Executive Change-in-Control  Severance Plan

Chiron
Corporation
January 2001

TIER II

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CONTENTS

|Article 1.  |  | Establishment, Term, and Purpose      |  | 1
|----------- |  | ------------------------------------- |  | -
|Article 2.  |  | Definitions                           |  | 1
|Article 3.  |  | Participation                         |  | 5
|Article 4.  |  | Severance Benefits                    |  | 5
|Article 5.  |  | Form and Timing of Severance Benefits |  | 7
|Article 6.  |  | Excise Tax Equalization Payment       |  | 7
|Article 7.  |  | The Company's Payment Obligation      |  | 8
|Article 8.  |  | Arbitration                           |  | 9
|Article 9.  |  | Successors and Assignment             |  | 9
|Article 10. |  | Miscellaneous                         |  | 9

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Chiron Corporation  Executive Change-in-Control Severance Plan

Article 1. Establishment, Term, and Purpose

1.1  Establishment of the Plan.Chiron Corporation (hereinafter referred to as the "Company") hereby
establishes a change-in-control severance plan to be known as the "Chiron Corporation Executive Change-in-Control Severance Plan" (the "Plan").

1.2  Term of the Plan.This Plan will commence upon December 9, 2000 (the "Effective Date") and
shall continue in effect for two (2) full calendar years. However, at the end of such two (2) year period and, if extended, at the end of each additional year thereafter, the term of
this Plan shall be extended automatically for one (1) additional year, unless the Committee delivers written notice six (6) months prior to the end of such term, or extended term, to
each Participant, that the Plan will not be extended. However, in the event a Change in Control occurs during the original or any extended term, this Plan will remain in effect, solely with respect to
obligations relating to such Change in Control, for the longer of: (i) two (2) years beyond the month in which such Change in Control occurred; or (ii) until all obligations of the
Company hereunder have been fulfilled, and until all benefits required hereunder have been paid to Participants.

1.3.  Purpose of the Plan.The purpose of the Plan is to provide certain key employees of the Company
with greater incentive to remain in the employ of the Company, particularly in the event of any possible change or threatened change in control of the Company.

Article 2. Definitions

Whenever used in this Plan, the following terms shall have the meanings set forth below and, when the meaning is intended, the initial letter of the word is
capitalized.

2.1  "Base Salary"as of any date means the annual rate of a Participant's base salary, excluding
amounts received under incentive or other bonus plans, computed before any deferrals or pre-or post-tax payroll deductions.

2.2  "Beneficial Owner"shall have the meaning ascribed to such term in Rule 13d-3 of the General
Rules and Regulations under the Exchange Act.

2.3  "Beneficiary"means the persons or entities designated or deemed designated by the Participant
pursuant to Section 9.2 herein.

2.4  "Board"means the Board of Directors of the Company.

2.5  "Cause"means:



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2.6  "Change in Control"of the Company shall be deemed to have occurred as of the first day during the
term of this Plan that any one or more of the following conditions is satisfied and regulatory approval has been granted if necessary:



Notwithstanding
anything else contained herein to the contrary, in no event shall a Change in Control be deemed to have occurred by reason of a purchase, or series of purchases of
Company stock by Novartis or its successor such that the acquiring entity remains subject to the terms of that certain Governance Agreement dated as of January 5, 1995, as amended through
December 9, 2000, provided the acquiring entity's Company stock holdings, direct or indirect, in the aggregate, represent seventy-nine percent (79%) or less of the combined voting power of all
outstanding Company securities.

However,
in no event shall a Change in Control be deemed to have occurred, with respect to the Participant, if the Participant is part of a purchasing group that consummates the
Change-in-Control transaction. The Participant shall be deemed "part of a purchasing group" for purposes of the preceding sentence if the Participant is an equity participant in the purchasing company
or group (except for: (i) passive ownership of less than three percent (3%) of the stock or other equity of the purchasing company; or (ii) ownership of equity participation in the
purchasing company or group which is otherwise not significant, as determined prior to the Change in Control by a majority of the nonemployee continuing Directors).

