<PAGE>

                                                                      EXHIBIT 10

                              EMPLOYMENT AGREEMENT

      THIS AGREEMENT (this "Agreement"), dated as of February 12, 2003, is made
by and between Biopure Corporation, a Delaware corporation, having its principal
place of business at 11 Hurley Street, Cambridge, MA 02141 (the "Company"), and
Mr. Ronald F. Richards (the "Executive").

                                    Recitals

      1. The Company wishes to employ the Executive as the Chief Financial
Officer and Senior Vice President, Business Development of the Company.

      2. The Company has determined that it is essential to enter into an
employment agreement having the compensation and benefits herein to induce the
Executive to be so employed.

      3. The Executive agrees to accept such employment by the Company on the
terms set forth herein.

                                    Agreement

      NOW, THEREFORE, in consideration of the mutual covenants and premises
herein contained, and other good and valuable consideration, the receipt of
which is mutually acknowledged, the Company and the Executive hereby agree as
follows.

      1. CERTAIN DEFINITIONS.

      1.1 "Effective Date" shall mean the first day of Executive's employment,
which shall be February 12, 2003.

      1.2 "Employment Period" shall mean the period of time beginning on the
Effective Date and ending on the second anniversary of the Effective Date or as
further extended in accordance with the provisions of this Section 1.2. The
Employment Period (as it may have been extended pursuant to the provisions of
this sentence and subject to the provisions of Section 5 below) shall be
extended or further extended, as the case may be, without any action by the
Company or the Executive, on the second anniversary of the Effective Date and on
each subsequent anniversary thereof for an additional period of one year, unless
and until either party gives written notice to the other party at least sixty
(60) days in advance of any such anniversary that the Employment Period in
effect when such notice is given is not to be extended or further extended, as
the case may be.

      1.3 "Board" shall mean the Board of Directors of the Company.

      2. EMPLOYMENT. Subject to the terms and conditions provided herein, the
Company hereby agrees, during the Employment Period, to employ the Executive as
its Chief Financial Officer and Senior Vice President, Business Development. The
Executive hereby agrees to accept such employment during the Employment Period.

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      3. EMPLOYMENT DUTIES. During the Employment Period, the Executive shall
have such duties and responsibilities as are assigned to the Executive by the
Board or the Chief Executive Officer and shall not be required to do anything
inconsistent with the normal and customary responsibilities and duties of a
Chief Financial Officer and Senior Vice President, Business Development in
comparable companies. Executive shall take direction from and report to the
Chief Executive Officer. During the Employment Period, the Executive agrees to
devote substantially all of his business attention and time to the business and
affairs of the Company and its subsidiaries, and to use the Executive's
reasonable best efforts to perform faithfully the duties and responsibilities
assigned to the Executive under this Section 3. Notwithstanding the foregoing,
it is expressly understood that (a) the Executive may devote a reasonable amount
of time to the management of his investments and affairs and to such industry
associations, charitable and civic endeavors as shall not materially interfere
significantly with the obligations set forth in the preceding sentence, and (b)
with the prior approval of the Board (which shall not be unreasonably withheld
and subject to the non-competition provision in Section 9), the Executive may
serve as a member of one or more boards of directors of companies that are not
affiliated with the Company; the Executive shall have the right during the
Employment Period to continue to serve as a director of Nolo, Inc. and fulfill
all of the duties and responsibilities associated with that position.

      4. COMPENSATION.

      4.1 Base Salary. Beginning February 26, 2003 and during the balance of the
Employment Period, the Company shall pay the Executive a base salary (the "Base
Salary") of no less than $250,000 per annum, payable in accordance with the
Company's normal payroll practices for senior executives. The Base Salary shall
be reviewed at least once each year. When the Base Salary is reviewed, it may be
increased (but not decreased) in accordance with the Company's regular review of
senior executive salaries, and if increased, then such increased amount shall
become the Base Salary.

