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                                                                     EXHIBIT 4.3

                MASTER CERTIFICATE OF DESIGNATION OF CUMULATIVE
                     CONVERTIBLE PREFERRED STOCK, SERIES G

          Tim B. Tarrillion and Judith Knight Shields do hereby certify that
they are the President and Assistant Secretary, respectively, of NORTH AMERICAN
TECHNOLOGIES GROUP, INC., a Delaware corporation (hereinafter referred to as the
"Corporation" or the "Company"); that, pursuant to the Corporation's Certificate
of Incorporation and Section 151 of the Delaware General Corporation Law, the
Board of Directors of the Corporation adopted the following resolutions on March
31, 1997; and that none of the Series G Cumulative Convertible Preferred Stock
has been issued:

          WHEREAS, the Corporation has an outstanding series of preferred stock
designated as Cumulative Convertible Preferred Stock, Series F (the "Series F
Preferred") with such preferences, voting powers, relative, participating,
optional or other special rights and privileges and the qualifications,
limitations and restrictions as provided in that certain Certificate of
Designation filed with the Secretary of State of the State of Delaware on April
8,1996 (the "Series F Designation"); and

          WHEREAS, the Series F Designation requires the approval of the holders
of at  least a majority in interest of the Series F Preferred in order to create
a new class or series of shares of the Company's capital stock having a
preference over, or on parity with, the Series F Preferred; and

          WHEREAS, the Corporation has obtained the written consent of the
holders of a majority in interest of the Series F Preferred to the adoption of
the following resolutions.

          There is hereby created a series of preferred stock designated as
Cumulative Convertible Preferred Stock, Series G (the "Series G Preferred"),
which will consist of 60,000 shares. The Series G Preferred shall consist of one
or more subseries of the Series G Preferred (each, a "Subseries"), each
Subseries to be separately designated  with the preferences, voting powers,
relative, participating, optional or other special rights and privileges, and
the qualifications, limitations and restrictions as provided below and as
specified in a separate Certificate of Designation of Subseries in the form
attached as Exhibit A (with all blanks appropriately completed):

     (1)  DIVIDENDS AND DISTRIBUTIONS.

          (a) The holders of shares of Series G Preferred (regardless of
Subseries) shall be entitled to receive dividends at a rate of thirteen and one-
half percent (13.5 %) of the Series G Conversion Value (as defined in SECTION
(3)(A) below) per annum per share of Series G Preferred, which shall be fully
cumulative, prior and in preference to any declaration or payment of any
dividend (payable other than in Common Stock) or other distribution on any other
class or series of Preferred Stock or the Common Stock of the Corporation other
than with respect to dividends declared or paid with respect to shares of Series
F Preferred (and excluding any stock
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splits and subdivisions for which an adjustment is made under SECTION
(3)(D)(VI)(1) below). If the dividends on the Series F Preferred and the Series
G Preferred cannot legally be paid in full, dividends shall be paid, to the
maximum permissible extent, to the holders of the Series F Preferred and the
Series G Preferred, parri passu. The dividends on the Series G Preferred
(regardless of Subseries) shall accrue from the date of issuance of each share
and shall be payable semi-annually on June 30 and December 31 of each year (each
a "Dividend Date"), commencing on June 30, 1997, except that if any such date is
a Saturday, Sunday or legal holiday (a "Non-Business Day") then such dividend
shall be payable on the next day that is not a Saturday, Sunday or legal holiday
on which banks in the State of Texas are permitted to be closed (a "Business
Day") to holders of record as they appear on the stock books of the Corporation
on the applicable record date, which shall be not more than 60 nor less than 10
days preceding the payment date for such dividends, as fixed by the Board of
Directors (the "Record Date"). The dividends on the Series G Preferred shall be
payable only when, as and if declared by the Board of Directors out of funds
legally available therefor. The dividends shall, at the option of the
Corporation, either (1) be payable in cash, or (2) accrue, if prior to April 5,
1999, and thereafter shall be payable in cash; provided, however, that no
dividends shall be paid in cash to holders of Series G Preferred in respect of
any period if holders of Series F Preferred have not received dividends per
share in cash in respect of such period equal to or greater than the dividends
per share to be paid to holders of Series G Preferred for such period. Subject
to the provisions of the preceding sentence and the next paragraph, in the
absence of an election by the Board of Directors within 10 days of each Dividend
Date to pay dividends in cash, the dividends shall accrue. The amount of
dividends payable for any period that is shorter or longer than a full dividend
shall be computed on the basis of a 360-day year of twelve 30-day months. All
accrued but unpaid dividends shall accrue interest after each Dividend Date at a
rate of thirteen and one-half percent (13.5%) per annum (compounded on a semi-
annual basis) from each Dividend Date, computed on the basis of a 360-day year
of twelve 30-day months.

