Exhibit 18 March 10, 1995 Securities and Exchange Commission 450 Fifth Street, N.W. Washington, DC 20549 Re:Aluminum Company of America 1995 Proxy Soliciting Materials Ladies and Gentlemen: In accordance with the request set forth in the part D- (3) of the instructions to Form 10-K, I wish to inform you that the financial statements in the Annual Report do not reflect a change from the preceding year in any accounting principles or practices or in the method of applying any such principles or practices (except for the implementation of FAS 106 and 109 effective January 1, 1992 and described in footnotes S. Income Taxes and V. Postretirement Benefits of the Annual Report). Very truly yours, /s/Earnest J. Edwards Earnest J. Edwards Vice President and Controller Attachment cc: Corporate Savings Division New York Stock Exchange, Inc. 20 Broad Street New York, NY 10005 Attn: David F. Dolan American Stock Exchange 86 Trinity Place New York, NY 10006 1