      4.2 Incentive, Savings and Retirement Plans. During the Employment Period,
the Executive shall be eligible to participate in all bonus, short- or long-term
incentive plans and programs established by the Board from time to time and in
existence on or after the Effective Date for the benefit of senior executives of
the Company. It is understood that the Executive's target bonus opportunity
under the Company's bonus plan shall be approximately 50% of his Base Salary.
During the Employment Period, the Executive shall be eligible to participate in
all savings and retirement plans and programs (as the plan terms allow)
maintained by the Company from time to time on or after the Effective Date for
the benefit of employees and/or senior executives or employees of the Company.
In addition, the Executive shall be eligible to receive annual or periodic
awards under the Company's 2002 Omnibus Securities and Incentive Plan ("Plan")
or any other such plan in which senior executives may become eligible to
participate from time to time; provided, however, that such awards shall be
granted in the sole discretion of the Company.

      4.3 Welfare Benefit Plans. During the Employment Period and as of the
Effective Date, the Executive and/or the Executive's family as the terms allow
shall participate in all welfare benefit plans, programs and arrangements
maintained by the Company from time to


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time on or after the Effective Date for the benefit of senior executives or
employees of the Company.

      4.4 Vacation; Fringe Benefits. During the Employment Period, the Executive
shall be entitled to four (4) weeks of vacation annually, and any accrued and
unused vacation shall be carried over to the next year without any reduction;
provided, however, that the maximum carryover on a year-to-year basis shall be
four (4) weeks. During the Employment Period, the Executive shall receive such
perquisites and fringe benefits as are generally provided to senior executives
of the Company. The Executive shall be reimbursed for his reasonable business
expenses in accordance with Company policy. During the Employment Period, the
Company shall reimburse the Executive for reasonable travel expenses for his
wife to accompany him on extended business trips required to be taken in
carrying out his duties and responsibilities up to an annual limit of $15,000,
without carryover of any unused amount. Air travel shall be business class, and
if business class is not available, then the Executive may travel first class if
the flight is outside of the contiguous United States. Any benefit received by
the Executive under this Section 4.4 that is taxed as compensation (other than
vacation pay, if any) will be "grossed up" by the Company for all applicable
taxes.

      4.5 Stock Option Grant.

            (a) On the Effective Date, the Executive shall be granted stock
options under the Plan entitling the Executive to acquire 150,000 shares of the
Company's class A common stock at an exercise price equal to the Fair Market
Value on the date of grant. Such options shall be for a term of 10 years from
the Effective Date. The options shall be governed by one or more stock option
agreements, the terms of which shall be consistent with this Section 4.5 and
with the terms of the Plan. The options shall be or become exercisable, i.e.,
shall vest, in respect of the shares underlying such options as follows:

            1. 30,000 shares     on the Effective Date;

            2. 120,000 shares    5,000 shares per month on the first of each
                                 month over the next 24 months.

            (b) The Executive shall forfeit any unvested options upon
termination of employment with the Company for any reason, except as otherwise
specifically provided in this Agreement.

            (c) "Fair Market Value" shall have the meaning set forth in the
Plan.

            (d) If there is a Change in Control (as defined in the Plan as in
effect as of the date of this Agreement), then all outstanding unvested stock
options held by the Executive as of the date of such Change in Control shall
immediately vest as of the date of such Change in Control and shall remain
exercisable until the earlier of (i) the end of the 90-day period following the
date of the termination of the Executive's employment with the Company or (ii)
the tenth anniversary of the date of grant of such option

      4.6 Relocation. The Company shall reimburse Executive up to a maximum of
$50,000 for (i) his reasonable moving expenses in connection with his relocation
from Tiburon,


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California to the Boston area and (ii) expenses incurred in finding and securing
a residence in the Boston area, all subject to presentation of appropriate
receipts. These expenses may include travel expenses for the Executive and his
spouse between Tiburon, California and Boston, hotel or temporary housing costs.
Any benefit received by the Executive under this Section 4.6 that is taxed as
compensation will be "grossed up" by the Company for all applicable taxes. Real
estate brokerage fees shall not be reimbursable under this section.

