EXHIBIT 3.1

                          CERTIFICATE OF INCORPORATION

                                       OF

                  ENVIRONMENTAL SYSTEMS PRODUCTS HOLDINGS INC.

      FIRST. The name of the corporation is Environmental Systems Products
Holdings Inc.:

      SECOND. The address of its registered office in the State of Delaware is
1013 Centre Road, in the City of Wilmington, County of New Castle. The name of
its registered agent at such address is Corporation Service Company.

      THIRD. The nature of the business, or objects or purposes to be
transacted, promoted or carried on are to engage in any lawful activity for
which corporations may be organized under the General Corporation Law of
Delaware.

      FOURTH. The total number of shares of stock which the corporation shall
have authority to issue and the par value per share and class are as follows:




      CLASS       NUMBER OF SHARES         PAR VALUE PER SHARE
      -----       ----------------         -------------------
                                     
      Common            10,000                     $.01



      FIFTH. The name and mailing address of the incorporator is as follows:




                   Name                          Mailing Address
                   ----                          ---------------
                                          
               Donna Guihon                    2300 N Street, N.W.
                                               Washington, D.C. 20037





The powers of the incorporator are to terminate upon the filing of the 
Certificate of Incorporation.

      SIXTH. The name and mailing address of each person who is to serve as an
initial director until the first annual meeting of stockholders or until his
successor is elected and qualified are as follows:



                   Name                          Mailing Address
                   ----                          ---------------
                                         
                                            
               Terry Smith                  7 Kirpes Road                   
                                            East Gramby, Connecticut 06026  
                                                                            
               Alan J. Baxter               7 Kirpes Road                   
                                            East Gramby, Connecticut 06026  

                                            
      SEVENTH. The business of the corporation shall be managed by a board of
directors. The board of directors shall have the power, unless and to the extent
that the board may from time to time by resolution relinquish or modify the
power, without the assent or vote of the stockholders, to make, alter, amend,
change, add to, or repeal the bylaws of the corporation. The number of directors
which shall constitute the whole board of directors shall be fixed in the manner
provided in the bylaws.

      EIGHTH. The corporation is to have perpetual existence.



      NINTH. Elections of directors need not be by ballot unless the bylaws of
the corporation shall so provide.

      TENTH. The corporation reserves the right to amend, alter, change or
repeal any provision contained in this certificate of incorporation, in the
manner now or hereafter prescribed by statute.

      ELEVENTH. No director of the corporation shall be liable to the
corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, provided that this Article ELEVENTH shall not eliminate or
limit the liability of a director (i) for any breach of the director's duty of
loyalty to the Corporation or its stockholders; (ii) for acts or omissions not
in good faith or which involve intentional misconduct or a knowing violation of
law, (iii) under section 174 of Title 8 of the Delaware Code (the Delaware
General Corporation Law); or (iv) for any transaction from which the director
derived an improper personal benefit. In the event that the Delaware General
Corporation Law or any successor thereto is amended with respect to the
permissible limits of directors' liability, this Article ELEVENTH shall be
deemed to provide the fullest limitation on liability permitted under such
amended statute. Any repeal or modification of this Article ELEVENTH by the
stockholders of the corporation only shall be applied prospectively, to the
extent that such repeal or modification would, if applied retrospectively,
adversely 



affect any limitation on the personal liability of a director of the corporation
existing immediately prior to such repeal or modification.

      THE UNDERSIGNED, being the incorporator hereinbefore named, for the
purpose of forming a corporation pursuant to the General Corporation Law of the
State of Delaware, does make this certificate, hereby declaring and certifying
that the facts herein stated are true, and accordingly has hereunto set her hand
this 12th day of March, 1998.


                                    /s/ Donna Guihon
                                    --------------------------
                                    Donna Guihon, Incorporator



                AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

                                       OF

                  ENVIRONMENTAL SYSTEMS PRODUCTS HOLDINGS INC.

      Environmental Systems Products Holdings Inc., a corporation organized and
existing under the laws of the State of Delaware (the "Corporation"), hereby
certifies that:

      1. The Corporation's original Certificate of Incorporation was filed with
the Secretary of State of the State of Delaware on March 12, 1998.

      2. This Amended and Restated Certificate of Incorporation amends and
restates the original Certificate of Incorporation.

      3. This Amended and Restated Certificate of Incorporation and the
amendments to the Certificate of Incorporation contained herein were declared
advisable and adopted by the Board of Directors on May 18, 1998 and have been
duly adopted in accordance with the provisions of Section 241 and 245 of the
General Corporation Law of the State of Delaware, as the Corporation has not yet
received any payment for its capital stock.

