SECOND AMENDMENT TO CREDIT AGREEMENT


                            BETWEEN


                    HOWELL CRUDE OIL COMPANY


                              AND


             BANK ONE, TEXAS, NATIONAL ASSOCIATION,
                      AS AGENT AND LENDER






                          May 22, 1996

                       TABLE OF CONTENTS

                                                             Page

ARTICLE I      DEFINITIONS AND INTERPRETATION

     1.1       Terms Defined Above                                   1
     1.2       Terms Defined in Credit Agreement                     1
     1.3       References                                            1
     1.4       Articles and Sections                                 2
     1.5       Number and Gender                                     2

ARTICLE II     AMENDMENT TO CREDIT AGREEMENT

ARTICLE III    CONDITIONS

     3.1       Receipt of Loan Documents and Other Items             2
     3.2       Accuracy of Representations and Warranties;
               No Default or Event of Default                        3
     3.3       Payment of Other Fees and Expenses                    3
     3.4       Matters Satisfactory to Agent.                        3

ARTICLE IV     REPRESENTATIONS AND WARRANTIES

     4.1       Due Authorization                                     3
     4.2       Valid and Binding Obligations                         3
     4.3       Representations and Warranties in Credit Agreement    3
     4.4       No Default or Event of Default                        3

ARTICLE V      MISCELLANEOUS

     5.1       Rights of Third Parties                               4
     5.2       Survival Upon Unenforceability                        4
     5.3       Ratification                                          4
     5.4       Governing Law                                         4
     5.5       Jurisdiction and Venue                                4
     5.6       Entire Agreement; No Oral Agreements                  4
     5.7       Waiver of Rights to Jury Trial                        5
     5.8       Counterparts                                          5

              SECOND AMENDMENT TO CREDIT AGREEMENT


          THIS SECOND AMENDMENT TO CREDIT AGREEMENT (this "Amendment"), dated as
of May 22, 1996, is entered into by and among HOWELL CRUDE OIL COMPANY, a
Delaware corporation (the "Borrower"), each lender that is or becomes a party to
the Credit Agreement (as defined below) as provided in Section 9.1 thereof
(individually, together with its successors and assigns, a "Lender" and,
collectively, together with their respective successors and assigns, the
"Lenders"), and BANK ONE, TEXAS, NATIONAL ASSOCIATION, a national banking
association, as agent for the Lenders (in such capacity, together with its
successors in such capacity, the "Agent").


                      W I T N E S S E T H:

          WHEREAS, the Borrower, the Agent, and the Lenders are parties to the
Credit Agreement dated as of March 31, 1995, as amended from time to time (as
amended, the "Credit Agreement"); and

          WHEREAS, the Borrower, the Agent, and the Lenders desire to amend the
Credit Agreement as provided hereinbelow;

          NOW THEREFORE, in consideration of the premises and the mutual
agreements, representations and warranties herein set forth and for other good
and valuable consideration, the parties hereby agree as follows:


                           ARTICLE I

                 DEFINITIONS AND INTERPRETATION

         1.1   Terms Defined Above.  As used in this Amendment, the terms
"Agent," "Amendment," "Borrower," "Credit Agreement," "Lender," and "Lenders"
shall have the meanings assigned to them hereinabove.

         1.2   Terms Defined in Credit Agreement.  Each term defined in the
Credit Agreement and used herein without definition shall have the meaning
assigned to such term in the Credit Agreement, unless expressly provided herein
to the contrary.

         1.3   References.  References in this Amendment to Article or Section
numbers shall be to Articles and Sections of this Amendment, unless expressly
stated herein to the contrary.  References in this Amendment to "hereby,"
"herein," "hereinabove," "hereinafter," "hereinbelow," "hereof," "hereunder" and
words of similar import shall be to this Amendment in its entirety and not only
to the particular Article or Section in which such reference appears.

         1.4   Articles and Sections.  This Amendment, for convenience only, has
been divided into Articles and Sections, and all rights, powers, privileges,
duties, and other legal relations of the parties hereto shall be determined from
this Amendment as an entirety and without regard to such divisions into Articles
and Sections and without regard to headings prefixed to such Articles and
Sections.

