1
                                                                    EXHIBIT 99.1


                          INTERNATIONAL ISOTOPES, INC.

                        2000 EMPLOYEE STOCK PURCHASE PLAN

         The following constitute the provisions of the 2000 Employee Stock
Purchase Plan of International Isotopes, Inc.

         1. Purpose. The purpose of the Plan is to provide employees of the
Company and its Designated Subsidiaries with an opportunity to purchase Common
Stock of the Company through accumulated payroll deductions. It is the intention
of the Company to have the Plan qualify as an "Employee Stock Purchase Plan"
under Section 423 of the Internal Revenue Code of 1986, as amended. The
provisions of the Plan, accordingly, shall be construed so as to extend and
limit participation in a manner consistent with the requirements of that section
of the Code.

         2. Definitions.

            (a) "Board" shall mean the Board of Directors of the Company.

            (b) "Code" shall mean the Internal Revenue Code of 1986, as amended.

            (c) "Common Stock" shall mean the Common Stock of the Company.

            (d) "Company" shall mean International Isotopes, Inc. and any
                Designated Subsidiary of the Company.

            (e) "Compensation" shall mean all Form W-2 compensation of the
                participant.

            (f) "Designated Subsidiary" shall mean any Subsidiary which has been
                designated by the Board from time to time in its sole discretion
                as eligible to participate in the Plan.

            (g) "Employee" shall mean any individual who is an Employee of the
                Company whose customary employment with the Company is at least
                twenty (20) hours per week and more than five (5) months in any
                calendar year. For purposes of the Plan, the employment
                relationship shall be treated as continuing intact while the
                individual is on sick leave or other leave of absence approved
                by the Company. Where the period of leave exceeds 90 days and
                the individual's right to reemployment is not guaranteed either
                by statute or by contract, the employment relationship shall be
                deemed to have terminated on the 91st day of such leave.

            (h) "Enrollment Date" shall mean the first day of each Offering
                Period.

            (i) "Exercise Date" shall mean the last Trading Day of each calendar
                quarter.


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2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 1

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            (j) "Fair Market Value" shall mean, as of any date, the value of
                Common Stock determined as follows:

                (1) If the Common Stock is listed on any established stock
                    exchange or a national market system, including without
                    limitation the Nasdaq National Market or The Nasdaq SmallCap
                    Market of The Nasdaq Stock Market, its Fair Market Value
                    shall be the closing sales price for such stock (or the
                    closing bid, if no sales were reported) as quoted on such
                    exchange or system for the last market trading day on the
                    date of such determination, as reported in The Wall Street
                    Journal or such other source as the Administrator deems
                    reliable, or;

                (2) If the Common Stock is regularly quoted by a recognized
                    securities dealer but selling prices are not reported, its
                    Fair Market Value shall be the mean of the closing bid and
                    asked prices for the Common Stock on the date of such
                    determination, as reported in The Wall Street Journal or
                    such other source as the Board deems reliable, or;

                (3) In the absence of an established market for the Common
                    Stock, the Fair Market Value thereof shall be determined in
                    good faith by the Board.

            (k) "Offering Periods" shall mean the period of approximately twelve
                (12) months during which an option granted pursuant to the Plan
                may be exercised, commencing on the first Trading Day on or
                after August 1 of each year, and terminating on the last Trading
                Day on or after July 31. The duration and timing of Offering
                Periods may be changed pursuant to Section 4 of this Plan.

            (l) "Plan" shall mean this Employee Stock Purchase Plan.

            (m) "Purchase Period" shall mean the approximately three-month
                period commencing after one Exercise Date and ending with the
                next Exercise Date, except that the first Purchase Period of any
                Offering Period shall commence on the Enrollment Date and end
                with the next Exercise Date.

            (n) "Purchase Price" shall mean an amount equal to 85% of the Fair
                Market Value of a share of Common Stock on the Enrollment Date,
                or on the Exercise Date, whichever is lower.