2.7  "Code"means the United States Internal Revenue Code of 1986, as amended, and any successors
thereto.

2.8  "Committee"means the Compensation Committee of the Board or any other committee appointed by the
Board to perform the functions of the Compensation Committee for purposes of administering this Plan.

2.9  "Company"means Chiron Corporation, a Delaware corporation, or any successor thereto as provided in
Article 9 herein.

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2.10  "Disability"means complete and permanent inability by reason of illness or accident to perform
the duties of the occupation at which the Participant was employed when such disability commenced, where inability is expected to last one year or longer.

2.11  "Effective Date"means the date of this Plan set forth above.

2.12  "Effective Date of Termination"means the date on which a Qualifying Termination occurs which
triggers the payment of Severance Benefits hereunder.

2.13  "Exchange Act"means the United States Securities Exchange Act of 1934, as amended.

2.14  "Good Reason"shall mean, without the Participant's express written consent, the occurrence of any
one or more of the following:



For
purposes of this Plan, long-term incentive plans shall mean the Chiron Executive Long-Term Incentive Plan, the 1991 Stock Option Plan, and any other similar plans instituted by
the Company;



The
existence of Good Reason shall not be affected by the Participant's temporary incapacity due to physical or mental illness not constituting a Disability. However, the occurrence
of an event set forth in (a) through(f) above shall not constitute Good Reason if the Company has cured such event within fifteen (15) days of receipt of written notice from the Participant
that such event has occurred and constitutes Good Reason.

2.15  "Notice of Termination"shall mean a written notice which shall indicate the specific termination
provision in this Plan relied upon, and shall set forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of the Participant's employment under the provision
so indicated.

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2.16  "Participant"means an employee of the Company who fulfills the eligibility and participation
requirements, as provided in Article 3 herein.

2.16  "Person"shall have the meaning ascribed to such term in Section 3(a)(9) of the
Exchange Act and used in Sections 13(d) and 14(d) thereof, including a "group" as provided in Section 13(d).

2.17  "Qualifying Termination"means any of the events described in Section 4.2 herein.

2.18  "Severance Benefits"means the payment of severance compensation as provided in Section 4.3
herein.

2.19  "Target Bonus"shall mean the target bonus amount established under the Company's annual incentive
plan.

Article 3. Participation

3.1  Eligible Employees.Individuals eligible to participate in the Plan shall include all key employees
of the Company, as determined by the Committee in its sole discretion.

3.2  Participation.Subject to the terms of the Plan, the Committee may, from time to time, select from
all eligible employees those who shall participate in the Plan.

Article 4. Severance Benefits

4.1  Right to Severance Benefits.A Participant shall be entitled to receive from the Company Severance
Benefits, as described in Section 4.3 herein, if (i) there has been a Change in Control of the Company, (ii) within twenty-four (24) calendar months following the Change in
Control, a Qualifying Termination of the Participant has occurred, and (iii) Participant has executed a Release, as described in Section 4.8 herein. The benefits provided under this Plan
shall be reduced to the extent similar benefits are provided under the Chiron Corporation Executive Officer Severance Plan or any other severance protection arrangements provided by the Company either
as a plan or in the form of individual agreement or contract.

The
Participant shall not be entitled to receive Severance Benefits if he/she is terminated for Cause, or if his/her employment with the Company ends due to death or Disability or due
to a voluntary termination of employment by the Participant without Good Reason.

4.2  Qualifying Termination.The term Qualifying Termination means any of the following events:



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4.3  Description of Severance Benefits.In the event the Participant becomes entitled to receive
Severance Benefits, as provided in Sections 4.1 and 4.2 herein, the Company shall pay to the Participant and provide him/her with the following:





The
aggregate vested benefits accrued by the Participant as of the Effective Date of Termination under all other savings and retirement plans sponsored by the Company shall be
distributed pursuant to the terms of the applicable plans.

