EXHIBIT 10.(c)





                       EMPLOYMENT AND CONSULTING AGREEMENT



          This EMPLOYMENT AND CONSULTING AGREEMENT (the "Agreement"), dated as
of September 22, 1996, but effective as provided herein, is made and entered
into by and between Diamond Shamrock, Inc., a Delaware corporation (the
"Company" or "Diamond Shamrock, Inc.", as the context requires), and Roger R.
Hemminghaus (the "Executive").



          WHEREAS, the Executive has been serving as the Chairman of the Board,
Chief Executive Officer and President of Diamond Shamrock, Inc.;

          WHEREAS, the Executive is a party to an Employment Agreement with
Diamond Shamrock, Inc., dated as of February 6, 1996 (the "Prior Agreement");

          WHEREAS, pursuant to the Agreement and Plan of Merger between Ultramar
Corporation, a Delaware corporation ("Ultramar Corporation") and Diamond
Shamrock, Inc., dated as of September 22, 1996 (the "Merger Agreement"), as of
the effective time of the Merger (the "Effective Date"), Diamond Shamrock, Inc.
will be merged with and into Ultramar Corporation, with Ultramar Corporation as
the surviving entity (the "Merger");

          WHEREAS, pursuant to the Merger Agreement it is contemplated that
Executive will execute this Agreement upon the signing of the Merger Agreement
and upon the Effective Date, Executive will serve as the Chairman of the Board
and Chief Executive Officer of the Company; 

          WHEREAS, the Company considers it in the best interests of its
stockholders to foster the continuous employment of certain key management
personnel; 

          WHEREAS, the Company recognizes that, as is the case for most publicly
held companies, the possibility of a Change in Control (as defined herein)
exists; 

          WHEREAS, the Company wishes to assure itself of both present and
future continuation of management in light of the Merger and in the event of a
Change in Control subsequent to the Merger;

          WHEREAS, the Company wishes to employ the Executive and the Executive
is willing to render services, both on the terms and subject to the conditions
set forth in this Agreement;

          NOW, THEREFORE, in consideration of the promises and of the mutual
covenants herein contained, it is agreed as follows:















     1.   Employment and Consulting.
          -------------------------

          1.1  The Company hereby agrees to employ the Executive and to
subsequently retain the Executive as a consultant, and the Executive hereby
agrees to undertake employment with, and provide consulting services to, the
Company, upon the terms and conditions herein set forth.

          1.2  Employment will be for a term commencing on the Effective Date
and, subject to earlier expiration upon the Executive's termination under
Section 5, expiring on December 31, 1998 (the "Employment Term").  Consulting
services will be provided during the "Consulting Term" (as defined in Section
11.1(ii)).

     2.   Positions and Duties.
          --------------------

          2.1  Positions and Duties.  During the Employment Term, the Executive
               --------------------
will serve in the positions of Chairman of the Company's Board of Directors (the
"Board") and Chief Executive Officer of the Company and will have such duties,
functions, responsibilities and authority as are (i) consistent with the
Executive's position as the Company's most senior executive officer; or
(ii) assigned to his office in the Company's bylaws; or (iii) reasonably
assigned to him by the Board.  The Executive will report directly to the Board. 
The Company will use its best efforts to cause the Executive to be elected as a
member of the Board (initially, with a term that expires in 1997) and as
Chairman of the Board throughout the Employment Term and will use its best
efforts to cause him to be included in the management slate for election as a
director at every stockholders' meeting at which his term as a director would
otherwise expire.

          2.2  Commitment.  During the Employment Term, the Executive will be
               ----------
the Company's full-time employee and, except as may otherwise be approved in
advance in writing by the Board, and except during vacation periods and
reasonable periods of absence due to sickness, personal injury or other
disability, the Executive will devote substantially all of his business time and
attention to the performance of his duties to the Company.  Notwithstanding the
foregoing, the Executive may, (i) subject to the approval of the Board, serve as
a director of a company which is not engaged in "Competition" (as defined in
Section 9.1) with the Company, (ii) serve as an officer, director or otherwise
participate in purely educational, welfare, social, religious and civic
organizations, (iii) serve as an officer, director or trustee of, or otherwise
participate in, any organizations and activities with respect to which the
Executive's participation was disclosed in the last Proxy Statement prepared by
the Company prior to the date hereof, and (iv) manage personal and family
investments.

     3.   Place of Performance.  In connection with his employment during the
          --------------------
Employment Term, unless otherwise agreed by 

















                                       -2-


the Executive, the Executive will be based at the Company's principal executive
offices.  The Executive will undertake normal business travel on behalf of the
Company.

     4.   Compensation and Related Matters.
          --------------------------------

          4.1  Compensation and Benefits. 
               -------------------------

               (i)  Annual Base Salary.  During the Employment Term, the Company
will pay to the Executive an annual base salary of not less than $725,000, which
annual base salary may be increased (but not decreased) from time to time by the
Board (or the Compensation Committee thereof) in its sole discretion, payable at
the times and in the manner consistent with the Company's general policies
regarding compensation of executive employees.  The Board may from time to time
authorize such additional compensation to the Executive, in cash or in property,
as the Board may determine in its sole discretion to be appropriate.

               (ii) Annual Incentive Compensation.  If the Board (or the
Compensation Committee thereof) authorizes any cash incentive compensation or
approves any other management incentive program or arrangement, the Executive
will be eligible to participate in such plan, program or arrangement under the
general terms and conditions applicable to executive and management employees. 
The annual cash incentive compensation paid to the Executive for calendar year
1996 will be paid in accordance with Diamond Shamrock, Inc.'s annual incentive
compensation plan, subject to any equitable adjustment determined by the Board
(or the Compensation Committee thereof) to be necessary in light of the Merger. 
Nothing in this Section 4.1(ii) will guarantee to the Executive any specific
amount of incentive compensation, or prevent the Board (or the Compensation
Committee thereof) from establishing performance goals and compensation targets
applicable only to the Executive.

               (iii) Retirement Benefits.  Upon the expiration of the Employment
Term for any reason other than the termination of the Executive's employment for
Cause or voluntary termination other than for death or Disability (as those
terms are defined herein), the Executive will be credited with additional years
of age and service under any supplemental executive retirement plan or other
nonqualified retirement plan of the Company at the time of such Executive's
retirement (as defined under such plan) as may be required to provide a
retirement benefit at least equal to the benefit such Executive would have
received if the Executive had continued in the active employment of Diamond
Shamrock, Inc. or, as successor, Ultramar Diamond Shamrock Corp., until
December 31, 2001.