            (o) "Reserves" shall mean the number of shares of Common Stock
                covered by each option under the Plan which have not yet been
                exercised and the number of shares of Common Stock which have
                been authorized for issuance under the Plan but not yet placed
                under option.


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2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 2

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            (p) "Subsidiary" shall mean a corporation, domestic or foreign, of
                which not less than 50% of the voting shares are held by the
                Company or a Subsidiary, whether or not such corporation now
                exists or is hereafter organized or acquired by the Company or a
                Subsidiary.

            (q) "Trading Day" shall mean a day on which national stock exchanges
                and the Nasdaq System are open for trading.

         3. Eligibility.

            (a) Any Employee who shall be employed by the Company on a given
                Enrollment Date shall be eligible to participate in the Plan.

            (b) Any provisions of the Plan to the contrary notwithstanding, no
                Employee shall be granted an option under the Plan (i) to the
                extent that, immediately after the grant, such Employee (or any
                other person whose stock would be attributed to such Employee
                pursuant to Section 424(d) of the Code) would own capital stock
                of the Company and/or hold outstanding options to purchase such
                stock possessing five percent (5%) or more of the total combined
                voting power or value of all classes of the capital stock of the
                Company or of any Subsidiary, or (ii) to the extent that his or
                her rights to purchase stock under all employee stock purchase
                plans of the Company and its subsidiaries accrues at a rate
                which exceeds Twenty-Five Thousand Dollars ($25,000) worth of
                stock (determined at the fair market value of the shares at the
                time such option is granted) for each calendar year in which
                such option is outstanding at any time.

         4. Offering Periods. The Plan shall be implemented by consecutive
Offering Periods on such dates as the Board shall determine, and continuing
thereafter until terminated in accordance with Section 20 hereof. The Board
shall have the power to change the duration of Offering Periods (including the
commencement dates thereof) with respect to future offerings without shareholder
approval if such change is announced at least five (5) days prior to the
scheduled beginning of the first Offering Period to be affected thereafter.

         5. Participation.

            (a) An eligible Employee may become a participant in the Plan by
                completing a subscription agreement authorizing payroll
                deductions in the form of Exhibit A to this Plan and filing it
                with the Company's payroll office prior to the applicable
                Enrollment Date.

            (b) Payroll deductions for a participant shall commence on the first
                payroll following the Enrollment Date and shall end on the last
                payroll in the Offering Period to which such authorization is
                applicable, unless sooner terminated by the participant as
                provided in Section 10 hereof.


EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 3

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         6. Payroll Deductions.

            (a) At the time a participant files his or her subscription
                agreement, he or she shall elect to have payroll deductions made
                on each pay day during the Offering Period in an amount not
                exceeding fifteen percent (15%) of the Compensation which he or
                she receives on each pay day during the Offering Period.

            (b) All payroll deductions made for a participant shall be credited
                to his or her account under the Plan and shall be withheld in
                whole percentages only. A participant may not make any
                additional payments into such account.

            (c) A participant may discontinue his or her participation in the
                Plan as provided in Section 10 hereof, or may increase or
                decrease the rate of his or her payroll deductions during the
                Offering Period by completing or filing with the Company a new
                subscription agreement authorizing a change in payroll deduction
                rate. The Board may, in its discretion, limit the number of
                participation rate changes during any Offering Period. The
                change in rate shall be effective with the first full payroll
                period following five (5) business days after the Company's
                receipt of the new subscription agreement unless the Company
                elects to process a given change in participation more quickly.
                A participant's subscription agreement shall remain in effect
                for successive Offering Periods unless terminated as provided in
                Section 10 hereof.

            (d) Notwithstanding the foregoing, to the extent necessary to comply
                with Section 423(b)(8) of the Code and Section 3(b) hereof, a
                participant's payroll deductions may be decreased to zero
                percent (0%) at any time during a Purchase Period. Payroll
                deductions shall recommence at the rate provided in such
                participant's subscription agreement at the first Offering
                Period in the following calendar year, unless terminated by the
                participant as provided in Section 10 hereof.