          (b)  Each holder of Series G Preferred may, by written notice to the
Corporation, within twenty (20) days of each Dividend Date, elect (the "Series G
Dividend Election") to receive the dividends which, pursuant to the preceding
paragraph, have accrued for such period on such Dividend Date in shares of the
same Subseries of Series G Preferred for which the dividend is declared (the
"Series G Payments-in-Kind") rather than have such dividends accrue.  A Series G
Dividend Election for any particular Dividend Date shall operate only for such
Dividend Date.  Series G Payments-in-Kind shall be payable as of the Dividend
Date of each period for which the election is made, except that if such date is
a Non-Business Day then such Series G Payment-in-Kind shall be payable as of the
next Business Day to holders of record as they appear on the stock books of the
Corporation on the applicable Record Date.  Each Series G Payment-in-Kind shall
be equal in amount to that number of shares of the Subseries of Series G
Preferred for which the dividend is paid that is equal in number to the
aggregate cash dividends payable on any such dividend date divided by the Series
G Conversion Value (as defined in SECTION (3)(A) below), and shall be payable to
each holder who makes a Series G Divided Election.  Certificates representing
the shares of the Subseries of Series G Preferred issuable on payment of any
Series G Payment-in-Kind shall be delivered to each holder entitled to receive
such Series G Payment-in-Kind (in appropriate denominations) on or before the
forty-fifth (45th)

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day following the Dividend Date for which such Series G Payment-in-Kind is
elected to be received hereunder. If a Series G Payment-in-Kind is not made in
compliance with the terms hereof, the Corporation shall be obligated to pay the
cash dividends under the procedures in the previous paragraph.

          (2) LIQUIDATION RIGHTS.  In the event of any liquidation, dissolution
or winding up of the Corporation, whether voluntary or involuntary,
distributions shall be made to the holders of Series G Preferred (regardless of
Subseries) in respect of such Series G Preferred, in the following manner:

          (A) SERIES G PREFERRED.  The holders of the Series G Preferred
(regardless of Subseries), the Series F Preferred and the Series E Convertible
Preferred Stock (the "Series E Preferred") shall be entitled to be paid first
out of the assets of the Corporation available for distribution to holders of
its capital stock, on a pro rata basis, in proportion to the consideration paid
for such shares by each holder thereof to the aggregate consideration paid for
all such shares by all holders thereof (in contrast to distributions made by
numbers of shares, due to the difference in the price per share of each series),
to the maximum extent allowable by law, including all enforceable waivers and
agreements.  The Series G Preferred liquidation preference shall be equal to (i)
the Series G Conversion Value (as defined in SECTION A(3)(A) below), as
appropriately adjusted to reflect any stock split, stock dividend, combination,
recapitalization and the like (collectively a "Recapitalization") of the Series
G Preferred, plus (ii) all accrued or declared but unpaid dividends (including
any interest accrued thereon calculated through the date of liquidation).  The
liquidation preference of the Series F Preferred and the Series E Preferred
liquidation preference shall be as stated in their respective Certificates of
Designation.  If, upon the occurrence of a liquidation, dissolution or winding
up, the assets and funds thus distributed among the holders of the Series G
Preferred, the Series F Preferred and the Series E Preferred shall be
insufficient to permit the payment to such holders of their full liquidation
preferences, then the entire assets and funds of the Corporation legally
available for distribution to the holders of capital stock shall be distributed
ratably among the holders of the Series G Preferred, the Series F Preferred and
the Series E Preferred.

          (B) REMAINING ASSETS.  If assets are remaining after payment of the
full preferential amount with respect to the Series G Preferred, the Series F
Preferred and the Series E Preferred set forth in SECTION (2)(A) above, then the
holders of any other class or series of Preferred Stock, if any, shall be
entitled to their respective preferential amounts on liquidation, and thereafter
the holders of the Common Stock shall be entitled to share ratably in all such
remaining assets and surplus funds based on the number of shares of Common Stock
held by each.

          (C) EVENTS DEEMED A LIQUIDATION.  For purposes of this SECTION (2),
the holders of a majority of the Series G Preferred of all Subseries then
outstanding, voting together as a single class, may elect to have treated as a
liquidation, dissolution or winding up of the Corporation, the consolidation or
merger of the Corporation with or into any other corporation or

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the sale or other transfer in a single transaction or a series of related
transactions of all or substantially all of the assets of the Corporation, or
any other reorganization of the Corporation.

