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                                                                   Exhibit 10.37

                             THIRD AMENDMENT TO THE
                         PREMCOR RETIREMENT SAVINGS PLAN

PREAMBLE

1.     Adoption and effective date of amendment. This amendment of the plan is
adopted to reflect certain provisions of the Economic Growth and Tax Relief
Reconciliation Act of 2001 ("EGTRRA"). This amendment is intended as good faith
compliance with the requirements of EGTRRA and is to be construed in accordance
with EGTRRA and guidance issued thereunder. Except as otherwise provided, this
amendment shall be effective as of the first day of the first plan year
beginning after December 31, 2001.

2.     Suppression of inconsistent provisions. This amendment shall supersede
the provisions of the plan to the extent those provisions are inconsistent with
the provisions of this amendment.

3.     Only the provisions checked below shall apply.

[ ]    SECTION I. PLAN LOANS FOR OWNER-EMPLOYEES AND SHAREHOLDER EMPLOYEES

Effective for plan loans made after December 31, 2001, plan provisions
prohibiting loans to any owner-employee or shareholder-employee shall cease to
apply.

[X]    SECTION II. LIMITATIONS ON CONTRIBUTIONS

1.     Effective date. This section shall be effective for limitation years
beginning after December 31, 2001.

2.     Maximum annual addition. Except to the extent permitted under section
XIII of this amendment and section 414(v) of the Code, if applicable, the annual
addition that may be contributed or allocated to a participant's account under
the plan for any limitation year shall not exceed the lesser of:

(a)    $40,000, as adjusted for increases in the cost-of-living under section
       415(d) of the Code, or

(b)    100 percent of the participant's compensation, within the meaning of
       section 415(c)(3) of the Code, for the limitation year.

The compensation limit referred to in (b) shall not apply to any contribution
for medical benefits after separation from service (within the meaning of
section 401(h) or section 419A(f)(2) of the Code) which is otherwise treated as
an annual addition.

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[X]    SECTION III. INCREASE IN COMPENSATION LIMIT

The annual compensation of each participant taken into account in determining
allocations for any plan year beginning after December 31, 2001, shall not
exceed $200,000, as adjusted for cost-of-living increases in accordance with
section 401(a)(17)(B) of the Code. Annual compensation means compensation during
the plan year or such other consecutive 12-month period over which compensation
is otherwise determined under the plan (the determination period). The
cost-of-living adjustment in effect for a calendar year applies to annual
compensation for the determination period that begins with or within such
calendar year.

[X]    SECTION IV. MODIFICATION OF TOP-HEAVY RULES

1.     Effective date. This section shall apply for purposes of determining
whether the plan is a top-heavy plan under section 416(g) of the Code for plan
years beginning after December 31, 2001, and whether the plan satisfies the
minimum benefits requirements of section 416(c) of the Code for such years. This
section amends sections 18 and 19 of the plan.

2.     Determination of top-heavy status.

2.1.   Key employee. Key employee means any employee or former employee
(including any deceased employee) who at any time during the plan year that
includes the determination date was an officer of the employer having annual
compensation greater than $130,000 (as adjusted under section 416(i)(1) of the
Code for plan years beginning after December 31, 2002), a 5-percent owner of the
employer, or a 1-percent owner of the employer having annual compensation of
more than $150,000. For this purpose, annual compensation means compensation
within the meaning of section 415(c)(3) of the Code. The determination of who is
a key employee will be made in accordance with section 416(i)(1) of the Code and
the applicable regulations and other guidance of general applicability issued
thereunder.

2.2.   Determination of present values and amounts. This section 2.2 shall apply
for purposes of determining the present values of accrued benefits and the
amounts of account balances of employees as of the determination date.