            (e) At the time the option is exercised, in whole or in part, or at
                the time some or all of the Company's Common Stock issued under
                the Plan is disposed of, the participant must make adequate
                provision for the Company's federal, state, or other tax
                withholding obligations, if any, which arise upon the exercise
                of the option or the disposition of the Common Stock. At any
                time, the Company may, but shall not be obligated to, withhold
                from the participant's Compensation the amount necessary for the
                Company to meet applicable withholding obligations, including
                any withholding required to make available to the Company any
                tax deductions or benefits attributable to sale or early
                disposition of Common Stock by the Employee.


EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 4

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         7. Grant of Option. On the Enrollment Date of each Offering Period,
each eligible Employee participating in such Offering Period shall be granted an
option to purchase on each Exercise Date during such Offering Period (at the
applicable Purchase Price) up to a number of shares of the Company's Common
Stock determined by dividing such Employee's payroll deductions accumulated
prior to such Exercise Date and retained in the Participant's account as of the
Exercise Date by the applicable Purchase Price; provided that such purchase
shall be subject to the limitations set forth in Sections 3(b) and 12 hereof.
Exercise of the option shall occur as provided in Section 8 hereof, unless the
participant has withdrawn pursuant to Section 10 hereof. The option shall expire
on the last day of the Offering Period.

         8. Exercise of Option. Unless a participant withdraws from the Plan as
provided in Section 10 hereof, his or her option for the purchase of shares
shall be exercised automatically on the Exercise Date, and the maximum number of
full shares subject to option shall be purchased for such participant at the
applicable Purchase Price with the accumulated payroll deductions in his or her
account. No fractional shares shall be purchased; any payroll deductions
accumulated in a participant's account which are not sufficient to purchase a
full share shall be retained in the participant's account for the subsequent
Purchase Period or Offering Period, subject to earlier withdrawal by the
participant as provided in Section 10 hereof. Any other monies left over in a
participant's account after the Exercise Date shall be returned to the
participant. During a participant's lifetime, a participant's option to purchase
shares hereunder is exercisable only by him or her.

         9. Delivery. As promptly as practicable after each Exercise Date on
which a purchase of shares occurs, the Company shall arrange the delivery to
each participant, as appropriate, of a certificate representing the shares
purchased upon exercise of his or her option.

         10. Withdrawal.

             (a) A participant may withdraw all but not less than all the
                 payroll deductions credited to his or her account and not yet
                 used to exercise his or her option under the Plan at any time
                 by giving written notice to the Company in the form of Exhibit
                 B to this Plan. All of the participant's payroll deductions
                 credited to his or her account shall be paid to such
                 participant promptly after receipt of notice of withdrawal and
                 such participant's option for the Offering Period shall be
                 automatically terminated, and no further payroll deductions for
                 the purchase of shares shall be made for such Offering Period.
                 If a participant withdraws from an Offering Period, payroll
                 deductions shall not resume at the beginning of the succeeding
                 Offering Period unless the participant delivers to the Company
                 a new subscription agreement.

             (b) A participant's withdrawal from an Offering Period shall not
                 have any effect upon his or her eligibility to participate in
                 any similar plan which may hereafter be adopted by the Company
                 or in succeeding Offering Periods which commence after the
                 termination of the Offering Period from which the participant
                 withdraws.


EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 5

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         11. Termination of Employment.

             Upon a participant's ceasing to be an Employee, for any reason, he
or she shall be deemed to have elected to withdraw from the Plan and the payroll
deductions credited to such participant's account during the Offering Period but
not yet used to exercise the option shall be returned to such participant or, in
the case of his or her death, to the person or persons entitled thereto under
Section 15 hereof, and such participant's option shall be automatically
terminated. The preceding sentence notwithstanding, a participant who receives
payment in lieu of notice of termination of employment shall be treated as
continuing to be an Employee for the participant's customary number of hours per
week of employment during the period in which the participant is subject to such
payment in lieu of notice.