          (D) VALUATION OF SECURITIES AND PROPERTY.  In the event the
Corporation proposes to distribute assets other than cash in connection with any
liquidation, dissolution or winding up of the Corporation, the value of the
assets to be distributed to the holders of shares of Series G Preferred of all
Subseries shall be determined in good faith by the Board of Directors.  Any
securities not subject to investment letter or similar restrictions on free
marketability shall be valued as follows:

               (i) If traded on a national securities exchange or the NASDAQ
     National Market System ("NASDAQ/NMS"), the value shall be deemed to be the
     average of the security's closing prices on such exchange or NASDAQ/NMS
     over the thirty (30) calendar day period ending three (3) days prior to the
     distribution;

               (ii) If actively traded over-the-counter (other than NASDAQ/NMS),
     the value shall be deemed to be the average of the closing bid prices over
     the thirty (30) calendar day period ending three (3) days prior to the
     distribution; and

               (iii)  If there is no active public market, the value shall be
     the fair market value thereof as determined in good faith by the Board of
     Directors.

The method of valuation of securities subject to investment letter or other
restrictions on free marketability shall be adjusted to make an appropriate
discount from the market value determined as above in clauses (i), (ii) or (iii)
to reflect the fair market value thereof as determined in good faith by the
Board of Directors.  The holders of at least 50% of the outstanding Series G
Preferred of all Subseries shall have the right to challenge any determination
by the Board of Directors of fair market value pursuant to this SECTION (2)(D),
in which case the determination of fair market value shall be made by an
independent appraiser selected jointly by the Board of Directors and the
challenging parties, the cost of such appraisal to be borne equally by the
Corporation and the challenging parties.

     (3) CONVERSION.  The holders of the Series G Preferred have conversion
rights as follows (the "Conversion Rights"):

          (A)  RIGHT TO CONVERT.

          (i) Each share of Series G Preferred of a Subseries shall initially be
convertible, at the option of the holder thereof, at any time at the principal
office of the Corporation or any transfer agent for the Subseries of the Series
G Preferred, into the number of fully paid and nonassessable shares of Common
Stock which results from dividing the Subseries Conversion Price (as hereinafter
specified) per share in effect for such series at the time of conversion into
the per share Series G Conversion Value (as hereinafter specified) of such
series.  The initial Conversion Price of a Subseries of the Series G Preferred
(the "Subseries Conversion

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Price") shall be as stated in the applicable Certificate of Designation of
Subseries and the Conversion Value of the Series G Preferred of all Subseries
(the "Series G Conversion Value") shall be $100.00 per share. The initial
Subseries Conversion Price shall be subject to adjustment from time to time as
provided in SECTION (3)(C) hereof. The Series G Conversion Value shall not be
subject to adjustment (except in connection with a Recapitalization). Upon
conversion, all accrued or declared but unpaid dividends (including any interest
accrued thereon calculated as of the date of conversion) on the Subseries of
Series G Preferred shall either be paid in cash, to the extent permitted by
applicable law or, at the option of the holder of the Subseries of Series G
Preferred, converted into the number of fully paid and nonassessable shares of
Common Stock which results from dividing the Subseries Conversion Price in
effect at such time into the aggregate of all such accrued or declared but
unpaid dividends (including any interest accrued thereon calculated as of the
date of conversion).

          (ii) On and after April 5, 2001, each share of a Subseries of Series G
Preferred shall be convertible, at the option of the holder thereof, at any time
at the principal office of the Corporation or any transfer agent for the
Subseries of the Series G Preferred, into the number of fully paid and
nonassessable shares of Common Stock which results from dividing the lower of
(1) the then applicable Subseries Conversion Price and (2) ninety percent (90%)
of the applicable Market Price (as defined herein) per share of Common Stock
into the per share Series G Conversion Value of such series.  Upon conversion,
all accrued or declared but unpaid dividends (including any interest accrued
thereon calculated as of the date of conversion) on the Subseries of the Series
G Preferred shall either be paid in cash, to the extent permitted by applicable
law or, at the option of the holder of the Subseries of the Series G Preferred,
converted into the number of fully paid and nonassessable shares of Common Stock
which results from dividing the lower of (1) and (2) above in effect at such
time into the aggregate of all such accrued or declared but unpaid dividends
(including any interest accrued thereon calculated as of the date of
conversion).  The "Market Price" per share of Common Stock shall be the average
closing bid price per share of Common Stock during the twenty (20) trading days
immediately preceding the date of determination , as such bid price is reported
by NASDAQ/NMS, or the average closing bid price in the over-the-counter market
if other than NASDAQ/NMS, or in the event the Common Stock is listed on a stock
exchange, the Market Price shall be the average closing bid price on such
exchange, as reported in the Wall Street Journal.

