Exhibit 10.4

                             FIRST SUPPLEMENT TO THE
                             KERR-McGEE CORPORATION
                            BENEFITS RESTORATION PLAN
                  AS AMENDED AND RESTATED EFFECTIVE MAY 1, 1999
           -----------------------------------------------------------
           (As it applies to Participants who were Participants in the
                  Oryx Energy Company Pension Restoration Plan
                            As of December 31, 1999)

(A)  Applicability of First Supplement
     ---------------------------------

     (1)  This  First   Supplement  to  the  Kerr-McGee   Corporation   Benefits
          Restoration  Plan  (the  "First  Supplement")  forms  a  part  of  the
          Kerr-McGee  Corporation  Benefits Restoration Plan as in effect on and
          after May 1, 1999 ("Plan").  The  provisions of this First  Supplement
          shall apply only to those  Participants  who were  Participants in the
          Oryx Energy  Company  Pension  Restoration  Plan  ("Oryx  Plan") as of
          December 31, 1999 ("Former Oryx Participants") who became Participants
          in the Plan  effective  January 1, 2000  (hereinafter  referred  to as
          "First Supplement Participants").


     (2)  There shall be no duplication of benefits  provided under the Plan and
          this First Supplement, and the actuarially equivalent benefits payable
          under one shall be inclusive of the  actuarially  equivalent  benefits
          payable under the other unless specifically  provided otherwise in the
          provisions of the Plan or this First Supplement.

     (3)  All  terms  used in this  First  Supplement  shall  have the  meanings
          assigned  to them in the  provisions  of the Plan,  unless a different
          meaning is plainly required by the context.


(B)  Merger of Oryx Plan into the Plan Effective January 1, 2000
     -----------------------------------------------------------

     (1)  The Oryx Plan had  previously  been  sponsored by Oryx Energy  Company
          ("Oryx"). Oryx was merged with the Company effective February 26, 1999
          (the "Merger").  Due to the Merger,  the Company assumed the Oryx Plan
          and  obligations   thereunder  including  those  to  the  Former  Oryx
          Participants.

     (2)  The Company believes that it would be in the best interest of the Oryx
          Plan,  the Plan and the  Participants  therein  that the Oryx  Plan be
          merged and continued in the Plan effective January 1, 2000.

     (3)  The effective  date of the merger of the Oryx Plan into the Plan shall
          be January 1, 2000.

     (4)  Upon merger of the Oryx Plan into the Plan effective  January 1, 2000,
          there shall be no further  benefit  accruals  pursuant to the terms of
          the Oryx Plan,  and  benefits  for all First  Supplement  Participants
          shall  accrue  thereafter  in  accordance  with the terms of the Plan.
          Following the merger, all benefits earned under the Oryx Plan prior to
          January 1, 2000,  and  benefits  earned  pursuant to the Plan from and
          after such date will be paid in accordance  with the terms of the Plan
          and this First Supplement.


(C)  Benefits Applicable to First Supplement Participants
     ----------------------------------------------------

     (1)  The term "Defined  Benefit Plan" as applicable for a First  Supplement
          Participant  means the Kerr-McGee  Corporation  Retirement Plan or its
          successor plan or the Oryx Energy Company Retirement Plan prior to its
          merger with the Plan on January 1, 2000.

     (2)  The Restored  Defined Benefit Plan Benefit under the Plan accrued by a
          First  Supplement  Participant  under Section 7 of the Oryx Plan as of
          January 1, 2000, immediately prior to the merger of the Oryx Plan with
          the Plan (hereinafter referred to as the "Oryx Plan Restored Benefit")
          will be paid  at the  same  time as the  benefits  under  the  Defined
          Benefit Plan and in the form of a lump sum, subject to offset pursuant
          to Section 9 of the Oryx Plan, if  applicable,  regardless of the form
          of payment of the benefit under the Defined  Benefit Plan.  The amount
          of such lump sum will be determined as the actuarial equivalent of the
          Oryx  Plan  Restored  Benefit.  Such  actuarial  equivalency  will  be
          determined  in  the  same  manner  as and on  the  same  basis  as the
          actuarial  assumptions  provided  in the  Defined  Benefit  Plan.  The
          provisions  of Section 6.1 of the Plan are not  applicable to the Oryx
          Plan Restored Benefit of a First Supplement Participant.

     (3)  Effective  January 1, 2000,  that  portion,  if any,  of the  Restored
          Defined  Benefit  Plan  Benefit  under  the  Plan  payable  to a First
          Supplement  Participant  that is in excess of the  Participant's  Oryx
          Plan Restored  Benefit will be payable in accordance  with Section 6.1
          of the Plan.

     (4)  Former Oryx  Participants  who were  receiving or who were eligible to
          receive benefits from the Sun Company,  Inc. Pension  Restoration Plan
          and who were  transferred  to the Oryx Plan as of  November  1,  1988,
          shall  continue to receive or be eligible  to receive  their  benefits
          under this Plan.


(D)  Right to Amend or Terminate First Supplement
     --------------------------------------------

     The  provisions  of Section 8.1 of the Plan with respect to  amendment  and
     termination thereof shall apply with equal force to this First Supplement.


     IN WITNESS WHEREOF, Kerr-McGee Corporation has, on its behalf and on behalf
of its participating affiliates,  caused this First Supplement to be executed by
its duly authorized officers on the 10th day of January,  2001,  effective as of
January 1, 2000.


ATTEST:                                  KERR-McGEE CORPORATION



/s/ Don Hager                            By: /s/ John M. Rauh
------------------------------               -----------------------------------
Don Hager                                    John M. Rauh
Assistant Secretary                          Chairman of the Benefits Committee,
                                             Vice President and Treasurer