EXHIBIT 10.11

CERBCO, Inc.


                          INSITUFORM EAST, INCORPORATED
                         1999 EMPLOYEE STOCK OPTION PLAN
                        INCENTIVE STOCK OPTION AGREEMENT

         THIS INCENTIVE STOCK OPTION AGREEMENT,  hereinafter  referred to as the
"Option"  or the  "Agreement",  is made as of the  8th  day of  December,  2000,
between Insituform East,  Incorporated,  a Delaware Corporation (the "Company"),
and Robert F. Hartman (the "Optionee"),  an officer of the Company,  residing at
2814 Durmont Court, Annapolis, MD 21401.

         The Company hereby grants to the Optionee an option to purchase  shares
of Common Stock of the Company,  par value $0.04 per share ("Common Stock"),  at
the price,  and in all respects subject to the terms,  obligations,  definitions
and provisions of the Insituform East,  Incorporated  1999 Employee Stock Option
Plan (the "Plan") and this Agreement, as set forth below. Capitalized terms used
but not defined herein have the meanings ascribed to them in the Plan.

     1. Number of Shares.  The number of shares for which the Company  grants an
option is thirty-thousand (30,000).

     2.  Option  Price.  The option  price is  $1.5625  for each share of Common
Stock.

     3. Term. Unless earlier forfeited,  the Option shall,  notwithstanding  any
other  provision  of this  Agreement,  expire  in its  entirety  upon the  fifth
anniversary of the date hereof (the  "Expiration  Date").  The Option shall also
expire and be  forfeited  at such times and in such  circumstances  as otherwise
provided hereunder or under the Plan.

     4. Exercise of Option.

     (i) Subject to Paragraph 3 above, the Option,  to the extent there has been
no  termination  of the  Optionee's  employment and the Option has not otherwise
expired or been  forfeited,  shall  vest and first  become  exercisable  (unless
sooner  exercisable in accordance with Section  Fourteen of the Plan relating to
certain corporate transactions), on the 24-month anniversary of the date hereof;
provided, however, that the Option, if not already vested and exercisable, shall
vest and first become exercisable upon a Change in Control (as defined below) at
any time after the date  hereof,  if and to the  extent  that the Option has not
otherwise expired or been forfeited.

     (ii) Right to  Exercise.  This Option shall be  exercisable  in whole or in
part by the  Optionee  during  the term of the  Option,  but not  before  it has
vested:

     (a) while the Optionee continues to serve as an officer of the Company, its
subsidiaries, its parent, or its successor companies;

     (b) for a period ending three (3) months after the Optionee has  terminated
his services in such capacity; or

     (c) if the  Optionee  should  die while  serving in such  capacity,  by the
estate of the Optionee,  within six (6) months after the date of the  Optionee's
death;  provided,  however, that in no event shall the Option be exercised after
the Expiration Date.

     (iii) Method of Exercise.  This Option shall be  exercisable in whole or in
part by a written notice,  which shall state the election to exercise the Option
and the  number of shares in respect  of which it is being  exercised,  shall be
signed by the person or persons  entitled  to exercise  the Option,  and, if the
Option is being  exercised  by any person or persons  other than the Optionee in
accordance  with  Section  Ten of the  Plan,  shall  be  accompanied  by  proof,
satisfactory to counsel for the Company,  of the right of such person or persons
to exercise the Option.

     Payment  of the  purchase  price of any  shares  with  respect to which the
Option is being  exercised  shall be delivered  with the notice of exercise.  No
fractional  shares of Common Stock shall be issued upon any such  exercise.  The
certificate  or  certificates  for shares of Common Stock as to which the Option
shall be  exercised  shall be  registered  in the name of the  Optionee or other
person exercising the Option.

     (iv)  Restrictions  on  Exercise.  As a condition  to the  exercise of this
Option,  the Company may require the person  exercising  this Option to make any
representation  and warranty to the Company as may be required by applicable law
or regulation and execute such other agreements as the Company,  in its sole and
absolute discretion, deems necessary or appropriate.

     (v) Employment Agreement. The Optionee agrees to serve as an officer of the
Company  for a period of not less than  twenty-four  (24)  months  from the date
hereof.

     (vi) Change in Control. For purposes of this Agreement, "Change in Control"
shall mean the happening of any of the following:

     (a) any  "person,"  including a "group" (as such terms are used in Sections
13(d)  and  14(d) of the  Securities  Exchange  Act of  1934,  as  amended  (the
"Exchange Act"), but excluding the Company,  any entity controlling,  controlled
by or under common  control with the Company,  any employee  benefit plan of the
Company or any such entity,  and, with respect to any particular  Optionee,  the
Optionee  and any  "group"  (as such  term is used in  Section  13(d)(3)  of the
Exchange Act) of which the Optionee is a member),  is or becomes the "beneficial
owner"  (as  defined in Rule  13(d)(3)  under the  Exchange  Act),  directly  or
indirectly,  of securities of the Company representing 50% or more of either (A)
the combined  voting power of the Company's then  outstanding  securities or (B)
the then outstanding shares of Class B Common Stock; or