          4.2  Executive Benefits.  In addition to the compensation described in
               ------------------
Section 4.1, the Company will make available to the Executive and his eligible
dependents, subject 



















                                       -3-


to the terms and conditions of the applicable plans, including without
limitation the eligibility rules, participation in all Company-sponsored
employee benefit plans including all employee retirement income and welfare
benefit policies, plans, programs or arrangements in which senior executives of
the Company participate, including any stock option, stock purchase, stock
appreciation, savings, pension, supplemental executive retirement or other
retirement income or welfare benefit, disability, salary continuation, and any
other deferred compensation, incentive compensation, group and/or executive
life, health, medical/hospital or other insurance (whether funded by actual
insurance or self-insured by the Company), expense reimbursement or other
employee benefit policies, plans, programs or arrangements or any equivalent
successor policies, plans, programs or arrangements that may now exist or be
adopted hereafter by the Company.

          4.3  Expenses.  The Company will promptly reimburse the Executive for
               --------
all travel and other business expenses the Executive incurs in order to perform
his duties to the Company under this Agreement in a manner commensurate with the
Executive's position and level of responsibility with the Company, and in
accordance with the Company's policy regarding substantiation of expenses.

     5.   Termination.  Notwithstanding the Employment Term specified in Section
          -----------
1.2, the termination of the Executive's employment hereunder will be governed by
the following provisions:

          5.1  Death.  In the event of the Executive's death during the
               -----
Employment Term, the Company will pay to the Executive's beneficiaries or
estate, as appropriate, promptly after the Executive's death, (i) the unpaid
annual base salary to which the Executive is entitled, pursuant to Section 4.1,
through the date of the Executive's death, and (ii) for any accrued but unused
vacation days, to the extent and in the amounts, if any, provided under the
Company's usual policies and arrangements.  This Section 5.1 will not limit the
entitlement of the Executive's estate or beneficiaries to any death or other
benefits then available to the Executive under any life insurance, stock
ownership, stock options, or other benefit plan or policy that is maintained by
the Company for the Executive's benefit.

          5.2  Disability.
               ----------

               (i)  If the Company determines in good faith that the Executive
has incurred a Disability (as defined below) during the Employment Term, the
Company may give the Executive written notice of its intention to terminate the
Executive's employment.  In such event, the Executive's employment with the
Company will terminate effective on the 30th day after receipt of such notice by
the Executive, provided that within the 30 days after such 





















                                       -4-


receipt, the Executive will not have returned to full-time performance of his
duties.  The Executive will continue to receive his annual base salary and
benefits until the date of termination.  In the event of the Executive's
Disability, the Company will pay the Executive, promptly after the Executive's
termination, (a) the unpaid annual base salary to which he is entitled, pursuant
to Section 4.1, through the date of the Executive's termination, (b) for any
accrued but unused vacation days, to the extent and in the amounts, if any,
provided under the Company's usual policies and arrangements, and (c) a lump sum
in cash in an amount equal to 50% of his annual base salary at the time of
termination.  This Section 5.2 will not limit the entitlement of the Executive,
the Executive's estate or beneficiaries to any disability or other benefits then
available to the Executive under any disability insurance or other benefit plan
or policy that is maintained by the Company for the Executive's benefit.

               (ii) For purposes of this Agreement, "Disability" will mean the
Executive's incapacity due to physical or mental illness substantially to
perform his duties on a full-time basis for six consecutive months and within 30
days after a notice of termination is thereafter given by the Company the
Executive will not have returned to the full-time performance of the Executive's
duties; provided, however, if the Executive disagrees with a determination to
terminate him because of Disability, the question of the Executive's disability
will be subject to the certification of a qualified medical doctor agreed to by
the Company and the Executive or, in the event of the Executive's incapacity to
designate a doctor, the Executive's legal representative.  In the absence of
agreement between the Company and the Executive, each party will nominate a
qualified medical doctor and the two doctors will select a third doctor, who
will make the determination as to Disability.  In order to facilitate such
determination, the Executive will, as reasonably requested by the Company,
(a) make himself available for medical examinations by a doctor in accordance
with this Section 5.2(ii), and (b) grant the Company and any such doctor access
to all relevant medical information concerning him, arrange to furnish copies of
medical records to such doctor and use his best efforts to cause his own doctor
to be available to discuss his health with such doctor.

          5.3  Cause.
               -----

               (i)  The Company may terminate the Executive's employment
hereunder for Cause (as defined below).  In the event of the Executive's
termination for Cause, the Company will promptly pay to the Executive (or his
representative) the unpaid annual base salary to which he is entitled, pursuant
to Section 4.1, through the date the Executive is terminated and the Executive
will be entitled to no other compensation, except as otherwise due to him under
applicable law.






















                                       -5-



               (ii) For purposes of this Agreement, the Company will have
"Cause" to terminate the Executive's employment hereunder upon a finding by the
Board that (a) the Executive committed an illegal act or acts that were intended
to and did defraud the Company, (b) the Executive engaged in gross negligence or
gross misconduct against the Company or another employee, or in carrying out his
duties and responsibilities, or (c) the Executive materially breached any of the
express covenants set forth in Section 9.1, 9.2 or 9.3.  The Company will not
have Cause unless and until the Company provides the Executive with written
notice that the Company intends to terminate his employment for Cause.  Such
written notice will specify the particular act or acts, or failure to act, that
is or are the basis for the decision to so terminate the Executive's employment
for Cause.  The Employee will be given the opportunity within 30 calendar days
of the receipt of such notice to meet with the Board to defend such act or acts,
or failure to act.  The Executive's employment by the Company automatically will
be terminated under this Section 5.3 for Cause as of the receipt of the written
notice from the Company or, if later, the date specified in such notice.  A
notice given under this Section 5.3 must set forth in reasonable detail the
facts and circumstances claimed to provide a basis for termination of the
Executive's employment for Cause, and if the termination date is other than the
date of receipt of such notice, specify the date on which the Executive's
employment is to be terminated (which date will not be earlier than the date on
which such notice is given in accordance with Section 13.5).  Such notice must
be given no later than 180 business days after a director of the Company
(excluding the Executive, if applicable) first has actual knowledge of the
events justifying the purported termination.

          5.4  Termination.
               -----------

               (i)  Involuntary Termination.  The Executive's employment
hereunder may be terminated by the Company for any reason by written notice as
provided in Section 13.5.  The Executive will be treated for purposes of this
Agreement as having been involuntarily terminated by the Company other than for
Cause if the Executive terminates his employment with the Company for any of the
following reasons (each, a "Good Reason"):  (a) the Company has breached any
material provision of this Agreement and within 30 days after notice thereof
from the Executive, the Company fails to cure such breach; (b) a successor or
assign (whether direct or indirect, by purchase, merger, consolidation or
otherwise) to all or substantially all of the business and/or assets of the
Company fails to assume liability under the Agreement; (c) a material reduction
in the aggregate benefits described by Section 4.2 (other than stock-based
compensation) provided to the Executive, unless such decrease is required by law
or is applicable to all employees of the Company eligible to participate in any
employee benefit arrangement affected by such reduction; (d) the Executive is
not elected to or is removed from the Board; or (e) the Board fails to appoint 




















                                       -6-


the Executive as Chief Executive Officer or to elect the Executive as Chairman
of the Board, or the Executive is removed from either position.

