<PAGE>   1
===============================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                              ---------------------

                                  FORM 10-KSB/A

[ ]  FOR ANNUAL AND TRANSITION REPORTS PURSUANT TO SECTIONS 13 OR 15(d) OF THE
     SECURITIES AND EXCHANGE ACT OF 1934

[X]  AMENDMENT NO. 1 TO ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
     SECURITIES EXCHANGE ACT OF 1934

                   For the fiscal year ended December 31, 1999

                                       OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934

                          -----------------------------

                         Commission file number: 0-21325

                             MANSUR INDUSTRIES INC.
-------------------------------------------------------------------------------
             (Exact name of registrant as specified in its charter)

                    Florida                              65-0226813
        ---------------------------------             -------------------
          (State or other jurisdiction                (I.R.S. Employer
       of incorporation or organization)             Identification No.)





             8305 N.W. 27TH STREET, SUITE 107, MIAMI, FLORIDA 33122
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                    (Address of principal executive offices)

                  Registrant's telephone number: (305) 593-8015

                          -----------------------------

           SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:

                                                          Name of each exchange
         Title of each class                               on which registered
         -------------------                               -------------------

                                         None

           SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT:

                          Common Stock, $.001 par value

     Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. Yes [X] No [ ]

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [X]

     As of April 28, 2000, the aggregate market value of the voting stock of the
registrant held by non-affiliates of the Registrant was $12,901,214, based on a
closing price of $4.875 for the Common Stock, par value $.001 per share (the
"Common Stock"), as reported on NASDAQ on such date.

     As of April 28, 2000, the number of outstanding shares of Common Stock of
the registrant was 4,742,923.

===============================================================================


<PAGE>   2

                                    PART III

ITEM 9.       DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

         The directors and executive officers of the Company are as follows:
<TABLE>
<CAPTION>

                        NAME                           AGE                            POSITION
                        ----                           ---                            --------

<S>                                                     <C>     <C>
  Pierre G. Mansur.............................         48      Chairman of the Board, President and Director

  Paul I. Mansur...............................         49      Chief Executive Officer and Director

  Richard P. Smith.............................         42      Vice President of Finance and Chief Financial Officer

  Dr. Jan Hedberg..............................         52      Director

  Joseph E. Jack...............................         72      Director

  Ronald J. Korn...............................         59      Director
</TABLE>

         PIERRE G. MANSUR founded the Company and has served as its Chairman and
President since its inception in November 1990. From June 1973 to August 1990,
Mr. Mansur served as President of Mansur Industries Inc., a privately held New
York corporation that operated a professional race engine machine shop. Mr.
Mansur has over twenty years of advanced automotive and machinery operations
experience including developing innovative automotive machine shop applications;
designing, manufacturing, customizing, modifying and retooling high performance
engines and component parts; developing state of the art automotive and
powerboat race engines which have consistently achieved world championship
status; and providing consulting services and publishing articles with respect
to automotive technical research data. Mr. Mansur has conducted extensive
research and development projects for several companies, including testing and
evaluating engine parts and equipment for Direct Connection, a high performance
racing division of the Chrysler Corporation; researching and developing
specialized engine piston rings and codings for Seal Power Corporation;
researching high-tech plastic polymers for internal combustion engines for ICI
Americas; and designing and developing specialized high performance engine oil
pan applications. Pierre Mansur is the brother of Paul I. Mansur. Pierre Mansur
is a graduate of the City University of New York.

         PAUL I. MANSUR has been Chief Executive Officer and a Director of the
Company since September 1993. From September 1986 to July 1993, Mr. Mansur
served as Chief Executive Officer of Atlantic Entertainment Inc., a privately
held regional retail chain of video superstores. From March 1981 to September
1986, Mr. Mansur served as the Chief Executive Officer and President of
Ameritrade Corporation, a privately held international distributor of factory
direct duty free products. From June 1972 to March 1981, Mr. Mansur held various
finance and operation positions, including Assistant Vice President Finance and
Operations for Mott's USA, Inc., a division of American Brands. Paul Mansur is
the brother of Pierre G. Mansur. Paul Mansur is a graduate of the City
University of New York.

