SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* GATES WILLIAM H III (Last) (First) (Middle) ONE MICROSOFT WAY (Street) REDMOND WA 98052 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol ECOLAB INC [ ECL ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) X Other (specify below) See footnotes (2) and (3)
	3. Date of Earliest Transaction (Month/Day/Year) 06/04/2012
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	06/04/2012		P		526,707	A	$61.7922(1)	27,911,711	I(2)	by Cascade Investment, L.L.C.(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* GATES WILLIAM H III (Last) (First) (Middle) ONE MICROSOFT WAY (Street) REDMOND WA 98052 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) X Other (specify below) See footnotes (2) and (3)

1. Name and Address of Reporting Person* CASCADE INVESTMENT LLC (Last) (First) (Middle) 2365 CARILLON POINT (Street) KIRKLAND WA 98033 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) See footnote (2)

Explanation of Responses:

1. This transaction was executed in multiple trades at prices ranging from $61.45 to $61.98. The price set forth above reflects the weighted-average price per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

2. For purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the "Act"), Mr. Gates, as the sole member of Cascade Investment, L.L.C. ("Cascade") and co-trustee of Bill & Melinda Gates Foundation Trust ("Trust"), may be deemed to beneficially own more than 10% of the common stock of the Issuer. Mr. Gates has no pecuniary interest in the shares held by the Trust. Neither the filing of this Form 4 nor any of its contents shall be deemed an admission that Mr. Gates and any other person or persons constitute a "group" under Section 13(d) and Mr. Gates expressly disclaims membership in a group.

3. For purposes of Section 13(d) of the Act, Cascade may be deemed to be a member of a "group" that beneficially owns more than 10% of the common stock of the Issuer. Neither the filing of this Form 4 nor any of its contents shall be deemed an admission that Cascade and any other person or persons constitute a "group" under Section 13(d) or is otherwise subject to Section 16 of the Act and Cascade expressly disclaims membership in a group.

	/s/ Alan Heuberger, Attorney-in-fact for William H. Gates III	06/06/2012
	/s/ Cascade Investment, L.L.C. by Alan Heuberger as attorney-in-fact for Michael Larson, Business Manager	06/06/2012
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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