      4. The test of the Certificate of Incorporation is hereby amended and
restated to read in its entirety as follows:

                                    ARTICLE I

                                      NAME

      The name of the corporation is: Environmental Systems Products Holdings
Inc. (the "Corporation").



                                   ARTICLE II

                     REGISTERED OFFICE AND REGISTERED AGENT

      The address of the Corporation's registered office in the State of
Delaware is 1013 Centre Road, in the City of Wilmington, County of New Castle.
The name of its registered agent at such address is Corporation Service Company.

                                   ARTICLE III

                                     PURPOSE

      The purpose or purposes for which the Corporation is organized are to
engage in any lawful act or activity for which corporations may be organized
under the General Corporation Law of the State of Delaware as from time to time
amended.

                                   ARTICLE IV

                                  CAPITAL STOCK

      The Corporation shall have the authority to issue a total of 125,000,000
shares of capital stock, each with a par value of $ 0.01, consisting of
120,000,000 shares of Common Stock and 5,000,000 shares of Preferred Stock.

                                    ARTICLE V

                                  COMMON STOCK

      Except as required by law, all shares of Common Stock shall be identical
in all respects and shall entitle the holders thereof to the same rights and
privileges, subject to the same qualifications, limitations and restrictions.
Except as required by law, the holders of shares of Common Stock shall be
entitled to one vote per share of Common Stock on all matters on which
stockholders of the Corporation have the right to vote.



                                   ARTICLE VI

                                 PREFERRED STOCK

                  Section A. Preferred Stock. The Corporation is authorized to
issue shares of Preferred Stock from time to time in one or more series as may
from time to time be determined by the Board of Directors of the Corporation
(the "Board"), each of such series to be distinctly designated. The voting
powers, preferences and relative, participating, optional and other special
rights, and the qualifications, limitations or restrictions thereof, if any, of
each such series may differ from those of any and all other series of Preferred
Stock at any time outstanding, and the Board is hereby expressly granted
authority to fix or alter, by resolution or resolutions, the designation,
number, voting powers, preferences and relative, participating, optional and
other special rights, and the qualifications, limitations and restrictions, of
each such series, including, but without limiting the generality of the
foregoing, the following:

            1. The distinctive designation of, and the number of shares of
Preferred Stock that shall constitute, such series, which number (except where
otherwise provided by the Board in the resolution establishing such series) may
be increased (but not above the total number of shares of Preferred Stock) or
decreased (but not below the number of shares of such series then outstanding)
from time to time by like action of the Board.

            2. The rights in respect of dividends, if any, of such series of
Preferred Stock, the extent of the preference or relation, if any, of such
dividends to the dividends payable on any other class or classes or any other
series of the same or other class or classes of capital stock of the
Corporation, and whether such dividends shall be cumulative or noncumulative.

            3. The right, if any, of the holders of such series of Preferred
Stock to convert the same into, or exchange the same for, shares of any other
class or classes or of any 



other series of the same or any other class or classes of capital stock of the
Corporation, and the terms and conditions of such conversion or exchange.

            4. Whether or not shares of such series of Preferred Stock shall be
subject to redemption, and the redemption price or prices and the times at
which, and the terms and conditions on which, shares of such series of Preferred
Stock may be redeemed.

            5. The rights, if any, of the holders of such series of Preferred
Stock upon the voluntary or involuntary liquidation, dissolution or winding-up
of the Corporation or in the event of any merger or consolidation of or sale of
assets by the Corporation.

            6. The terms of any sinking fund or redemption or purchase account,
if any, to be provided for shares of such series of the Preferred Stock.

            7. The voting powers, if any, of the holders of any series of
Preferred Stock generally or with respect to any particular matter, which may be
less than, equal to or greater than one vote per share, and which may, without
limiting the generality of the foregoing, include the right, voting as a series
by itself or together with the holders of any other series of Preferred Stock or
all series of Preferred Stock as a class, to elect one or more directors of the
Corporation generally or under such specific circumstances and on such
conditions as shall be provided in the resolution or resolutions of the Board
adopted pursuant hereto, including, without limitation, in the event there shall
have been a default in the payment of dividends on or redemption of any one or
more series of Preferred Stock.

                  Section B. Rights of Preferred Stock.

