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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No. 16)*

AIRGAS, INC.

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

009363 10 2

(CUSIP Number)

December 31, 2006

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

     o Rule 13d-1(b)

     o Rule 13d-1(c)

     þ Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 009363102

1	NAMES OF REPORTING PERSONS: Peter McCausland
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   o
	(b)   þ
3	SEC USE ONLY:
4	CITIZENSHIP OR PLACE OF ORGANIZATION:
	United States
		5	SOLE VOTING POWER:
NUMBER OF			1,044,526
SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			7,149,860
EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			1,044,526
WITH:		8	SHARED DISPOSITIVE POWER:
			7,149,860
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	8,194,386
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):
	10.3%
12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	IN

Item 1(a)	Name of Issuer
	Airgas, Inc.

Item 1(b)	Address of Issuer’s Principal Executive Offices
	Airgas, Inc.
	Radnor Court
	259 North Radnor-Chester Road, Suite 100
	Radnor, Pennsylvania 19087-5283

Item 2(a)	Name of Person Filing
	Peter McCausland

Item 2(b)	Address of Principal Business Office, or, if none, Residence
	Airgas, Inc.
	Radnor Court
	259 North Radnor-Chester Road, Suite 100
	Radnor, Pennsylvania 19087-5283

Item 2(c)	Citizenship
	United States

Item 2(d)	Title of Class of Securities
	Common Stock, par value $0.01 per share

Item 2(e)	CUSIP Number
	009363 10 2

Item 3 If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:

(a)	___	Broker or dealer registered under Section 15 of the Exchange Act;
(b)	___	Bank as defined in Section 3(a)(6) of the Exchange Act;
(c)	___	Insurance company as defined in Section 3(a)(19) of the Exchange Act;
(d)	___	Investment company registered under Section 8 of the Investment Company Act;
(e)	___	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);
(f)	___	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);
(g)	___	A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);
(h)	___	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act;
(i)	___	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act;
(j)	___	Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

Item 4 Ownership

               (a) and (b). Peter McCausland beneficially owned an aggregate of 8,194,386 shares of the issuer’s Common Stock, or approximately 10.3% of the shares outstanding, as of December 31, 2006, of which 986,250 shares were issuable upon exercise of employee stock options.

               (c). Peter McCausland had sole power to vote or to direct the vote, and sole power to dispose or to direct the disposition of, 1,044,526 shares of the issuer’s Common Stock, of which 986,250 shares were issuable upon exercise of employee stock options. Mr. McCausland had shared power to vote or to direct the vote, and/or shared power to dispose or to direct the disposition of, 7,149,860 shares of the Common Stock, which included 35,470 shares held by a charitable foundation (the “Foundation”) of which Mr. McCausland is an officer and director.

Item 5	Ownership of Five Percent or Less of a Class
	Not applicable

Item 6 Ownership of More than Five Percent on Behalf of Another Person

               No other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the issuer’s shares which are the subject of this Schedule 13G, except that, with respect to 7,114,390 shares, members of Mr. McCausland’s family share with Mr. McCausland the right, and, with respect to 35,470 shares, the Foundation has the exclusive right, to receive the dividends from and the proceeds of sale as to such shares.

Item 7	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company
	Not Applicable

Item 8	Identification and Classification of Members of the Group
	Not Applicable

Item 9	Notice of Dissolution of Group
	Not Applicable

Item 10	Certification
	Not Applicable

SIGNATURE

          After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: February 9, 2007

/s/ Peter McCausland Peter McCausland