ECOLAB
                               MIRROR SAVINGS PLAN

                         FOURTH DECLARATION OF AMENDMENT


Pursuant to Section 1.3 of the Ecolab Mirror Savings Plan ("Plan") and 
Section 5.1 of the Ecolab Inc. Administrative Document for Non-Qualified 
Benefit Plans which is incorporated into the Plan by reference 
("Administrative Document"), the Company amends the Plan as set forth below.

1.       Subsection (2) of Section 6.1 of the Plan is hereby amended to read 
as follows:

                  "(2) HYPOTHETICAL INVESTMENT FUNDS FOR EXECUTIVE DEFERRALS.
         The Hypothetical Investment Funds for purposes of the portion of an
         Executive's Account which is attributable to his Executive Deferrals
         shall be those same Investment Funds designated by the Company from
         time to time under the Savings Plan. Each Executive (or his Death
         Beneficiary) may elect, in a manner prescribed by the Administrator
         from time to time, one or more Hypothetical Investment Funds in which
         his Executive Deferrals are deemed to have been invested for purposes
         of crediting earnings and losses to the portion of the Executive's
         Account which is attributable to Executive Deferrals. The Company may
         deem an Executive's Executive Deferrals to have been invested in the
         Hypothetical Investment Fund elected by the Executive, if any, or may
         instead, in its sole discretion, deem such Executive Deferrals to have
         been invested in one or more Hypothetical Investment Funds selected by
         the Company. Earnings on any amounts deemed to have been invested in
         any Hypothetical Investment Fund shall be deemed to have been
         reinvested in such Hypothetical Investment Fund. Notwithstanding the
         foregoing, any Executive who is subject to Section 16(b) of the
         Securities Exchange Act of 1934 may not elect and shall not be deemed
         to have directed any Executive Deferrals to the Ecolab Stock Fund. An
         Executive shall be deemed, on the day prior to becoming subject to
         Section 16(b) or at such other time as he is subject to Section 16(b),
         to have elected to have Executive Deferrals then deemed to be invested
         in the Ecolab Stock Fund invested in the Hypothetical Investment Fund
         known as the Fidelity Retirement Money Market Portfolio unless another
         permitted election is in place."

2. This amendment to the Plan shall be effective as of September 1, 1998.

IN WITNESS WHEREOF, the Company has caused this instrument to be executed by 
its authorized officers and its corporate seal affixed, this 24th day of 
August, 1998.

                                   ECOLAB INC.
  (Seal)
                                   By: /s/ Michael E. Shannon               
                                      --------------------------------------
                                      Michael E. Shannon
                                      Chairman of the Board, Chief Financial
                                      and Administrative Officer
Attest: /s/ Kenneth A. Iverson      
        --------------------------------
         Kenneth A. Iverson
         Vice President and Secretary