          (iii) Notwithstanding anything else contained herein to the contrary,
if the Corporation shall default in its obligations pursuant to the terms of
SECTION 4.16 of that certain Stock Purchase Agreement pursuant to which the
shares of Series G Preferred were issued (as the same may be amended, modified
or restated from time to time, the "Series G Stock Purchase Agreement"), then
during the term of such default each share of a Subseries of the Series G
Preferred shall be convertible, at the option of the holder thereof, at any time
at the principal office of the Corporation or any transfer agent for the
Subseries of the Series G Preferred, into the number of fully paid and
nonassessable shares of Common Stock which results from dividing the lower of
(1) the then applicable Subseries Conversion Price and (2) seventy-five percent
(75%) of the applicable Market Price per share of Common Stock into the per
share Series G Conversion Value of such series.  Upon conversion, all accrued or
declared but unpaid dividends

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(including any interest accrued thereon calculated as of the date of conversion)
on the Subseries of the Series G Preferred shall either be paid in cash, to the
extent permitted by applicable law or, at the option of the holder of the
Subseries of the Series G Preferred, converted into the number of fully paid and
nonassessable shares of Common Stock which results from dividing the lower of
(1) and (2) above in effect at such time into the aggregate of all such accrued
or declared but unpaid dividends (including any interest accrued thereon
calculated as of the date of conversion).

          (B)   MECHANICS OF CONVERSION.  Before any holder of a Subseries of
the Series G Preferred shall be entitled to convert the same into shares of
Common Stock and to receive certificates therefor, such holder shall surrender
the certificate or certificates therefor, duly endorsed, at the principal office
of the Corporation or of any transfer agent for the Subseries of the Series G
Preferred, and shall give written notice to the Corporation at such office that
such holder elects to convert the same.  The Corporation shall, as soon as
practicable after such delivery, issue and deliver at such office to such holder
of the Subseries of the Series G Preferred, a certificate or certificates for
the number of shares of Common Stock to which such holder shall be entitled as
aforesaid and a check payable to such holder in the amount of any unconverted
accrued or declared but unpaid dividends (including any interest accrued thereon
calculated as of the date of conversion) payable pursuant to SECTION (1) hereof,
if any.  Such conversion shall be deemed to have been made immediately prior to
the close of business on the date of such surrender of the shares of the
Subseries of the Series G Preferred to be converted, and the holder or holders
entitled to receive the shares of Common Stock issuable upon such conversion
shall be treated for all purposes as the record holder or holders of such shares
of Common Stock on such date.  If the Corporation fails to pay all such
dividends (and interest thereon), if any, within twenty (20) days of the date of
conversion, the holder entitled to such dividends (and interest thereon) may
elect to have the Corporation issue to such holder, in lieu of such cash
payment, additional shares of Common Stock calculated by dividing the total
amount payable on such date by the applicable Subseries Conversion Price,
determined pursuant to SECTION (3)(A) above.

          (C) ADJUSTMENTS TO SUBSERIES CONVERSION PRICE.

               (i) SPECIAL DEFINITIONS.  For purposes of this SECTION (3)(C),
     the following definitions shall apply:

                   (1) "OPTIONS" shall mean rights, options or warrants to
     subscribe for, purchase or otherwise acquire either Common Stock or
     Convertible Securities.

                   (2) "CONVERTIBLE SECURITIES" shall mean any evidences of
     indebtedness, shares or other securities convertible into or exchangeable
     for Common Stock.

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               (3) "ADDITIONAL SHARES OF COMMON STOCK" shall mean all shares of
     Common Stock issued (or, pursuant to SECTION 3(C)(III), deemed to be
     issued) by the Corporation after the Series G Original Issue Date (as
     defined herein), other than shares of Common Stock issued or issuable:

                  (A) upon conversion of shares of Series F Preferred and Series
     G Preferred (regardless of Subseries);

                  (B) pursuant to a stock grant, option plan or purchase plan,
     other employee stock incentive program or agreement approved by the Board
     of Directors and pursuant to the terms of SECTION 4.13 of the Series G
     Stock Purchase Agreement (as adjusted for Other Adjustments under SECTION
     3(C)(VI)) (the "Option Pool");

                  (C) in a transaction described in SECTION (3)(C)(VI);

                  (D) pursuant to the terms of any stock grant, option, warrant,
     employment agreement or other written obligation, agreement or commitment
     to which the Company was a party as of the Series G Original Issue Date and
     which was disclosed in the Series G Stock Purchase Agreement; or

                  (E) by way of dividend or other distribution on shares of
     Common Stock excluded from the definition of Additional Shares of Common
     Stock by the foregoing clauses (A), (B), (C) or (D).

                (4) "SERIES G ORIGINAL ISSUE DATE" shall mean the date on which
     the first share of Series G Preferred (regardless of Subseries) was issued.

               (ii) NO ADJUSTMENT OF SUBSERIES CONVERSION PRICE.  No adjustment
     in a Subseries' Conversion Price shall be made in respect of the issuance
     of Additional Shares of Common Stock unless the consideration per share for
     an Additional Share of Common Stock issued or deemed to be issued by the
     Corporation is less than the Subseries Conversion Price in effect on the
     date of, and immediately prior to, such issue.

               (iii)  DEEMED ISSUE OF ADDITIONAL SHARES OF COMMON STOCK.
 