            1. After the provisions with respect to preferential dividends on
any series of Preferred Stock (fixed in accordance with the provisions of
Section (A) of this Article VI), 



if any, shall have been satisfied and after the Corporation shall have complied
with all the requirements, if any, with respect to redemption of, or the setting
aside of sums as sinking funds or redemption or purchase accounts with respect
to, any series of Preferred Stock (fixed in accordance with the provisions of
Section (A) of this Article VI), and subject further to any other conditions
that may be fixed in accordance with the provisions of Section (A) of this
Article VI, then and not otherwise the holders of Common Stock shall be entitled
to receive such dividends as may be declared from time to time by the Board.

            2. In the event of the voluntary or involuntary liquidation,
dissolution or winding-up of the Corporation, after distribution in full of the
preferential amounts, if any (fixed in accordance with the provisions of Section
(A) of this Article VI), to be distributed to the holders of Preferred Stock by
reason thereof, the holders of Common Stock shall, subject to the additional
rights, if any (fixed in accordance with the provisions of Section (A) of this
Article VI), of the holders of any outstanding shares of Preferred Stock, be
entitled to receive all of the remaining assets of the Corporation, tangible or
intangible, of whatever kind available for distribution to stockholders ratably
in proportion to the number of shares of Common Stock held by them respectively.

            3. Except as may otherwise be required by law, and subject to the
provisions of such resolution or resolutions as may be adopted by the Board
pursuant to Section (A) of this Article VI granting the holders of one or more
series of Preferred Stock exclusive voting powers with respect to any matter,
each holder of Common Stock may have one vote in respect to each share of Common
Stock held on all matters voted upon by the stockholders.

            4. The number of authorized shares of Preferred Stock and each class
of Common Stock may, without a class or series vote, be increased or decreased
from time to time by the affirmative vote of the holders of shares having a
majority of the total 



number of votes which may be cast in the election of directors of the
Corporation by all stockholders entitled to vote in such an election, voting
together as a single class.

                                   ARTICLE VII

                               BOARD OF DIRECTORS

                  Section A. Powers of the Board of Directors. The business of
the Corporation shall be managed by a board of directors. The board of directors
shall have the power, unless and to the extent that the board may from time to
time by resolution relinquish or modify the power, without the assent or vote of
the stockholders, to make, alter, amend, change, add to, or repeal the Bylaws of
the Corporation.

                  Section B. Vacancies. Except as otherwise provided for or
fixed pursuant to the provisions of Article VI hereof relating to the rights of
the holders of any series of Preferred Stock to elect additional directors,
newly created directorships resulting from any increase in the authorized number
of directors and any vacancies on the Board resulting from death, resignation,
disqualification, removal or other cause shall be filled as set forth in the
Bylaws of the Corporation.

                  Section C. Directors Elected by Holders of Preferred Stock.
During any period when the holders of any series of Preferred Stock have the
right to elect additional directors as provided for or fixed pursuant to the
provisions of Article VI hereof, then upon commencement and for the duration of
the period during which such right continues (i) the then otherwise total
authorized number of directors of the Corporation shall automatically be
increased by such specified number of directors, and the holders of such
Preferred Stock shall be entitled to elect the additional directors so provided
for or fixed pursuant to such provisions, and (ii) each such additional director
shall serve until such director's successor shall have been duly elected and
qualified, or until such director's right to hold such office terminates
pursuant to such provisions, 



whichever occurs earlier. Except as otherwise provided by the Board in the
resolution or resolutions establishing such series, whenever the holders of any
series of Preferred Stock having such right to elect additional directors are
divested of such right pursuant to the provisions of such stock, the terms of
office of all such additional directors elected by the holders of such stock, or
elected to fill any vacancies resulting from death, resignation,
disqualification or removal of such additional directors, shall forthwith
terminate and the total and authorized number of directors of the Corporation
shall be reduced accordingly. Notwithstanding the foregoing, whenever, pursuant
to the provisions of Article VI hereof, the holders of any one or more series of
Preferred Stock shall have the right, voting separately as a series or together
with holders of other such series, to elect directors at an annual or special
meeting of stockholders, the election, term of office, filling of vacancies and
other features of such directorships shall be governed by the terms of the
Certificate of Incorporation.

                  Section D. Number of Directors Constituting the Board. The
number of directors that shall constitute the full Board, other than any
directors elected by the holders of any series of Preferred Stock as provided
for or fixed pursuant to the provisions of Article VI hereof, shall be fixed by
the Bylaws of the Corporation.

                  Section E. Election of Directors. The directors of the
Corporation shall not be required to be elected by written ballots unless the
Bylaws of the Corporation so provide.

                                  ARTICLE VIII

                      [RESTRICTION ON BUSINESS COMBINATIONS

      The Corporation will be governed by Del. Code Ann. tit. 8, Section 203
(1991).]