      4.7 Signing Bonus. Executive will be paid a one-time, signing bonus of
$80,000, to be paid 30 days after the Effective Date.

      4.8 Power of Board Unimpaired. Nothing in this Section 4 shall impair the
ability of the Board in its discretion to amend or eliminate any plan or policy
described or referred to in this Section 4, provided, however, that any such
amendment or elimination shall not adversely affect, impair or impact any
outstanding stock-based award held by the Executive as of the date of such
amendment or elimination.

      5. TERMINATION.

      5.1 Death or Disability. The Employment Period shall terminate
automatically upon the Executive's death. If, during the Employment Period, the
Disability (as defined below) of the Executive has occurred, the Company may
give to the Executive written notice of its intention to terminate the
Executive's employment due to such Disability. The Executive's employment with
the Company shall be terminated by the Company on the 30th day after receipt by
the Executive of such notice (the "Disability Effective Date"), if, within such
thirty (30) day period, the Executive shall not have returned to full-time
performance of the Executive's duties. For purposes of this Agreement,
"Disability" means a physical or mental disability resulting in the inability of
the Executive to substantially perform his duties full-time under this
Agreement, as set forth in Section 3, during any consecutive six-month period,
as determined by a licensed physician mutually selected by the Company and the
Executive or his legal representative. If the Company and the Executive cannot
agree as to the selection of a licensed physician for purposes of making such
determination, then each party shall select a licensed physician and these two
licensed physicians shall select a third licensed physician who shall make such
determination. Nothing in this Section 5.1 is intended to be inconsistent with
or in any way alter the parties' responsibilities under applicable federal or
state law regarding disabilities, if any.

      5.2 Cause.

            (a) The Board may terminate the employment of the Executive for
Cause by written notice to the Executive. Upon receipt of such written notice,
the Executive shall have the right to seek (within ten (10) business days) an
opportunity to be heard by the Board, which opportunity the Board shall arrange
as promptly and in such format as directors' schedules permit. For purposes of
this Agreement, "Cause" shall mean (a) an act or acts of material personal
dishonesty taken by, or committed at the request of, Executive, intended to
result in the personal enrichment of the Executive at the expense of the
Company, or any of its Affiliates, (b) repeated willful violations by Executive
of the material terms of this Agreement,


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which have not been cured within thirty (30) days after written notice has been
given by the Board to the Executive, or (c) the conviction of Executive of a
felony.

            (b) In the event the Board wishes to terminate the Executive for
breach of this Agreement pursuant to Section 5.2(a), and such breach is capable
of being cured, the Board shall provide the Executive with written notice
specifying in reasonable detail the services or matters which it contends the
Executive has not adequately performed, or the material provisions of this
Agreement of which the Executive is in violation and the acts constituting such
violation, why the Company has Cause to terminate this Agreement and what the
Executive should do to adequately perform his obligations hereunder along with a
copy of a resolution, duly adopted by the Board at a meeting called and held for
the purpose (after reasonable notice to Executive and an opportunity for him to
be heard before the Board), finding that Executive is in default hereunder. If
within ten (10) days of receipt of the notice, the Board reasonably believes
that the Executive has performed the required services or has modified his
performance to correct the matters complained of, the Executive's breach will be
deemed cured, and the Executive shall not be terminated. However, if the nature
of the service not performed by the Executive or the matters complained of are
such that more than ten (10) days are reasonably required to perform the
required service or to correct the matters complained of, then his breach will
be deemed cured if the Executive commences to perform such service or to correct
such matters within the ten (10) day period and thereafter diligently prosecutes
such performance or correction to completion in a time frame established by the
Board, in its reasonable judgment. If the Executive does not perform the
required services or modify his performance to correct the matter complained of
within the ten (10) day period or the Board-approved extension thereof, the
Board shall have the right to terminate this Agreement at the end of the ten
(10) day period or extension thereof. If the Board, in its reasonable judgment,
determines that the Executive's breach of this Agreement pursuant to Section
5.2(a) is not capable of being cured, and in the event of any breach of Section
8 or of any of Sections 1 through 5 of the Protection of Company Property
Agreement (defined in Section 8), the Board may terminate the Executive
immediately for Cause by written notice to the Executive.