4.4  Termination for Disability.Following a Change in Control of the Company, if a Participant's
employment is terminated due to Disability, the Participant shall receive his/her Base Salary through the Effective Date of Termination, at which point in time the Participant's benefits shall be
determined in accordance with the Company's disability, retirement, insurance, and other applicable plans and programs then in effect.

4.5  Termination for Death.Following a Change in Control of the Company, if the Participant's
employment is terminated by reason of his/her death, the Participant's benefits shall be determined in accordance with the Company's survivor's benefits, insurance, and other applicable programs of
the Company then in effect.

4.6  Termination for Cause or Other Than for Good Reason.Following a Change in Control of the Company,
if the Participant's employment is terminated either: (a) by the Company for Cause; or (b) by the Participant (other than for Good Reason under circumstances giving rise to a Qualifying
Termination described in Section 4.2(b) herein), the Company shall pay the Participant his/her full Base

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Salary and accrued but unused paid time off in accordance with company policy through the Effective Date of Termination, at the rate then in effect, plus all other amounts to which the Participant is
entitled under any compensation plans of the Company, at the time such payments are due.

4.7  Notice of Termination.Any termination of employment by the Company or by the Participant for Good
Reason shall be communicated by a Notice of Termination.

4.8  Release.The Severance Benefits are in consideration of Participant's release of all claims against
the Company and its employees and agents, in the form provided by the Company and in substantially the form as attached hereto as Exhibit A (the "Release"). If Participant does not properly
execute the Release or if the Participant effectively revokes it, he or she will not be entitled to any Severance Benefits.

Article 5. Form and Timing of Severance Benefits

5.1  Form and Timing of Cash Severance Benefits.The Severance Benefits described in Sections 4.3(a),
4.3(b), and 4.3(c) herein shall be paid in cash to the Participant in a single lump sum as soon as practicable following the latest of (i) the Effective Date of Termination or
(ii) the date that the Participant executes the Release or (iii) the last day following Participant's execution of the Release that the Participant may, by its terms, revoke such
Release, but in no event beyond thirty (30) days from such date.

5.2  Withholding of Taxes.The Company shall be entitled to withhold from any amounts payable under this
Plan all taxes as legally shall be required (including, without limitation, any United States federal taxes and any other state, city, or local taxes).

Article 6. Excise Tax Equalization Payment

6.1  Excise Tax Equalization Payment.In the event that the Participant becomes entitled to Severance
Benefits or any other payment or benefit under this Plan, or under any other agreement with or plan of the Company (in the aggregate, the "Total Payments"), if all or any part of the Total Payments
will be subject to the tax (the "Excise Tax") imposed by Section 4999 of the Code (or any similar tax that may hereafter be imposed), the Company shall pay to the Participant in cash an
additional amount (the "Gross-Up Payment") such that the net amount retained by the Participant from the Total Payments
and the Gross-Up Payment after deduction of any Excise Tax upon the Total Payments and any federal, state, and local income and employment tax, penalties, interest, and Excise Tax upon the Gross-Up
Payment provided for by this Section 5.1 (including FICA), shall be equal to the Total Payments. Such payment shall be made by the Company to the Participant as soon as practicable following
the latest of (i) the Effective Date of Termination or (ii) the date that the Participant executes the Release or (iii) the last day following Participant's execution of the
Release that the Participant may, by its terms, revoke such Release, but in no event beyond thirty (30) days from such date.

6.2  Tax Computation.For purposes of determining whether any of the Total Payments will be subject to
the Excise Tax and the amounts of such Excise Tax:



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For
purposes of determining the amount of the Gross-Up Payment, the Participant shall be deemed to pay federal income taxes at the highest marginal rate of federal income taxation
(including the effects of applicable phase-outs of deductions and other benefits) in the calendar year in which the Gross-Up Payment is to be made, and state and local income taxes at the highest
marginal rate of taxation in the state and locality of the Participant's residence on the Effective Date of Termination.