         RICHARD P. SMITH has been the Chief Financial Officer of the Company
since September 1, 1996. From April 1987 to August 1996, Mr. Smith held various
positions, including Vice President, Chief Financial Officer, Treasurer,
Secretary, Director of Business Planning, and Controller of the European
Operations of Telematics International, Inc., a manufacturer and supplier of
intelligent networking technologies and products. From August 1983 to April
1987, Mr. Smith served as Manager of Internal Controls and Cost Analysis for





                                       2
<PAGE>   3

Motorola, Inc., a worldwide manufacturer of a diverse line of electronic
equipment and components, including communications systems, semiconductors,
electronic controls and computer systems. From January 1980 to March 1981, Mr.
Smith worked as an accountant for Arthur Young and Co. C.P.A. Mr. Smith is a
graduate of Illinois Wesleyan University and holds a Masters of Business
Administration degree from the University of Illinois and a Masters of Finance
degree from Cambridge University.

         DR. JAN HEDBERG has been a Director of the Company since August 1995.
From October 1987 to March 1993, Dr. Hedberg served as the Chairman and Chief
Executive Officer of Enprotec International Group, N.V., a company he co-founded
which is in the business of researching and developing advanced waste oil
recycling technologies. Since March 1993, Dr. Hedberg has been the Chairman of
the Board and Chief Executive Officer of Enprotec (USA) Inc., a wholly owned
subsidiary of Enprotec International Group, N.V., which manufactures, designs
and assembles oil re-refining plants. Dr. Hedberg was the co-recipient of the
1991 International Technology Award for Enterprising Innovation and Creativity
for the development of the Vaxon Re-refining Process, which is a proprietary
process that transforms used oil into useable oil products. Dr. Hedberg has over
15 years of experience in oil related and environmental companies and 12 years
of research and teaching experience, including executive management and advisory
positions, with several multinational organizations. Dr. Hedberg received his
Doctor of Philosophy (Ph.D.) in Geotechnical Engineering from the Massachusetts
Institute of Technology, Cambridge, Massachusetts in 1977.

         JOSEPH E. JACK has been a Director of the Company since August 1995.
From May 1989 to June 1991, Mr. Jack served as Vice President of Waste
Management Europe, a waste collection and recycling company that is a publicly
traded company on the London Stock Exchange and a controlled subsidiary of WMX
Technologies, a publicly traded New York Stock Exchange company. From May 1978
to June 1991, Mr. Jack has served in various executive capacities with several
subsidiaries and/or affiliates of Waste Management, Inc. Mr. Jack has been an
active investor in companies since he retired in June 1991.

         RONALD J. KORN has been a Director of the Company since June 1998.
Since July 1991, Mr. Korn has served as President of Ronald Korn Consulting, a
business consulting firm, and as Chairman of the Board of Carole Korn Interiors,
Inc., an interior design firm. From 1961 to 1991, Mr. Korn was a partner with
the certified public accounting firm of KPMG Peat Marwick, including six years
in which Mr. Korn served as Managing Partner of KPMG Peat Marwick's Miami,
Florida office. Since October 1991, Mr. Korn has served as a director and
Chairman of the Compensation and Audit Committee of the Board of Directors of
Engle Homes, Inc., a company whose common stock is traded on the National Market
of the Nasdaq Stock Market. Since 1996, Mr. Korn has served as a director of
Magicworks Entertainment Incorporated, a public company whose common stock is
traded on the American Stock Exchange. From December 1995 to December, 1997, Mr.
Korn served as a director of Vacation Break U.S.A., Inc., a company whose common
stock was traded on the National Market of the Nasdaq Stock Market.

COMMITTEES AND MEETINGS OF THE BOARD OF DIRECTORS

         During 1999, the Board of Directors held four meetings. Each Director
attended more than 75% of the total number of meetings of the Board of Directors
and committees on which he served.

         The Board of Directors has a standing Audit Committee and Compensation
Committee. We do not have a nominating or similar committee. Our Board of
Directors performs the functions of a nominating or similar committee.

         During 1999, the Audit Committee consisted of Dr. Hedberg and Messrs.
Korn and Jack. The Audit Committee held two meetings during 1999. The duties and
responsibilities of the Audit Committee include (a) recommending to the Board
the appointment of our auditors and any termination of engagement, (b) reviewing
the plan and scope of audits, (c) reviewing our significant accounting policies
and internal controls and (d) having general responsibility for all related
auditing matters.