         12. Interest. No interest shall accrue on the payroll deductions of a
participant in the Plan.

         13. Stock.

             (a) Subject to Section 19, the maximum number of shares of the
                 Company's Common Stock which shall be made available for sale
                 under the Plan shall be 100,000 shares, together with an annual
                 increase to the number of shares reserved thereunder to take
                 effect each year on the date of the Annual Meeting of
                 Shareholders (commencing with the 2001 Annual Meeting of
                 Shareholders) equal to 50,000 shares. If, on a given Exercise
                 Date, the number of shares with respect to which options are to
                 be exercised exceeds the number of shares then available under
                 the Plan, the Company shall make a pro rata allocation of the
                 shares remaining available for purchase in as uniform a manner
                 as shall be practicable and as it shall determine to be
                 equitable.

             (b) The participant shall have no interest or voting right in
                 shares covered by his option until such option has been
                 exercised.

             (c) Shares to be delivered to a participant under the Plan shall be
                 registered in the name of the participant or in the name of the
                 participant and his or her spouse.

         14. Administration. The Plan shall be administered by the Board or a
committee of members of the Board appointed by the Board. The Board or its
committee shall have full and exclusive discretionary authority to construe,
interpret and apply the terms of the Plan, to determine eligibility and to
adjudicate all disputed claims filed under the Plan. Every finding, decision and
determination made by the Board or its committee shall, to the full extent
permitted by law, be final and binding upon all parties.


EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 6

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         15. Designation of Beneficiary.

             (a) A participant may file a written designation of a beneficiary
                 who is to receive any shares and cash, if any, from the
                 participant's account under the Plan in the event of such
                 participant's death subsequent to an Exercise Date on which the
                 option is exercised but prior to delivery to such participant
                 of such shares and cash. In addition, a participant may file a
                 written designation of a beneficiary who is to receive any cash
                 from the participant's account under the Plan in the event of
                 such participant's death prior to exercise of the option. If a
                 participant is married and the designated beneficiary is not
                 the spouse, spousal consent shall be required for such
                 designation to be effective.

             (b) Such designation of beneficiary may be changed by the
                 participant at any time by written notice. In the event of the
                 death of a participant and in the absence of a beneficiary
                 validly designated under the Plan who is living at the time of
                 such participant's death, the Company shall deliver such shares
                 and/or cash to the executor or administrator of the estate of
                 the participant, or if no such executor or administrator has
                 been appointed (to the knowledge of the Company), the Company,
                 in its discretion, may deliver such shares and/or cash to the
                 spouse or to any one or more dependents or relatives of the
                 participant, or if no spouse, dependent or relative is known to
                 the Company, then to such other person as the Company may
                 designate.

         16. Transferability. Neither payroll deductions credited to a
participant's account nor any rights with regard to the exercise of an option or
to receive shares under the Plan may be assigned, transferred, pledged or
otherwise disposed of in any way (other than by will, the laws of descent and
distribution or as provided in Section 15 hereof) by the participant. Any such
attempt at assignment, transfer, pledge or other disposition shall be without
effect, except that the Company may treat such act as an election to withdraw
funds from an Offering Period in accordance with Section 10 hereof.

         17. Use of Funds. All payroll deductions received or held by the
Company under the Plan may be used by the Company for any corporate purpose, and
the Company shall not be obligated to segregate such payroll deductions.

         18. Reports. Individual accounts shall be maintained for each
participant in the Plan. Statements of account shall be given to participating
Employees at least annually, which statements shall set forth the amounts of
payroll deductions, the Purchase Price, the number of shares purchased and the
remaining cash balance, if any.