     (b) any  consolidation  or merger of the Company where the  stockholders of
the  Company,  immediately  prior to the  consolidation  or  merger,  would not,
immediately after the consolidation or merger, beneficially own (as such term is
defined in Rule 13d-3 under the Exchange Act),  directly or  indirectly,  shares
representing  in the aggregate  50% or more of the combined  voting power of the
securities of the corporation issuing cash or securities in the consolidation or
merger (or of its ultimate parent corporation, if any); or

     (c) there shall occur (x) any sale,  lease,  exchange or other transfer (in
one  transaction  or a series of  transactions  contemplated  or arranged by any
party  as a  single  plan)  of all or  substantially  all of the  assets  of the
Company, other than a sale or disposition by the Company of all or substantially
all of the Company's  assets to an entity,  at least 50% of the combined  voting
power of the voting  securities  of which are owned by Persons in  substantially
the same proportion as their ownership of the Company  immediately prior to such
sale or (y) the approval by  stockholders of the Company of any plan or proposal
for the liquidation or dissolution of the Company.

     4.  Nontransferability of Option. This Option may not be transferred in any
manner  otherwise than by will or the laws of descent or distribution and may be
exercised during the lifetime of the Optionee only by the Optionee. The terms of
this  Option  shall  be  binding  upon  the  executors,  administrators,  heirs,
successors and assigns of the Optionee.

     5. Adjustments upon Changes in Capitalization. If all or any portion of the
Option   is   exercised   subsequent   to   any   stock   dividend,    split-up,
recapitalization,  combination  or  exchange of shares,  merger,  consolidation,
acquisition of property or stock, separation,  reorganization,  or other similar
change or transaction  of or by the Company,  as a result of which shares of any
class shall be issued in respect of  outstanding  shares of the class covered by
the Option or shares of the class  covered by the Option  shall be changed  into
the same or different  number of shares of the same or another class or classes,
the  person or persons  so  exercising  such an Option  shall  receive,  for the
aggregate  option price payable upon such exercise of the Option,  the aggregate
number and class of shares equal to the number and class of shares he would have
had on the date of exercise had the shares been purchased for the same aggregate
price at the date the Option was granted and had not been  disposed  of,  taking
into  consideration  any  such  stock  dividend,   split-up,   recapitalization,
combination  or  exchange  of  shares,  merger,  consolidation,  acquisition  of
property  or  stock,  separation,  reorganization,  or other  similar  change or
transaction;  provided,  however,  that no fractional share shall be issued upon
any such exercise,  and the aggregate price paid shall be appropriately  reduced
on account of any fractional share not issued.

     6. Notices.  Each notice relating to this Agreement shall be in writing and
delivered  in person or by  certified  mail to the proper  address.  Each notice
shall be deemed to have been given on the date it is  received.  Each  notice to
the Company  shall be addressed to it at its principal  office,  now 3421 Pennsy
Drive, Landover,  Maryland 20785, to the attention of the Corporate Secretary of
the  Company.  Each  notice to the  Optionee  or other  person or  persons  then
entitled to exercise the Option shall be addressed to the Optionee or such other
person or persons at the  Optionee's  address set forth in the  forepart of this
Agreement.  Anyone  to whom a  notice  may be given  under  this  Agreement  may
designate a new address by written notice to that effect.

     7. Incorporation for Reference. The obligations,  terms,  definitions,  and
provisions of the Plan are hereby incorporated in this Agreement by reference.

     8. Benefits of Agreement.  This Agreement  shall inure to be benefit of and
be binding upon each successor of the Company.  All obligations imposed upon the
Optionee and all rights  granted to the Company  under this  Agreement  shall be
binding  upon  the  Optionee's  heirs,  legal  representatives,  successors  and
assigns.

     9. Rights,  Terms, etc. With respect to the shares of Common Stock that the
Optionee may purchase hereunder,  this Agreement shall be the sole and exclusive
source  of  any  and  all  rights   that  the   Optionee,   his   heirs,   legal
representatives,  successors or assigns may have with respect to the Plan or any
options or Common Stock granted or issued thereunder, whether to the Optionee or
to any other person.

     10.  Resolution  of  Disputes.   This  Agreement  is  subject  to  all  the
provisions,  requirements  and  conditions of the Plan,  and in the event of any
ambiguity or  inconsistency  of provisions of this  Agreement  with those of the
Plan,  the  provisions of the Plan shall  control.  Any dispute or  disagreement
which  may  arise  under,  or as a  result  of,  or in any way  relate  to,  the
interpretation,  construction,  or application of this Agreement will be decided
by the Board and any such determination made hereunder shall be final,  binding,
and conclusive for all purposes.

         IN WITNESS WHEREOF, the Company and the Optionee have caused this
Agreement to be executed as of the day, month, and year first above written.


INSITUFORM EAST, INCORPORATED

By /s/ Robert W. Erikson                  /s/ Robert F. Hartman
-------------------------------           -----------------------------------
Assistant Corporate Secretary             Optionee