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                                                                       EXHIBIT 5
 
                    [KAISER ALUMINUM CORPORATION LETTERHEAD]
 
                                January 24, 1997
 
Securities and Exchange Commission
Division of Corporation Finance
450 Fifth Street, N.W., Mail Stop 3-11
Washington, D.C. 20549
 
    Re: Registration Statement on Form S-3 ; Registration No. 333-16239
 
Ladies and Gentlemen:
 
     I am deputy general counsel of Kaiser Aluminum Corporation, a Delaware
corporation (the "Company") in connection with the registration by the Company
of (i) common stock, $.01 par value per share (the "Common Stock"), (ii)
preferred stock, $.05 par value per share (the "Preferred Stock"), (iii)
depositary shares representing fractional interests in Preferred Stock (the
"Depositary Shares"), and (iv) warrants to purchase Common Stock, Preferred
Stock or Depositary Shares (collectively, the "Securities Warrants" and together
with the Common Stock, Preferred Stock, and Depositary Shares, the "Securities")
with an aggregate public offering price of up to $150,000,000, all of which
Securities may be offered and sold, from time to time, by the Company, as set
forth in the prospectus (the "Prospectus") which forms a part of the
Registration Statement on Form S-3 filed with the Securities and Exchange
Commission on November 15, 1996 (the "Registration Statement"), as amended, and
as may be set forth in one or more supplements to the Prospectus (each, a
"Prospectus Supplement"). Capitalized terms used but not otherwise defined
herein shall have the same meanings ascribed to them in the Registration
Statement.
 
     Each series of the Preferred Stock, whether or not represented by
Depositary Shares, and the Common Stock will be issued under the Company's
Restated Certificate of Incorporation (the "Certificate of Incorporation") and,
in the case of the Preferred Stock and Preferred Stock represented by Depositary
Shares, a Certificate of Designation will be filed with the Secretary of State
of Delaware (a "Certificate of Designation"). Each series of Depositary Shares
will be represented by depositary receipts (the "Receipts") and issued under a
depositary agreement (the "Depositary Agreement") to be entered into between the
Company and a financial institution identified therein as depositary (the
"Depositary"). The Securities Warrants will be issued under one or more warrant
agreements (each, a "Warrant Agreement") to be entered into between the Company
and a financial institution identified therein as the warrant agent (the
"Warrant Agent"). Certain terms of the Securities to be issued by the Company
from time to time will be approved by the Board of Directors of the Company or a
committee thereof as part of the corporate action taken and to be taken in
connection with the authorization of the issuance of the Securities, such
corporate action to be in accordance with the terms of the Certificate of
Incorporation and the By-laws of the Company, to the extent applicable thereto
(the "Corporate Proceedings").
 
     I have examined originals or copies certified or otherwise identified to my
satisfaction of the Certificate of Incorporation of the Company, the Company's
By-Laws, as amended, resolutions of the Company's Board of Directors and such of
the Company's records, certificates and other documents and such questions of
law as I considered necessary or appropriate for the purpose of this opinion. As
to certain facts material to this opinion, I have relied, to the extent I have
deemed such reliance proper, upon certificates of public officials and officers
of the Company. In rendering this opinion, I have assumed the genuineness of all
signatures, the authenticity of all documents submitted to me as originals and
the conformity to authentic original documents of all documents submitted to me
as copies.
 
     Based upon and subject to the foregoing and to the assumptions, conditions
and limitations set forth herein, I am of the opinion that:
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          (1) when the Registration Statement becomes effective under the
     Securities Act of 1933, as amended (the "Act"), and upon the completion of
     the Corporate Proceedings relating to the Common Stock and the due
     execution, countersignature and delivery of the Common Stock, the Common
     Stock, when sold in exchange for the consideration set forth in the
     Prospectus and any Prospectus Supplement relating thereto or issued upon
     conversion of any Security convertible into Common Stock as described in
     the Prospectus and any Prospectus Supplement relating thereto, will be duly
     authorized, validly issued, fully paid and nonassessable; and
 
          (2) when the Registration Statement becomes effective under the Act,
     and upon the completion of the Corporate Proceedings relating to a series
     of the Preferred Stock, and the due execution, countersignature and
     delivery of the Preferred Stock of such series and the filing of a
     Certificate of Designation pertaining to the Preferred Stock of such series
     with the Secretary of State of Delaware, the Preferred Stock of such
     series, when sold in exchange for the consideration set forth in the
     Prospectus and any Prospectus Supplement relating thereto or issued upon
     conversion of any Security convertible into Preferred Stock as described in
     the Prospectus and any Prospectus Supplement relating thereto, will be duly
     authorized, validly issued, fully paid and nonassessable;
 
