EXHIBIT 10.4

                                 THIRD AMENDMENT
                            TO THE HOWELL CORPORATION
                             1988 STOCK OPTION PLAN


     WHEREAS,  Howell Corporation (the "Company") presently maintains the Howell
Corporation 1988 Stock Option Plan that became effective on January 25, 1988, as
amended (the "Plan"); and

     WHEREAS,  the Board of Directors of the Company,  pursuant to Section 13 of
the Plan,  has the right to amend the Plan from time to time  subject to certain
limitations and has heretofore amended the Plan on two occasions;

     NOW,  THEREFORE,  in order to make the  revisions  desired  by the Board of
Directors  as outlined  in the Proxy  Statement  of the Company  dated March 24,
1994, the Plan is hereby amended in the following manner:

     1.  Effective as of the date hereof,  the first sentence of Section 2(b) of
the Plan is hereby amended in its entirety to read as follows:

          The Committee,  from time to time, shall determine and designate those
     members  of the  Committee  who  are to  receive  options  under  the  Plan
     ("Special  Optionees"),  the number of shares to be covered by such options
     and the terms  thereof.  The  Committee  shall  thereupon  grant options in
     accordance  with  such  determination  as  evidenced  by a  written  option
     agreement;  provided, however, that the number of shares covered by options
     granted  pursuant  to the Plan by the  Committee  shall not  exceed  10,000
     shares in the case of an option  granted  to any  Special  Optionee  and an
     aggregate of 150,000 shares for all Special Optionees as a group.

     2. Effective as of the date hereof, Section 4 of the Plan is hereby amended
in its entirety to read as follows:

     4. Stock Reserved.

          Subject to  adjustment  as provided in Paragraph 9, a total of 750,000
     shares ("Stock") of Common Stock, par value $1.00 per share, of the Company
     ("Common Stock") shall be subject to this Plan. The shares of Stock subject
     to this Plan shall consist of unissued  shares or previously  issued shares
     reacquired  and held by the Company or its  Affiliates,  and such number of
     shares shall be and is hereby  reserved for sale for such purposes.  Any of
     such  shares  which  may  remain  unsold  and  which  are  not  subject  to
     outstanding  Options  at the  expiration  of this  Plan  shall  cease to be
     reserved for the purpose of this Plan,  but until  termination of this Plan
     and the expiration, exercise or lapse of all Options granted hereunder, the
     Company  shall at all times  reserve a sufficient  number of shares to meet
     the requirements of this Plan.  Should any Option expire or be cancelled or
     surrendered  prior to its exercise or  relinquishment  in full,  the shares
     theretofore  subject  to such  Option may again be  subjected  to an Option
     under this Plan,  except  that shares  subject to purchase  pursuant to any
     Option or portion thereof  relinquished  and not required to be issued upon
     such  relinquishment  shall not again be available  for Options  under this
     Plan.

     IN WITNESS  WHEREOF,  the Company has executed this Third  Amendment to the
Plan on this 25th day of April, 1994.

                               HOWELL CORPORATION



                               /s/ Paul W. Funkhouser
                               ------------------------------------
                               Paul W. Funkhouser
                               President

ATTEST:



      /s/ Allyn R. Skelton, II
      ------------------------------------
      Allyn R. Skelton, II
      Secretary