Rule 424(b)(3)
                                                              File No. 33-38033

                             NALCO CHEMICAL COMPANY

                         COMMON STOCK ACQUIRED UNDER THE
                             NALCO CHEMICAL COMPANY
                             1990 STOCK OPTION PLAN

                           APPENDIX DATED MAY 14, 1996
                      TO PROSPECTUS DATED NOVEMBER 30, 1990


This Appendix  updates certain  information in the Prospectus dated November 30,
1990 (the "Prospectus")  relating to shares of Common Stock which may be offered
by the stockholders listed herein under the caption "Selling Stockholders" or by
their  transferees  (or by their donees or  pledgees).  The Company will furnish
without charge to participants additional copies of the Prospectus upon request.

                              SELLING STOCKHOLDERS

The following  table sets forth the name and position within the Company for the
last three  years of each  Selling  Stockholder,  the number of shares of Common
Stock of the Company  beneficially  owned by him on the date of this  Prospectus
and, the number of shares offered by the Prospectus.


                                                                                       

                                                                                          Shares Offered
                                                                Shares                     By This
Name and Position                                            Owned (1)(2)                  Prospectus (2)
W. E. Buchholz                                                   28,000                        42,800
Vice President-Chief
Financial Officer

P. Dabringhausen                                                 44,517                        70,600
Group Vice President,
President, Process Chemicals Division

M. B. Harp                                                      106,310(3)                    109,400
Executive Vice President,
International Operations from January, 1993 to
December, 1994; and Executive Vice President,
Operations as of January, 1995
                                                         
E. J. Mooney                                                    291,066                       278,600
President and Chief Operating Officer from
January, 1992 to March 1994; President as of
March, 1990; Chief Executive Officer as of April, 1994; and Chairman as of July,
1994.

S. D. Newlin                                                     41,749                        64,000
General Manager, Pulp & Paper Chemicals Group
from January, 1992 to December, 1992; Vice
President, President, Nalco Pacific from January,
1993 through February, 1994; Group Vice
President, President, Nalco Europe as of March,
1994.

J. D. Tinsley                                                    62,439(3)                     75,700
Group Vice President, President, Water & Waste
Treatment Division

W. S. Weeber                                                    109,129                       107,800
Executive Vice President, Operations Staff



(1)   Includes shares which are subject to outstanding stock options 
exercisable within sixty days of April 30, 1996 as follows:  W. E. Buchholz, 
27,000 shares; P. Dabringhausen, 42,200 shares; M. B. Harp, 70,400 shares; 
E. J. Mooney, 249,600 shares; S. D. Newlin 37,200 shares; J. D. Tinsley, 47,900
shares; W. S. Weeber, 93,400 shares.
(2)   Includes shares which may be acquired by exercise of stock options.
(3)   Includes beneficial/ownership of shares held indirectly by wife.

Additional Selling Stockholders will be identified by a subsequent appendix. One
or more of the Selling  Stockholders  may from time to time make gifts of any or
all of his shares as  collateral  for  loans.  In the event of such gift or of a
default under any such loan,  the donee may elect to sell donated  shares or the
lender may elect to sell shares held as collateral by means of the prospectus as
supplemented.