<PAGE>

                                                                    Exhibit 3(n)
                                  BY-LAWS of
                           ICF KAISER SYSTEMS, INC.

                                   ARTICLE I
                                   ---------
                                    Offices

Section 1.01.  Registered Office in Delaware.  The registered office shall be in
------------   -----------------------------
Wilmington, Delaware.  The name of the registered agent of the Corporation at
such location is Corporation Service Company.

Section 1.02.  Principal Office.  The Board of Directors is granted full power
------------   ----------------
and authority to fix and thereafter change the location of the principal office
of the Corporation at any location within the United States.

Section 1.03.  Other Offices.  The Corporation may have such other offices
------------   -------------
either within or without the State of Delaware as the Board of Directors may
from time to time determine.

                                  ARTICLE II
                                  ----------
                           Meetings of Stockholders

Section 2.01.  Time and Place of Meeting.  Annual meetings of the stockholders
------------   -------------------------
for the purpose of electing directors, making reports of the affairs of the
Corporation and transacting such other business as may properly come before the
meeting shall be held at such place, within or without the State of Delaware, on
such date and at such time as the Board of Directors shall each year fix, which
date shall be within thirteen months subsequent to the later of the date of
incorporation or the last annual meeting of stockholders.  Meetings of
stockholders for any other purpose may  be held at such time and place, within
or without the State of Delaware, as shall be fixed by the Board of Directors
and stated in the notice of meeting.  If no other place is fixed by the Board of
Directors, meetings of stockholders shall be held at the principal executive
office of the Corporation.  Failure to hold the annual meeting at the designated
time shall not work a forfeiture or dissolution of the Corporation.

Section 2.02.  Notice of Meeting.  Written notice of meetings of stockholders,
-------------  ------------------
stating the place, date and hour thereof, and in the case of a special meeting,
the purpose or purposes for which the meeting is being called, shall be given
not less than ten nor more than sixty days before the date of the meeting to
each stockholder entitled to vote thereat.

Section 2.03.  Qualified Voters.  The officer who has charge of the stock ledger
------------   ----------------
of the Corporation shall prepare, at least ten days before every meeting of
stockholders, a complete list of the stockholders entitled to vote at the
meeting, arranged in alphabetical order showing the address of each stockholder
and the number of shares registered in the name of each stockholder.  Such list
shall be open to the examination of any stockholder for any purpose germane to
the meeting during ordinary business hours for a period of at least ten days
prior to the meeting, either at a place within the city where the meeting is to
be held, which place shall be specified in the notice of the meeting, or if not
so specified, at the place where the meeting is to be held.  The list shall be
produced and kept at the time and place of the meeting during the whole time
thereof, and may be inspected by any stockholder who is present and entitled to
vote.

Section 2.04.  Special Meetings.  Special meetings of the stockholders may be
-------------  ----------------
called by the Board of Directors or by the President or by a writing signed by
stockholders owning a majority in amount of the entire capital stock of the
Corporation issued and outstanding and entitled to vote at such meeting.  Such
call shall state the purpose or purposes of the proposed meeting.  The Secretary
shall give notice of such meeting to the stockholders entitled to vote thereat,
in accordance with such call.

Section 2.05.  Business at Special Meetings.  Business transacted at any special
-------------  ----------------------------
meeting of stockholders shall be limited to the purposes stated in the notice.

Section 2.06.  Quorum.  The holders of a majority of the stock issued and
outstanding and entitled to vote thereat, present in person or represented by
proxy, shall constitute a quorum at all meetings of the stockholders for the
transaction of business except as otherwise provided by statute or by the
Certificate of Incorporation.  If, however, such quorum shall not be present or
represented at any meeting of the stockholders, the stockholders entitled to
vote thereat, present in person or represented by proxy, shall have power to
adjourn the meeting from time to time without notice other than announcement at
the meeting (if the adjournment is not for more than thirty days and a new
record date for the determination of stockholders entitled to vote is not
fixed), until a quorum shall be present or represented.  At such adjourned
meeting at which a quorum shall be present or represented, any business may be
transacted which might have been transacted at the meeting as originally
notified.
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                                                        ICF KAISER SYSTEMS, INC.
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Section 2.07.  Vote Required.  When a quorum is present at any meeting, the vote
-------------  -------------
of the holders of a majority of the shares of stock having voting power voting,
in person or by proxy, on a  question shall decide any question brought before
such meeting, unless the question is one upon which by express provision of the
statutes, the Certificate of Incorporation or these By-laws a different vote is
required, in which case such express provision shall govern and control the
decision of such question.

