Exhibit 4.8

THIRD AMENDMENT TO CREDIT AGREEMENT

This THIRD AMENDMENT TO CREDIT AGREEMENT (this Amendment) is entered into as of July 28, 2008 among AIRGAS, INC.,
a Delaware corporation (Airgas and also a Borrower), AIRGAS CANADA INC., a Canada corporation, and RED-D-ARC LIMITED, an Ontario corporation (each a Canadian Borrower and together with Airgas
and the Foreign Borrowers executing this Amendment, the Borrowers), the Guarantors signatory hereto, the Lenders signatory hereto BANK OF AMERICA, N.A., as administrative agent for the Lenders (in such capacity, the U.S.
Agent), and THE BANK OF NOVA SCOTIA, as Canadian administrative agent for the Lenders (in such capacity, the Canadian Agent). Capitalized terms used herein and not otherwise defined shall have the meanings set forth in
the Credit Agreement (as defined below).

RECITALS

WHEREAS, the Borrowers, the Guarantors, the Lenders and the Agents are parties to that certain Credit Agreement dated as of July 25,
2006 (as amended pursuant to that certain First Amendment to Credit Agreement, dated as of July 3, 2007, and that certain Second Amendment to Credit Agreement, dated as of April 2, 2008, the Credit Agreement).

WHEREAS, the Required Lenders have agreed to amend certain terms of the Credit Agreement on the terms, and subject to the
conditions, set forth below.

NOW THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto agree as follows:

AGREEMENT

1. Amendments to Credit Agreement. Effective upon satisfaction of the conditions precedent set forth in Section 3 below, the
Credit Agreement is hereby amended as follows:

(a) The Credit Agreement (but not the Schedules and
Exhibits thereto, except as otherwise provided in this Amendment) is hereby amended and restated as set forth in Annex I attached hereto.

(b) Schedules 1.1D, 2.1(a) and 8.1 to the Credit Agreement are hereby deleted and new Schedules
1.1D, 2.1(a) and 8.1 in the forms of Schedules 1.1D, 2.1(a) and 8.1 attached to Annex I hereof, respectively, are substituted therefor.

(c) Exhibits 2.1(b)(i), 4.2, 7.12 and 11.3 to the Credit Agreement are hereby deleted and
new Exhibits 2A.1(b)(i), 4.2, 7.12 and 11.3 in the forms of Exhibits 2A.1(b)(i), 4.2, 7.12 and 11.3 attached to Annex I hereof, respectively, are substituted therefor.

(d) New Exhibits 2B.1(b)(i), 2B.5(a) and 2B.5(b) in the forms of Exhibits
2B.1(b)(i), 2B.5(a) and 2B.5(b) attached to Annex I hereof, respectively, are hereby added to the Credit Agreement.



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2. Amendments to Intercreditor Agreement. Effective upon satisfaction of the
conditions precedent set forth in Section 3 below, the penultimate paragraph of Section 1 of the Intercreditor Agreement is hereby amended as follows:

In calculating each Lenders Pro Rata Share, all obligations owed to a Lender in Canadian Dollars or a Foreign
Currency shall be converted to U.S. Dollars at the U.S. Dollar Equivalent in effect as of the date each Lenders Pro Rata Share is calculated. Any amounts received hereunder by the U.S. Agent in Canadian Dollars or a Foreign Currency shall
be converted to U.S. Dollars at the U.S. Dollar Equivalent in effect as of the date received by the U.S. Agent.

3.
Effectiveness; Conditions Precedent. This Amendment shall become effective upon receipt by the U.S. Agent of the following:

(a) copies of this Amendment duly executed by the Credit Parties, the Required Lenders and each Foreign Currency Lender;

(b) subject to Section 11 hereof, with respect to each Foreign Borrower executing this Amendment, all
documents the U.S. Agent may reasonably request relating to the existence and good standing of each such Foreign Borrower, the corporate or other necessary authority of each such Foreign Borrower for and the validity of the Credit Documents, and any
other matters relevant thereto, all in form and substance reasonably satisfactory to the U.S. Agent; and

(c)
with respect to each Foreign Borrower executing this Amendment, (i) a legal opinion of Cravath, Swaine & Moore LLP, and (ii) a legal opinion of foreign counsel to each Foreign Borrower (other than Immaterial Subsidiaries)
executing this Amendment, each in form and substance reasonably satisfactory to the U.S. Agent.

