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             KAISER ALUMINUM & CHEMICAL CORPORATION, as Issuer,
                                      
                   KAISER ALUMINA AUSTRALIA CORPORATION,
                            ALPART JAMAICA INC.,
                        KAISER JAMAICA CORPORATION,
                        KAISER FINANCE CORPORATION,
                      KAISER MICROMILL HOLDINGS, LLC,
                       KAISER SIERRA MICROMILLS, LLC,
                    KAISER TEXAS SIERRA MICROMILLS, LLC,
                   KAISER TEXAS MICROMILL HOLDINGS, LLC,
                      KAISER BELLWOOD CORPORATION, and
                        KAISER TRANSACTION CORP., as
                           Subsidiary Guarantors

                                    and

              STATE STREET BANK AND TRUST COMPANY, as Trustee
                                      
                                      
                       FOURTH SUPPLEMENTAL INDENTURE

                         Dated as of March 31, 1999

                                     to

                                 INDENTURE

                        Dated as of February 1, 1993
                                      
                                      
                                      
                 12-3/4% Senior Subordinated Notes due 2003

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          FOURTH SUPPLEMENTAL INDENTURE, dated as of March 31, 1999, among
KAISER ALUMINUM & CHEMICAL CORPORATION, a Delaware corporation (the
"Company"), as Issuer, KAISER ALUMINA AUSTRALIA CORPORATION, a Delaware
corporation ("KAAC"), ALPART JAMAICA INC., a Delaware corporation ("AJI"),
KAISER JAMAICA CORPORATION, a Delaware corporation ("KJC"), KAISER FINANCE
CORPORATION, a Delaware corporation ("Kaiser Finance"), KAISER MICROMILL
HOLDINGS, LLC, a Delaware limited liability company ("KMH"), KAISER SIERRA
MICROMILLS, LLC, a Delaware limited liability company ("KSM"), KAISER TEXAS
SIERRA MICROMILLS, LLC, a Texas limited liability company ("Texas Sierra"),
KAISER TEXAS MICROMILL HOLDINGS, LLC, a Texas limited liability company
("Texas Holdings"), KAISER BELLWOOD CORPORATION, a Delaware corporation
("Kaiser Bellwood"), and KAISER TRANSACTION CORP., a Delaware corporation
("Kaiser Transaction"), as Subsidiary Guarantors, and State Street Bank and
Trust Company (as successor to The First National Bank of Boston), a
Massachusetts trust company, as Trustee (the "Trustee").

          WHEREAS, the Company, KAAC, AJI, KJC and The First National Bank
of Boston executed an Indenture, dated as of February 1, 1993 (the
"Original Indenture"), in respect of $400,000,000 aggregate principal
amount of the Company's 12-3/4% Senior Subordinated Notes due 2003 (the
"Securities"), and the Original Indenture was amended by a First
Supplemental Indenture, dated as of May 1, 1993, by a Second Supplemental
Indenture, dated as of February 1, 1996, and by a Third Supplemental
Indenture, dated as of July 15, 1997 (the Original Indenture, as amended by
such First Supplemental Indenture, Second Supplemental Indenture, and Third
Supplemental Indenture being hereinafter referred to as the "Indenture");
and

          WHEREAS, State Street Bank and Trust Company is the successor to
The First National Bank of Boston, as Trustee under the Indenture; and

          WHEREAS, Section 5.12 of the Indenture requires, under
circumstances specified in Section 5.12, that the Company shall cause
certain Subsidiaries of the Company to execute and deliver to the Trustee a
supplemental indenture in form and substance satisfactory to the Trustee
pursuant to which such Subsidiaries of the Company shall be named as
additional Subsidiary Guarantors; and

          WHEREAS, all conditions and requirements necessary to make this
Fourth Supplemental Indenture a valid, binding and legal instrument in
accordance with its terms have been performed and fulfilled and the
execution and delivery hereof have been in all respects duly authorized;

          NOW, THEREFORE, in consideration of the above premises, each
party agrees, for the benefit of the other and for the equal and ratable
benefit of the Holders of the Securities, as follows:

                                 ARTICLE I

                                 AMENDMENTS

          Section 1.  The Company, KAAC, AJI, KJC, Kaiser Finance, KMH,
KSM, Texas Sierra, Texas Holdings, Kaiser Bellwood, Kaiser Transaction and
the Trustee hereby amend the Indenture and agree that Kaiser Transaction
shall be a Subsidiary Guarantor for all purposes under the Indenture and
the term "Subsidiary Guarantor" shall for all purposes under the Indenture
specifically include Kaiser Transaction.



                                 ARTICLE II

                          MISCELLANEOUS PROVISIONS

          Section 2.1.  Terms Defined.  For all purposes of this Fourth
Supplemental Indenture, except as otherwise defined or unless the context
otherwise requires, terms used in capitalized form in this Fourth
Supplemental Indenture and defined in the Indenture have the meanings
specified in the Indenture.

          Section 2.2.  Indenture.  Except as amended hereby, the Indenture
and the Securities are in all respects ratified and confirmed and all their
terms shall remain in full force and effect.

