EXHIBIT 21
                            HOWELL CORPORATION
                          Parent and Subsidiaries



                            December 31, 1999

     The following is a list of all  significant  operating  subsidiaries of the
Company on  December  31,  1999.  Each of the  subsidiaries  is  included in the
Company's Consolidated Financial Statements.



                                                                 Percentage of
                                                               Voting Securities
                                          Jurisdiction of           Held by
                                          Incorporation         Immediate Parent
                                          --------------        ----------------
   Howell Corporation ...................    Delaware                  (1)

   Howell Hydrocarbons & Chemicals, Inc..    Delaware                 100%

   Howell Petroleum Corporation..........    Delaware                 100%

   Howell Crude Oil Company..............    Delaware                 100%

- - --------------------------
(1)   Paul N. Howell may be  considered a "parent" of the  Company.  On December
      31,  1999,  Mr.  Howell is deemed to own  "beneficially,"  as that term is
      defined in Rule  13(d)(3) of the General Rules and  Regulations  under the
      Securities  Exchange  Act of 1934,  22% of the  voting  securities  of the
      Company.