          (3) when the Registration Statement becomes effective under the Act
     and the relevant Depositary Agreement has been duly executed and delivered
     by the Company, and the Receipts evidencing the Depositary Shares have been
     duly established by the relevant Depositary Agreement and such Receipts
     have been duly issued against the deposit of the Preferred Stock in
     accordance with the Depositary Agreement, and upon completion of the
     Corporate Proceedings relating to the Depositary Shares and Preferred Stock
     underlying the Depositary Shares, and the due execution, countersignature
     and delivery of the Preferred Stock related to such Depositary Shares and
     the filing of the applicable Certificate of Designation with the Secretary
     of State of Delaware, (i) such Depositary Shares, when sold in exchange for
     the consideration set forth in the Prospectus and any Prospectus Supplement
     relating thereto, will be duly authorized, validly issued and entitle the
     holders thereof to the rights specified in the Depositary Agreement and the
     Receipts evidencing the Depositary Shares and (ii) the Preferred Stock
     represented by such Depositary Shares will be duly authorized, validly
     issued, fully paid and nonassessable;
 
          (4) when the Registration Statement becomes effective under the Act
     and the relevant Warrant Agreement has been duly executed and delivered by
     the Company, and when the Securities Warrants have been duly established by
     the relevant Warrant Agreement, and upon completion of the Corporate
     Proceedings relating to the Securities Warrants and the due execution,
     authentication, issuance and delivery of the Securities Warrants, the
     Securities Warrants, when sold in exchange for the consideration set forth
     in the Prospectus and any Prospectus Supplement relating thereto, will be
     duly authorized and will be binding obligations of the Company enforceable
     against the Company in accordance with their respective terms and entitled
     to the benefits of the applicable Warrant Agreement, except as such
     enforceability may be limited by bankruptcy, insolvency, reorganization or
     similar laws affecting creditor's rights generally and subject to general
     principles of equity.
 
     To the extent that the obligations of the Company under an applicable
Depositary Agreement or Warrant Agreement may be dependent upon such matters, I
assume for purposes of this opinion that the Depositary or the Warrant Agent, as
the case may be, will be duly organized, validly existing and in good standing
under the laws of its jurisdiction of organization; that the Depositary or
Warrant Agent will be duly qualified to engage in the activities contemplated by
the applicable Depositary Agreement or Warrant Agreement, as applicable, that
the applicable Depositary Agreement or Warrant Agreement will be duly
authorized, executed and delivered by the Depositary or Warrant Agent, as the
case may be, and will constitute the legally valid and binding obligation of
such Depositary or Warrant Agent enforceable against such Depositary or Warrant
Agent in accordance with its terms; that such Depositary or Warrant Agent will
be in compliance, generally with respect to acting as a depositary or warrant
agent under the applicable Depositary Agreement or Warrant Agreement, as the
case may be, with all applicable laws and regulations; and that such Depositary
or Warrant Agent will have the requisite organizational and legal power and
authority to perform its obligations under the Depositary Agreement or Warrant
Agreement, as applicable.
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     I have been informed that the Company intends to issue the Securities from
time to time on a delayed or continuous basis. This opinion is limited to the
laws, including the rules and regulations, as in effect on the date hereof. I
understand that prior to issuing any Securities, the Company will advise me in
writing of the terms thereof, will afford me an opportunity to review the
operative documents pursuant to which such Securities are to be issued
(including any applicable Prospectus Supplement) and will file such supplement
or amendment to this opinion (if any) as I may reasonably consider necessary or
appropriate by reason of the terms of such Securities.
 
     I hereby consent to the use of this opinion as an exhibit to the
Registration Statement, and I further consent to the use of my name under the
caption "Legal Opinions" in the Registration Statement and in the Prospectus and
any form of Prospectus Supplement. In giving such consent I do not thereby
concede that I am within the category of persons whose consent is required under
Section 7 of the Securities Act or the rules and regulations promulgated
thereunder.
 
                                          Very truly yours,
 
                                                   /s/ BYRON L. WADE
                                          --------------------------------------
                                                      Byron L. Wade
                                           Vice President, Secretary and Deputy
                                                     General Counsel