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                            SUPPLEMENTAL INDENTURE


      SUPPLEMENTAL INDENTURE (this "Supplemental Indenture") dated as of
December 1, 1999, among FOREST OIL CORPORATION, a New York corporation (the
"Company"), CANADIAN FOREST OIL LTD., an Alberta corporation (the "Issuer"),
PRODUCERS MARKETING LTD., an Alberta corporation and an indirect subsidiary of
the Company (the "New Subsidiary Guarantor"), and STATE STREET BANK AND TRUST
COMPANY, as trustee under the indenture referred to below (the "Trustee").

                             W I T N E S S E T H:

      WHEREAS the Issuer and the Company have heretofore executed and delivered
to the Trustee an Indenture (the "Indenture") dated as of September 29, 1997,
providing for the issuance of an aggregate principal amount of up to
$200,000,000 of 8 3/4% Senior Subordinated Notes due 2007 (the "Securities");

      WHEREAS Section 4.13 of the Indenture provides that under certain
circumstances the Company is required to cause the New Subsidiary Guarantor to
execute and deliver to the Trustee a supplemental indenture pursuant to which
the New Subsidiary Guarantor shall unconditionally guarantee all the Issuer's
obligations under the Securities pursuant to a Subsidiary Guarantee on the terms
and conditions set forth herein; and

      WHEREAS pursuant to Section 9.01 of the Indenture, the Trustee, the
Issuer, the Company and the New Subsidiary Guarantor are authorized to execute
and deliver this Supplemental Indenture;

      NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the New
Subsidiary Guarantor, the Issuer, the Company and the Trustee mutually covenant
and agree for the equal and ratable benefit of the holders of the Securities as
follows:

      1. AGREEMENT TO GUARANTEE. The New Subsidiary Guarantor hereby agrees,
jointly and severally with all other Subsidiary Guarantors, to unconditionally
guarantee the Issuer's obligations under the Securities on the terms and subject
to the conditions set forth in Article XI of the Indenture and to be bound by
all other applicable provisions of the Indenture.

      2. RATIFICATION OF INDENTURE; SUPPLEMENTAL INDENTURES PART OF INDENTURE.
Except as expressly amended hereby, the Indenture is in all respects ratified
and confirmed and all the terms, conditions and provisions thereof shall remain
in full force and effect. This Supplemental Indenture shall form a part of the
Indenture for all purposes, and every holder of Securities heretofore or
hereafter authenticated and delivered shall be bound hereby.

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      3. GOVERNING LAW. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK BUT WITHOUT
GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

      4.    TRUSTEE MAKES NO REPRESENTATION.  The Trustee makes no
representation as to the validity or sufficiency of this Supplemental Indenture.

      5.    COUNTERPARTS.  The parties may sign any number of copies of this
Supplemental Indenture. Each signed copy shall be an original, but all of them
together represent the same agreement.

      6.    EFFECT OF HEADINGS.  The Section headings herein are for
convenience only and shall not effect the construction thereof.

      IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed as of the date first above written.

                                          PRODUCERS MARKETING LTD.


                                          By: /s/ W. F. Bauer
                                             -------------------------------
                                          Name:  W.F. Bauer
                                          Title: Vice President, Marketing


                                          PRODUCERS MARKETING LTD.


                                          By: /s/ R.E. Pratt
                                             -------------------------------
                                          Name:  R.E. Pratt
                                          Title: Secretary

                                          CANADIAN FOREST OIL LTD.


                                          By: /s/ Joan C. Sonnen
                                             -------------------------------
                                          Name:  Joan C. Sonnen
                                          Title: Vice President and Secretary


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                                          CANADIAN FOREST OIL LTD.


                                          By: /s/ R.E. Pratt
                                             -------------------------------
                                          Name:  R.E. Pratt
                                          Title: Vice President-Finance

                                          FOREST OIL CORPORATION


                                          By: /s/ David H. Keyte
                                             -------------------------------
                                          Name:  David H. Keyte
                                          Title: Executive Vice President


                                          FOREST OIL CORPORATION


                                          By: /s/ Donald H. Stevens
                                             -------------------------------
                                          Name:  Donald H. Stevens
                                          Title: Vice President and Treasurer


                                          STATE STREET BANK AND TRUST
                                          COMPANY, as Trustee


                                          By: /s/ Kathy A. Larimore
                                             -------------------------------
                                          Name:  Kathy A. Larimore
                                          Title: A.V.P.

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