               (ii) Voluntary Termination.  The Executive may voluntarily
terminate the Agreement at any time by notice to the Company as provided in
Section 13.5.  The Executive's death or Disability (as defined in Section
5.2(ii)) during the term of the Agreement will constitute a voluntary
termination of employment for purposes of eligibility for termination payments
and benefits as provided in Section 5.5, but for no other purpose.

          5.5  Termination Payments and Benefits.
               ---------------------------------

               (i) Form and Amount.  Upon the Executive's involuntary
termination other than for Cause, (a) subject to Section 5.5(iii), the Company
will pay or provide to the Executive (1) his annual base salary and benefits
until the date of termination, (2) within five business days after termination
of his employment, a lump sum cash payment equal in amount to (A) three times
the sum of (x) the Executive's highest annual base salary in effect during the
three years prior to his date of termination, and (y) the highest annual
incentive compensation earned by the Executive during the same three-year
period, plus (B) the aggregate fees that would have been due under Section
11.2(i)(a) if the Executive had rendered services for the entire Consulting Term
(as defined in Section 11), based upon Executive's highest annual base salary
during the three-year period prior to termination of employment, (3) additional
years of age and service credit as are required to permit the Executive to
retire under the qualified defined benefit retirement plans of the Company in
which the Executive participates at the time of termination as though he had
attained age 62 and such years of service required to receive an actuarially
unreduced retirement benefit; provided, however, that in such case, the present
value of the additional benefit the Executive would have accrued if he had been
credited for all purposes with the additional years of age and service under
such plan as of the Executive's date of termination with the Company will be
paid in a lump sum in cash within five business days after termination of the
Executive's employment, and (4) for a period of one year after termination of
his employment, the continuation of the employee welfare benefits set forth in
Section 4.2 except as offset by benefits paid or provided by other sources as
set forth in Section 8, or as prohibited by law or as a condition of maintaining
the tax-favored status of any such benefits to the Company or its employees; and
(b) the Executive's benefit under the applicable supplemental executive
retirement plan will be not less than the benefit the Executive would have
received under the terms of the corresponding plan (including any individual
modifications thereof) applicable to the Executive as in effect immediately
prior to the Effective Date determined as if the Executive had continued
employment under the terms of such corresponding plan (and modifications) until
his actual termination of employment.  




















                                       -7-


For purposes of Section 5.5(i)(a)(2), the three-year period will include
employment with Diamond Shamrock, Inc. or any of its affiliates.

               (ii) Maintenance of Benefits.  During the period set forth in
Section 5.5(i)(a)(4), the Company will use its best efforts to maintain in full
force and effect for the continued benefit of the Executive all referenced
benefits or will arrange to make available to the Executive benefits
substantially similar to those that the Executive would otherwise have been
entitled to receive if his employment had not been terminated.  Such benefits
will be provided to the Executive on the same terms and conditions (including
employee contributions toward the premium payments) under which the Executive
was entitled to participate immediately prior to his termination.

               (iii) Release.  No benefit will be paid or made available under
Section 5.5(i) (a) unless the Executive first executes a release in the form
attached as an exhibit to this Agreement, and (b) to the extent any portion of
such release is subject to the seven-day revocation period prescribed by the Age
Discrimination in Employment Act of 1967, as amended, or to any similar
revocation period in effect on the date of termination of Executive's
employment, such revocation period has expired.

     6.   Change in Control Provisions.  
          ----------------------------

          6.1  Impact of Change in Control.  In the event of a "Change in
               ---------------------------
Control" of the Company, as defined in Section 6.2, (i) the Company will cause
all cash benefits due under this Agreement to be secured by an irrevocable trust
for the benefit of the Executive, the assets of which will be subject to the
claims of the Company's creditors, and will transfer to such trust cash and
other property adequate to satisfy all of the expenses of the trust for at least
five years after the Change in Control and any of the Company's actual and
potential cash obligations under this Agreement, (ii) if the Executive's
employment is involuntarily terminated without Cause after the Change in
Control, (A) the covenants of Sections 9.1 and 10 will be inapplicable to the
Executive, and (B) the covenant of Section 9.2 will expire on the third
anniversary of the date of termination of the Executive's employment, and (iii)
the definition of Good Reason, as set forth in Section 5.4(i) above, will be
expanded to include the following:

               (a) Without the Executive's written consent, a significant
reduction in the Executive's duties or the addition of duties, which in either
case are materially inconsistent with the Executive's title or position;

               (b) A good faith determination by the Executive that, as a result
of the Change in Control and a change in circumstances thereafter significantly
affecting his positions, including a change in the scope of business or other
activities 



















                                       -8-


for which he was responsible, he has been rendered substantially unable to carry
out, has been substantially hindered in the performance of, or has suffered a
substantial reduction in, any of the authorities, powers, functions,
responsibilities or duties attached to any of the Executive's positions; the
Executive's determination will be presumed to have been made in good faith
unless otherwise shown by the Company by clear and convincing evidence; or

               (c) The relocation of the Company's principal executive offices,
or requirement that the Executive have as his principal location of work any
location that is, in excess of 50 miles from the location thereof immediately
preceding the Change in Control or to travel away from his home or office
significantly more often that required immediately prior to the Change in
Control.

          6.2  Definition of Change in Control.  For purposes of this Agreement,
               -------------------------------
a "Change in Control" will be deemed to occur if at any time during the term of
the Agreement any of the following events will occur:

               (i) The Company is merged, consolidated or reorganized into or
with another corporation or other legal person, and as a result of such merger,
consolidation or reorganization, less than 50% of the combined voting power of
the then-outstanding securities of such corporation or person immediately after
such transaction are held in the aggregate by the holders of Voting Stock (as
that term is hereafter defined) of the Company immediately prior to such
transaction;

               (ii) The Company sells or otherwise transfers all or
substantially all of its assets to any other corporation or other legal person,
and as a result of such sale or transfer, less than 50% of the combined voting
power of the then-outstanding voting securities of such corporation or person
are held in the aggregate by the holders of Voting Stock of the Company
immediately prior to such sale;

               (iii) There is a report filed on Schedule 13D or Schedule 14D-1
(or any successor schedule, form or report), each as promulgated pursuant to the
Securities Exchange Act of 1934 (the "Exchange Act"), disclosing that any person
(as the term "person" is used in Section 13(d)(3) or Section 14(d)(2) of the
Exchange Act) has become the beneficial owner (as the term "beneficial owner" is
defined under Rule 13d-3 or any successor rule or regulation promulgated under
the Exchange Act) of securities representing 20% or more of the combined voting
power of the then-outstanding securities of the Company entitled to vote
generally in the election of Directors of the Company ("Voting Stock");

               (iv) The Company files a report or proxy statement with the
Securities and Exchange Commission pursuant to the 




















                                       -9-


Exchange Act disclosing in response to Form 8-K or Schedule 14A (or any
successor schedule, form or report or item therein) that a change in control of
the Company has or may have occurred or will or may occur in the future pursuant
to any then-existing contract or transaction; or

               (v) If during the period of two consecutive years individuals who
at the beginning of any such period constitute the Directors of the Company
cease for any reason to constitute at least a majority thereof unless the
election, or the nomination for election by the Company's shareholders, of each
Director of the Company first elected during such period was approved by a vote
of at least two-thirds of the Directors of the Company then still in office who
were Directors of the Company at the beginning of any such period (excluding for
this purpose the election of any new Director in connection with an actual or
threatened election or proxy contest).