                                       3
<PAGE>   4


         During 1999, the Compensation Committee consisted of Dr. Hedberg and
Messers. Korn and Pierre Mansur. The Compensation Committee reviews and approves
the compensation of our executive officers and administers our stock option
plan.

ADDITIONAL INFORMATION CONCERNING DIRECTORS

         No Director of the Company receives any fee for attendance at meetings
of the Board of Directors or committees thereof, although members of the Board
of Directors do receive reimbursement for actual travel-related expenses
incurred in connection with their attendance at meetings of the Board of
Directors. Directors of the Company who are also employees of the Company do not
receive additional compensation for their services as Directors.

         Directors are eligible to receive options under the Company's Incentive
Plan. The Incentive Plan provides for an automatic grant of an option to
purchase 3,500 shares of the Company's Common Stock, par value $.001 per share
(the "Common Stock"), upon a person's election as a non-employee Director of the
Company, as well as an automatic annual grant of an option to purchase 3,500
shares of Common Stock on the day the Company issues its earnings release for
the prior fiscal year.

COMPLIANCE WITH SECTION 16(a) OF THE SECURITIES EXCHANGE ACT OF 1934

         Section 16(a) of the Securities Exchange Act of 1934, as amended,
requires the Company's directors and executive officers, and persons who own
more than ten percent of the Company's outstanding Common Stock, to file with
the Securities and Exchange Commission (the "SEC") initial reports of ownership
and reports of changes in ownership of Common Stock. Such persons are required
by SEC regulation to furnish the Company with copies of all such reports they
file.

         To the Company's knowledge, based solely on a review of the copies of
such reports furnished to the Company and written or oral representations that
no other reports were required for such persons, all Section 16(a) filing
requirements applicable to its officers, directors and greater than ten percent
(10%) beneficial owners have been complied with.



                                       4
<PAGE>   5



ITEM 10.      EXECUTIVE COMPENSATION

         The following table sets forth, for the years ended December 31, 1999,
1998 and 1997, the aggregate compensation awarded to, earned by or paid to
Pierre G. Mansur, our Chairman and President, Paul I. Mansur, our Chief
Executive Officer, and Richard P. Smith, our Chief Financial Officer
(collectively known as the "named executive officers"). None of our other
officers earned compensation in excess of $100,000 during 1999. We did not grant
any restricted stock awards or stock appreciation rights or make any long-term
incentive plan payouts during these three fiscal years.
<TABLE>
<CAPTION>

                                                                                                    LONG TERM
                                                      ANNUAL COMPENSATION                          COMPENSATION
                                    -------------------------------------------------------     ----------------
                                                                                                    SECURITIES
             NAME AND                                                          OTHER ANNUAL         UNDERLYING
        PRINCIPAL POSITION           YEAR         SALARY         BONUS         COMPENSATION        OPTIONS/SARS
        ------------------           ----         ------         -----         ------------        ------------
<S>                                  <C>        <C>           <C>              <C>                    <C>
Pierre G. Mansur............         1999       $ 150,000     $ 150,000        $  8,040(1)            22,115
   Chairman and President            1998       $ 130,000            --        $  8,040(1)             9,231
                                     1997       $ 120,000            --        $  6,605(1)            41,460

Paul I. Mansur..............         1999       $ 150,000            --        $  5,099(1)            22,115
     Chief Executive Officer         1998       $ 130,000            --        $  5,099(1)             9,231
                                     1997       $ 120,000            --        $  5,099(1)            30,438

Richard P. Smith............         1999       $ 125,000            --        $  4,800(1)            13,568
     Vice President and Chief        1998       $ 115,000            --        $  4,800(1)             5,641
     Financial Officer               1997       $ 110,000            --        $  4,800(1)                --
</TABLE>


-----------------------
(1)      Automobile allowance paid by the Company.