                                   ARTICLE IX

                         DURATION OF CORPORATE EXISTENCE

      The Corporation is to have perpetual existence.

                                    ARTICLE X

                               DIRECTOR LIABILITY

      No director of the Corporation shall be liable to the Corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
provided that this Article X shall not eliminate or limit the liability of a
director (i) for any breach of the director's duty of loyalty to the Corporation
or its stockholders; (ii) for acts or omissions not in good faith or which
involve intentional misconduct or a knowing violation of law, (iii) under
section 174 of Title 8 of the Delaware Code (the Delaware General Corporation
Law); or (iv) for any transaction from which the director derived an improper
personal benefit. In the event that the Delaware General Corporation Law or any
successor thereto is amended with respect to the permissible limits of
directors' liability, this Article X shall be deemed to provide the fullest
limitation on liability permitted under such amended statute. Any repeal or
modification of this Article X by the stockholders of the Corporation only shall
be applied prospectively, to the extent that such repeal or modification would,
if applied retrospectively, adversely affect any limitation on the personal
liability of a director of the Corporation existing immediately prior to such
repeal or modification.

                                   ARTICLE XI

                              RESERVATION OF RIGHTS

      The Corporation reserves the right to amend, alter, change or repeal any
provision contained in this Certificate of Incorporation, in the manner now or
hereafter prescribed by statute.



      IN WITNESS WHEREOF, this Amended and Restated Certificate of
Incorporation, which amends and restates the provisions of the Certificate of
Incorporation of the Corporation and which has been duly adopted in accordance
with Section 241 and 245 of the General Corporation Law of the State of
Delaware, as the Corporation has not yet received payment for its capital stock,
has been executed by its directors this 18th day of May, 1998.


                                        /s/ Terrence P. McKenna
                                        -------------------------------
                                        Terrence P. McKenna, Director


                                        /s/ Rinaldo R. Tedeschi
                                        -------------------------------
                                        Rinaldo R. Tedeschi, Director


                                        /s/ David J. Langevin
                                        -------------------------------
                                        David J. Langevin, Director



                               FIRST AMENDMENT TO

                AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

                                       OF

                  ENVIRONMENTAL SYSTEMS PRODUCTS HOLDINGS INC.

      Environmental Systems Products Holdings Inc., a corporation organized and
existing under the laws of the State of Delaware (the "Corporation"), hereby
certifies that:

      1. The Corporation's original Certificate of Incorporation was filed with
the Secretary of State of the State of Delaware on March 12, 1998.

      2. The Corporation's Amended and Restated Certificate of Incorporation,
which amended and restated the original Certificate of Incorporation, was filed
on May 19, 1998.

      3. This First Amendment to the Amended and Restated Certificate of
Incorporation contained herein was declared advisable and adopted by the Board
of Directors on June 9, 1998 and has been duly adopted in accordance with the
provisions of Section 241 of the General Corporation Law of the State of
Delaware, as the Corporation has not yet received any payment for its capital
stock.

      4. The text of Article IV of the Amended and Restated Certificate of
Incorporation is hereby amended and restated to read in its entirety as follows:



                                   ARTICLE IV

                                  CAPITAL STOCK

      The Corporation shall have the authority to issue a total of 125,000,000
shares of capital stock, consisting of 120,000,000 shares of Common Stock with a
par value of $.0001 and 5,000,000 shares of Preferred Stock with a par value of
$.01.

      IN WITNESS WHEREOF, this First Amendment to the Amended and Restated
Certificate of Incorporation, has been duly adopted in accordance with Section
241 of the General Corporation Law of the State of Delaware and has been
executed by all of its directors on this 9th day of June, 1998.


                                        /s/ Terrence P. McKenna
                                        ------------------------------
                                        Terrence P. McKenna, Director


                                        /s/ Rinaldo R. Tedeschi
                                        ------------------------------
                                        Rinaldo R. Tedeschi, Director


                                        /s/ David J. Langevin
                                        ------------------------------
                                        David J. Langevin, Director


                                        /s/ Amanda Shipman
                                        ------------------------------
                                        Amanda Shipman, Director


            SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

                                       OF

                  ENVIRONMENTAL SYSTEMS PRODUCTS HOLDINGS INC.

      Environmental Systems Products Holdings Inc., a corporation organized and
existing under the laws of the State of Delaware (the "Corporation"), hereby
certifies that:

      1. The Corporation's original Certificate of Incorporation was filed with
the Secretary of State of the State of Delaware on March 12, 1998.