Section 2.08.  Proxies.  Each stockholder shall at every meeting of the
-------------  -------
stockholders be entitled to one vote in person or by proxy for each share of the
capital stock having voting power held by such stockholder, but no proxy shall
be voted on after three years from its date unless the proxy provides for a
longer period.  No proxy or power of attorney to vote shall be used to vote at a
meeting of the stockholders unless it shall have been filed with the Secretary
of the meeting when required by the inspectors of election.  All questions
regarding the qualification of voters, the validity of proxies and the
acceptance or rejection of votes shall be decided by two inspectors of election
who shall be appointed by the Board of Directors, or if not so appointed, then
by the presiding officer of the meeting.

Section 2.09.  Presiding Officer.  The President of the Corporation shall
-------------  -----------------
preside over all meetings of stockholders.

Section 2.10.  Consent.  Whenever the vote of stockholders at a meeting thereof
-------------  -------
is required or permitted to be taken in connection with any corporate action by
any provisions of the statutes, the By-laws or the Certificate of Incorporation,
the meeting and vote may be dispensed with if the number of stockholders who
would have been entitled to vote upon the action if such meeting were held,
having not less than the minimum number of votes that would be necessary to
authorize or take such action at a meeting, shall consent in writing to such
corporate action being taken.  Prompt notice shall be given by the Secretary to
all stockholders of the  taking of corporate action without a meeting by less
than unanimous written consent.

                                  ARTICLE III
                                  -----------
                                   Directors

Section 3.01.  Number and Election. The number of directors which shall
------------   -------------------
constitute the whole Board shall be no less than one (1) or more than ten (10).
By amendment of this By-law, the number may be increased or decreased from time
to time by the Board of Directors or stockholders within the limits permitted by
law, but no decrease in the number of directors shall change the term of any
director in office at the time thereof.  The directors shall be elected at the
annual meeting of the stockholders, except as provided in Section 3.02, and each
director shall hold office until his successor is elected and accepts office
unless he earlier resigns or is removed.  Directors need not be stockholders.  A
director may resign at any time upon written notice to the Corporation or orally
at any meeting of the directors or stockholders.

Section 3.02.  Removal and Vacancies.  A director may be removed with or without
-------------  ---------------------
cause by a majority vote of the holders of the outstanding shares entitled to
vote.  [Subject to any Stockholder's Agreement] Vacancies and newly created
directorships resulting from any increase in the authorized number of directors
may be filled by a majority of the directors then in office, though less than a
quorum, and the directors so chosen shall hold office until the next annual
election and until their successors are duly elected and accept office, unless
sooner displaced.

Section 3.03.  Management, The business of the Corporation shall be managed by
-------------  ----------
its Board of Directors, which may exercise all such powers of the Corporation
and do all such lawful acts and things as are not by statute or by the
Certificate of Incorporation or by  these By-laws directed or required to be
exercised or done by the stockholders.

Section 3.04.  Place of Meetings.  The Board of Directors of the Corporation may
-------------  -----------------
hold meetings, both regular and special, either within or without the State of
Delaware.  Meetings may be held by means of conference telephone or similar
communications equipment by means of which all persons participating in the
meeting can hear each other, and such participation in a meeting shall
constitute presence in person at such meeting.

Section 3.05.  Annual Meeting.  The first meeting of each newly elected Board of
------------   --------------
Directors shall be held immediately following the adjournment of the annual
meeting of stockholders and at the place thereof.  No notice of such meeting
shall be necessary to the directors in order legally to constitute the meeting,
provided a quorum is present.  In the event such meeting is not so held, the
meeting may be held at such time and place as shall be specified in a notice
given as hereinafter provided for special meetings of the Board of Directors.
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                                                        ICF KAISER SYSTEMS, INC.
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Section 3.06.  Notice for Regular Meetings.  Regular meetings of the Board of
-------------  ---------------------------
Directors may be held without notice at such time and at such place as shall
from time to time be determined by the Board of Directors.

Section 3.07.  Special Meetings.  Special meetings of the Board of Directors
-------------  ----------------
may be called by a majority of the Board of Directors or the President and shall
be held on notice by letter mailed or delivered for transmission not later than
on the third day immediately preceding the day of such meeting, or by written
notice delivered or received not later than the day immediately preceding the
day of such meeting. Neither the business to be transacted at, nor the purpose
of, any special meeting of the Board of Directors need be specified in the
notice or waiver of notice of such meeting.

Section 3.08.  Quorum.  At meetings of the Board of Directors, a majority of
-------------  ------
the full number of directors shall constitute a quorum for the transaction of
business, and the act of a majority of the directors present at any meeting at
which there is a quorum shall be the act of the Board of Directors.  If a quorum
shall not be present at any meeting of the Board of Directors, the directors
present thereat may adjourn the meeting from time to time, without notice other
than announcement at the meeting, until a quorum shall be present.