EMPLOYMENT CONTRACTS AND TERMINATION OF EMPLOYMENT ARRANGEMENTS

         We had entered into a two year employment agreement with Pierre Mansur,
our Chairman of the Board and President, which agreement terminated in September
1999. Pursuant to the terms of the employment agreement, during the three years
following the termination of his employment, Mr. Mansur is prohibited from
disclosing any confidential information, including without limitation,
information regarding our patents, research and development, manufacturing
process or knowledge or information with respect to our confidential trade
secrets. In addition, Mr. Mansur is prohibited from, directly or indirectly,
engaging in any business in substantial competition with us or any of our
affiliates and from becoming an officer, director or employee of any
corporation, partnership or any other business in substantial competition with
us or any of our affiliates for three years following such termination.

         We also entered into a two year employment agreement with Paul Mansur,
the Company's Chief Executive Officer, which agreement terminated in September
1999. As with Mr. Pierre Mansur's employment agreement, for a period of three
years following his termination of employment, Mr. Paul Mansur is prohibited
from disclosing any confidential information, including without limitation,
information regarding our patents, research and development, manufacturing
process or knowledge or information with respect to our confidential trade
secrets. The employment agreement also provides that Mr. Mansur is prohibited
from, directly or indirectly, engaging in any business in substantial
competition with us or any of our affiliates and from becoming an officer,
director or employee of any corporation, partnership or any other business in
substantial competition with us or any of our affiliates during the three years
following such termination.



                                       5
<PAGE>   6



COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

         Pierre G. Mansur, our Chairman of the Board and President, participated
in deliberations of the Compensation Committee of our Board of Directors
concerning executive compensation during 1999. Mr. Mansur was compensated in
accordance with his employment agreement, which agreement was approved by our
Board of Directors.

INCENTIVE PLAN

         The Company adopted the Incentive Plan in September 1996 in connection
with its initial public offering of Common Stock (the "IPO"). The Incentive Plan
provides for grants of stock options, stock appreciation rights ("SARs"),
restricted stock, deferred stock, other stock-related awards and performance or
annual incentive awards that may be settled in cash, stock or other property
(collectively, the "Awards"). A total of 375,000 shares of Common Stock have
been reserved for the grant of Awards under the Incentive Plan. The purpose of
the Incentive Plan is to advance the interests of the Company by providing
additional incentive in attracting, motivating and retaining qualified
executives and other employees, officers, directors and independent contractors
(collectively, the "Participants") by enabling Participants to acquire or
increase a proprietary interest in the Company in order to strengthen the
mutuality of interests between Participants and the Company's shareholders, and
providing Participants with annual and long term performance incentives to
expend their maximum efforts in the creation of shareholder value.

         The persons eligible to receive Awards under the Incentive Plan are the
officers, directors, employees and independent contractors of the Company and
any subsidiary. No director of the Company who is not an employee of the Company
or any subsidiary (a "non-employee director") is eligible to receive any Awards
under the Incentive Plan other than automatic formula grants of stock options
and restricted stock as described below, and no independent contractor will be
eligible to receive any Awards other than stock options.

         The Incentive Plan is required to be administered by a committee
designated by the Board of Directors consisting of not less than two directors
(the "Committee"), each member of which must be a "disinterested person," as
defined under Rule 16b-3 under the Securities Exchange Act of 1934, as amended,
and an "outside director" for purposes of Section 162(m) of the Internal Revenue
Code of 1986, as amended (the "Code"). The Compensation Committee of the Board
has been appointed as the Committee for the purpose of administering the
Incentive Plan. Subject to the terms of the Incentive Plan, the Committee is
authorized to select eligible persons to receive Awards, determine the type of
and number of Awards to be granted and the number of shares of Common Stock to
which Awards will relate, specify times at which Awards will be exercisable or
settleable (including performance conditions that may be required as a condition
thereof), set other terms and conditions of Awards, prescribe forms of Award
agreements, interpret and specify rules and regulations relating to the
Incentive Plan, and make any other determinations that may be necessary or
advisable for the administration of the Incentive Plan.

         In addition, the Incentive Plan imposes individual limitations on the
amount of certain Awards in part to comply with Code Section 162(m). Under these
limitations, during any fiscal year the number of options, SARS, restricted
shares of Common Stock, deferred shares of Common Stock, shares as a bonus or in
lieu of other Company obligations, and other stock-based Awards granted to any
one participant may not exceed 250,000 for each type of such Award, subject to
adjustment in certain circumstances. The maximum amount that may be paid out as
a final annual incentive Award or other cash Award in any fiscal year to any one
participant is $1,000,000, and the maximum amount that may be earned as a final
performance Award or other cash Award in respect of a performance period by any
one participant is $5,000,000.