      5.3 Without Cause. During the Employment Period, upon written notice given
to the Executive, the Board may terminate the Executive's employment hereunder
other than for Cause.

      5.4 Termination by Executive for Good Reason. During the Employment
Period, the Executive may terminate his employment hereunder by written notice
for Good Reason. For purposes of this Agreement, "Good Reason" shall mean: (a)
the reduction of the Executive's Base Salary or target bonus opportunity without
the Executive's prior written consent; (b) the diminution, without his consent,
of the Executive's title, authority, duties or responsibilities as specified in
Section 3, or the assignment of duties and responsibilities that are
inconsistent with his positions as Chief Financial Officer and Senior Vice
President, Business Development of the Company, or if the Executive reports to
anyone other than the Chief Executive Officer and the Board; (c) the Company
requiring the Executive, without his consent, to be based in any office or
location other than the Company's headquarters office, and such headquarters
shall not be located during the Employment Period outside of a 30-mile radius of
Cambridge; (d) the material breach by the Company of any provision of this
Agreement which has not been cured within thirty (30) days after a notice of
termination has been given by the


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Executive to the Company; (e) a request by the Chief Executive Officer or the
Board that the Executive engage in activities that would result in materially
misleading or inaccurate financial reporting by the Company under generally
accepted accounting principles or (f) failure of the Company to obtain the
assumption in writing of its obligations under this Agreement as a condition
precedent of such succession.

      5.5 Termination by Executive Without Good Reason. During the Employment
Period the Executive may terminate employment hereunder by written notice
without Good Reason, and such termination shall not be deemed to be a breach of
this Agreement.

      5.6 Date of Termination. "Date of Termination" shall mean:

            (a) if the Executive's employment is terminated by the Company,
other than for Cause or Disability, the Date of Termination shall be the date on
which the Company notifies the Executive in writing of such termination under
Section 5.3;

            (b) if the Executive's employment is terminated by the Company for
Cause, the Date of Termination shall be at the end of the 10-day period or any
extension given under Section 5.2;

            (c) if the Executive's employment is terminated by the Executive,
the date of termination shall be the date on which the Executive notifies the
Company of such termination (or the date on which the Company otherwise first
learns of such termination);

            (d) if the Executive's employment is terminated by reason of death
or Disability, the Date of Termination shall be the date of death of the
Executive or the Disability Effective Date, as the case may be.

      6. OBLIGATIONS OF THE COMPANY UPON TERMINATION.

      6.1 Cause, Death, Disability or Voluntarily by the Executive. If the
Executive's employment is terminated by reason of the Executive's death, the
Executive's Disability, for Cause by the Company or by the Executive voluntarily
(other than for Good Reason), the Executive, or the Executive's legal
representative, as the case may be, shall be entitled to receive (a) the
Executive's Base Salary through the Date of Termination; (b) any compensation
previously deferred by the Executive (together with any accrued interest thereon
through the Date of Termination) and not yet paid by the Company, and any bonus
earned in the previous year and not yet paid by the Company; (c) any accrued
vacation pay through the Date of Termination not yet paid by the Company; and
(d) a pro rata bonus for the year of termination calculated and payable after
year-end, if any, provided, however that no such pro rata bonus shall be paid to
the Executive if his employment is terminated for Cause or voluntarily by the
Executive without Good Reason (such amounts specified in clauses (a), (b), (c)
and (d) are hereinafter referred to as the "Accrued Obligations"). Accrued
Obligations shall not include other compensation not described in the preceding
sentence accrued but not yet paid through the Date of Termination. All such
Accrued Obligations except for that specified in clause (d) shall be paid to the
Executive or to the Executive's estate or beneficiary, as applicable, in a lump
sum in cash within thirty (30) days after the Date of Termination or as
otherwise provided by law,


