SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 13)* AIRGAS, INC. ______________________________________________ (Name of Issuer) COMMON STOCK _____________________________________________ (Title of Class of Securities) 009363 10 2 __________________________ (CUSIP Number) December 31, 2003 _______________________________________________________ (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [ ] Rule 13d-1(b) [ ] Rule 13d-1(c) [X] 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). (Continued on following page(s)) Page 1 of 6 pages CUSIP No. 009363 10 2 13G Page 2 of 6 pages ___________ __ __ ______________________________________________________________________________ 1. NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Peter McCausland ______________________________________________________________________________ 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [ ] (b) [X] ______________________________________________________________________________ 3. SEC USE ONLY ______________________________________________________________________________ 4. CITIZENSHIP OR PLACE OF ORGANIZATION United States ______________________________________________________________________________ 5. SOLE VOTING POWER 725,925 __________________________________________________________ NUMBER OF 6. SHARED VOTING POWER SHARES BENEFICIALLY 10,225,937 OWNED BY EACH __________________________________________________________ REPORTING 7. SOLE DISPOSITIVE POWER PERSON WITH 725,925 __________________________________________________________ 8. SHARED DISPOSITIVE POWER 10,225,937 ______________________________________________________________________________ 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 10,951,862 ______________________________________________________________________________ 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* [ ] ______________________________________________________________________________ 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 14.8% ______________________________________________________________________________ 12. TYPE OF REPORTING PERSON* IN ______________________________________________________________________________ CUSIP No. 009363 10 2 13G Page 3 of 6 pages ___________ __ __ ______________________________________________________________________________ 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 $.01 per share Item 2(e) CUSIP Number ____________ 009363 10 2 CUSIP No. 009363 10 2 13G Page 4 of 6 pages ____________ __ __ ______________________________________________________________________________ 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 10,951,862 shares of the issuer's Common Stock, or approximately 14.8% of the shares outstanding, as of December 31, 2003, of which 1,068,750 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, 725,925 shares of the issuer's Common Stock, of which 670,486 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, 10,225,937 shares of the Common Stock, which included 398,264 shares issuable upon exercise of stock options held by a trust for Mr. McCausland's children, and 4,079 shares held by a charitable foundation (the "Foundation") of which Mr. McCausland is an officer and director. CUSIP No. 009363 10 2 13G Page 5 of 6 pages ___________ __ __ ______________________________________________________________________________ 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 10,221,858 shares, members of Mr. McCausland's family share with Mr. McCausland the right, and, with respect to 4,079 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 CUSIP No. 009363 10 2 13G Page 6 of 6 pages ___________ __ __ ______________________________________________________________________________ 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. February 10, 2004 __________________________________ Date /S/Peter McCausland __________________________________ Signature Peter McCausland __________________________________ Name