Section 3.09.  Chairman of the Board.  At its first meeting after each annual
-------------  ---------------------
meeting of stockholders, the Board of Directors shall elect from among its
members a Chairman.  The Board of Directors may also choose a Vice Chairman from
among its members.  The Chairman shall preside at all meetings of the Board of
Directors, and shall perform such other duties as the Board may prescribe.  The
Chairman may participate and act in any meeting of the Board of Directors as a
director.  The Vice Chairman, if any, shall act under the direction of the
Chairman and in the absence or disability of the Chairman shall perform the
duties and exercise the powers of the Chairman.  The Chairman and the Vice
Chairman, if any, (i) shall hold their respective offices at the pleasure of the
Board of Directors, and (ii) may be removed with or without cause at any time by
the Board of Directors.  Any vacancy occurring in the office of the Chairman or
Vice Chairman by death, resignation, removal or otherwise shall be filled by the
Board of Directors.

Section 3.10.  Committees.  The Board of Directors may, by resolution adopted by
-------------  ----------
a majority of the whole Board, designate one or more committees of the Board of
Directors, each committee to consist of one or more of the directors of the
Corporation, which, to the extent provided in the resolution, may have and
exercise any or all the powers of the Board of Directors in the management of
the business and affairs of the Corporation including, but not limited to, the
power and authority of the Board of Directors:  (i) to authorize the seal of the
Corporation to be affixed to all papers; (ii) to declare a dividend; (iii) to
authorize the issuance of stock; (iv) to adopt a certificate of ownership and
merger pursuant to Section 253, of Title 8, Delaware Code; and (v) to the extent
authorized in the resolution or resolutions providing for the issuance of shares
of stock adopted by the Board of Directors as provided in Section 151(a) of
Title 8, Delaware Code, fix any of the preferences or rights of such shares
relating to dividends, redemption, dissolution, any distribution of assets of
the Corporation or the conversion into, or the exchange of such shares for
shares of any other class or classes or any other series of the same of any
other class or classes of stock of the Corporation.  Such committee or
committees shall have such name or names as may be determined from time to time
by the Board of Directors.  The member or members of any such committee present
at any meeting and not disqualified from voting may, whether or not they
constitute a quorum, unanimously appoint another member of the Board of
Directors to act at the meeting in the place of any absent or disqualified
member.  At meetings of such committees, a majority of the members or alternate
members at any meeting at which there is a quorum shall be the act of the
committee.

Section 3.11.  Committee Minutes.  The committees shall keep regular minutes of
-------------  -----------------
their proceedings and report the same to the Board of Directors.

Section 3.12.  Consent.  Any action required or permitted to be taken at any
-------------  -------
meeting of the Board of Directors or of any committee thereof may be taken
without a meeting if a written consent thereto is signed by all members of the
Board of Directors or of such committee, as the case may be, and such written
consent is filed with the minutes of proceedings of the Board or committee.

Section 3.13.  Compensation.  The directors may be paid their expenses of
-------------  ------------
attendance at each meeting of the Board of Directors and may be paid a fixed sum
for attendance at each meeting of the Board of Directors or a stated salary as
director.  No such payment shall preclude any director from serving the
Corporation in any other capacity and receiving compensation therefor.  Members
of committees of the Board of Directors may be allowed like reimbursement and
compensation for attending committee meetings.

                                  ARTICLE IV
                                  ----------
                                    Notices
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                                                        ICF KAISER SYSTEMS, INC.
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Section 4.01.  Notice.  Notices to directors and stockholders mailed to them at
------------   ------
their addresses appearing on the books of the Corporation shall be deemed to be
given at the time when deposited in the United States mail, postage prepaid.  An
affidavit of the Secretary or an Assistant Secretary or of the transfer agent of
the Corporation that the notice has been given shall, in the absence of fraud,
be prima facie evidence of the facts stated therein.

Section 4.02.  Waiver.  Whenever any notice is required to be given under the
------------   ------
provisions of the statute, the Certificate of Incorporation or of these By-laws,
a waiver thereof in writing, signed by the person or persons entitled to said
notice, whether  before or after the time stated therein, shall be deemed
equivalent thereto.  Neither the business to be transacted at, nor the purposes
of, any meeting need be specified in such waiver.  Attendance at a meeting shall
constitute a waiver of notice of such meeting, except when the person attends a
meeting for the express purpose of objecting, at the beginning of the meeting,
to the transaction of any business because the meeting is not lawfully called or
convened.

                                   ARTICLE V
                                   ---------
                                   Officers

Section 5.01.  Election.  The officers of the Corporation shall be chosen by the
------------   --------
Board of Directors at its first meeting after each annual meeting of
stockholders and shall be a President, a Secretary and a Treasurer.  The Board
of Directors may also choose one or more Vice Presidents and one or more
Assistant Secretaries and Assistant Treasurers.  Two or more offices may be held
by the same person.

Section 5.02.  Other Officers.  The Board of Directors may appoint such other
-------------  --------------
officers and agents as it shall deem necessary who shall hold their offices for
such terms and shall exercise such powers and perform such duties as shall be
determined from time to time by the Board of Directors.