      2. The Certificate of Incorporation was amended and restated by the
Amended and Restated Certificate of Incorporation filed with the Secretary of
State of the State of Delaware on May 19, 1998.

      3. This Second Amended and Restated Certificate of Incorporation amends
and restates the original Certificate of Incorporation as amended and restated
by the Amended and Restated Certificate of Incorporation.

      4. This Second Amended and Restated Certificate of Incorporation and the
amendments to the Certificate of Incorporation contained herein were declared
advisable and adopted by the Board of Directors on October 13, 1998 and have
been duly adopted in accordance with the provisions of Section 241 and 245 of
the General Corporation Law of the State of Delaware, as the Corporation has not
yet received any payment for its capital stock.

      5. The text of the Certificate of Incorporation is hereby amended and
restated to read in its entirety as follows:



                                    ARTICLE I

                                      NAME

      The name of the corporation is: Environmental Systems Products Holdings
Inc. (the "Corporation").

                                   ARTICLE II

                     REGISTERED OFFICE AND REGISTERED AGENT

      The address of the Corporation's registered office in the State of
Delaware is 1013 Centre Road, in the City of Wilmington, County of New Castle.
The name of its registered agent at such address is Corporation Service Company.

                                   ARTICLE III

                                     PURPOSE

      The purpose or purposes for which the Corporation is organized are to
engage in any lawful act or activity for which corporations may be organized
under the General Corporation Law of the State of Delaware as from time to time
amended.

                                   ARTICLE IV

                                  CAPITAL STOCK

      The Corporation shall have the authority to issue a total of 125,000,000
shares of capital stock, each with a par value of $ 0.0001, consisting of
120,000,000 shares of Common Stock and 5,000,000 shares of Preferred Stock.

                                    ARTICLE V

                                  COMMON STOCK

      The Common Stock shall be divided into two series, of which 110,000,000
shares shall be designated "Voting Common Stock" and 10,000,000 shares shall be
designated "Nonvoting Common Stock." All shares of the Voting Common Stock and
the Nonvoting 



Common Stock shall be identical in all respects and shall entitle the holders
thereof to the same rights and privileges, subject to the same qualifications,
limitations and restrictions, except that the Nonvoting Common Stock shall be
denied all voting rights except as otherwise required by the General Corporation
Law of the State of Delaware. Except as required by law, the holders of shares
of Voting Common Stock shall be entitled to one vote per share of Voting Common
Stock on all matters on which stockholders of the Corporation have the right to
vote.

                                   ARTICLE VI

                                 PREFERRED STOCK

                  Section A. Preferred Stock. The Corporation is authorized to
issue shares of Preferred Stock from time to time in one or more series as may
from time to time be determined by the Board of Directors of the Corporation
(the "Board"), each of such series to be distinctly designated. The voting
powers, preferences and relative, participating, optional and other special
rights, and the qualifications, limitations or restrictions thereof, if any, of
each such series may differ from those of any and all other series of Preferred
Stock at any time outstanding, and the Board is hereby expressly granted
authority to fix or alter, by resolution or resolutions, the designation,
number, voting powers, preferences and relative, participating, optional and
other special rights, and the qualifications, limitations and restrictions, of
each such series, including, but without limiting the generality of the
foregoing, the following:

            1. The distinctive designation of, and the number of shares of
Preferred Stock that shall constitute, such series, which number (except where
otherwise provided by the Board in the resolution establishing such series) may
be increased (but not above the total number of shares of Preferred Stock) or
decreased (but not below the number of shares of such series then outstanding)
from time to time by like action of the Board.



            2. The rights in respect of dividends, if any, of such series of
Preferred Stock, the extent of the preference or relation, if any, of such
dividends to the dividends payable on any other class or classes or any other
series of the same or other class or classes of capital stock of the
Corporation, and whether such dividends shall be cumulative or noncumulative.

            3. The right, if any, of the holders of such series of Preferred
Stock to convert the same into, or exchange the same for, shares of any other
class or classes or of any other series of the same or any other class or
classes of capital stock of the Corporation, and the terms and conditions of
such conversion or exchange.

            4. Whether or not shares of such series of Preferred Stock shall be
subject to redemption, and the redemption price or prices and the times at
which, and the terms and conditions on which, shares of such series of Preferred
Stock may be redeemed.

            5. The rights, if any, of the holders of such series of Preferred
Stock upon the voluntary or involuntary liquidation, dissolution or winding-up
of the Corporation or in the event of any merger or consolidation of or sale of
assets by the Corporation.