Notwithstanding the foregoing provisions of Section 6.2(iii) or (iv) hereof,
unless otherwise determined in a specific case by majority vote of the Board (or
the Compensation Committee thereof), a "Change in Control" will not be deemed to
have occurred for purposes of this Agreement solely because the Company, an
entity in which the Company directly or beneficially owns 50% or more of the
voting securities of such entity, any Company-sponsored employee stock ownership
plan or any other employee benefit plan of the Company either files or becomes
obligated to file a report or a proxy statement under or in response to Schedule
13D, Schedule 14D-1, Form 8-K or Schedule 14A (or any successor schedule, form
or report or item therein) under the Exchange Act, disclosing beneficial
ownership by it of shares of voting securities of the Company, whether in excess
of 20% or otherwise, or because the Company reports that a change in control of
the Company has or may have occurred or will or may occur in the future by
reason of such beneficial ownership.  Notwithstanding the foregoing provisions
of Section 6.2, the Merger will not constitute a Change in Control.

     7. Certain Additional Payments by the Company:
        ------------------------------------------

          (i) Anything in this Agreement to the contrary notwithstanding, if it
is determined (as hereafter provided) that any payment or distribution by the
Company to or for the benefit of the Executive, whether paid or payable or
distributed or distributable pursuant to the terms of this Agreement or
otherwise pursuant to or by reason of any other agreement, policy, plan, program
or arrangement, including without limitation any stock option, stock
appreciation right or similar right, or the lapse or termination of any
restriction on or the vesting or exercisability of any of the foregoing (a
"Payment"), would be subject to the excise tax imposed by Section 4999 of the
Code (or any successor provision thereto) by reason of being "contingent on a
change in ownership or control" of Diamond Shamrock, Inc. or the Company, within
the meaning of Section 280G 




















                                      -10-


of the Code (or any successor provision thereto) or to any similar tax imposed
by state or local law, or any interest or penalties with respect to such excise
tax (such tax or taxes, together with any such interest and penalties, are
hereafter collectively referred to as the "Excise Tax"), then the Executive will
be entitled to receive an additional payment or payments (a "Gross-Up Payment")
in an amount such that, after payment by the Executive of all taxes (including
any interest or penalties imposed with respect to such taxes), including any
Excise Tax, imposed upon the Gross-Up Payment, the Executive retains an amount
of the Gross-Up Payment equal to the Excise Tax imposed upon the Payments.  No
Gross-Up Payment will be made with respect to the Excise Tax, if any,
attributable to (a) any incentive stock option, as defined by Section 422 of the
Code ("ISO") granted prior to the execution of this Agreement (unless a
comparable Gross-Up Payment has theretofore been made available with respect to
such option), or (b) any stock appreciation or similar right, whether or not
limited, granted in tandem with any ISO described in clause (a).

          (ii) Subject to the provisions of Section 7(vi) hereof, all
determinations required to be made under this Section 7, including whether an
Excise Tax is payable by the Executive and the amount of such Excise Tax and
whether a Gross-Up Payment is required and the amount of such Gross-Up Payment,
will be made by a nationally recognized firm of certified public accountants
(the "Accounting Firm") selected by the Executive in his sole discretion.  The
Executive will direct the Accounting Firm to submit its determination and
detailed supporting calculations to both the Company and the Executive within 15
calendar days after the Termination Date, if applicable, and any other such time
or times as may be requested by the Company or the Executive.  If the Accounting
Firm determines that any Excise Tax is payable by the Executive, the Company
will pay the required Gross-Up Payment to the Executive within five business
days after receipt of such determination and calculations.  If the Accounting
Firm determines that no Excise Tax is payable by the Executive, it will, at the
same time as it makes such determination, furnish the Executive with an opinion
that he has substantial authority not to report any Excise Tax on his 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.  As a result of the uncertainty in the application of
Section 4999 of the Code (or any successor provision thereto) and the
possibility of similar uncertainty regarding applicable state or local tax law
at the time of any determination by the Accounting Firm hereunder, it is
possible that Gross-Up Payments that will not have been made by the Company
should have been made (an "Underpayment"), consistent with the calculations
required to be made hereunder.  In the event that the Company exhausts or fails
to pursue its remedies pursuant to Section 7(vi) hereof and the Executive
thereafter is required to make a payment of any Excise Tax, the Executive will
direct the Accounting Firm to determine the amount of the 





















                                      -11-


Underpayment that has occurred and to submit its determination and detailed
supporting calculations to both the Company and the Executive as promptly as
possible.  Any such Underpayment will be promptly paid by the Company to, or for
the benefit of, the Executive within five business days after receipt of such
determination and calculations.

               (iii) The Company and the Executive will each provide the
Accounting Firm access to and copies of any books, records and documents in the
possession of the Company or the Executive, as the case may be, reasonably
requested by the Accounting Firm, and otherwise cooperate with the Accounting
Firm in connection with the preparation and issuance of the determination
contemplated by Section 7(ii) hereof.

               (iv) The federal, state and local income or other tax returns
filed by the Executive will be prepared and filed on a consistent basis with the
determination of the Accounting Firm with respect to the Excise Tax payable by
the Executive.  The Executive will make proper payment of the amount of any
Excise Tax, and at the request of the Company, provide to the Company true and
correct copies (with any amendments) of his federal income tax return as filed
with the Internal Revenue Service and corresponding state and local tax returns,
if relevant, as filed with the applicable taxing authority, and such other
documents reasonably requested by the Company, evidencing such payment.  If
prior to the filing of the Executive's federal income tax return, or
corresponding state or local tax return, if relevant, the Accounting Firm
determines that the amount of the Gross-Up Payment should be reduced, the
Executive will within five business days pay to the Company the amount of such
reduction.

               (v) The fees and expenses of the Accounting Firm for its services
in connection with the determinations and calculations contemplated by
Sections 7(ii) and (iv) hereof will be borne by the Company.  If such fees and
expenses are initially paid by the Executive, the Company will reimburse the
Executive the full amount of such fees and expenses within five business days
after receipt from the Executive of a statement therefor and reasonable evidence
of his payment thereof.