         The Incentive Plan provides that each non-employee director shall
receive (i) on the date of his or her appointment as a director of the Company,
an automatic grant of an option to purchase 3,500 shares of Common Stock, and
(ii) each year, on the day the Company issues its earnings release for the prior
fiscal year, an automatic grant of an option to purchase 3,500 shares of Common
Stock. Such options will have a term of 7 years and become exercisable at the
rate of 33-1/3 per year commencing on the first anniversary of the date of
grant; provided, however, that the options become fully exercisable in the event
that, while serving as a director of the Company, the non-employee director



                                       6
<PAGE>   7



dies, or suffers a "disability," or "retires" (within the meaning of such terms
as defined in the Incentive Plan). The per share exercise price of all options
granted to non-employee directors will be equal to the fair market value of a
share of Common Stock on the date such option is granted.

OPTION/SAR GRANTS IN LAST FISCAL YEAR

         The table below sets forth the following information with respect to
options granted to the named executive officers during 1999 and the potential
realizable value of such option grants:

         o  the number of shares of common stock underlying options granted
            during the year;

         o  the percentage that such options represent of all options granted to
            employees during the year;

         o  the exercise price; and

         o  the expiration date.

<TABLE>
<CAPTION>
                                                                 INDIVIDUAL GRANTS
                                        ---------------------------------------------------------------------
                                                             PERCENT OF
                                           NUMBER OF           TOTAL
                                          SECURITIES        OPTIONS/SARS
                                          UNDERLYING         GRANTED TO
                                         OPTIONS/SARS       EMPLOYEES IN       EXERCISE          EXPIRATION
               NAME                        GRANTED          FISCAL YEAR      PRICE ($/SH)           DATE
------------------------------------     -------------      -------------    ------------        ------------
<S>                                         <C>                <C>             <C>                 <C> <C>
Pierre G. Mansur................            22,115             10.5%           $8.8125             3/1/06
    Chairman of the Board and
    President

Paul I. Mansur..................            22,115             10.5%           $8.8125             3/1/06
    Chief Executive Officer

Richard P. Smith................            13,568              6.4%           $8.8125             3/1/06
    Vice President and Chief
    Financial Officer
</TABLE>

AGGREGATED FISCAL YEAR-END OPTION VALUE TABLE

         The following table sets forth certain information concerning
unexercised stock options held by our named executive officers as of December
31, 1999. No stock options were exercised by the named executive officers during
1999. No stock appreciation rights have been granted or are outstanding.
<TABLE>
<CAPTION>

                                                          NUMBER OF SECURITIES
                                                               UNDERLYING
                                                     UNEXERCISED OPTIONS AT FY-END      VALUE OF UNEXERCISED IN THE
                               SHARES                     DECEMBER 31, 1999(#)          MONEY OPTIONS AT FY-END(1)
                             ACQUIRED ON    VALUE    -----------------------------     ------------------------------
NAME                         EXERCISE(#)  REALIZED   EXERCISABLE   UNEXERCISABLE       EXERCISABLE     UNEXERCISABLE
----                         -----------  --------   -----------   -------------       -----------     -------------
<S>                               <C>        <C>         <C>           <C>                 <C>              <C>
Pierre G. Mansur........          0          $ 0         44,537        28,269              (2)              (2)
Paul I. Mansur..........          0          $ 0         33,515        28,269              (2)              (2)
Richard P. Smith........          0          $ 0         11,880        17,329              (2)              (2)
</TABLE>


----------------

(1)  The closing price of the common stock as reported on the Nasdaq SmallCap
     Market on December 31, 1999 was $5.125.
(2)  The option exercise price exceeds $5.125 and accordingly, such options are
     "underwater."