            6. The terms of any sinking fund or redemption or purchase account,
if any, to be provided for shares of such series of the Preferred Stock.

            7. The voting powers, if any, of the holders of any series of
Preferred Stock generally or with respect to any particular matter, which may be
less than, equal to or greater than one vote per share, and which may, without
limiting the generality of the foregoing, include the right, voting as a series
by itself or together with the holders of any other series of Preferred Stock or
all series of Preferred Stock as a class, to elect one or more directors of the
Corporation generally or under such specific circumstances and on such
conditions as shall be provided in the resolution or resolutions of the Board
adopted 



pursuant hereto, including, without limitation, in the event there shall have
been a default in the payment of dividends on or redemption of any one or more
series of Preferred Stock.

                  Section B. Rights of Preferred Stock.

            1. After the provisions with respect to preferential dividends on
any series of Preferred Stock (fixed in accordance with the provisions of
Section (A) of this Article VI), if any, shall have been satisfied and after the
Corporation shall have complied with all the requirements, if any, with respect
to redemption of, or the setting aside of sums as sinking funds or redemption or
purchase accounts with respect to, any series of Preferred Stock (fixed in
accordance with the provisions of Section (A) of this Article VI), and subject
further to any other conditions that may be fixed in accordance with the
provisions of Section (A) of this Article VI, then and not otherwise the holders
of Common Stock shall be entitled to receive such dividends as may be declared
from time to time by the Board.

            2. In the event of the voluntary or involuntary liquidation,
dissolution or winding-up of the Corporation, after distribution in full of the
preferential amounts, if any (fixed in accordance with the provisions of Section
(A) of this Article VI), to be distributed to the holders of Preferred Stock by
reason thereof, the holders of Common Stock shall, subject to the additional
rights, if any (fixed in accordance with the provisions of Section (A) of this
Article VI), of the holders of any outstanding shares of Preferred Stock, be
entitled to receive all of the remaining assets of the Corporation, tangible or
intangible, of whatever kind available for distribution to stockholders ratably
in proportion to the number of shares of Common Stock held by them respectively.

            3. Except as may otherwise be required by law, and subject to the
provisions of such resolution or resolutions as may be adopted by the Board
pursuant to Section (A) 



of this Article VI granting the holders of one or more series of Preferred Stock
exclusive voting powers with respect to any matter, each holder of Common Stock
may have one vote in respect of each share of Common Stock held on all matters
voted upon by the stockholders.

            4. The number of authorized shares of Preferred Stock and each class
of Common Stock may, without a class or series vote, be increased or decreased
from time to time by the affirmative vote of the holders of shares having a
majority of the total number of votes which may be cast in the election of
directors of the Corporation by all stockholders entitled to vote in such an
election, voting together as a single class.

                                   ARTICLE VII

                               BOARD OF DIRECTORS

                  Section A. Powers of the Board of Directors. The business of
the Corporation shall be managed by a board of directors. The board of directors
shall have the power, unless and to the extent that the board may from time to
time by resolution relinquish or modify the power, without the assent or vote of
the stockholders, to make, alter, amend, change, add to, or repeal the Bylaws of
the Corporation.

                  Section B. Vacancies. Except as otherwise provided for or
fixed pursuant to the provisions of Article VI hereof relating to the rights of
the holders of any series of Preferred Stock to elect additional directors,
newly created directorships resulting from any increase in the authorized number
of directors and any vacancies on the Board resulting from death, resignation,
disqualification, removal or other cause shall be filled as set forth in the
Bylaws of the Corporation.



                  Section C. Directors Elected by Holders of Preferred Stock.
During any period when the holders of any series of Preferred Stock have the
right to elect additional directors as provided for or fixed pursuant to the
provisions of Article VI hereof, then upon commencement and for the duration of
the period during which such right continues (i) the then otherwise total
authorized number of directors of the Corporation shall automatically be
increased by such specified number of directors, and the holders of such
Preferred Stock shall be entitled to elect the additional directors so provided
for or fixed pursuant to such provisions, and (ii) each such additional director
shall serve until such director's successor shall have been duly elected and
qualified, or until such director's right to hold such office terminates
pursuant to such provisions, whichever occurs earlier. Except as otherwise
provided by the Board in the resolution or resolutions establishing such series,
whenever the holders of any series of Preferred Stock having such right to elect
additional directors are divested of such right pursuant to the provisions of
such stock, the terms of office of all such additional directors elected by the
holders of such stock, or elected to fill any vacancies resulting from death,
resignation, disqualification or removal of such additional directors, shall
forthwith terminate and the total and authorized number of directors of the
Corporation shall be reduced accordingly. Notwithstanding the foregoing,
whenever, pursuant to the provisions of Article VI hereof, the holders of any
one or more series of Preferred Stock shall have the right, voting separately as
a series or together with holders of other such series, to elect directors at an
annual or special meeting of stockholders, the election, term of office, filling
of vacancies and other features of such directorships shall be governed by the
terms of the Certificate of Incorporation.