         1.5   Number and Gender.  Whenever the context requires, reference
herein made to the single number shall be understood to include the plural, and
likewise, the plural shall be understood to include the singular.  Definitions
of terms defined in the singular or plural shall be equally applicable to the
plural or singular, as the case may be, unless otherwise indicated.  Words
denoting sex shall be construed to include the masculine, feminine, and neuter,
when such construction is appropriate; and specific enumeration shall not
exclude the general but shall be construed as cumulative.


                           ARTICLE II

                 AMENDMENT TO CREDIT AGREEMENT

          Amendment of Section 1.2.  The definition of the term "Commitment
Termination Date" set forth in Section 1.2 of the Credit Agreement is hereby
amended to read as follows:

               "'Commitment Termination Date' shall mean June 1, 1997."


                          ARTICLE III

                           CONDITIONS

          The obligation of the Agent and the Lenders to amend the Credit
Agreement as provided herein is subject to the fulfillment of the following
conditions precedent:

         3.1   Receipt of Loan Documents and Other Items.  The Agent shall have
received multiple counterparts, as requested by the Agent, of the following
documents and other items, appropriately executed when necessary and in form and
substance satisfactory to the Agent:

          (a)  this Amendment executed by the Borrower;

               (b)  a Notice of Final Agreement; and

               (c)  such other agreements, documents, instruments,
          opinions, certificates, waivers, consents, and evidence as
          the Agent or any Lender may reasonably request.

         3.2   Accuracy of Representations and Warranties; No Default or Event
of Default.  The representations and warranties contained in Article IV of this
Amendment shall be true and correct in all material respects; and, after giving
effect to this Amendment, no Default or Event of Default shall have occurred and
be continuing.

         3.3   Payment of Other Fees and Expenses.  The Agent shall have
received reimbursement from the Borrower, or special legal counsel for the Agent
shall have received payment from the Borrower, for all reasonable fees and
expenses of counsel to the Agent for which the Borrower is responsible pursuant
to applicable provisions of this Amendment and the Credit Agreement for which
invoices have been presented as of or prior to the date hereof.

         3.4   Matters Satisfactory to Agent.  All matters incident to the
consummation of the transactions hereby contemplated shall be reasonably
satisfactory to the Agent.


                           ARTICLE IV

                 REPRESENTATIONS AND WARRANTIES

          To induce the Agent and the Lenders to enter into this Amendment and
amend the Credit Agreement as provided herein, the Borrower represents and
warrants to the Agent and each Lender that:

         4.1   Due Authorization.  The execution and delivery by the Borrower of
this Amendment and the performance of its obligations hereunder are within the
corporate power of the Borrower, have been duly authorized by all necessary
corporate action by the Borrower, and do not and will not (a) require the
consent of any Governmental Authority, (b) contravene or conflict with any
Requirement of Law or the articles or certificate of incorporation, or bylaws,
or other organizational or governing documents of the Borrower, (c) contravene
or conflict with any indenture, instrument, or other agreement to which the
Borrower is a party or by which any Property of the Borrower may be presently
bound or encumbered, or (d) result in or require the creation or imposition of
any Lien in or upon any Property of the Borrower under any such indenture,
instrument, or other agreement other than the Loan Documents.

         4.2   Valid and Binding Obligations.  This Amendment, when duly
executed and delivered by the Borrower, will be the legal, valid, and binding
obligation of the Borrower, enforceable against the Borrower in accordance with
its terms.

         4.3   Representations and Warranties in Credit Agreement.  As of the
date hereof, all representations and warranties set forth in the Credit
Agreement are true and correct in all material respects.

         4.4   No Default or Event of Default.  After giving effect to this
Amendment, no Default or Event of Default exists.


                           ARTICLE V

                         MISCELLANEOUS

         5.1   Rights of Third Parties.  All provisions herein are imposed
solely and exclusively for the benefit of the Agent, the Lenders, and the
Borrower and their successors and permitted assigns.  No other Person shall have
any right, benefit, priority, or interest hereunder or as a result hereof or
have standing to require satisfaction of provisions hereof in accordance with
their terms.

         5.2   Survival Upon Unenforceability.  In the event any one or more of
the provisions contained in this Amendment shall, for any reason, be held to be
invalid, illegal or unenforceable in any respect, such invalidity, illegality,
or unenforceability shall not affect any other provision hereof.