               (vi) The Executive will notify the Company in writing of any
claim by the Internal Revenue Service that, if successful, would require the
payment by the Company of a Gross-Up Payment.  Such notification will be given
as promptly as practicable but no later than 10 business days after the
Executive actually receives notice of such claim and the Executive will further
apprise the Company of the nature of such claim and the date on which such claim
is requested to be paid (in each case, to the extent known by the Executive). 
The Executive will not pay such claim prior to the earlier of (a) the expiration
of the 30-calendar-day period following the date on which he gives such notice
to the Company and (b) the date that any payment of amount with respect to such
claim is due.  If the 


















                                      -12-


Company notifies the Executive in writing prior to the expiration of such period
that it desires to contest such claim, the Executive will:

               (1) provide the Company with any written records or documents in
          his possession relating to such claim reasonably requested by the
          Company;

               (2) take such action in connection with contesting such claim as
          the Company will reasonably request in writing from time to time,
          including without limitation accepting legal representation with
          respect to such claim by an attorney competent in respect of the
          subject matter and reasonably selected by the Company;

               (3) cooperate with the Company in good faith in order effectively
          to contest such claim; and

               (4) permit the Company to participate in any proceedings relating
          to such claim;

provided, however, that the Company will bear and pay directly all costs and
expenses (including interest and penalties) incurred in connection with such
contest and will indemnify and hold harmless the Executive, on an after-tax
basis, for and against any Excise Tax or income tax, including interest and
penalties with respect thereto, imposed as a result of such representation and
payment of costs and expenses.  Without limiting the foregoing provisions of
this Section 7(vi), the Company will control all proceedings taken in connection
with the contest of any claim contemplated by this Section 7(vi) and, at its
sole option, may pursue or forego any and all administrative appeals,
proceedings, hearings and conferences with the taxing authority in respect of
such claim (provided, however, that the Executive may participate therein at his
own cost and expense) and may, at its option, either direct the Executive to pay
the tax claimed and sue for a refund or contest the claim in any permissible
manner, and the Executive agrees to prosecute such contest to a determination
before any administrative tribunal, in a court of initial jurisdiction and in
one or more appellate courts, as the Company will determine; provided, however,
that if the Company directs the Executive to pay the tax claimed and sue for a
refund, the Company will advance the amount of such payment to the Executive on
an interest-free basis and will indemnify and hold the Executive harmless, on an
after-tax basis, from any Excise Tax or income tax, including interest or
penalties with respect thereto, imposed with respect to such advance; and
provided further, however, that any extension of the statute of limitations
relating to payment of taxes for the taxable year of the Executive with respect
to which the contested amount is claimed to be due is limited solely to such
contested amount.  Furthermore, the Company's control of any such contested
claim will be limited to issues with respect to which a Gross-Up Payment would
be payable hereunder and the Executive will be 



















                                      -13-


entitled to settle or contest, as the case may be, any other issue raised by the
Internal Revenue Service or any other taxing authority.

               (vii) If, after the receipt by the Executive of an amount
advanced by the Company pursuant to Section 7(vi) hereof, the Executive receives
any refund with respect to such claim, the Executive will (subject to the
Company's complying with the requirements of Section 7(vi) hereof) promptly pay
to the Company the amount of such refund (together with any interest paid or
credited thereon after any taxes applicable thereto).  If, after the receipt by
the Executive of an amount advanced by the Company pursuant to Section 7(vi)
hereof, a determination is made that the Executive will not be entitled to any
refund with respect to such claim and the Company does not notify the Executive
in writing of its intent to contest such denial or refund prior to the
expiration of 30 calendar days after such determination, then such advance will
be forgiven and will not be required to be repaid and the amount of such advance
will offset, to the extent thereof, the amount of Gross-Up Payment required to
be paid pursuant to this Section 7.

     8.   Mitigation and Offset.  The Executive is under no obligation to
          ---------------------
mitigate damages or the amount of any payment or benefit provided for hereunder
by seeking other employment or otherwise; provided, however, that the
Executive's coverage under the Company's welfare benefit plans will be reduced
to the extent that the Executive becomes covered under any comparable employee
benefit plan made available by another employer and covering the same type of
benefits.  The Executive will report to the Company any such benefits actually
received by him.

     9.   Competition; Confidentiality; Nonsolicitation
          ---------------------------------------------

          9.1  (i) Subject to Section 6.1(ii), the Executive hereby covenants
and agrees that during the Employment Term and for one year following the
Employment Term he will not, without the prior written consent of the Company,
engage in Competition (as defined below) with the Company.  For purposes of this
Agreement, if the Executive takes any of the following actions he will be
engaged in "Competition": engaging in or carrying on, directly or indirectly,
any enterprise, whether as an advisor, principal, agent, partner, officer,
director, employee, stockholder, associate or consultant to any person,
partnership, corporation or any other business entity, that is principally
engaged in the business of refining and/or marketing oil or related products in
States in which the Company has significant operations; provided, however, that
"Competition" will not include (a) the mere ownership of securities in any
enterprise and exercise of rights appurtenant thereto or (b) participation in
management of any enterprise or business operation thereof other than in
connection with the competitive operation of such enterprise.





















                                      -14-



               (ii) Subject to Section 6.1(ii), the Executive hereby covenants
and agrees that during the Employment Term and for three years following the
Employment Term he will not assist a third party in preparing or making an
unsolicited bid for the Company, engaging in a proxy contest with the Company,
or engaging in any other similar activity.

          9.2  During the Employment Term, the Company agrees that it will
disclose to Executive its confidential or proprietary information (as defined in
this Section 9.2) to the extent necessary for Executive to carry out his
obligations under this Agreement.  Subject to Section 6.1(ii), the Executive
hereby covenants and agrees that he will not, without the prior written consent
of the Company, during the Employment Term or thereafter disclose to any person
not employed by the Company, or use in connection with engaging in Competition
with the Company, any confidential or proprietary information of the Company. 
For purposes of this Agreement, the term "confidential or proprietary
information" will include all information of any nature and in any form that is
owned by the Company and that is not publicly available or generally known to
persons engaged in businesses similar or related to those of the Company. 
Confidential information will include, without limitation, the Company's
financial matters, customers, employees, industry contracts, and all other
secrets and all other information of a confidential or proprietary nature.  The
foregoing obligations imposed by this Section 9.2 will cease if such
confidential or proprietary information will have become, through no fault of
the Executive, generally known to the public or the Executive is required by law
to make disclosure (after giving the Company notice and an opportunity to
contest such requirement).

          9.3  Subject to Section 6.1(ii), the Executive hereby covenants and
agrees that during the Employment Term and for one year thereafter he will not
attempt to influence, persuade or induce, or assist any other person in so
persuading or inducing, any employee of the Company to give up, or to not
commence, employment or a business relationship with the Company.