         19. Adjustments Upon Changes in Capitalization, Dissolution,
Liquidation, Merger or Asset Sale.


EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 7

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             (a) Changes in Capitalization. Subject to any required action by
                 the shareholders of the Company, the Reserves, as well as the
                 price per share and the number of shares of Common Stock
                 covered by each option under the Plan which has not yet been
                 exercised, shall be proportionately adjusted for any increase
                 or decrease in the number of issued shares of Common Stock
                 resulting from a stock split, reverse stock split, stock
                 dividend, combination or reclassification of the Common Stock,
                 or any other increase or decrease in the number of shares of
                 Common Stock effected without receipt of consideration by the
                 Company; provided, however, that conversion of any convertible
                 securities of the Company shall not be deemed to have been
                 "effected without receipt of consideration". Such adjustment
                 shall be made by the Board, whose determination in that respect
                 shall be final, binding and conclusive. Except as expressly
                 provided herein, no issuance by the Company of shares of stock
                 of any class, or securities convertible into shares of stock of
                 any class, shall affect, and no adjustment by reason thereof
                 shall be made with respect to, the number or price of shares of
                 Common Stock subject to an option.

             (b) Dissolution or Liquidation. In the event of the proposed
                 dissolution or liquidation of the Company, the Offering Period
                 then in progress shall be shortened by setting a new Exercise
                 Date (the "New Exercise Date"), and shall terminate immediately
                 prior to the consummation of such proposed dissolution or
                 liquidation, unless provided otherwise by the Board. The New
                 Exercise Date shall be before the date of the Company's
                 proposed dissolution or liquidation. The Board shall notify
                 each participant in writing, at least ten (10) business days
                 prior to the New Exercise Date, that the Exercise Date for the
                 participant's option has been changed to the New Exercise Date
                 and that the participant's option shall be exercised
                 automatically on the New Exercise Date, unless prior to such
                 date the participant has withdrawn from the Offering Period as
                 provided in Section 10 hereof.

             (c) Merger or Asset Sale. In the event of a proposed sale of all or
                 substantially all of the assets of the Company, or the merger
                 of the Company with or into another corporation, each
                 outstanding option shall be assumed or an equivalent option
                 substituted by the successor corporation or a Parent or
                 Subsidiary of the successor corporation. In the event that the
                 successor corporation refuses to assume or substitute for the
                 option, any Purchase Periods then in progress shall be
                 shortened by setting a new Exercise Date (the "New Exercise
                 Date") and the current Offering Period shall end on the New
                 Exercise Date. The New Exercise Date shall be before the date
                 of the Company's proposed sale or merger. The Board shall
                 notify each participant in writing, at least ten (10) business
                 days prior to the New Exercise Date, that the Exercise Date for
                 the participant's option has been changed to the New Exercise
                 Date and that the participant's option shall be exercised
                 automatically on the New Exercise Date, unless prior to such


EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 8

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                 date the participant has withdrawn from the Offering Period as
                 provided in Section 10 hereof.

         20. Amendment or Termination.

             (a) The Board of Directors of the Company may at any time and for
                 any reason terminate or amend the Plan. Except as provided in
                 Section 19 hereof, no such termination can affect options
                 previously granted, provided that an Offering Period may be
                 terminated by the Board of Directors on any Exercise Date if
                 the Board determines that the termination of the Plan is in the
                 best interests of the Company and its shareholders. Except as
                 provided in Section 19 hereof, no amendment may make any change
                 in any option theretofore granted which adversely affects the
                 rights of any participant. To the extent necessary to comply
                 with Section 423 of the Code (or any successor rule or
                 provision or any other applicable law, regulation or stock
                 exchange rule), the Company shall obtain shareholder approval
                 in such a manner and to such a degree as required.