Section 5.03.  Salaries.  The salaries of all officers of the Corporation shall
-------------  --------
be fixed by or under the direction of the Board of Directors.

Section 5.04.  Vacancies.  The officers of the Corporation shall hold office at
-------------  ---------
the pleasure of the Board of Directors.  Any officer may be removed with or
without cause at any time by the Board  of Directors.  Each officer shall hold
his office until his successor is elected and qualified or until his earlier
resignation or removal.  The Board of Directors may fill any vacancy occurring
in any office of the Corporation by death, resignation, removal or otherwise.

Section 5.05.  President.  The President shall serve as Chief Executive Officer
-------------  ---------
of the Corporation, shall have general and active management of the business of
the Corporation and shall see that all orders and resolutions of the Board of
Directors are carried into effect.  He shall execute on behalf of the
Corporation, and may affix or cause the seal to be affixed to, all instruments
requiring such execution except to the extent the signing and execution thereof
shall be expressly delegated by the Board of Directors to some other officer or
agent of the Corporation.  He shall perform such additional duties and have such
additional powers as the Board of Directors may from time to time prescribe.

Section 5.06.  Vice Presidents.  The Vice Presidents shall act under the
-------------  ---------------
direction of the President and in the absence or disability of the President
shall perform the duties and exercise the powers of the President.  They shall
perform such other duties and have such other powers as the President or the
Board of Directors may from time to time prescribe.  The Board of Directors may
designate one or more Executive Vice Presidents or may otherwise specify the
order of seniority of the Vice Presidents.  The duties and powers of the
President shall descend to the Vice Presidents in such specified order of
seniority.

Section 5.07.  Secretary.  The Secretary shall act under the direction of the
-------------  ---------
President.  Subject to the direction of the President, he shall attend all
meetings of the Board of Directors and  all meetings of the stockholders and
record the proceedings in a book to be kept for that purpose.  He shall perform
like duties for committees when required.  He shall give, or cause to be given,
notice of all meetings of the stockholders and special meetings of the Board of
Directors, and shall perform such other duties as may be prescribed by the
President or the Board of Directors.  He shall keep in safe custody the seal of
the Corporation and, when authorized by the President or the Board of Directors,
cause it to be affixed to any instrument requiring it.

Section 5.08.  Assistant Secretaries.  The Assistant Secretaries shall act under
-------------  ---------------------
the direction of the President.  In the order of their seniority, unless
otherwise determined by the President or the Board of Directors, they shall, in
the absence or
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                                                                      BY-LAWS OF
                                                        ICF KAISER SYSTEMS, INC.
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disability of the Secretary, perform the duties and exercise the powers of the
Secretary. They shall perform such other duties and have such other powers as
the President or the Board of Directors may from time to time prescribe.

Section 5.09.  Treasurer.  The Treasurer shall act under the direction of the
-------------  ---------
President.  Subject to the direction of the President he shall have custody of
the corporate funds and securities and shall keep full and accurate accounts of
receipts and disbursements in books belonging to the Corporation and shall
deposit all moneys and other valuable effects in the name and to the credit of
the Corporation in such depositories as may be designated by the Board of
Directors.  He shall disburse the funds of the Corporation as may be ordered by
the President or the Board of Directors, taking proper vouchers for such
disbursements, and shall render to the President and the Board of Directors at
its regular meetings, or when the Board of Directors so requires, an account of
all his transactions as Treasurer and of the financial  condition of the
Corporation.  He may affix or cause to be affixed the seal of the Corporation to
documents so requiring.

Section 5.10.  Assistant Treasurers.  The Assistant Treasurers in the order of
-------------  --------------------
their seniority, unless otherwise determined by the President or the Board of
Directors, shall, in the absence or disability of the Treasurer, perform the
duties and exercise the powers of the Treasurer. They shall perform such other
duties and have such other powers as the President or the Board of Directors may
from time to time prescribe.

                                  ARTICLE VI
                                  ----------
                             Certificates of Stock

Section 6.01.  Certificate.  Every holder of stock in the Corporation shall be
------------   -----------
entitled to have a certificate signed by the Chairman or Vice-Chairman of the
Board of Directors, or the President or a Vice President, and by the Treasurer
or an Assistant Treasurer, or the Secretary or an Assistant Secretary of the
Corporation, certifying the number of shares owned by him in the Corporation.
Every such certificate shall contain a statement of the restrictions provided in
Section 4 of this Article.

Section 6.02.  Facsimile Signature.  Any or all the signatures on the
-------------  -------------------
certificate may be facsimiles.  In case any officer, transfer agent or registrar
who has signed or whose facsimile signature has been placed upon a certificate
shall have ceased to be such officer, transfer agent or registrar before such
certificate is issued, such certificate may be issued with the same effect as
though the person had not ceased to be such officer, transfer agent or
registrar.  The seal of the Corporation or a facsimile thereof may, but need
not, be affixed to certificates of stock.