2.2.1. Distributions during year ending on the determination date. The present
values of accrued benefits and the amounts of account balances of an employee as
of the determination date shall be increased by the distributions made with
respect to the employee under the plan and any plan aggregated with the plan
under section 416(g)(2) of the Code during the 1-year period ending on the
determination date. The preceding sentence shall also apply to distributions
under a terminated plan which, had it not been terminated, would have been
aggregated with the plan under section 416(g)(2)(A)(i) of the Code. In the case
of a distribution made for a reason other than separation from service, death,
or disability, this provision shall be applied by substituting "5-year period"
for "1-year period."

2.2.2. Employees not performing services during year ending on the determination
date. The accrued benefits and accounts of any individual who has not performed
services for the employer during the 1-year period ending on the determination
date shall not be taken into account.

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3.     Minimum benefits.

3.1.   Matching contributions. Employer matching contributions shall be taken
into account for purposes of satisfying the minimum contribution requirements of
section 416(c)(2) of the Code and the plan. The preceding sentence shall apply
with respect to matching contributions under the plan or, if the plan provides
that the minimum contribution requirement shall be met in another plan, such
other plan. Employer matching contributions that are used to satisfy the minimum
contribution requirements shall be treated as matching contributions for
purposes of the actual contribution percentage test and other requirements of
section 401(m) of the Code.

3.2.   Contributions under other plans. The employer may provide in the space
below that the minimum benefit requirement shall be met in another plan
(including another plan that consists solely of a cash or deferred arrangement
which meets the requirements of section 401(k)(12) of the Code and matching
contributions with respect to which the requirements of section 401(m)(11) of
the Code are met). (The employer should describe below the extent, if any, to
which the top-heavy minimum benefit requirement of section 416(c) of the Code
and the plan shall be met in another plan. This should include the name of the
other plan, the minimum benefit that will be provided under such other plan, and
the employees who will receive the minimum benefit under such other plan.)

[ ]    SECTION V. VESTING OF EMPLOYER MATCHING CONTRIBUTIONS

1.     Applicability. This section shall apply to participants with accrued
benefits derived from employer matching contributions who complete an hour of
service under the plan in a plan year beginning after December 31, 2001[, but
only with respect to matching contributions for plan years beginning after
December 31, 2001]. Note -- remove bold and brackets if applicable, otherwise
delete.

2.     Vesting schedule. A participant's accrued benefit derived from employer
matching contributions shall vest as provided by the employer below.

Vesting Schedule for Employer Matching Contributions (Check one):

[ ]    Option 1. A participant's accrued benefit derived from employer matching
contributions shall be fully and immediately vested.

[ ]    Option 2. A participant's accrued benefit derived from employer matching
contributions shall be nonforfeitable upon the participant's completion of three
years of vesting service.

[ ]    Option 3. A participant's accrued benefit derived from employer matching
contributions shall vest according to the following schedule:

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<TABLE>
<CAPTION>
Years of vesting service             Nonforfeitable percentage
<S>                                  <C>
         2                                         20
         3                                         40
         4                                         60
         5                                         80
         6                                         100
</TABLE>

[X]    SECTION VI. DIRECT ROLLOVERS OF PLAN DISTRIBUTIONS

1.     Effective date. This section shall apply to distributions made after
December 31, 2001.

2.     Modification of definition of eligible retirement plan. For purposes of
the direct rollover provisions in section 17.14 of the plan, an eligible
retirement plan shall also mean an annuity contract described in section 403(b)
of the Code and an eligible plan under section 457(b) of the Code which is
maintained by a state, political subdivision of a state, or any agency or
instrumentality of a state or political subdivision of a state and which agrees
to separately account for amounts transferred into such plan from this plan. The
definition of eligible retirement plan shall also apply in the case of a
distribution to a surviving spouse, or to a spouse or former spouse who is the
alternate payee under a qualified domestic relation order, as defined in section
414(p) of the Code.

3.     Modification of definition of eligible rollover distribution to exclude
hardship distributions. For purposes of the direct rollover provisions in
section 17.14 of the plan, any amount that is distributed on account of hardship
shall not be an eligible rollover distribution and the distributee may not elect
to have any portion of such a distribution paid directly to an eligible
retirement plan.