6.3  Subsequent Recalculation.In the event the Participant ultimately owes more Excise Tax on the Total
Payments and the Gross-Up Payments than computed by the Company under Section 6.1 herein, the Gross-Up Payment shall be recalculated based on the actual Excise Tax.

Article 7. The Company's Payment Obligation

The Company's obligation to make the payments and the benefits provided for herein, to the extent that the Participant qualifies for such payments and benefits
under the terms of this Plan, shall be absolute and unconditional, and shall not be affected by any circumstances, including, without limitation, any offset, counterclaim, recoupment, defense, or
other right which the Company may have against the Participant or anyone else.

The
Participant shall not be obligated to seek other employment in mitigation of the amounts payable or arrangements made under any provision of this Plan, and the obtaining of any
such other employment shall in no event effect any reduction of the Company's obligations to make the payments and arrangements required to be made under this Plan, except to the extent provided in
Section 4.3(d) herein.

Article 8. Arbitration

Any dispute or controversy arising under or in connection with this Plan shall be settled by arbitration, conducted before a panel of three (3) arbitrators
sitting in a location selected by the Participant within fifty (50) miles from the location of his/her employment with the Company, in accordance with the rules of the American Arbitration
Association then in effect.

Judgment
may be entered on the award of the arbitrator in any court having proper jurisdiction. All expenses of such arbitration, including the fees and expenses of the counsel for
the Participant, shall be borne by the Company.

Article 9. Successors and Assignment

9.1  Successors to the Company.The Company will require any successor (whether direct or indirect, by
purchase, merger, consolidation, or otherwise) of all or substantially all of the business and/or assets of the Company or of any division or subsidiary thereof to expressly assume and agree to

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perform the Company's obligations under this Plan in the same manner and to the same extent that the Company would be required to perform them if no such succession had taken place.

9.2  Assignment by the Participant.This Plan shall inure to the benefit of and be enforceable by the
Participant's personal or legal representatives, executors, administrators, successors, heirs, distributees, devisees, and legatees. If the Participant dies while any amount would still be payable to
him/her hereunder had he/she continued to live, all such amounts, unless otherwise provided herein, shall be paid in accordance with the terms of this Plan to the Participant's Beneficiary. If the
Participant has not named a Beneficiary, then such amounts shall be paid to the Participant's devisee, legatee, or other designee, or if there is no such designee, to the Participant's estate.

Article 10. Miscellaneous

10.1  Employment Status.Except as may be provided under any other agreement between the Participant and
the Company, the employment of the Participant by the Company is "at will," and may be terminated by either the Participant or the Company at any time and for any or no reason, subject to applicable
law.

10.2  Beneficiaries.The Participant may designate one or more persons or entities as the primary and/or
contingent Beneficiaries of any Severance Benefits owing to the Participant under this Plan. Such designation must be in the form of a signed writing acceptable to the Committee. The Participant may
make or change such designations at any time.

10.3  Severability.In the event any provision of this Plan shall be held illegal or invalid for any
reason, the illegality or invalidity shall not affect the remaining parts of the Plan, and the Plan shall be construed and enforced as if the illegal or invalid provision had not been included.
Further, the captions of this Plan are not part of the provisions hereof and shall have no force and effect.

10.4  Modification.No provision of this Plan may be modified, waived, or discharged unless such
modification, waiver, or discharge is agreed to in writing and signed by the Participant and by an authorized member of the Committee, or by the respective parties' legal representatives and
successors.

10.5  Applicable Law.To the extent not preempted by the laws of the United States, the substantive laws
of the state of California, without regard to conflict of law principles, shall be the controlling law in all matters relating to this Plan.[End of
Plan]

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