Section 6.03.  Lost Certificates.  The Board of Directors may direct a new
-------------  -----------------
certificate or certificates to be issued in place of any certificate or
certificates theretofore issued by the Corporation alleged to have been lost,
stolen or destroyed, upon the making of an affidavit of that fact by the person
claiming the certificate of stock to be lost, stolen or destroyed.  When
authorizing such issue of a new certificate or certificates, the Board of
Directors may, in its discretion and as a condition precedent to the issuance
thereof, require the owner of such lost, stolen or destroyed certificate or
certificates, or his legal representative, to give the Corporation a bond in
such sum as it may direct as indemnity against any claim that may be made
against the Corporation with respect to the certificate alleged to have been
lost, stolen or destroyed.

Section 6.04.  Transfer.  Upon surrender to the Corporation or the transfer
-------------  --------
agent of the Corporation of a certificate for shares duly endorsed or
accompanied by proper evidence of succession, assignment or authority to
transfer, the Corporation shall issue a new certificate to the person entitled
thereto, cancel the old certificate and record the transaction upon its books,
provided, however, the Corporation shall have no obligation to issue new
certificates, cancel old certificates or record transactions unless and until it
is satisfied that (i) all provisions of the Certificate of Incorporation, these
By-laws and any legends on the certificate regarding transfer of shares and
restrictions on such transfers have been complied with, and (ii) all other
applicable restrictions, including restrictions imposed by law, including
federal and state securities law, and by any stockholders agreement to which the
Corporation is a party, have been complied with.

Section 6.05.  Record Date.  The Board of Directors may fix in advance a date,
-------------  -----------
not more than sixty days nor less than ten days preceding the date of any
meeting of stockholders, or not more than sixty days before the date for the
payment of any dividend, or the date for the allotment of rights, or the date
when any change or conversion or exchange of capital stock shall go into effect,
or a date in connection with obtaining a consent, as a record date for the
determination of the stockholders entitled to notice of, and to vote at, any
such meeting and any adjournment thereof, or entitled to receive payment of any
such dividend, or to any such allotment of rights, or to exercise the rights in
respect of any such change, conversion or exchange of capital stock, or to give
such consent, and in such case such stockholders and only
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                                                        ICF KAISER SYSTEMS, INC.
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such stockholders as shall be stockholders of record on the date so fixed shall
be entitled to such notice of, and to vote at, such meeting and any adjournment
thereof, or to receive payment of such dividend, or to receive such allotment of
rights, or to exercise such rights, or to give such consent, as the case may be
notwithstanding any transfer of any stock on the books of the Corporation after
any such record date fixed as aforesaid.

Section 6.06.  Recognition of Ownership.  The Corporation shall be entitled to
-------------  ------------------------
recognize the person registered on its books as the owner of shares to be the
exclusive owner for all purposes including voting and dividends, and the
Corporation shall not be bound to recognize any equitable or other claim to or
interest in such share or shares on the part of any other person, whether or not
it shall have express or other notice thereof, except as otherwise provided by
the laws of Delaware.

                                  ARTICLE VII
                                  -----------
                                 Miscellaneous

Section 7.01.  Reserves.  There may be set aside out of any funds  of the
------------   --------
Corporation available for dividends such sum or sums as the Board of Directors
may from time to time, in its absolute discretion, think proper, as a reserve or
reserves to meet contingencies, or for equalizing dividends, or for repairing or
maintaining any property of the Corporation, or for the purchase of additional
property, or for such other purpose as the directors shall think conducive to
the interest of the Corporation, and the Board of Directors may modify or
abolish any such reserve.

Section 7.02.  Checks, Demands and Notes.  All checks or demands for money and
-------------  -------------------------
notes of the Corporation shall be signed by such officer or officers or such
other person or persons as the Board of Directors may from time to time
designate.

Section 7.03.  Fiscal Year.  The fiscal year of the Corporation shall be as
-------------  -----------
fixed by the Board of Directors.

Section 7.04.  Seal.  The corporate seal shall have inscribed thereon the name
-------------  ----
of the Corporation, the year of its organization and the words "Corporate Seal,
Delaware".  The seal may be used by causing it or a facsimile thereof to be
impressed or affixed or in any manner reproduced.