                                       7
<PAGE>   8



ITEM 11.      SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

         The following table shows the amount of securities beneficially owned
by (a) each of our directors, (b) each of our executive officers named in the
Summary Compensation Table below, (c) all of our directors and executive
officers as a group and (d) each person known by us to beneficially own more
than 5% of any class of our outstanding securities. Unless otherwise provided,
the address of each holder listed under the heading "Common Stock" is c/o Mansur
Industries Inc., 8305 N.W. 27th Street, Suite 107, Miami, Florida 33122. The
address of each holder listed under the heading "Series B Convertible Preferred
Stock" is c/o Sanders Morris Mundy, 3100 Chase Tower, 600 Travis Street, Suite
3100, Houston, Texas 77002. Additionally, the address of holder of the Series C
convertible preferred stock is 450 Park Avenue, Suite 2302, New York, New York
10022. As of April 28, 2000, each share of Series B and Series C convertible
preferred stock is convertible into approximately 12 shares of common stock or
an aggregate of 488,384 shares of common stock representing approximately 31.4%
of the outstanding shares of common stock.

<TABLE>
<CAPTION>

                                             AGGREGATE NUMBER      ACQUIRABLE          TOTAL NUMBER        PERCENTAGE
                                                OF SHARES            WITHIN         OF SHARES OF CLASS    OF SHARES OF
                                            BENEFICIALLY OWNED     60 DAYS(1)       BENEFICIALLY OWNED       CLASS
NAME                                               (A)                 (B)          (COLUMNS (A)+(B))     OUTSTANDING
----                                        ------------------     ----------       -----------------     -----------
<S>                                                <C>                <C>                 <C>                 <C>
COMMON STOCK
Pierre G. Mansur.......................            2,000,000          44,537              2,044,537           43.1%
Paul I. Mansur.........................                   --          33,515                 33,515            *
Richard P. Smith.......................                1,000          11,880                 12,880            *
Joseph E. Jack.........................               59,520           6,833                 66,353            1.4%
Dr. Jan Hedberg........................               35,000           9,167                 44,167            *
Ronald J. Korn.........................                1,000           1,167                  2,167            *
All directors and executive officers as a
   group (6 persons)...................            2,096,520         107,099
Oppenheimer Funds, Inc.(2).............                   --         245,000(3)             245,000            5.1%
The Commingled Pension Trust Fund
   (Multi-Market Special Investment Fund
   II) of Morgan Guaranty Trust Company of
   New York............................                   --         247,058(3)             247,058            5.1%

SERIES B CONVERTIBLE PREFERRED STOCK
Environmental Opportunities Fund II
   (Institutional), L.P.(4)............               25,035              --                 25,035           47.2%
Environmental Opportunities Fund II, L.P.              6,816              --                  6,816           12.8%
Environmental Opportunities Fund, L.P..               18,888              --                 18,888           35.6%
Environmental Opportunities Fund (Cayman),
   L.P.................................                2,346              --                  2,346            4.4%

SERIES C CONVERTIBLE PREFERRED STOCK
Hanseatic Americas LDC(5)..............               70,947              --                 70,947          100.0%
</TABLE>

-------------------------

*    Represents less than 1% of the outstanding stock of the class.

(1)  Reflects the number of shares that could be purchased by the holder by
     exercise of options granted under our stock option plans or warrants at
     June 25, 1999 or within 60 days thereafter.

(2)  The address of the Oppenheimer Funds, Inc. is Two World Trade Center, 34th
     Floor, New York, New York 10048-0203.

(3)  Shares issuable upon conversion of 8 1/4% Subordinated Convertible Notes
     due 2003.

(4)  Upon conversion of all of its shares of Series B convertible preferred
     stock, Environmental Opportunities Fund II (Institutional), L.P. would hold
     approximately 6.3% of the common stock.

(5)  Upon conversion of all of its shares of Series C convertible preferred
     stock, Hanseatic Americas LDC would hold approximately 17.9% of the common
     stock.


                                       8
<PAGE>   9


ITEM 12.      CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

COMMON STOCK OWNERSHIP

         In connection with the organization of the Company in November 1990,
the Company issued 2,000,000 shares of Common Stock to Mr. Pierre Mansur in
exchange for the assignment to the Company of (i) certain ongoing research and
development and rights to any related patents and patents pending, and (ii) real
estate and equipment valued at $52,000.