          9.4  Executive acknowledges and agrees that the remedy at law
available to the Company for breach of any of his post-termination obligations
under Sections 9.1, 9.2 and 9.3 would be inadequate and that damages flowing
from such a breach may not readily be susceptible to being measured in monetary
terms.  Accordingly, Executive acknowledges, consents and agrees that, in
addition to any other rights or remedies which the Company may have at law, in
equity or under this Agreement, upon adequate proof of his violation of any such
provision of this Agreement, the Company will be entitled to immediate
injunctive relief and may obtain a temporary order restraining any threatened or
further breach, without the necessity of proof of actual damage.

     10.  Post-termination Assistance.  Subject to Section 
          ---------------------------



















                                      -15-


6.1(ii), the Executive agrees that after his employment with the Company has
terminated he will provide, upon reasonable notice, such information and
assistance to the Company as may reasonably be requested by the Company in
connection with any litigation in which it or any of its affiliates is or may
become a party; provided, however, that the Company agrees to reimburse the
Executive for any related out-of-pocket expenses, including travel expenses.

     11.  Consulting Services Agreement.  
          -----------------------------

          11.1 Services.  
               --------

               (i) During the Consulting Term (as defined in Section 11.1(ii)),
the Company will retain the Executive to perform consulting and advisory
services (as the "Consultant") to the Company as such services may be needed
from time to time and as the President and Chief Executive Officer of the
Company and his designees may request.  The Consultant agrees that, during the
Consulting Term, he will be available in person and by telephone in and around
the geographic areas of the Company's operations and at such other designated
areas of assignment as may from time to time be requested by the President and
Chief Executive Officer of the Company and his designees.  The Company will
furnish the Consultant with secretarial assistance to the extent necessary for
the Consultant to perform services under this Agreement and an office that is
located in the executive area of the Company's corporate offices and that is
comparable to offices provided to senior executive officers of the Company.  In
addition, the Company agrees that it is intended that during the Consulting
Term, the Executive will retain the position of Chairman of the Board and will
be a member of the Board.  The Company will use its best efforts to cause the
Executive to be elected as a member of the Board and as Chairman of the Board
during such period.  The Consultant may also serve as a director of any
corporation that is not engaged in "Competition" (as defined in Section 9.1)
with the Company.

               (ii)  The "Consulting Term" will commence upon the day after the
expiration of the Employment Term, as set forth in Section 1.2 and will
terminate at the end of the third year thereafter; provided, however, if this
Agreement has been terminated pursuant Section 5 or Section 6 prior to the
original expiration date of the Employment Term (other than in the case of a
voluntary termination), this Section 11 will not become operative and the
Executive will have no obligation to render consulting services to the Company.

               (iii)  The Company and the Consultant agree that the Consultant
will perform services pursuant to this Section 11 as an independent contractor
and not as an employee, agent, partner, or joint venturer of the Company.  The
Consultant acknowledges that as an independent contractor he is not eligible to
participate in employee benefit plans of the Company and will 




















                                      -16-


not be entitled to employee benefits except as he may be otherwise entitled to
such benefits as a result of his prior service to the Company as an employee,
subject to the provisions of the applicable employee benefit plans.

          11.2 Consulting Fee and Expenses.
               ---------------------------

               (i)    In consideration of the Consultant's willingness to be
available during the Consulting Term to provide the services contemplated by
Section 11.1, the Company will pay to the Consultant a fixed consulting fee per
year equal to one-half of the Consultant's highest annual base salary in effect
during the Employment Term, payable in equal monthly installments on the last
day of each calendar month during the Consulting Term (with the amount of such
payment to be prorated with respect to any partial calendar month included in
the Consulting Term); and

               (ii)   If, in the performance of the Consultant's obligations
under this Agreement, the Consultant is required to travel more than 50 miles
from his principal residence, wherever that might be, the Company will reimburse
the Consultant for reasonable expenses (supported by receipts satisfactory to
the Company) incurred as a result of such travel, including without limitation
reasonable expenses for travel to and from the Consultant's principal residence
and food and lodging while away from his principal residence.  Further, if the
Consultant is required to incur any other actual out-of-pocket expenses in
connection with the performance of his obligations under this Agreement, the
Company will reimburse the Consultant for such expenses, provided such expenses
are approved in advance by the Company and the Consultant furnishes the Company
with receipts for such expenses satisfactory to the Company. 

          11.3 Termination of Consulting Services.  If the services of the
               ----------------------------------
Consultant are terminated during the Consulting Term for any reason (including
the death or disability of the Consultant) other than a voluntary termination by
the Consultant, the Consultant will be entitled to a lump sum payment in an
amount equal to the sum of the fixed monthly payments described in Section
11.1(i)(a) that would otherwise have been paid during the Consulting Term.  For
purposes of this Section 11.3, a voluntary termination will not include
termination by the Consultant after any of the following events:  (a) the Board
fails to elect Consultant as Chairman of the Board or the Consultant is removed
from such position; (b) a Change in Control of the Company, or (c) the Company
relocates its principal executive offices in excess of 50 miles from the
location thereof at the commencement of the Consulting Term; provided, however,
that before clause (c), above, will be applicable, Consultant must first resign
as Chairman of the Board and tender his resignation as a member of the Board.

          11.4 Confidential Information.  The Consultant recognizes and
               ------------------------
acknowledges that in the course of his employment 




















                                      -17-


with the Company he has obtained, and during the Consulting Term may obtain,
private or confidential information and proprietary data relating to the
Company, whether specifically designated as such or not (the "Confidential
Information"), and the Consultant agrees that he will maintain in confidence any
Confidential Information obtained by or from the Company and will not, during
the Consulting Term or any time thereafter, either directly or indirectly,
disclose or use Confidential Information except with the prior written consent
of the President and Chief Executive Officer of the Company or until such
Confidential Information will be in the public domain (other than as a result of
an unauthorized disclosure by the Consultant).

          11.5 Director Status.  While serving as a director of the Company
               ---------------
during the Consulting Term, the Consultant will be treated in the same manner as
other directors of the Company for all outside director compensation purposes.

     12.  Survival.  The expiration or termination of the Employment Term or the
          --------
Consulting Term will not impair the rights or obligations of any party hereto
that accrue hereunder prior to such expiration or termination, except to the
extent specifically stated herein.  In addition to the foregoing, the
Executive's covenants contained in Sections 9.1, 9.2, 9.3 and 10 and the
Company's obligations under Sections 5, 7 and 13.1 will survive the expiration
or termination of Executive's employment.

     13.  Miscellaneous Provisions.
          ------------------------

          13.1 Legal Fees and Expenses.  Without regard to whether the Executive
               -----------------------
prevails, in whole or in part, in connection therewith, the Company will pay and
be financially responsible for 100% of any and all attorneys' and related fees
and expenses incurred by the Executive in connection with any dispute associated
with the interpretation, enforcement or defense of the Executive's rights under
this Agreement by litigation or otherwise; provided that, in regard to such
dispute, the Executive has not acted in bad faith or with no colorable claim of
success.  All such fees and expenses will be paid by the Company as incurred by
the Executive on a monthly basis upon an undertaking by the Executive to repay
such advanced amounts if a court determines, in a decision against which no
appeal may be taken or with respect to which the time period to appeal has
expired, that he acted in bad faith or with no colorable claim of success.