                                 ARTICLE VIII
                                 ------------
                                Indemnification

Section 8.01.  Indemnification of Directors and Officers for Actions, Suits, or
------------   ----------------------------------------------------------------
Proceedings Other Than By Or In The Right of the Corporation.  To the full
------------------------------------------------------------
extent permitted by law, the Corporation shall indemnify any person who was or
is a party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative or
investigative (other than an action by or in the right of the Corporation) by
reason of the fact that he is or was or has agreed  to become a director or
officer of the Corporation or is or was serving or has agreed to serve at the
request of the Corporation as a director or officer of another corporation,
partnership, joint venture, trust or other enterprise (including employee
benefit plans) or by reason of any action alleged to have been taken or omitted
in such capacity against costs, charges, expenses (including attorneys' fees),
judgments, fines and amounts paid in settlement actually and reasonably incurred
by him or on his behalf in connection with any threatened, pending or completed
action, suit or proceeding and any appeal therefrom including but not limited to
liability and expenses incurred on account of profits realized by him in the
purchase or sale of securities of the Corporation, if and only if he acted in
                                                   --------------
good faith and in a manner he reasonably believed to be in or not opposed to the
best interests of the Corporation, and, with respect to any criminal action or
proceeding, had no reasonable cause to believe his conduct was unlawful; the
termination of any action, suit or proceeding by judgment, order, settlement,
conviction, or upon a plea of nolo contendere or its equivalent shall not, of
                              ---- ----------
itself, create a presumption that the person did not act in good faith and in a
manner which he reasonably believed to be in or not opposed to the best
interests of the Corporation, and, with respect to any criminal action or
proceeding, had reasonable cause to believe that his conduct was unlawful.

Section 8.02.  Indemnification of Directors and Officers for Actions or Suits By
-------------  -----------------------------------------------------------------
Or In The Right of the Corporation.  To the full extent permitted by law, the
----------------------------------
Corporation shall indemnify any person who was or is a party or is threatened to
be made a party to any threatened, pending or completed action or suit by or in
the right of the Corporation to procure a judgment in its favor by reason of the
fact that he is or was or has agreed to become a director or officer of the
Corporation, or is or was serving or  has agreed to serve at the request of the
Corporation as a director or officer of another corporation, partnership, joint
venture, trust or other enterprise (including employee benefit plans), or by
reason of any action alleged to have been taken or omitted in such capacity,
against costs, charges and expenses (including
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                                                        ICF KAISER SYSTEMS, INC.
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attorneys' fees) actually and reasonably incurred by him or on his behalf in
connection with the defense or settlement of any threatened, pending or
completed action or suit and any appeal therefrom, or the defense or settlement
of any claim, issue or matter, if and only if he acted in good faith and in a
manner he reasonably believed to be in or not opposed to the best interests of
the Corporation except that no indemnification shall be made in respect of any
claim, issue or matter as to which such person shall have been adjudged to be
liable to the Corporation unless and only to the extent that the Court of
Chancery of Delaware or the court in which such action or suit was brought shall
determine upon application that, despite the adjudication of such liability but
in view of all the circumstances of the case, such person is fairly and
reasonably entitled to indemnity for such costs, charges and expenses which the
Court of Chancery or such other court shall deem proper.

Section 8.03.  Indemnification of Others for Actions, Suits, or Proceedings
-------------  ------------------------------------------------------------
Other Than By Or In The Right of the Corporation.  To the full extent permitted
------------------------------------------------
by law, the Corporation, in the sole discretion of the Board of Directors of the
Corporation, may indemnify any person who was or is a party or is threatened to
be made a party to any threatened, pending or completed action, suit or
proceeding, whether civil, criminal, administrative or investigative (other than
an action by or in the right of the Corporation), by reason of the fact that he
is or was or has agreed to become an employee, agent or contractor of the
Corporation, or is  or was serving or has agreed to serve at the request of the
Corporation as a director, officer, employee, agent or contractor of another
corporation, partnership, joint venture, trust or other enterprise (including
employee benefit plans), or by reason of any action alleged to have been taken
or omitted in such capacity, against costs, charges, expenses (including
attorneys' fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by him or on his behalf in connection with any threatened,
pending or completed action, suit or proceeding and any appeal therefrom,
including but not limited to liability and expenses incurred on account of
profits realized by him in the purchase or sale of securities of the
Corporation, if and only if he acted in good faith and in a manner he reasonably
believed to be in or not opposed to the best interests of the Corporation, and,
with respect to any criminal action or proceeding, had no reasonable cause to
believe his conduct was unlawful; the termination of any action, suit or
proceeding by judgment, order, settlement, conviction, or upon a plea of nolo
contendere or its equivalent, shall not, of itself, create a presumption that
the person did not act in good faith and in a manner which he reasonably
believed to be in or not opposed to the best interests of the Corporation, and,
with respect to any criminal action or proceeding, had reasonable cause to
believe that his conduct was unlawful.