             (b) Without shareholder consent and without regard to whether any
                 participant rights may be considered to have been "adversely
                 affected," the Board (or its committee) shall be entitled to
                 change the Offering Period, limit the frequency and/or number
                 of changes in the amount withheld during an Offering Period,
                 establish the exchange ratio applicable to amounts withheld in
                 a currency other than U.S. dollars, permit payroll withholding
                 in excess of the amount designated by a participant in order to
                 adjust for delays or mistakes in the Company's processing of
                 properly completed withholding elections, establish reasonable
                 waiting and adjustment periods and/or accounting and crediting
                 procedures to ensure that amounts applied toward the purchase
                 of Common Stock for each participant properly correspond with
                 amounts withheld from the participant's Compensation, and
                 establish such other limitations or procedures as the Board (or
                 its committee) determines in its sole discretion advisable
                 which are consistent with the Plan.

         21. Notices. All notices or other communications by a participant to
the Company under or in connection with the Plan shall be deemed to have been
duly given when received in the form specified by the Company at the location,
or by the person, designated by the Company for the receipt thereof.

         22. Conditions Upon Issuance of Shares. Shares shall not be issued with
respect to an option unless the exercise of such option and the issuance and
delivery of such shares pursuant thereto shall comply with all applicable
provisions of law, domestic or foreign, including, without limitation, the
Securities Act of 1933, as amended, the Securities Exchange Act of 1934, as
amended, the rules and regulations promulgated thereunder, and the requirements
of any stock exchange upon which the shares may then be listed, and shall be
further subject to the approval of counsel for the Company with respect to such
compliance.


EXHIBIT B - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                         PAGE 9

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         As a condition to the exercise of an option, the Company may require
the person exercising such option to represent and warrant at the time of any
such exercise that the shares are being purchased only for investment and
without any present intention to sell or distribute such shares if, in the
opinion of counsel for the Company, such a representation is required by any of
the aforementioned applicable provisions of law.

         23. Term of Plan. The Plan shall become effective upon the earlier to
occur of its adoption by the Board of Directors or its approval by the
shareholders of the Company. It shall continue in effect for a term of ten (10)
years unless sooner terminated under Section 20 hereof.


EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                        PAGE 10

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                                    EXHIBIT A

                          INTERNATIONAL ISOTOPES, INC.

                        2000 EMPLOYEE STOCK PURCHASE PLAN

                             SUBSCRIPTION AGREEMENT

      ORIGINAL APPLICATION                           ENROLLMENT DATE:
- -----                                                                 ----------
      CHANGE IN PAYROLL DEDUCTION RATE
- -----
      CHANGE OF BENEFICIARY(IES)
- -----

1.       _______________________ hereby elects to participate in the
         International Isotopes, Inc. 2000 Employee Stock Purchase Plan (the
         "Employee Stock Purchase Plan") and subscribes to purchase shares of
         the Company's Common Stock in accordance with this Subscription
         Agreement and the Employee Stock Purchase Plan.

2.       I hereby authorize payroll deductions from each paycheck in the amount
         of ____% of my Compensation on each payday (from 1 to 15%) during the
         Offering Period in accordance with the Employee Stock Purchase Plan.
         (Please note that no fractional percentages are permitted.)

3.       I understand that said payroll deductions shall be accumulated for the
         purchase of shares of Common Stock at the applicable Purchase Price
         determined in accordance with the Employee Stock Purchase Plan. I
         understand that if I do not withdraw from an Offering Period, any
         accumulated payroll deductions will be used to automatically exercise
         my option.

4.       I have received a copy of the complete Employee Stock Purchase Plan. I
         understand that my participation in the Employee Stock Purchase Plan is
         in all respects subject to the terms of the Plan.

5.       Shares purchased for me under the Employee Stock Purchase Plan should
         be issued in the name(s) of (Employee or Employee and Spouse only):
         ___________________________.