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whichever occurs first. In addition to the foregoing, if the Executive's
employment is terminated by reason of the Executive's death or Disability,
unvested options granted to the Executive during his employment shall
immediately vest and remain exercisable for one (1) year from the Date of
Termination. In the case of death, the Executive's family shall be entitled to
receive any family death benefits provided by the Company to surviving families
of senior executives. In the case of the Executive's Disability, the Executive
shall be entitled as of the Disability Effective Date to receive the disability
benefits provided by the Company to disabled senior executives.

      6.2 Other Than for Cause, Death or Disability, or by the Executive for
Good Reason. If, during the Employment Period, the Company terminates the
Executive's employment (other than for Cause, death or Disability) or the
Executive terminates his employment for Good Reason, the Executive shall be
entitled to receive, within thirty (30) days after the Date of Termination, the
following:

            (a) The Company shall pay to the Executive all Accrued Obligations.

            (b) The Company shall pay to the Executive in cash a lump sum amount
equal to the Executive's then current Base Salary for one year, provided,
however, that if the Executive's employment terminates other than for Cause,
death or Disability or if the Executive terminates his employment for Good
Reason during the 2-year period beginning on the date of a Change in Control (as
defined in the Company's 2002 Omnibus Securities and Incentive Plan), then the
Executive shall receive a lump sum payment equal to 200% of the Executive's then
current Base Salary.

            (c) The Company shall pay its proportionate share of the cost of the
Executive's COBRA continuation coverage for a period of 12 months or 24 months
if the Executive's employment terminates during the 2-year period beginning on
the date of Change in Control (as defined in the Plan).

            (d) All unvested options granted to the Executive during his
employment shall immediately vest and remain exercisable for ninety (90) days
from the Date of Termination.

            (e) The parties recognize and agree that, if the Company terminates
the Executive's employment during the Employment Period other than for Cause,
death or Disability or if the Executive terminates his employment during the
Employment Period for Good Reason, the actual damages to the Executive would be
difficult if not impossible to ascertain and agree that the Executive shall be
paid in accordance with the provisions of this Section 6.2. The Executive shall
not be required to mitigate the amount of any payment provided for in this
Section 6.2 by seeking other employment or otherwise, nor shall any compensation
earned by the Executive in other employment or otherwise reduce the amount of
any payment provided for in this Section 6.2.

      6.3 Full Satisfaction. The payments actually received, accepted and
retained by the Executive (or his legal representatives) under this Agreement
that are attributable to the termination of the Executive's employment shall be
in full and complete satisfaction of any and all claims the Executive (or his
legal representatives) may have against the Company which are


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in any way related to the employment relationship (including the Executive's
hiring) between the Executive and the Company or the termination of that
relationship.

      6.4 Other Payments. Notwithstanding anything to the contrary contained
herein (including without limitation Section 6.3), any compensation or benefits,
if any, which are vested in the Executive or which the Executive is otherwise
entitled to receive under any plan, program or arrangement of the Company
before, at or subsequent to the Date of Termination shall be payable in
accordance with the terms and provisions of such plan, program or arrangement.
Any incentive, savings, retirement, or welfare or fringe benefit plan or program
may be changed by the Company in its discretion, provided, however, that such
change shall not adversely affect, impair or impact the Executive (unless such
change is broad-based and applies to all current and former employees of the
Company).