                  Section D. Number of Directors Constituting the Board. The
number of directors that shall constitute the full Board, other than any
directors elected by the 



holders of any series of Preferred Stock as provided for or fixed pursuant to
the provisions of Article VI hereof, shall be fixed by the Bylaws of the
Corporation.

                  Section E. Election of Directors. The directors of the
Corporation shall not be required to be elected by written ballots unless the
Bylaws of the Corporation so provide.

                                  ARTICLE VIII

                      RESTRICTION ON BUSINESS COMBINATIONS

      The Corporation will be governed by Del. Code Ann. tit. 8, Sections 203 
(1991).

                                   ARTICLE IX

                         DURATION OF CORPORATE EXISTENCE

      The Corporation is to have perpetual existence.

                                    ARTICLE X

                               DIRECTOR LIABILITY

      No director of the Corporation shall be liable to the Corporation or its 
stockholders for monetary damages for breach of fiduciary duty as a director, 
provided that this Article X shall not eliminate or limit the liability of a 
director (i) for any breach of the director's duty of loyalty to the 
Corporation or its stockholders; (ii) for acts or omissions not in good faith 
or which involve intentional misconduct or a knowing violation of law, (iii) 
under section 174 of Title 8 of the Delaware Code (the General Corporation Law 
of the State of Delaware); or (iv) for any transaction from which the director 
derived an improper personal benefit. In the event that the Delaware General 
Corporation Law or any successor thereto is amended with respect to the 
permissible limits of directors' liability, this Article X shall be deemed to 
provide the fullest limitation on liability permitted under such amended 
statute. Any repeal or modification of 



this Article X by the stockholders of the Corporation only shall be applied
prospectively, to the extent that such repeal or modification would, if applied
retrospectively, adversely affect any limitation on the personal liability of a
director of the Corporation existing immediately prior to such repeal or
modification.

                                   ARTICLE XI

                              RESERVATION OF RIGHTS

      The Corporation reserves the right to amend, alter, change or repeal any
provision contained in this Certificate of Incorporation, in the manner now or
hereafter prescribed by statute.



      IN WITNESS WHEREOF, this Second Amended and Restated Certificate of
Incorporation, which amends and restates the provisions of the Certificate of
Incorporation of the Corporation and which has been duly adopted in accordance
with Section 241 and 245 of the General Corporation Law of the State of
Delaware, as the Corporation has not yet received payment for its capital stock,
has been executed by its directors this 8th day of October, 1998.


                                        /s/ Terrence P. McKenna
                                        -----------------------------
                                        Terrence P. McKenna, Director


                                        /s/ Rinaldo R. Tedeschi
                                        -----------------------------
                                        Rinaldo R. Tedeschi, Director


                                        /s/ David J. Langevin
                                        -----------------------------
                                        David J. Langevin, Director


                                        /s/ Eric Walters
                                        -----------------------------
                                        Eric Walters, Director



                 CERTIFICATE OF CORRECTION OF SECOND AMENDED AND
                    RESTATED CERTIFICATE OF INCORPORATION OF

                  ENVIRONMENTAL SYSTEMS PRODUCTS HOLDINGS INC.

                             A Delaware Corporation

      Environmental Systems Products Holdings Inc., a corporation organized and
existing under the laws of the State of Delaware (the "Corporation"), hereby
certifies to the following:

      1.    The Corporation's original Certificate of Incorporation was filed
            with the Secretary of State of the State of Delaware on March 12,
            1998;

      2.    The Corporation's original Certificate of Incorporation was amended
            and restated pursuant to the Amended and Restated Certificate of
            Incorporation filed with the Secretary of State of the State of
            Delaware on May 19, 1998;

      3.    The Corporation's Amended and Restated Certificate of Incorporation
            was further amended pursuant to the First Amendment to Amended and
            Restated Certificate of Incorporation filed with the Secretary of
            State of the State of Delaware on June 17, 1998:

      4.    The Corporation filed the Second Amended and Restated Certificate of
            Incorporation with the Secretary of State of the State of Delaware
            on October 9, 1998;

      5.    The Second Amended and Restated Certificate of Incorporation
            contained an error in paragraph number 4 in which the Corporation
            certified that the Second Amended and Restated Certificate of
            Incorporation was declared advisable and adopted by the Board of
            Directors of the Corporation on August 5, 1998.