                      (1) OPTIONS AND CONVERTIBLE SECURITIES.  In the event the
      Corporation at any time or from time to time after the Series G Original
     Issue Date shall issue any Options (other than the issuance of Options
     pursuant to the Option Pool) or Convertible Securities or shall fix a
     record date for the determination of holders of any class of securities
     entitled to receive any such Options or Convertible Securities, then the
     maximum number of shares (as set forth in the instrument relating thereto
     without regard to any provisions contained therein for a subsequent
     adjustment of such number) of Common Stock issuable upon the exercise of
     such Options or, in the case of Convertible

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     Securities and Options therefor, the exercise of such Options and
     conversion or exchange of such Convertible Securities shall be deemed to be
     Additional Shares of Common Stock issued as of the time of such issue or,
     in case such a record date shall have been fixed, as of the close of
     business on such record date, provided that Additional Shares of Common
     Stock shall not be deemed to have been issued unless the consideration per
     share (determined pursuant to SECTION (3)(C)(V) hereof) of such Additional
     Shares of Common Stock would be less than the Subseries Conversion Price in
     effect on the date of and immediately prior to such issue, or such record
     date, as the case may be, and provided further that in any such case in
     which Additional Shares of Common Stock are deemed to be issued:

               (A) except as provided in SECTION (3)(C)(III)(1)(B), no further
     adjustment in the Subseries Conversion Price shall be made upon the
     subsequent issue of Convertible Securities or shares of Common Stock upon
     the exercise of such Options or conversion or exchange of such Convertible
     Securities;

               (B) if such Options or Convertible Securities by their terms
     provide, with the passage of time or otherwise, for any change in the
     consideration payable to the Corporation, or change in the number of shares
     of Common Stock issuable, upon the exercise, conversion or exchange thereof
     (other than under or by reason of provisions designed to protect against
     dilution), the Subseries Conversion Price computed upon the original issue
     thereof (or upon the occurrence of a record date with respect thereto) and
     any subsequent adjustments based thereon, shall, upon any such increase or
     decrease becoming effective, be recomputed to reflect such increase or
     decrease insofar as it affects such Options or the rights of conversion or
     exchange under such Convertible Securities; and

               (C) no readjustment pursuant to clause (B) above shall have the
     effect of increasing the Subseries Conversion Price to an amount which
     exceeds the lower of (1) the Subseries Conversion Price on the original
     adjustment date or (2) the Subseries Conversion Price that would have
     resulted from any issuance of Additional Shares of Common Stock between the
     original adjustment date and such readjustment date.

               (iv) ADJUSTMENT OF SUBSERIES CONVERSION PRICE UPON ISSUANCE OF
     ADDITIONAL SHARES OF COMMON STOCK.  In the event the Corporation shall
     issue Additional Shares of Common Stock without consideration or for a
     consideration per share less than the Subseries Conversion Price in effect
     on the date of and immediately prior to such issue, then and in each such
     event the Subseries Conversion Price shall be reduced to a price
     (calculated to the nearest cent) determined by multiplying such Subseries
     Conversion Price by a fraction, the numerator of which shall be the number
     of shares of Common Stock outstanding immediately prior to such issue plus
     the number of shares of Common Stock which the aggregate consideration
     received by the Corporation for the total number of Additional Shares of
     Common Stock so issued would

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     purchase at such Subseries Conversion Price; and the denominator of which
     shall be the number of shares of Common Stock outstanding immediately prior
     to such issue plus the number of such Additional Shares of Common Stock so
     issued.

               (v) DETERMINATION OF CONSIDERATION.  For purposes of this SECTION
     (3)(C), the consideration received by the Corporation for the issuance of
     any Additional Shares of Common Stock shall be computed as follows:

                         (1) CASH AND PROPERTY: Such consideration shall:

                             (A) insofar as it consists of cash, be computed at
     the aggregate amount of cash received by the Corporation;

                             (B) insofar as it consists of property other than
     cash, be computed at the fair value thereof at the time of such issue, as
     determined by the Board of Directors in the good faith exercise of its
     reasonable business judgment; and

                             (C) in the event Additional Shares of Common Stock
     are issued together with other shares or securities or other assets of the
     Corporation for consideration which covers both, be the proportion of such
     consideration so received, computed as provided in clauses (A) and (B)
     above, as determined by the Board of Directors in the good faith exercise
     of its reasonable business judgment.

