X0306 4 2017-05-08 0 0000031462 ECOLAB INC. ECL 0001275967 HANDLEY THOMAS W 1 ECOLAB PLACE SAINT PAUL MN 55102 0 1 0 0 President and COO Common Stock 2017-05-08 4 M 0 31400 45.665 A 45229.664 D Common Stock 2017-05-08 4 F 0 21003 126.555 D 24226.664 D Common Stock 27675 I By 2015 GRAT Common Stock 75556.155 I By 2016 GRAT Common Stock 717 I By child #1 trust Common Stock 717 I By child #2 trust Common Stock 558.083 I By Ecolab Savings Plan Employee Stock Option (Right to Buy) 45.665 2017-05-08 4 M 0 31400 0 D 2010-12-02 2019-12-02 Common Stock 31400 0 D Reflects the reporting person's payment of the exercise price and withholding taxes for a stock option issued in accordance with Rule 16b-3 by delivering or withholding shares of Ecolab common stock. Number of UNITS in the Ecolab Stock Fund of the Ecolab Savings Plan (401(k) Plan) as of April 30, 2017. Includes 1.613 UNITS acquired since the reporting person's last report. (The 558.083 UNITS are the equivalent of approximately 1,027 SHARES of the issuer's Common Stock.) The option became exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share), on each of the first and second anniversaries of the date of grant and as to the remaining shares on the third anniversary of the date of grant. The date listed in the "Date Exercisable" column represents the first anniversary date of the date of grant. /s/ David F. Duvick, as Attorney-in-Fact for Thomas W. Handley 2017-05-10