      7. TAXES. The Company may withhold from any amounts payable under this
Agreement such federal, state or local taxes or other withholdings as shall be
required or permitted to be withheld pursuant to any applicable law or
regulation, the operation of any incentive, savings, retirement, or welfare or
fringe benefit plan, or by written agreement with the Executive. In addition, if
any payment to the Executive would trigger "golden parachute" excise taxes
pursuant to Section 4999 of the Internal Revenue Code of 1986, as amended (the
"Code"), or any successor provision, a gross-up payment will be provided in an
amount sufficient to make the Executive whole for applicable excise taxes and
all income, employment, additional excise taxes or any interest or penalties
with respect to such gross-up payment (the "Gross-Up Payment"). All
determinations concerning whether a Gross-Up Payment is due to the Executive and
the amount of such Gross-Up Payment will be made by a nationally recognized
certified public accounting firm (the "Accounting Firm") selected by the Company
and subject to the approval of the Executive, such approval not to be
unreasonably withheld. If the Accounting Firm determines that any Gross-Up
Payment is due to the Executive, the Company shall pay the required Gross-Up
Payment to the Executive or on the Executive's behalf within ten (10) business
days after receipt of such determination and calculations. If the Accounting
Firm determines that no "golden parachute" excise taxes would be triggered, it
will, at the same time as it makes such determination, furnish the Executive
with an opinion that the Executive has substantial authority not to report any
excise tax on the Executive's federal, state, local income or other tax return.
Any determination by the Accounting Firm as to the amount of the Gross-Up
Payment will be binding upon the Company and the Executive.

      8. CONFIDENTIAL INFORMATION. The Executive shall execute and deliver to
the Company on or prior to the Effective Date an Employee Agreement Concerning
Protection of Company Property and the Arbitration of Legal Disputes
("Protection of Company Property Agreement") in the form attached hereto, the
terms of which are incorporated herein by reference; provided, however, that to
the extent that a term or provision of this Agreement conflicts with any term or
provision of the Protection of Company Property Agreement, such term or
provision of this Agreement shall prevail over such term or provision of the
Protection of Company Property Agreement..

      9. INDEMNIFICATION.


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            (a) During the Employment Period, the Company agrees that if the
Executive is made a party, or is threatened to be made a party, to any action,
suit or proceeding, whether civil, criminal, administrative or investigative (a
"Proceeding"), by reason of the fact that he is or was a director, officer or
employee of the Company or is or was serving at the request of the Company as a
director, officer, member, employee or agent of another corporation,
partnership, joint venture, trust or other enterprise, including service with
respect to employee benefit plans, whether or not the basis of such Proceeding
is the Executive's alleged action in an official capacity while serving as a
director, officer, member, employee or agent, the Executive shall be indemnified
and held harmless by the Company to the fullest extent legally permitted or
authorized by the Company's certificate of incorporation or bylaws or
resolutions of the Board or, if greater, by the laws of the State of Delaware,
against all cost, expense, liability and loss (including, without limitation,
attorney's fees, judgments, fines, ERISA excise taxes or penalties and amounts
paid or to be paid in settlement) reasonably incurred or suffered by the
Executive in connection therewith, and such indemnification shall continue as to
the Executive even if he has ceased to be a director, member, employee or agent
of the Company or other entity and shall inure to the benefit of the Executive's
heirs, executors and administrators. The Company shall advance to the Executive
all reasonable costs and expenses incurred by him in connection with a
Proceeding within 20 days after receipt by the Company of a written request for
such advance. Such request shall include an undertaking by the Executive to
repay the amount of such advance if it shall ultimately be determined in a final
judgment by a court (not subject to further appeal) that he is not entitled to
be indemnified against such costs and expenses.

            (b) Neither the failure of the Company (including its Board,
independent legal counsel or stockholders) to have made a determination prior to
the commencement of any proceeding concerning payment of amounts claimed by the
Executive under Section 9(a) that indemnification of the Executive is proper
because he has met the applicable standard of conduct, nor a determination by
the Company (including its Board, independent legal counsel or stockholders)
that the Executive has not met such applicable standard of conduct, shall create
a presumption that the Executive has not met the applicable standard of conduct.

            (c) The Company agrees to continue and maintain a directors and
officers' liability insurance policy covering the Executive to the extent the
Company provides such coverage for its other executive officers.