          13.2 Binding on Successors.  This Agreement will be binding upon and
               ---------------------
inure to the benefit of the Company, the Executive and each of their respective
successors, assigns, personal and legal representatives, executors,
administrators, heirs, distributees, devisees, and legatees, as applicable.

          13.3 Governing Law.  This Agreement will be governed, construed,
               -------------
interpreted and enforced in accordance with the 




















                                      -18-


substantive laws of the State of Delaware, without regard to conflicts of law
principles.

          13.4 Severability.  Any provision of this Agreement that is deemed
               ------------
invalid, illegal or unenforceable in any jurisdiction will, as to that
jurisdiction, be ineffective to the extent of such invalidity, illegality or
unenforceability, without affecting in any way the remaining provisions hereof
in such jurisdiction or rendering that or any other provisions of this Agreement
invalid, illegal, or unenforceable in any other jurisdiction.  If any covenant
should be deemed invalid, illegal or unenforceable because its scope is
considered excessive, such covenant will be modified so that the scope of the
covenant is reduced only to the minimum extent necessary to render the modified
covenant valid, legal and enforceable. 

          13.5 Notices.  For all purposes of this Agreement, all communications,
               -------
including without limitation notices, consents, requests or approvals, required
or permitted to be given hereunder will be in writing and will be deemed to have
been duly given when hand delivered or dispatched by electronic facsimile
transmission (with receipt thereof confirmed), or five business days after
having been mailed by United States registered or certified mail, return receipt
requested, postage prepaid, or three business days after having been sent by a
nationally recognized overnight courier service such as Federal Express, UPS, or
Purolator, addressed to the Company (to the attention of the Secretary of the
Company) at its principal executive offices and to the Executive at his
principal residence, or to such other address as any party may have furnished to
the other in writing and in accordance herewith, except that notices of changes
of address will be effective only upon receipt.

               (i) To The Company.  If to the Company, addressed to the
                   --------------
attention of General Counsel at 9830 Colonnade Boulevard, San Antonio, Texas
78230.

               (ii) To the Executive.  If to the Executive, to him care of the
                    ----------------
Company at the above address.

          13.6 Counterparts.  This Agreement may be executed in several
               ------------
counterparts, each of which will be deemed to be an original, but all of which
together will constitute one and the same Agreement.

          13.7 Entire Agreement.  The terms of this Agreement are intended by
               ----------------
the parties to be the final expression of their agreement with respect to the
Executive's employment by the Company and may not be contradicted by evidence of
any prior or contemporaneous agreement.  The parties further intend that this
Agreement will constitute the complete and exclusive statement of its terms and
that no extrinsic evidence whatsoever may be introduced in any judicial,
administrative or other legal proceeding to vary the terms of this Agreement.



















                                      -19-



          13.8 Amendments; Waivers.  This Agreement may not be modified,
               --------------------
amended, or terminated except by an instrument in writing, approved by the
Company and signed by the Executive and the Company. Failure on the part of
either party to complain of any action or omission, breach or default on the
part of the other party, no matter how long the same may continue, will never be
deemed to be a waiver of any rights or remedies hereunder, at law or in equity. 
The Executive or the Company may waive compliance by the other party with any
provision of this Agreement that such other party was or is obligated to comply
with or perform only through an executed writing; provided, however, that such
waiver will not operate as a waiver of, or estoppel with respect to, any other
or subsequent failure.

          13.9 No Inconsistent Actions.  The parties will not voluntarily
               ------------------------
undertake or fail to undertake any action or course of action that is
inconsistent with the provisions or essential intent of this Agreement. 
Furthermore, it is the intent of the parties hereto to act in a fair and
reasonable manner with respect to the interpretation and application of the
provisions of this Agreement.

          13.10 Headings and Section References.  The headings used in this
                -------------------------------
Agreement are intended for convenience or reference only and will not in any
manner amplify, limit, modify or otherwise be used in the construction or
interpretation of any provision of this Agreement.  All section references are
to sections of this Agreement, unless otherwise noted.

     14.  Effectiveness, Prior Agreement and Consent.  This Agreement will
          ------------------------------------------
become effective upon and the Prior Agreement will terminate immediately prior
to, the Effective Date, whereupon all references to the "Company" herein will be
treated as references to Ultramar Corporation.  By executing this Agreement,
Executive hereby consents to the assumption of this Agreement by Ultramar
Corporation upon the Effective Date.  Notwithstanding any other provision of
this Agreement, if the Merger Agreement is terminated prior to the Effective
Date, this Agreement will have no further force or effect, and the Prior
Agreement will continue in effect as though this Agreement had not been entered
into.





























                                      -20-


          IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date and year first above written, but effective as provided in Section 14.




                                                                           
                                        -----------------------------------
                                        Roger R. Hemminghaus


                                        DIAMOND SHAMROCK, INC.,
                                        a Delaware corporation


                                        By:                                
                                             ------------------------------
                                             Name:                         
                                                    -----------------------
                                             Title:                        
                                                    -----------------------
















































                                      -21-


                                     Exhibit


                          GENERAL RELEASE OF ALL CLAIMS


     This General Release of all Claims (this "Agreement") is entered into by
and between _____________________ ("Executive") and Ultramar Diamond Shamrock
Corp. (including its subsidiaries) (collectively the "Company") effective as of
__________________.

     In consideration of the promises set forth in the employment agreement
between Executive and the Company, dated September ___, 1996, as amended as of
the effective date hereof (the "Employment Agreement"), as well as any promises
set forth in this Agreement, Executive and the Company agree as follows:

(1)  Employment Agreement Entitlements
     ---------------------------------

     The Company will provide Executive the post-termination payments and
     benefits to which he is entitled under the Employment Agreement.

(2)  Return of Property
     ------------------

     All Company files, access keys, desk keys, ID badges and credit cards, and
     such other property of the Company as the Company may reasonably request,
     in Executive's possession must be returned no later than the date of
     Executive's termination from the Company (the "Termination Date").