Section 8.04.  Indemnification of Others for Actions or Suits By Or In The Right
-------------  -----------------------------------------------------------------
of the Corporation.  To the full extent permitted by law, the Corporation, in
------------------
the sole discretion of the Board of Directors of the Corporation, may indemnify
any person who was or is a party or is threatened to be made a party to any
threatened, pending or completed action or suit by or in the right of the
Corporation to procure a judgment in its favor by reason of the fact that he is
or was or has agreed to become an employee, agent  or contractor of the
Corporation, or is or was serving or has agreed to serve at the request of the
Corporation as a director, officer, employee, agent or contractor of another
corporation, partnership, joint venture, trust or other enterprise (including
employee benefit plans), or by reason of any action alleged to have been taken
or omitted in such capacity, against costs, charges and expenses (including
attorneys' fees) actually and reasonably incurred by him or on his behalf in
connection with the defense or settlement of any threatened, pending or
completed action or suit and any appeal therefrom, or the defense or settlement
of any claim, issue or matter, if and only if he acted in good faith and in a
manner he reasonably believed to be in or not opposed to the best interests of
the Corporation except that no indemnification shall be made in respect of any
claim, issue or matter as to which such person shall have been adjudged to be
liable to the Corporation unless and only to the extent that the Court of
Chancery of Delaware or the court in which such action or suit was brought shall
determine upon application that, despite the adjudication of such liability but
in view of all the circumstances of the case, such person is fairly and
reasonably entitled to indemnity for such costs, charges and expenses which the
Court of Chancery or such other court shall deem proper.

Section 8.05.  Indemnification for Costs, Charges and Expenses of Successful
-------------  -------------------------------------------------------------
Party.  Notwithstanding the other provisions of these By-laws, to the extent
-----
that a director or officer of the Corporation or other person indemnified under
Sections 8.01 through 8.04, herein, has been successful on the merits or
otherwise, including, without limitation, the dismissal of an action without
prejudice, in defense of any action, suit or proceeding referred to above, or in
defense of any claim, issue or matter therein, he shall be indemnified against
all costs, charges and expenses  (including attorneys' fees) actually and
reasonably incurred by him or on his behalf in connection therewith.

Section 8.06.  Determination of Right to Indemnification.  Unless otherwise
-------------  -----------------------------------------
ordered by a court, any indemnification under Sections 8.01 through 8.04,
herein, shall be paid by the Corporation unless a determination is made (i) by
the Board of Directors by a majority vote of a quorum consisting of directors
who were not parties to such action, suit or proceeding, or (ii) if such a
quorum is not obtainable, or, even if obtainable a quorum of disinterested
directors so
<PAGE>

                                                                      BY-LAWS OF
                                                        ICF KAISER SYSTEMS, INC.
                                                                     Page 8 of 9

directs, by independent legal counsel in a written opinion, or (iii) by the
stockholders, that indemnification of an individual entitled to indemnification
under Sections 8.01 through 8.04, herein, is not proper in the circumstances
because he has not met the applicable standard of conduct set forth in Sections
8.01 through 8.04, herein.

Section 8.07.  Advance Payment of Costs, Charges and Expenses.  To the full
-------------  ----------------------------------------------
extent permitted by law, the Corporation shall, upon request, pay costs, charges
and expenses (including attorneys' fees) incurred by a person entitled to
indemnification pursuant to Sections 8.01 and 8.02, herein, and, if applicable,
pursuant to Sections 8.03 and 8.04, herein, in defending a civil or criminal
action, suit or proceeding in advance of the final disposition of such action,
suit or proceeding; provided, however, that the payment of such costs, charges
and expenses incurred by a director or officer in his capacity as a director or
officer (and not in any other capacity in which service was or is rendered by
such person while a director or officer) in advance of the final disposition of
such action, suit or proceeding shall be made only upon receipt of an
undertaking by or on behalf of the director or officer to repay all amounts so
advanced in the event that it shall ultimately be determined that such director
or officer is not entitled  to be indemnified by the Corporation as authorized
in these By-laws; such costs, charges and expenses incurred by other employees,
agents and contractors may be so paid upon such terms and conditions, if any, as
the Board of Directors deems appropriate.

Section 8.08.  Procedure for Indemnification.  Any indemnification or advance of
-------------  -----------------------------
costs, charges and expenses provided for in Sections 8.01 through 8.07, herein,
shall be made promptly, and in any event within sixty (60) days, upon the
written request of the person entitled to indemnification; the right to
indemnification or advances as granted by these By-laws shall be enforceable by
a director or officer or other person indemnified hereunder in any court of
competent jurisdiction.  If the Corporation denies such request, in whole or in
part, or if no disposition thereof is made within sixty (60) days, such person's
costs, charges and expenses incurred in connection with successfully
establishing his right to indemnification, in whole or in part, in any such
action shall also be indemnified by the Corporation; it shall be a defense to
any such action (other than an action brought to enforce a claim for the advance
of costs, charges and expenses pursuant to Section 8.07, herein, where the
required undertaking, if any, has been received by the Corporation) that the
claimant has not met the standard of conduct set forth in Sections 8.01 through
8.04, herein, but the burden of proving such defense shall be on the
Corporation.  Neither the failure of the Corporation (including its Board of
Directors, its independent legal counsel, and its stockholders) to have made a
determination prior to the commencement of such action that indemnification of
the claimant is proper in the circumstances because he has met the applicable
standard of conduct set forth in Sections 8.01 through 8.04, herein, nor the
fact that there has been an actual determination by the Corporation (including
its Board of Directors, its independent legal  counsel, and its stockholders)
that the claimant has not met such applicable standard of conduct, shall be a
defense to the action or create a presumption that the claimant has not met the
applicable standard of conduct.