                         (2) OPTIONS AND CONVERTIBLE SECURITIES. The
     consideration per share received by the Corporation for Additional Shares
     of Common Stock deemed to have been issued pursuant to SECTION
     (3)(C)(III)(1), relating to Options and Convertible Securities, shall be
     determined by dividing

                             (A) the total amount, if any, received or
     receivable by the Corporation as consideration for the issue of such
     Options or Convertible Securities, plus the minimum aggregate amount of
     additional consideration (as set forth in the instruments relating thereto,
     without regard to any provision contained therein for a subsequent
     adjustment of such consideration) payable to the Corporation upon the
     exercise of such Options or the conversion or exchange of such Convertible
     Securities, or in the case of Options for Convertible Securities, the
     exercise of such Options for Convertible Securities and the conversion or
     exchange of such Convertible Securities, by

                             (B) the maximum number of shares of Common Stock
     (as set forth in the instruments relating thereto, without regard to any
     provision contained therein for a subsequent adjustment of such number)
     issuable upon the exercise of such Options or the conversion or exchange of
     such Convertible Securities.

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          (vi) OTHER ADJUSTMENTS.

               (1) SUBDIVISIONS, COMBINATIONS, OR CONSOLIDATIONS OF COMMON
     STOCK.  In the event the outstanding shares of Common Stock shall be
     subdivided, combined or consolidated, by stock split, stock dividend,
     combination or like event, into a greater or lesser number of shares of
     Common Stock, the Subseries Conversion Price in effect immediately prior to
     such subdivision, combination, consolidation or stock dividend shall,
     concurrently with the effectiveness of such subdivision, combination or
     consolidation, be proportionately adjusted.

               (2) RECLASSIFICATIONS.  In the case, at any time after the date
     hereof, of any capital reorganization or any reclassification of the stock
     of the Corporation (other than as a result of a stock dividend or
     subdivision, split-up or combination of shares), or the consolidation or
     merger of the Corporation with or into another person (other than a
     consolidation or merger (A) in which the Corporation is the continuing
     entity and which does not result in any change in the Common Stock or (B)
     which is treated as a liquidation pursuant to SECTION (2)(C)), the shares
     of the Series G Preferred shall, after such reorganization,
     reclassification, consolidation or merger be convertible into the kind and
     number of shares of stock or other securities or property of the
     Corporation or otherwise to which such holder would have been entitled if
     immediately prior to such reorganization, reclassification, consolidation
     or merger such holder had converted its shares of the Series G Preferred
     into Common Stock.  The provisions of this SECTION (3)(C)(VI)(3) shall
     similarly apply to successive reorganizations, reclassifications,
     consolidations or mergers.

          (D) CERTIFICATE AS TO ADJUSTMENTS.  Upon the occurrence of each
adjustment or readjustment of the Subseries Conversion Price pursuant to this
SECTION (3), the Corporation at its expense shall promptly compute such
adjustment or readjustment in accordance with the terms hereof and furnish to
each holder of each Subseries of the Series G Preferred so adjusted a
certificate setting forth such adjustment or readjustment and showing in detail
the facts upon which such adjustment or readjustment is based.  The Corporation
shall, upon the written request at any time of any holder of a Subseries of the
Series G Preferred, furnish or cause to be furnished to such holder a like
certificate setting forth (i) such adjustments and readjustments, (ii) the
Subseries Conversion Price at the time in effect, and (iii) the number of shares
of Common Stock and the amount, if any, of other property which at the time
would be received upon the conversion of the Subseries of the Series G
Preferred.

          (E) STATUS OF CONVERTED STOCK.  In case any shares of a Subseries of
the Series G Preferred shall be converted pursuant to SECTION (3) hereof, the
shares so converted shall, at the option of the Corporation, be canceled, and,
if not canceled, shall not be reissuable as shares of Series G Preferred but
shall be part of the authorized but unissued capital stock of the Corporation.

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          (F) FRACTIONAL SHARES.  In lieu of any fractional shares to which the
holder of a Subseries of the Series G Preferred would otherwise be entitled upon
conversion, the Corporation shall pay cash equal to such fraction multiplied by
the fair market value of one share of Common Stock as determined by the Board of
Directors in the good faith exercise of its reasonable business judgment.

          (G)  MISCELLANEOUS.

               (i) All calculations under this SECTION (3) shall be made to the
     nearest cent or to the nearest one hundredth (1/100) of a share, as the
     case may be.

               (ii) The holders of at least 50% of the outstanding Series G
     Preferred of all Subseries shall have the right to challenge any
     determination by the Board of Directors of fair market value pursuant to
     this SECTION (3), in which case such determination of fair market value
     shall be made by an independent appraiser selected jointly by the Board of
     Directors and the challenging parties, the cost of such appraisal to be
     borne equally by the Corporation and the challenging parties.

               (iii)  No adjustment in the Subseries Conversion Price need be
     made if such adjustment would result in a change in such Subseries
     Conversion Price of less than $0.01. Any adjustment of less than $0.01
     which is not made shall be carried forward and shall be made at the time of
     and together with any subsequent adjustment which, on a cumulative basis,
     amounts to an adjustment of $0.01 or more in the Subseries Conversion
     Price.

