FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * MCCAUSLAND PETER   2. Issuer Name and Ticker or Trading Symbol AIRGAS INC [ARG] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director __X__ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chariman, President and CEO (Last) (First) (Middle) C/O AIRGAS, INC., 259 N. RADNOR-CHESTER RD, STE. 100 3. Date of Earliest Transaction (Month/Day/Year) 12/11/2008 (Street) RADNOR, PA 19087 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) 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 05/08/2008   G V 22,000 (1) A (2) 7,020,518 (3) D   Common Stock 06/17/2008   G V 5,678 D (2) 7,014,840 (3) D   Common Stock 06/18/2008   G V 1,217 D (2) 7,013,623 (3) D   Common Stock 12/11/2008   M   130,000 A $ 11.5 7,143,623 (3) D   Common Stock               228,000 (4) I By trusts Common Stock               41,500 (5) I By immediate family Common Stock               44,442 (6) I By 401(k) plan

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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 Underlying Securities (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 of Derivative Security: 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

Stock Option (Right to Buy)

$ 11.5

12/11/2008

M

130,000

(7)

05/18/2009

Common Stock

130,000

(2)

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
MCCAUSLAND PETER C/O AIRGAS, INC. 259 N. RADNOR-CHESTER RD, STE. 100 RADNOR, PA 19087	X	X	Chariman, President and CEO

Signatures

Robert H. Young, Jr., Attorney-in-Fact for Peter McCausland		12/15/2008
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Represents 22,000 shares of Airgas, Inc. common stock distributed to Peter McCausland and his spouse (and held jointly) from two separate grantor retained annuity trusts (each, a "GRAT") of which Peter McCausland is a co-trustee with his spouse and either he or his spouse is a beneficiary.
(2)	Not applicable.
(3)	Includes 15,700 shares of Airgas, Inc. common stock owned directly by Peter McCausland and indirectly by his spouse.
(4)	Represents 228,000 shares of Airgas, Inc. common stock held in two separate GRATs of which Peter McCausland is a co-trustee and either he or his spouse is a beneficiary.
(5)	Represents 41,500 shares of Airgas, Inc. common stock owned directly by his spouse and indirectly by Peter McCausland.
(6)	The information presented is as of 12/11/2008, the date of the latest available statement of the reporting person's holdings of Airgas, Inc. common stock in his 401(k) plan. Since March 7, 2008, the date of the statement relied upon for the amount reported on the reporting person's Form 4 dated March 11, 2008, a total of 735 shares of common stock have been acquired in the reporting person's 401(k) plan through transactions exempt under Section 16(b).
(7)	These options became exercisable in 25% equal increments on each of 5/18/2000, 5/18/2001, 5/18/2002 and 5/18/2003.

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