Section 8.09.  Authorization of Corporation Officers.  The proper officers of
-------------  -------------------------------------
the Corporation are, and each of them acting without the other is, authorized to
take any action, for and in the name of the Corporation, which he deems
necessary or appropriate (as conclusively presumed from the taking of such
action) to carry out and effect the foregoing Sections 8.01 through 8.08.

Section 8.10.  Other Rights; Continuation of Right to Indemnification.  The
-------------  ------------------------------------------------------
indemnification and advancement of expenses provided by these By-laws shall not
be deemed exclusive of any other rights to which a person seeking
indemnification or advancement of expenses may be entitled under any law
(present or future, common or statutory), by-law, agreement, vote of
stockholders or disinterested directors or otherwise, both as to action in his
official capacity and as to action in another capacity while holding office or
while employed by or acting as agent for the Corporation, and shall continue as
to a person who has ceased to serve in the capacity making him eligible for
indemnification, and shall inure to the benefit of the estate, heirs, executors
and administrators of such person; all rights to indemnification under these By-
laws shall be deemed to be a contract between the Corporation and each director
and officer of the Corporation and, as applicable, any other person indemnified
hereunder who serves or served in such capacity at any time while these By-laws
as well as the relevant provisions of the Delaware General Corporation Law or
any other applicable laws are or were in effect; any repeal or modification
hereof or of such provisions of such law shall not in any way diminish any
rights to indemnification of such director or officer or other  person entitled
to indemnification or the obligations of the Corporation arising hereunder.

Section 8.11.  Savings Clause.  If Sections 8.01 through 8.10 of these By-laws
-------------  --------------
or any portion hereof shall be invalidated on any ground by any court of
competent jurisdiction, then the Corporation shall nevertheless indemnify each
director and officer, and may indemnify any other person entitled to
indemnification, as to costs, charges and expenses (including attorneys' fees),
judgments, fines and amounts paid in settlement with respect to any action, suit
or proceeding, whether civil, criminal, administrative or investigative,
including an action by or in the right of the
<PAGE>

                                                                      BY-LAWS OF
                                                        ICF KAISER SYSTEMS, INC.
                                                                     Page 9 of 9

Corporation, to the full extent permitted by any applicable portion of these By-
laws that shall not have been invalidated and to the full extent permitted by
applicable law. To the full extent permitted by law, the Corporation may enter
into and perform agreements with persons, including, without limitation, present
and former officers, directors and employees of the Corporation and of companies
acquired by or merged with the Corporation, obligating the Corporation, among
other things, to provide indemnification and advancement of costs, charges and
expenses to such persons in addition to any indemnification or advancement which
may be available to such person under Sections 8.01 through 8.10 of these By-
laws.

Section 8.12.  Insurance.  The Board of Directors may cause the Corporation to
-------------  ---------
purchase and maintain insurance on behalf of any person who is or was or has
agreed to become a director or officer of the Corporation, or is or was serving
at the request of the Corporation as a director or officer of another
corporation, or as its representative in a partnership, joint venture, trust or
other enterprise (including employee benefit plans) against any liability
asserted against such person and incurred in any such  capacity or arising out
of such status, whether or not the Corporation would have the power to indemnify
such person.

Section 8.13.  Amendment of By-laws.  The Board of Directors may from time to
-------------  --------------------
time adopt further By-laws with respect to indemnification and may amend these
and such By-laws to provide at all times the fullest indemnification permitted
by the General Corporation Law of the State of Delaware.

                                  ARTICLE IX
                                  ----------
                                  Amendments

Section 9.01.  Amendment by Stockholders.  These By-laws may be amended by a
------------   -------------------------
majority vote of all the stock issued and outstanding and entitled to vote at
any annual or special meeting of the stockholders, provided notice of intention
to amend shall have been contained in the notice of the meeting.

Section 9.02.  Amendment by Board of Directors.  The Board of Directors by a
-------------  -------------------------------
majority vote of the whole Board at any meeting may amend these By-laws,
including By-laws adopted by the stockholders, but the stockholders may from
time to time specify particular provisions of the By-laws which shall not be
amended by the Board of Directors.