4.     Modification of definition of eligible rollover distribution to include
after-tax employee contributions. For purposes of the direct rollover provisions
in section 17.14 of the plan, a portion of a distribution shall not fail to be
an eligible rollover distribution merely because the portion consists of
after-tax employee contributions which are not includible in gross income.
However, such portion may be transferred only to an individual retirement
account or annuity described in section 408(a) or (b) of the Code, or to a
qualified defined contribution plan described in section 401(a) or 403(a) of the
Code that agrees to separately account for amounts so transferred, including
separately accounting for the portion of such distribution which is includible
in gross income and the portion of such distribution which is not so includible.

[X]    SECTION VII. ROLLOVERS FROM OTHER PLANS

       If provided by the employer below, the plan will accept participant
rollover contributions and/or direct rollovers of distributions made after
December 31, 2001, from the types of plans specified below, beginning on the
effective date specified below.

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Direct Rollovers:

The plan will accept a direct rollover of an eligible rollover distribution
from: (Check each that applies or none.)

           a qualified plan described in section 401(a) or 403(a) of the Code,
-----      excluding after-tax employee contributions.

  X        a qualified plan described in section 401(a) or 403(a) of the Code,
-----      including after-tax employee contributions.


  X        an annuity contract described in section 403(b) of the Code,
-----      excluding after-tax employee contributions.


  X        an eligible plan under section 457(b) of the Code which is maintained
-----      by a state, political subdivision of a state, or any agency or
           instrumentality of a state or political subdivision of a state.

Participant Rollover Contributions from Other plans:

The plan will accept a participant contribution of an eligible rollover
distribution from: (Check each that applies or none.)

  X        a qualified plan described in section 401(a) or 403(a) of the Code.
-----

  X        an annuity contract described in section 403(b) of the Code.
-----

  X        an eligible plan under section 457(b) of the Code which is maintained
-----      by a state, political subdivision of a state, or any agency or
           instrumentality of a state or political subdivision of a state.

Participant Rollover Contributions from IRAs:

The plan: (Choose one.)

  X        will
-----

           will not
-----

accept a participant rollover contribution of the portion of a distribution from
an individual retirement account or annuity described in section 408(a) or
408(b) of the Code that is eligible to be rolled over and would otherwise be
includible in gross income.

Effective Date of Direct Rollover and Participant Rollover Contribution
Provisions:

Section VII, Rollovers From Other Plans, shall be effective: January 1, 2002.


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[X]    SECTION VIII. ROLLOVERS DISREGARDED IN INVOLUNTARY CASH-OUTS

1.     Applicability and effective date. This section shall apply if elected by
the employer and shall be effective with respect to distributions made after
December 31, 2001 with respect to participants who separated from service after
December 31, 2001.)

2.     Rollovers disregarded in determining value of account balance for
involuntary distributions. If elected by the employer, for purposes of sections
9.1.1 and 10.1.1 of the plan, the value of a participant's nonforfeitable
account balance shall be determined without regard to that portion of the
account balance that is attributable to rollover contributions (and earnings
allocable thereto) within the meaning of sections 402(c), 403(a)(4), 403(b)(8),
408(d)(3)(A)(ii), and 457(e)(16) of the Code. If the value of the participant's
nonforfeitable account balance as so determined is $5,000 or less, the plan
shall immediately distribute the participant's entire nonforfeitable account
balance.

[ ]    SECTION IX. REPEAL OF MULTIPLE USE TEST

The multiple use test described in Treasury Regulation section 1.401(m)-2 and
section __ of the plan shall not apply for plan years beginning after
December 31, 2001.

[X]    SECTION X. ELECTIVE DEFERRALS -- CONTRIBUTION LIMITATION

No participant shall be permitted to have elective deferrals made under this
plan, or any other qualified plan maintained by the employer during any taxable
year, in excess of the dollar limitation contained in section 402(g) of the Code
in effect for such taxable year, except to the extent permitted under section
XIII of this amendment and section 414(v) of the Code, if applicable.

