shall  have  the  meaning  given to it in
Section 10.14.

         Subject  Stock shall have the meaning  given to it in the first Whereas
paragraph.

         Subsidiary shall mean, with respect to a Person,  any Entity a majority
of the capital stock  ordinarily  entitled to vote for the election of directors
of which,  or if no such voting stock is  outstanding,  a majority of the equity
interests of which, is owned directly or indirectly, legally or beneficially, by
such Person or any other Person controlled by such Person.

         Tax (and "Taxable",  which shall mean subject to Tax), shall mean, with
respect to any Person,  (a) all taxes (domestic or foreign),  including  without
limitation any income (net, gross or other including  recapture of any tax items
such as  investment  tax  credits),  alternative  or add-on  minimum tax,  gross
income,  gross receipts,  gains,  sales, use, leasing,  lease, user, ad valorem,
transfer, recording, franchise, profits, property (real or personal, tangible or
intangible),  fuel,  license,  withholding on amounts paid to or by such Person,
payroll,  employment,  unemployment,  social security, excise, severance, stamp,
occupation, premium, environmental or windfall profit tax, custom, duty or other
tax, or other like  assessment or charge of any kind  whatsoever,  together with
any  interest,  levies,  assessments,  charges,  penalties,  addition  to tax or
additional  amount  imposed  by any Taxing  Authority,  (b) any joint or several
liability of such Person with any other Person for the payment of any amounts of
the type  described in (a) and (c) any  liability of such Person for the payment
of any  amounts  of the type  described  in (a) as a result  of any  express  or
implied obligation to indemnify any other Person.

         Tax  Allocation  Schedule shall have the meaning given to it in Section
2.2(c).

         Tax  Claim  shall  mean any Claim  which  relates  to Taxes,  including
without limitation the representations and warranties set forth in Section 3.11.

         Tax Return or Returns shall mean all returns, consolidated or otherwise
(including without limitation  information  returns),  required to be filed with
any Authority with respect to Taxes.

         Taxing   Authority  shall  mean  any  Authority   responsible  for  the
imposition of any Tax.

         Title Reports shall have the meaning given to it in Section 6.7.

         Termination Date shall have the meaning given to it in Section 8.1.

                                       A-9


<PAGE>


         Transactions shall mean the transactions contemplated to be consummated
on or prior to the Closing Date,  including without  limitation the purchase and
sale of the Subject Stock and the  execution,  delivery and  performance  of the
Collateral Documents.





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