<PAGE>

                                                                   EXHIBIT 10.52

                FIRST AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT

         This Agreement, entered into and made effective as of July 29, 2002, by
and between EOTT ENERGY CORP., a Delaware corporation ("EOTT") having its
headquarters at 2000 W. Sam Houston Parkway, S., Suite 400 Houston, Texas 77042
and MOLLY M. SAMPLE ("Employee"), is an amendment to that certain Executive
Employment Agreement between the EOTT and Employee entered into the 19th day of
January, 2001, and made effective as of December 1, 2000 (the "Employment
Agreement").

         WHEREAS, the parties desire to amend the Employment Agreement as
provided herein;

         NOW, THEREFORE, in consideration thereof and of the mutual covenants
contained herein, the parties agree as follows:

                  1. Exhibit "A" to the Employment Agreement is hereby deleted
         in its entirety and the attached Exhibit "A" is inserted in its
         entirety.

         This Amendment is a First Amendment to the Employment Agreement, and
the parties agree that all other terms, conditions and stipulations contained in
the Employment Agreement, and any amendments thereto, shall remain in full force
and effect and without any change or modification, except as provided herein.

         IN WITNESS WHEREOF, the parties have duly executed this Agreement as of
the date first above written.

                                  EOTT ENERGY CORP.

                                  By: ______________________________
                                  Name:  Dana R. Gibbs
                                  Title:    President & Chief Operating Officer
                                  This _____ day of ______________, 2002

                                  MOLLY M. SAMPLE

                                  ___________________________________
                                  This ____ day of ________________, 2002

<PAGE>

                                 EXHIBIT "A" TO
                         EXECUTIVE EMPLOYMENT AGREEMENT
                                     BETWEEN
                      EOTT ENERGY CORP. AND MOLLY M. SAMPLE

Employee Name:             Molly M. Sample

Term:                      December 1, 2000 through December 31, 2003

Position:                  General Counsel

Location:                  Houston, Texas

Monthly Base Salary:       Employee's monthly base salary shall not be less than
                           Ten Thousand Eight Hundred Thirty-Three and
                           Thirty-Three/100 Dollars ($10,833.33).

Bonus:                     Employee may be eligible to participate in the EOTT
                           Energy Corp. Annual Incentive Plan ("Plan") or any
                           appropriate replacement bonus plan of Employer. All
                           bonuses are discretionary and shall be paid in
                           accordance with the terms and provisions of the Plan.

Long Term Incentives:      As recommended and approved in any EOTT Energy Long
                           Term Incentive Plan(s) by the Board of Directors of
                           EOTT Energy Corp.

EOTT ENERGY CORP.

By:    ________________________________________________
       Name:  Dana R. Gibbs
       Title:  President and Chief Operating Officer
       This ___ day of _______________, 2002

MOLLY M. SAMPLE

____________________________________________
This ___ day of  _____________, 2002


                                       -2-