6.       I understand that if I dispose of any shares received by me pursuant to
         the Plan within 2 years after the Enrollment Date (the first day of the
         Offering Period during which I purchased such shares) or one year after
         the Exercise Date, I will be treated for federal income tax purposes as
         having received ordinary income at the time of such disposition in an
         amount equal to the excess of the fair market value of the shares at
         the time such shares were purchased by me over the price which I paid
         for the shares. I hereby agree to notify the Company in writing within
         30 days after the date of any disposition of my shares and I


EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                        PAGE 1

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         will make adequate provision for Federal, state or other tax
         withholding obligations, if any, which arise upon the disposition of
         the Common Stock. The Company may, but will not be obligated to,
         withhold from my compensation the amount necessary to meet any
         applicable withholding obligation including any withholding necessary
         to make available to the Company any tax deductions or benefits
         attributable to sale or early disposition of Common Stock by me. If I
         dispose of such shares at any time after the expiration of the 2-year
         and 1-year holding periods, I understand that I will be treated for
         federal income tax purposes as having received income only at the time
         of such disposition, and that such income will be taxed as ordinary
         income only to the extent of an amount equal to the lesser of (1) the
         excess of the fair market value of the shares at the time of such
         disposition over the purchase price which I paid for the shares, or (2)
         15% of the fair market value of the shares on the first day of the
         Offering Period. The remainder of the gain, if any, recognized on such
         disposition will be taxed as capital gain.

7.       I hereby agree to be bound by the terms of the Employee Stock Purchase
         Plan. The effectiveness of this Subscription Agreement is dependent
         upon my eligibility to participate in the Employee Stock Purchase Plan.

8.       In the event of my death, I hereby designate the following as my
         beneficiary(ies) to receive all payments and shares due me under the
         Employee Stock Purchase Plan:

NAME:  (PLEASE PRINT)
                      ----------------------------------------------------------
                           (FIRST)              (MIDDLE)           (LAST)


- -----------------------------------          -----------------------------------
RELATIONSHIP

                                             -----------------------------------
                                                         (ADDRESS)

EMPLOYEE'S SOCIAL SECURITY NUMBER:
                                             -----------------------------------
EMPLOYEE'S ADDRESS:
                                             -----------------------------------

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

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


I UNDERSTAND THAT THIS SUBSCRIPTION AGREEMENT SHALL REMAIN IN EFFECT THROUGHOUT
SUCCESSIVE OFFERING PERIODS UNLESS TERMINATED BY ME.

DATED:
       ----------------------------          -----------------------------------
                                             SIGNATURE OF EMPLOYEE


                                             ----------------------------------
                                             SPOUSE'S SIGNATURE (IF BENEFICIARY
                                             OTHER THAN SPOUSE)



EXHIBIT A - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                        PAGE 2
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                                    EXHIBIT B

                          INTERNATIONAL ISOTOPES, INC.

                        2000 EMPLOYEE STOCK PURCHASE PLAN

                              NOTICE OF WITHDRAWAL

         The undersigned participant in the Offering Period of the International
Isotopes, Inc. 2000 Employee Stock Purchase Plan which began on August 1, 20____
(the "Enrollment Date") hereby notifies the Company that he or she hereby
withdraws from the Offering Period. He or she hereby directs the Company to pay
to the undersigned as promptly as practicable all the payroll deductions
credited to his or her account with respect to such Offering Period. The
undersigned understands and agrees that his or her option for such Offering
Period will be automatically terminated. The undersigned understands further
that no further payroll deductions will be made for the purchase of shares in
the current Offering Period and the undersigned shall be eligible to participate
in succeeding Offering Periods only by delivering to the Company a new
Subscription Agreement.

                                          NAME AND ADDRESS OF PARTICIPANT:

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

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

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

                                          SIGNATURE:

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

                                          DATE:
                                                --------------------------------



EXHIBIT B - INTERNATIONAL ISOTOPES, INC.
2000 EMPLOYEE STOCK PURCHASE PLAN                                        PAGE 1