          Section 2.3.  Governing Law.  This Fourth Supplemental Indenture
shall be deemed to be a contract made under the laws of the State of New
York, and for all purposes shall be governed by and construed in accordance
with the laws of said state without regard to the principles of the
conflict of laws provisions thereof.

          Section 2.4.  Successors and Assigns.  All agreements of the
Company, KAAC, AJI, KJC, Kaiser Finance, KMH, KSM, Texas Sierra, Texas
Holdings, Kaiser Bellwood, and Kaiser Transaction in this Fourth
Supplemental Indenture and the Securities shall bind its successors and
assigns.

          Section 2.5.  Multiple Counterparts.  This Fourth Supplemental
Indenture may be executed in any number of counterparts, each of which
shall be an original; but such counterparts shall together constitute but
one and the same instrument.

          Section 2.6.  Effectiveness.  The provisions of this Fourth
Supplemental Indenture shall become effective immediately upon its
execution and delivery by the Trustee in accordance with the provisions of
Article Eleven of the Indenture.

          Section 2.7.  Trustee Disclaimer.  The Trustee accepts the
amendment of the Indenture effected by this Fourth Supplemental Indenture
and agrees to execute the trust created by the Indenture as hereby amended,
but only upon the terms and conditions set forth in the Indenture,
including the terms and provisions defining and limiting the liabilities
and responsibilities of the Trustee, which terms and provisions shall in
like manner define and limit its liabilities and responsibilities in the
performance of the trust created by the Indenture as hereby amended, and,
without limiting the generality of the foregoing, the Trustee shall not be
responsible in any manner whatsoever for or with respect to any of the
recitals or statements contained herein, all of which recitals or
statements are made solely by the Company, KAAC, AJI, KJC, Kaiser Finance,
KMH, KSM, Texas Sierra, Texas Holdings, Kaiser Bellwood, and Kaiser
Transaction, or for or with respect to (i) the validity, efficacy or
sufficiency of this Fourth Supplemental Indenture or any of the terms or
provisions hereof, (ii) the proper authorization hereof by the Company,
KAAC, AJI, KJC, Kaiser Finance, KMH, KSM, Texas Sierra, Texas Holdings,
Kaiser Bellwood, and Kaiser Transaction by corporate action or limited
liability company action or otherwise, (iii) the due execution hereof by
the Company, KAAC, AJI, KJC, Kaiser Finance, KMH, KSM, Texas Sierra, Texas
Holdings, Kaiser Bellwood, and Kaiser Transaction, or (iv) the consequences
(direct or indirect and whether deliberate or inadvertent) of any amendment
herein provided for, and the Trustee makes no representation with respect
to any such matters.

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


                                   KAISER ALUMINUM & CHEMICAL
                                   CORPORATION, as Issuer



                                   By:     /s/    Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:    /s/      John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary

                                   KAISER ALUMINA AUSTRALIA
                                   CORPORATION, as a Subsidiary Guarantor



                                   By:    /s/     Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:    /s/      John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary

                                   ALPART JAMAICA INC., as a
                                   Subsidiary Guarantor
                                   By:     /s/    Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:     /s/     John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary



                                   KAISER JAMAICA CORPORATION,
                                   as a Subsidiary Guarantor



                                   By:     /s/    Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:     /s/     John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary

                                   KAISER FINANCE CORPORATION,
                                   as a Subsidiary Guarantor



                                   By:     /s/    Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:     /s/     John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary

                                   KAISER MICROMILL HOLDINGS, LLC,
                                   as a Subsidiary Guarantor



                                   By:     /s/    Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:     /s/     John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary



                                   KAISER SIERRA MICROMILLS, LLC,
                                   as a Subsidiary Guarantor



                                   By:     /s/    Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:     /s/     John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary

                                   KAISER TEXAS SIERRA MICROMILLS,
                                   LLC, as a Subsidiary Guarantor



                                   By:    /s/     Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:     /s/     John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary

                                   KAISER TEXAS MICROMILL HOLDINGS,
                                   LLC, as a Subsidiary Guarantor



                                   By:     /s/    Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:     /s/     John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary


                                   KAISER BELLWOOD CORPORATION,
                                   as a Subsidiary Guarantor


                                   By:    /s/     Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:    /s/      John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary

                                   KAISER TRANSACTION CORP.,
                                   as a Subsidiary Guarantor



                                   By:    /s/     Karen A. Twitchell
                                        -----------------------------------
                                   Name:          Karen A. Twitchell
                                   Title:         Treasurer

Dated:  March 31, 1999

Attest:     /s/     John Wm. Niemand II
          -----------------------------
          Name:     John Wm. Niemand II
          Title:    Secretary


                                   STATE STREET BANK AND TRUST
                                   COMPANY, as Trustee



                                   By:                                     
                                        -----------------------------------

                                   Name:                                   
                                        -----------------------------------

                                   Title:                                  
                                        -----------------------------------

Dated:  March 31, 1999

Attest:                                 
          ------------------------------

          Name:                         
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          Title:                        
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