[ ]    SECTION XI. MAXIMUM SALARY REDUCTION CONTRIBUTIONS

Except to the extent permitted under section XIII of this amendment and section
414(v) of the Code, if applicable, the maximum salary reduction contribution
that can be made to this plan is the amount determined under section
408(p)(2)(A)(ii) of the Code for the calendar year.

[X]    SECTION XII. MODIFICATION OF TOP-HEAVY RULES

The top-heavy requirements of section 416 of the Code and sections 18 and 19 of
the plan shall not apply in any year beginning after December 31, 2001, in which
the plan consists solely of a cash or deferred arrangement which meets the
requirements of section 401(k)(12) of the Code and matching contributions with
respect to which the requirements of section 401(m)(11) of the Code are met.

[X]    SECTION XIII. CATCH-UP CONTRIBUTIONS

If elected by the employer, all employees who are eligible to make elective
deferrals under this plan and who have attained age 50 before the close of the
calendar year shall be eligible to make

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catch-up contributions in accordance with, and subject to the limitations of,
section 414(v) of the Code with respect to contributions after June 17, 2002.
Such catch-up contributions shall not be taken into account for purposes of the
provisions of the plan implementing the required limitations of sections 402(g)
and 415 of the Code. The plan shall not be treated as failing to satisfy the
provisions of the plan implementing the requirements of section 401(k)(3),
401(k)(11), 401(k)(12), 410(b), or 416 of the Code, as applicable, by reason of
the making of such catch-up contributions.

[X]    SECTION XIV. SUSPENSION PERIOD FOLLOWING HARDSHIP DISTRIBUTION

A participant who receives a distribution of elective deferrals after December
31, 2001, on account of hardship shall be prohibited from making elective
deferrals and employee contributions under this and all other plans of the
employer for 6 months after receipt of the distribution. A participant who
receives a distribution of elective deferrals in calendar year 2001 on account
of hardship shall be prohibited from making elective deferrals and employee
contributions under this and all other plans of the employer for the period
specified by the employer below.

Suspension Period for Hardship Distributions: (Choose one)

  X        A participant who receives a distribution of elective deferrals in
-----      calendar year 2001 on account of hardship shall be prohibited from
           making elective deferrals and employee contributions under this and
           all other plans of the employer for 6 months after receipt of the
           distribution or until January 1, 2002, if later.

           A participant who receives a distribution of elective deferrals in
-----      calendar year 2001 on account of hardship shall be prohibited from
           making elective deferrals and employee contributions under this and
           all other plans of the employer for the period specified in the
           provisions of the plan relating to suspension of elective deferrals
           that were in effect prior to this amendment.

[X]    SECTION XV. DISTRIBUTION UPON SEVERANCE FROM EMPLOYMENT

1.     Effective date. If elected by the employer, this section shall apply for
distributions after December 31, 2001:

(Choose one)

  X        regardless of when the severance from employment occurred.
-----

           for severances from employment occurring after __________.
-----      (Enter date.)

2.     New distributable event. A participant's elective deferrals, qualified
nonelective contributions, qualified matching contributions, and earnings
attributable to these contributions shall be distributed on account of the
participant's severance from employment. However, such a

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distribution shall be subject to the other provisions of the plan regarding
distributions, other than provisions that require a separation from service
before such amounts may be distributed.

[X]    SECTION XVI. MAXIMUM EMPLOYEE CONTRIBUTION LIMITATION

Effective January 1, 2003, Sections 4.1 and 4.4 shall be amended by replacing
"15%" with "25%" each place that it appears.

[X]    SECTION XVII. ELIGIBILITY

After December 31, 1996 and prior to January 1, 2001, any employee otherwise
eligible to participate in the Plan shall become a participant as of the date
which is six (6) months after the date he or she performs his or her first hour
of employment with the Employer.

       IN WITNESS WHEREOF, this amendment has been executed on the date set
forth below.


December 30, 2002

                                                    By: /s/ James R. Voss
                                                        ------------------------
                                                    Name: James R. Voss
                                                    Title: Senior Vice President


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