          (H) NO IMPAIRMENT.  The Corporation will not, through any
reorganization, recapitalization, transfer of assets, consolidation, merger,
dissolution, issue or sale of securities or any other voluntary action, avoid or
seek to avoid the observance or performance of any of the terms to be observed
or performed hereunder by the Corporation, but will at all times in good faith
assist in the carrying out of all the provisions of this SECTION (3) and in the
taking of all such action as may be necessary or appropriate in order to protect
the conversion rights of the holders of the Subseries of Series G Preferred
against impairment.

          (I) RESERVATION OF STOCK ISSUABLE UPON CONVERSION.  The Corporation
shall at all times reserve and keep available out of its authorized but unissued
shares of Common Stock, solely for the purpose of effecting the conversion of
the shares of all Subseries of the Series G Preferred, such number of its shares
of Common Stock as shall from time to time be sufficient to effect the
conversion of all outstanding shares of all Subseries of the Series G Preferred.
If at any time the number of authorized but unissued shares of Common Stock
shall not be sufficient to effect the conversion of all then outstanding shares
of all Subseries of the Series G Preferred, the Corporation will take such
corporate action as may, in the opinion of its counsel, be necessary to increase
its authorized but unissued shares of Common Stock to such number of shares as
shall be sufficient for such purpose.

                                       11
<PAGE>
 
     (4)  REDEMPTION.

          (a) The Corporation may redeem, on the first day subsequent to April
5, 2004, all or a portion of the shares of all Subseries of the Series G
Preferred then outstanding on the Redemption Date (as defined below) out of
funds legally available therefor, pro rata on the basis of the number of shares
held by each holder.  The Corporation shall pay in cash therefor a sum per share
equal to one hundred dollars ($100) together with all accrued or declared but
unpaid dividends (including any interest accrued thereon) calculated as of the
Redemption Date (collectively the "Redemption Value").

          (b) Any notice of redemption (the "Notice of Redemption") given by the
Corporation shall be delivered by mail, first class postage prepaid, to each
holder of record (at the close of business on the business day preceding the day
on which notice is given) of all Subseries of the Series G Preferred, at the
address last shown on the records of the Corporation for such holder or given by
the holder to the Corporation, for the purpose of notifying such holder of the
redemption to be effected.  The Notice of Redemption shall specify a date (the
"Redemption Date") between 45 and 75 days after the mailing of the Notice of
Redemption on which all Subseries of the Series G Preferred then outstanding
shall be redeemed and the place at which payment may be obtained, which shall be
the principal offices of the Corporation or such other place as shall be
mutually agreeable to the Corporation and holders of a majority of the aggregate
number of then outstanding shares of all Subseries of the Series G Preferred.
The Notice of Redemption shall call upon each holder of Series G Preferred
(regardless of Subseries) to either (i) surrender to the Corporation, in the
manner and at the place designated, such holder's certificate or certificates
representing the shares to be redeemed or (ii) convert such Subseries of the
Series G Preferred into Common Stock prior to the Redemption Date in accordance
with the provisions of SECTION (3) above; provided, however, that if the Market
Price as of the Redemption Date is greater than or equal to the then applicable
Subseries Conversion Price (without regard to the adjustments to be made to the
Subseries Conversion Price pursuant to the terms of SECTION (3)(A)(II)) then the
holders of the Subseries of Series G Preferred shall have the absolute right to
convert such Subseries of the Series G Preferred into Common Stock prior to the
Redemption Date in accordance with the provisions of SECTION (3), and; provided,
further, however, that if the Market Price as of the Redemption Date is less
than the then applicable Subseries Conversion Price (without regard to the
adjustments to be made to the Subseries Conversion Price pursuant to the terms
of SECTION(3)(A)(II)) then the Corporation shall have the absolute right to
redeem the Subseries of the Series G Preferred in accordance with the provisions
of this SECTION (4).  If the Corporation elects to redeem shares pursuant to
this SECTION (4) and defaults or fails to perform its redemption obligations
pursuant to this SECTION (4) in connection therewith, the holders of the
Subseries of the Series G Preferred shall then have the absolute right to
convert such Subseries of the Series G Preferred into Common Stock in accordance
with the provisions of SECTION (3).

          (c) On the Redemption Date, the Corporation shall pay by cash or check
to the order of the person whose name appears on the certificate or certificates
of all Subseries of the Series G Preferred that (i) shall not have been
converted pursuant to SECTION (3) hereof and

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<PAGE>
 
(ii) shall have been surrendered to the Corporation in the manner and at the
place designated in the Notice of Redemption, the Redemption Value, and
thereupon each surrendered certificate shall be canceled.

          (d) If the funds of the Corporation legally available for redemption
of the Subseries of the Series G Preferred are insufficient to redeem the total
number of shares of all Subseries of the Series G Preferred outstanding on the
Redemption Date, the Series G Preferred of all Subseries shall be redeemed (on a
pro rata basis from the holders of all Subseries of the Series G Preferred from
time to time), to the extent the Corporation is legally permitted to do so, and
the redemption obligations of the Corporation hereunder will be a continuing
obligation until the Corporation's redemption of all Subseries of the Series G
Preferred.