      6.    Pursuant to Section 103(f) of the General Corporation Law of the
            State of Delaware, the Second Amended and Restated Certificate of
            Incorporation is hereby corrected to state accurately the date on
            which the Second Amended and Restated Certificate of Incorporation
            was declared advisable and adopted by the Board of Directors of the
            Corporation.

                  Paragraph 4 of the Second Amended and Restated Certificate of
Incorporation shall read as follows:

      "4. This Second Amended and Restated Certificate of Incorporation and the
      amendments to the Certificate of Incorporation contained herein were
      declared advisable and adopted by the Board of Directors on October 7,
      1998 and have been duly adopted in accordance with the provisions of
      Section 241 and 245 of the General Corporation Law of the State of
      Delaware, as the Corporation has not yet received any payments for its
      capital stock."



      The undersigned, Terrence P. McKenna, Chairman of the Board, President and
Chief Executive Officer of the Corporation, hereby declares and certifies that
the foregoing is the act of the Corporation and that the facts stated herein are
true and accordingly, has set his hand this 12th day of October, 1998.


                                    /s/ Terrence P. McKenna
                                    ------------------------------------
                                    Terrence P. McKenna
                                    Chairman of the Board, President and
                                    Chief Executive Officer



                         FIRST CERTIFICATE OF AMENDMENT

                                       OF

            SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION
                  AFTER THE PAYMENT OF ANY PART OF THE CAPITAL

                                       OF

                  ENVIRONMENTAL SYSTEMS PRODUCTS HOLDINGS INC.

It is hereby certificated that:

1. The name of the corporation (hereinafter called the "Corporation") is
Environmental Systems Products Holdings Inc.

2. The Corporation's original Certificate of Incorporation was filed with the
Secretary of State of the State of Delaware on March 12, 1998.

3. The Corporation's Certificate of Incorporation was amended and restated by
the Amended and Restated Certificate of Incorporation filed with the Secretary
of State of the State of Delaware on May 19,1998.

4. The Corporation's Amended and Restated Certificate of Incorporation was
amended by the First Amendment to the Amended and Restated Certificate of
Incorporation of the Corporation, filed with the Secretary of State of the State
of Delaware on June 17, 1998.

5. The Corporation's Amended and Restated Certificate of Incorporation was
amended and restated by the Second Amended and Restated Certificate of
Incorporation filed with the Secretary of State of the State of Delaware on
October 9, 1998.

6. The Corporation's Second Amended and Restated Certificate of Incorporation
was corrected by the Certificate of Correction filed with the Secretary of State
of the State of Delaware on October 13, 1998.

7. The Second Amended and Restated Certificate of Incorporation of the
Corporation is hereby amended by striking out Article IV thereof and
substituting in lieu of said Article the following new Article IV as follows:

                                   ARTICLE IV

                                  CAPITAL STOCK

The Corporation shall have the authority to issue a total of 3,000 shares of
capital stock, each with a par value of $.0001, consisting of 2,500 shares of
Common Stock and 500 shares of Preferred Stock.



The Second Amended and Restated Certificate of Incorporation of the Corporation
is hereby amended by striking out Article V thereof and substituting in lieu of
said Article the following new Article V as follows:




                                    ARTICLE V

                                  COMMON STOCK

      The Common Stock shall be divided into two series, of which 2,000 shares
shall be designated "Voting Common Stock" and 500 shares shall be designated
"Nonvoting Common Stock." All shares of the Voting Common Stock and the
Nonvoting Common Stock shall be identical in all respects and entitle the
holders thereof to the same rights and privileges, subject to the same
qualifications, limitations and restrictions, except that the Nonvoting Common
Stock shall be denied all voting rights except as otherwise required by the
General Corporation Law of the State of Delaware. Except as required by law, the
holders of shares of Voting Common Stock shall be entitled to one vote per share
of Voting Common Stock on all matters in which stockholders of the Corporation
have the right to vote.

      IN WITNESS WHEREOF, this First Amendment to the Second Amended and
Restated Articles of Incorporation has been duly adopted by the Sole Stockholder
of the Corporation in accordance with Sections 228 and 241 of the General
Corporation Law of the State of Delaware on this 22nd day of October, 1998.


                                     /s/ Terrence P. McKenna
                                     -------------------------------------
                                     Terrence P. McKenna, President and
                                     Chief Executive Officer