         5.3   Ratification.  Except as expressly amended by this Amendment, the
Credit Agreement shall remain in full force and effect.  The Credit Agreement,
as hereby amended, and all rights and powers created thereby or thereunder are
in all respects ratified and confirmed.

         5.4   Governing Law.  This Amendment and all issues arising in
connection herewith and the transactions contemplated hereby shall be governed
by and construed in accordance with the laws of the State of Texas (without
giving effect to principles thereof relating to conflicts of law).

         5.5   Jurisdiction and Venue.  All actions or proceedings with respect
to, arising directly or indirectly in connection with, out of, related to, or
from this Amendment may be litigated, at the sole discretion and election of the
Agent, in courts having situs in Houston, Harris County, Texas.  The Borrower
hereby submits to the jurisdiction of any local, state, or federal court located
in Houston, Harris County, Texas, and hereby waives any rights it may have to
transfer or change the jurisdiction or venue of any litigation brought against
it by the Agent or any Lender in accordance with this Section.

         5.6   Entire Agreement; No Oral Agreements.  This Amendment constitutes
the entire agreement of the parties hereto with respect to the subject hereof
and supersedes any prior agreement among the parties hereto, whether written or
oral, relating to the subject hereof.  This written agreement and the other writ
ten Loan Documents represent, collectively, the final agreement among the
parties hereto and thereto and may not be contradicted by evidence of prior,
contemporaneous, or subsequent oral agreements of the parties.  There are no
unwritten oral agreements among the parties.

         5.7   Waiver of Rights to Jury Trial.  The Borrower, the Agent, and
each Lender hereby knowingly, voluntarily, intentionally, irrevocably, and
unconditionally waive all rights to trial by jury in any action, suit,
proceeding, counterclaim, or other litigation that relates to or arises out of
this Amendment or the acts or omissions of the Agent or any Lender in the
enforcement of any of the terms or provisions of this Amendment or otherwise
with respect hereto.  The provisions of this Section are a material inducement
for the Agent and the Lenders entering into this Amendment.

         5.8   Counterparts.  For convenience of the parties, this Amendment may
be executed in multiple counterparts and by different parties hereto in separate
counterparts, each of which when so executed shall be deemed to be an original,
and all of which together shall constitute one and the same agreement.

     IN WITNESS WHEREOF, this Agreement is executed as of the date first above
written.

                                BORROWER:

                                HOWELL CRUDE OIL COMPANY


                                By:/s/ Mark J. Gorman
                                    ------------------------
                                      Mark J. Gorman
                                      President


                                AGENT AND LENDER:

                                BANK ONE, TEXAS, NATIONAL
                                ASSOCIATION


                                By: /s/ John B. Lane
                                    ------------------------
                                      John B. Lane
                                      Vice President





              (Signatures Continued on Next Page)
                                LENDER:

                                BANK OF MONTREAL


                                By: /s/ Robert L. Roberts
                                    ------------------------
                                      Robert L. Roberts
                                      Director, U. S. Corporate Banking


                                LENDER:

                                COMPASS BANK - HOUSTON


                                By: /s/ Dorothy Marchand Wilson
                                    ------------------------
                                      Dorothy Marchand Wilson
                                      Vice President


                                LENDER:

                                DEN NORSKE BANK AS


                                By: /s/ William V. Moyer
                                    ------------------------
                                      William V. Moyer
                                      Vice President


                                By: /s/ Haakon Sandborg
                                    ------------------------
                                Name:  Haakon Sandborg
                                Title: Senior Vice President

     Joining in the execution hereof to evidence their consent to the terms
hereof:


                              HOWELL CORPORATION


                              By: /s/ Allyn R. Skelton, II
                                    ------------------------
                                    Allyn R. Skelton II
                                    Senior Vice President
                                    and Chief Financial Officer


                              HOWELL PIPELINE TEXAS, INC.


                              By: /s/ Allen R. Stanley
                                    ------------------------
                                    Allen R. Stanley
                                    President


                              HOWELL PIPELINE USA, INC.


                              By: /s/ Allen R. Stanley
                                    ------------------------
                                    Allen R. Stanley
                                    President