            (d) If, at any time after the termination of this Agreement and any
associated severance period, the Executive is requested by the Company, or is
required, to testify or to provide evidence or otherwise to perform services in
relation to litigation or similar proceedings (civil, administrative, arbitral
or otherwise) in which the Company is a named party or is otherwise involved the
Company shall pay Executive: (i) with respect to each day that Executive appears
as a witness or is deposed, the sum of $2,000 per day or portion thereof and
(ii) with respect to each day that Executive is involved in the preparation
therefor, the sum of $1,000 per day or portion thereof. Notwithstanding the
foregoing, any time after the termination of this Agreement, the Company shall
reimburse Executive for reasonable travel and accommodation expenses if such
services are required to be performed outside of the city of Executive's
domicile.


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      10. SURVIVAL. The Executive agrees that Sections 8 and 9 of this Agreement
shall survive the termination of (a) this Agreement, (b) the Employment Period
and/or (c) the Executive's employment with the Company.

      11. SUCCESSORS. This Agreement is personal to the Executive and may not be
assigned by the Executive. This Agreement shall inure to the benefit of, and be
enforceable by, the Executive and the Executive's legal representatives, as
applicable. This Agreement shall inure to the benefit of and be binding upon the
Company and its successors and assigns. The Company will require any successor
(whether direct or indirect, by purchase, merger, consolidation or otherwise) to
all or substantially all of the business and/or assets of the Company to assume
expressly and agree to perform this Agreement in the same manner and to the same
extent that the Company would be required to perform it if no such succession
had taken place.

      12. NOTICES. All notices and other communications hereunder shall be in
writing and shall be given by facsimile transmission, hand delivery to the other
party or by registered or certified mail, return receipt requested, postage
prepaid, to the addresses set forth below:

If to the Company:         Biopure Corporation
                           11 Hurley Street
                           Cambridge, MA 02141

                           Attn: Chief Executive Officer

With a copy to:            General Counsel

If to the Executive, to Executive's then current address on file with the
Company's Human Resources Department. In the event of an address change, to
either party at such other address as either party shall have furnished to the
other in writing in accordance herewith. Any such notice and communications
shall be effective when actually received by the addressee.

      13. Miscellaneous. This Agreement shall be governed by and construed in
accordance with the laws of the Commonwealth of Massachusetts, without reference
to principles of conflict of laws thereunder. The captions of this Agreement are
not part of the provisions hereof and shall not have any force or effect. This
Agreement may not be amended or modified otherwise than by a written agreement
executed by the parties hereto or their respective successors, assigns and legal
representatives. This Agreement contains the entire understanding of the Company
and the Executive with respect to the subject matter hereof and supersedes any
prior oral or written agreement between the Company and the Executive. This
Agreement may be executed in two or more counterparts. This Agreement shall
inure to the benefit of and be enforceable by Executive's legal representatives.
This Agreement shall inure to the benefit of and be binding upon the Company and
its successors and assigns. All obligations of the Company under this Agreement
shall be irrevocably and unconditionally guaranteed by the Company. By its
signature below, the Company agrees to so guarantee all such obligations and
waives any rights to require Executive to proceed against the Company or to
pursue any other remedy against any other person or entity whatsoever. The
Company also waives any rights of


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presentments, demands for performance, notices of non performance, protests,
notices of protest, notices of dishonor, and notices of the acceptance of this
guaranty and of the existence, creation or incurring of new or additional
indebtedness or obligations.

      IN WITNESS WHEREOF, the Executive has signed this Agreement and, pursuant
to the authorization of its Board of Directors, the Company has caused this
Agreement to be signed in its name and on its behalf, all as of the day and year
first above written.

                                     BIOPURE CORPORATION



                                     By:   /s/  Thomas A. Moore
                                           -------------------------------------
                                           Title:  /s/  President/CEO
                                                   -----------------------------
                                           Name:  /s/  Thomas A. Moore
                                                  ------------------------------



                                           /s/  Ronald F. Richards
                                           -------------------------------------
                                                  Ronald F. Richards

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