CONSULTING AGREEMENT AND SERVICES

         In November 1994, the Company entered into a two-year consulting
agreement (the "Consulting Agreement") with Environmental Technologies BVI
Limited (the "Consultant"). Pursuant to the Consulting Agreement, the Consultant
agreed to advise, consult with, introduce to third parties and generally assist
the Company in its efforts to explore new manufacturing and marketing
arrangements. In exchange for such services, the Consulting Agreement provided
that the Consultant was entitled to receive certain fees in connection with the
sale of certain equipment, services, license rights, royalty rights,
manufacturing rights, marketing rights or the Company's entrance into a
partnership or joint venture arrangement or consummation of a merger. The
Consultant did not receive any commissions pursuant to the Consulting Agreement.
In December 1995, the Company issued the Consultant 10,000 shares of Common
Stock in exchange for the services rendered by the Consultant and to secure the
Consultant's agreement to terminate the Consulting Agreement and any and all
associated rights of the Consultant. Dr. Jan Hedberg, a Director of the Company,
owns 50% and serves as the managing director of the Consultant.

         Dr. Jan Hedberg and Joseph E. Jack have, from time to time, rendered
consulting services to the Company in connection with financing, marketing and
technical matters. In April 1996, Messrs. Hedberg and Jack were each issued
10,000 shares of the Company's Common Stock, valued at $3.50 per share, in
exchange for such previously rendered consulting services.

NOTE PAYABLE TO CHIEF EXECUTIVE OFFICER

         Pursuant to a revolving line of credit dated June 1, 1990, Mr. Paul
Mansur made a series of advances ranging from $5,000 to $30,000, totaling an
aggregate of $150,000, to us between June 1, 1990 and May 31, 1996. Under the
terms of the line of credit, interest accrued at a rate of 6% in 1994, 1995 and
the five month period ended May 31, 1996. On December 31, 1994, we paid Mr. Paul
Mansur $34,814 and on December 31, 1995, we paid him an additional $12,000, in
satisfaction of interest owed with respect to this debt. The note evidencing the
debt had a maturity date of December 31, 1995, which maturity date was extended
to December 31, 1996. On May 31, 1996, we paid Mr. Paul Mansur $150,000 in
satisfaction of the outstanding principal balance of and $5,000 in satisfaction
of the interest owed with respect to this debt.

CONVERTIBLE NOTES

         In connection with its issuance of an aggregate of $1,012,500 in
principal amount of convertible notes in June 1996, we issued promissory notes
in the principal amount of $101,250 to each of (1) Environmental Technologies
BVI Limited, a consulting firm of which Dr. Jan Hedberg, one of our directors,
is Managing Director, and (2) Joseph E. Jack, one of our directors. Upon
consummation of our initial public offering in September 1996, each of these
convertible notes was converted into 15,000 shares of our common stock.
Environmental Technologies BVI Limited and Mr. Jack acquired the convertible
notes on the same terms as other unaffiliated investors.



                                       9
<PAGE>   10

                                   SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

Dated: May 1, 2000

                                          MANSUR INDUSTRIES INC.

                                          By: /s/ PAUL I. MANSUR
                                            ------------------------------------
                                            Paul I. Mansur
                                            Chief Executive Officer
                                            (Principal Executive Officer)

     Pursuant to the requirements of the Securities Act of 1934, this report has
been signed below by the following persons on behalf of the Registrant and in
capacities and on the dates indicated.

<TABLE>
<CAPTION>
                      SIGNATURE                                     TITLE                  DATE
                      ---------                                     -----                  ----
<C>                                                    <S>                              <C>

                /s/ PIERRE G. MANSUR                   Chairman of the Board and        May 1, 2000
-----------------------------------------------------  President; Director
                  Pierre G. Mansur

                 /s/ PAUL I. MANSUR                    Chief Executive Officer;         May 1, 2000
-----------------------------------------------------  Principal Executive Officer;
                   Paul I. Mansur                      Director

                /s/ LYDIA WHITHAM                      Controller; Principal            May 1, 2000
-----------------------------------------------------  Accounting Officer
                  Lydia Whitham

                 /s/ RONALD J. KORN                    Director                         May 1, 2000
-----------------------------------------------------
                   Ronald J. Korn

                 /s/ DR. JAN HEDBERG                   Director                         May 1, 2000
-----------------------------------------------------
                   Dr. Jan Hedberg

                 /s/ JOSEPH E. JACK                    Director                         May 1, 2000
-----------------------------------------------------
                   Joseph E. Jack
</TABLE>

                                       10