          (e) From and after the Redemption Date, unless there shall have been a
default in payment of the Redemption Value, all rights of the holders of shares
of all Subseries of the Series G Preferred (except the right to receive the
Redemption Value subsequent to the Redemption Date upon surrender of their
certificate or certificates) shall cease with respect to such shares, and such
shares shall not thereafter be transferred on the books of the Corporation or be
deemed to be outstanding for any purpose whatsoever.

     (5)  VOTING RIGHTS.

          (A) GENERAL.  Except as otherwise required by law or by SECTION (8),
the holders of all each Subseries of the Series G Preferred issued and
outstanding, in the aggregate, shall be entitled to the number of votes equal to
the number of shares of Common Stock into which shares of such Subseries of
Series G Preferred are convertible on any record date, or, if no such record
date is established, at the date such vote is taken or any written consent of
stockholders is solicited, such votes to be counted together with all other
shares of stock of the Corporation having general voting power and not
separately as a class.  Fractional votes by the holders of a Subseries of the
Series G Preferred shall not, however, be permitted, and any fractional voting
rights shall (after aggregating all shares into which shares of Series G
Preferred held by each holder could be converted) be rounded to the nearest
whole number.  Notwithstanding the foregoing, the holders of Series G Preferred
shall be subject to the terms of SECTION 4.11 of the Series G Stock Purchase
Agreement.

     (6) NOTICES OF RECORD DATE.  In the event of any taking by the Corporation
of a record of the holders of any class of securities for the purpose of
determining the holders thereof who are entitled to receive any dividend or
other distribution, any right to subscribe for, purchase or otherwise acquire
any shares of stock of any class or any other securities or property, or to
receive any other right, the Corporation shall mail to each holder of all
Subseries of the Series G Preferred, at least twenty (20) days prior to the date
specified therein, a notice specifying the date on which any such record is to
be taken for the purpose of such dividend, distribution or right, and the amount
and character of such dividend distribution or right.

                                       13
<PAGE>
 
     (7) NOTICES.  Any notice required by the provisions of the Certificate to
be given to the holders of all Subseries of the Series G Preferred shall be
deemed given when deposited in the United States mail, postage prepaid, and
addressed to each holder of record at his or her address appearing on the books
of the Corporation, or upon actual receipt when personally delivered or sent by
overnight or other courier delivery.

     (8) PROTECTIVE PROVISIONS.  So long as any shares of any Subseries of the
Series G Preferred are outstanding, the Corporation shall not, without first
obtaining the approval of the holders of at least a majority of the aggregate
number of then outstanding shares of  all Subseries of the Series G Preferred
then outstanding, voting as a separate class, take any action that:

               (i) alters the rights, preferences or privileges of the Series G
Preferred;

               (ii) increases or decreases the authorized number of shares of
Series G Preferred of the Corporation;

               (iii) creates any new class or series of shares that has a
preference over or is on a parity with the Series G Preferred with respect to
voting, dividends or liquidation preferences, or any other rights and/or
remedies;

               (iv)  reclassifies stock into shares having a preference over or
parity with the Series G Preferred with respect to voting, dividends or
liquidation preferences, or any other rights and/or remedies; or

               (v) authorizes any dividend or other distribution other than with
respect to the Series G Preferred (except as required pursuant to the terms of
the Series E Preferred or Series F Preferred).

     (9) SPECIFIC ENFORCEMENT.  The Company agrees that the rights created by
this designation are unique, and that the loss of any such right is not
susceptible to monetary quantification.  Consequently, the Company agrees that
an action for specific performance (including for temporary and/or permanent
injunctive relief) of the obligations created by this designation is a proper
remedy for the breach of the provisions of this designation, without the
necessity of proving actual damages.  If any holder of any Subseries of the
Series G Preferred is forced to institute legal proceedings to enforce its
rights in accordance with the provisions hereof, such holder, if he prevails,
shall be entitled to recover from the Company his reasonable expenses, including
attorneys' fees, incurred in connection with any such action.

                                       14
<PAGE>
 
     IN WITNESS WHEREOF, the Company has caused this Master Certificate of
Designation to be duly executed by its President and attested to by its
Assistant Secretary, hereto, this 2nd day of April, 1997.

                         NORTH AMERICAN TECHNOLOGIES GROUP, INC.



Date:  April 2, 1997     /s/ Tim B. Tarrillion
                         -----------------------------------------------------
                         Tim B. Tarrillion
                         President and Chief Executive Officer



Date:  April 2, 1997     /s/ Judith Knight Shields
                         ------------------------------------------------------
                         Judith Knight Shields
                         Assistant Secretary

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