(3)  General Release and Waiver of Claims
     ------------------------------------

     Except as provided in the last sentence of this paragraph (3), Executive
     hereby unconditionally and forever releases, discharges and waives any and
     all claims of any nature whatsoever, whether legal, equitable or otherwise,
     which Executive may have against the Company arising at any time on or
     before the Termination Date, other than with respect to the obligations of
     the Company to the Executive under the Employment Agreement.  This release
     of claims extends to any and all claims of any nature whatsoever, other
     than with respect to the obligations of the Company to the Executive under
     the Employment Agreement, whether known, unknown or capable or incapable of
     being known as of the Termination Date of thereafter.  This Agreement is a
     release of all claims of any nature whatsoever by Executive against the
     Company, other than with respect to the obligations of the Company to the
     Executive under the Employment Agreement, and includes, other than as
     herein provided, any and all claims, demands, causes of action, liabilities
     whether known or unknown including those caused by, arising from or related
     to Executive's employment relationship with the Company including, but
     without limitation, any and all alleged discrimination or acts of
     discrimination which occurred or 

















                                      -22-


     may have occurred on or before the Termination Date based upon race, color,
     sex, creed, national origin, age, disability or any other violation of any
     Equal Employment Opportunity Law, ordinance, rule, regulation or order,
     including, but not limited to, Title VII of the Civil Rights Act of 1964,
     as amended; the Civil Rights Act of 1991; the Age Discrimination in
     Employment Act, as amended (as further described in Section 7 below); the
     Americans with Disabilities Act; claims under the Employee Retirement
     Income Security Act ("ERISA"); or any other federal, state or local laws or
     regulations regarding employment discrimination or termination of
     employment.  This also includes claims for wrongful discharge, fraud, or
     misrepresentation under any statute, rule, regulation or under the common
     law.

     The Executive agrees and understands and knowingly agrees to this release
     because it is his intent in executing this Agreement to forever discharge
     the Company from any and all present, future, foreseen or unforeseen causes
     of action except for the obligations of the Company set forth in the
     Employment Agreement.

     Notwithstanding the foregoing, Executive does not release, discharge or
     waive any rights to indemnification that he may have under the By-Laws of
     the Company, the laws of the State of Delaware, any indemnification
     agreement between the Executive and the Company or any insurance coverage
     maintained by or on behalf of the Company.

(4)  Release and Waiver of Claims Under the Age of Discrimination in Employment
     --------------------------------------------------------------------------
     Act
     ---

     Executive acknowledges that the Company encouraged him to consult with an
     attorney of his choosing, and through this Agreement encourages him to
     consult with his attorney with respect to possible claims under the Age
     Discrimination in Employment Act of 1967, as amended ("ADEA") and that
     Executive acknowledges that he understands that the ADEA is a federal
     statute that prohibits discrimination, on the basis of age, in employment,
     benefits, and benefit plans.  Executive wishes to waive any and all claims
     under the ADEA that he may have, as of the Termination Date, against the
     Company, its shareholders, employees, or successors and hereby waives such
     claims.  Executive further understands that by signing this Agreement he is
     in fact waiving, releasing and forever giving up any claim under the ADEA
     that may have existed on or prior to the Termination Date.  Executive
     acknowledges that the Company has informed him that he has at his option,
     twenty-one (21) days in which to sign the waiver of this claim under ADEA,
     and he does hereby knowingly and voluntarily waive said twenty-one (21) day
     period.  Executive also understands that he has seven (7) days following
     the Termination Date within which to revoke the release contained in this
     paragraph by providing a 



















                                      -23-


     written notice of his revocation of the release and waiver contained in
     this paragraph to the Company.  Executive further understands that this
     right to revoke the release contained in this paragraph relates only to
     this paragraph and does not act as a revocation of any other term of this
     Agreement.

(5)  Proceedings
     -----------

     Executive has not filed, and agrees not to initiate or cause to be
     initiated on his behalf, any complaint, charge, claim or proceeding against
     the Company before any local, state or federal agency, court or other body
     relating to his employment or the termination of his employment (each
     individually, a "Proceeding"), and agrees not to voluntarily participate in
     any Proceeding.  Executive waives any right he may have to benefit in any
     manner from any relief (whether monetary or otherwise) arising out of any
     Proceeding.

(6)  Remedies
     --------

     In the event Executive initiates or voluntarily participates in any
     Proceeding, or if he fails to abide by any of the terms of this Agreement
     or his post-termination obligations contained in the Employment Agreement,
     or if he revokes the ADEA release contained in Paragraph 4 of this
     Agreement within the seven-day period provided under Paragraph 4, the
     Company may, in addition to any other remedies it may have, reclaim any
     amounts paid to him under the termination provisions of the Employment
     Agreement or terminate any benefits or payments that are subsequently due
     under the Employment Agreement, without waiving the release granted herein.
     Executive acknowledges and agrees that the remedy at law available to the
     Company for breach of any of his post-termination obligations under the
     Employment Agreement or his obligations under Paragraphs 3, 4, and 5 of
     this Agreement would be inadequate and that damages flowing from such a
     breach may not readily be susceptible to being measured in monetary terms. 
     Accordingly, Executive acknowledges, consents and agrees that, in addition
     to any other rights or remedies which the Company may have at law, in
     equity or under this Agreement, upon adequate proof of his violation of any
     such provision of this Agreement, the Company shall be entitled to
     immediate injunctive relief and may obtain a temporary order restraining
     any threatened or further breach, without the necessity of proof of actual
     damage.

     Executive understands that by entering into this Agreement he will be
     limiting the availability of certain remedies that he may have against the
     Company and limiting also his ability to pursue certain claims against the
     Company.

(7)  Severability Clause
     -------------------


















                                      -24-



     In the event any provision or part of this Agreement is found to be invalid
     or unenforceable, only that particular provision or part so found, and not
     the entire agreement, will be inoperative.

(8)  Non-Admission
     -------------

     Nothing contained in this Agreement will be deemed or construed as an
     admission of wrongdoing or liability on the part of the Company.

(9)  Governing Law
     -------------

     This Agreement shall be governed by and construed in accordance with the
     laws of the State of Delaware, applicable to agreements made and to be
     performed in that State; and the parties agree to the jurisdiction of the
     U.S. District Court for the District of Delaware, and agree to appear in
     any action in such courts by service of process by certified mail, return
     receipt requested, at the following addresses:

               To Company:      ULTRAMAR DIAMOND SHAMROCK CORP.
                                9830 Colonnade Boulevard
                                San Antonio, Texas  78230

                                and

               To Executive:                                                    
                                ------------------------------------------------
                                                                                
                                ------------------------------------------------
                                                                                
                                ------------------------------------------------



THE EXECUTIVE ACKNOWLEDGES THAT HE HAS READ THIS AGREEMENT AND THAT HE FULLY
KNOWS, UNDERSTANDS, AND APPRECIATES ITS CONTENTS, AND THAT HE HEREBY EXECUTES
THE SAME AND MAKES THIS AGREEMENT AND THE RELEASE AND AGREEMENTS PROVIDED FOR
HEREIN VOLUNTARILY AND OF HIS OWN FREE WILL.

     IN WITNESS WHEREOF, the parties have executed this AGREEMENT as of the date
first set forth above.





                                                                           
                                        -----------------------------------
                                        Roger R. Hemminghaus


                                        ULTRAMAR DIAMOND SHAMROCK CORP.,
                                        a Delaware corporation


                                        By:                                
                                             ------------------------------
                                             Timothy J. Fretthold
                                             Executive Vice President and
                                             Chief Administrative Officer










                                      -25-