4. Construction. This
Amendment is a Credit Document executed pursuant to the Credit Agreement and shall (unless otherwise expressly indicated therein) be construed, administered and applied in accordance with the terms and provisions of the Credit Agreement.

5. Representations and Warranties. Each Credit Party hereby represents and warrants that (i) each Credit Party that is party
to this Amendment: (a) has the requisite corporate power and authority to execute, deliver and perform this Amendment, as applicable and (b) is duly authorized to, and has been authorized by all necessary corporate action, to execute,
deliver and perform this Amendment, (ii) the representations and warranties contained in Article VI of the Credit Agreement are, subject to the limitations set forth therein, true and correct in all material respects on and as of
the date hereof upon giving effect to this Amendment as though made on and as of such date (except for those which expressly relate to an earlier date) unless the failure to be so true and correct would not be reasonably expected to have a Material
Adverse Effect, (iii) no Default or Event of Default exists under the Credit Agreement on and as of the date hereof upon giving effect to this Amendment and (iv) as of the date hereof, the Immaterial Foreign Subsidiaries are Airgas, S.A.
de C.V.; Airgas West, S.A. de C.V.; Red-D-Arc, S.A. de C.V.; and Airgas Sakhalin Limited Liability Company.

6.
Acknowledgment. The Guarantors acknowledge and consent to all of the terms and conditions of this Amendment and agree that this Amendment does not operate to reduce or discharge the Guarantors obligations under the Credit Agreement or
the other Credit Documents. The Guarantors further acknowledge and agree that the Guarantors have no claims, counterclaims, offsets, or defenses to the Credit Documents and the performance of the Guarantors obligations thereunder or if the
Guarantors did have any such claims, counterclaims, offsets or defenses to the Credit Documents or any transaction related to the Credit Documents, the same are hereby waived, relinquished and released in consideration of the Lenders execution
and delivery of this Amendment.



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7. Counterparts. This Amendment may be executed by the parties hereto in several
counterparts, each of which shall be deemed to be an original and all of which shall constitute together but one and the same agreement.

8. Binding Effect. This Amendment, the Credit Agreement and the other Credit Documents embody the entire agreement between the
parties and supersede all prior agreements and understandings, if any, relating to the subject matter hereof. These Credit Documents represent the final agreement between the parties and may not be contradicted by evidence of prior, contemporaneous
or subsequent oral agreements of the parties. Except as expressly modified and amended in this Amendment, all the terms, provisions and conditions of the Credit Documents shall remain unchanged and shall continue in full force and effect.

9. GOVERNING LAW. THIS AGREEMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER SHALL BE GOVERNED BY AND
CONSTRUED AND INTERPRETED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

10. Severability.If any provision of
this Amendment is determined to be illegal, invalid or unenforceable, such provision shall be fully severable and the remaining provisions shall remain in full force and effect and shall be construed without giving effect to the illegal, invalid or
unenforceable provisions.

11. Foreign Borrowers. The parties hereto hereby confirm that, with effect from the date
hereof, each of the Subsidiaries identified on the signature pages hereto as a Foreign Borrower shall be designated as a Foreign Borrower for purposes of the Credit Agreement (as amended by this Amendment) and shall have all
rights, obligations, duties and liabilities of a Foreign Borrower thereunder vis-à-vis each of the other parties to the Credit Agreement (as amended by this Amendment). Each such Foreign Borrower confirms its acceptance of, and consents to,
all representations and warranties, covenants, and other terms and provisions of the Credit Agreement (as amended by this Amendment), including, without limitation, Section 11.5 thereof. Each such Foreign Borrower (together with Airgas) may
receive Foreign Currency Loans for its account on the terms and conditions set forth in the Credit Agreement (as amended by this Amendment). Notwithstanding the foregoing, to the extent that any of the documentation described in Section 3(b)
with respect to a Foreign Borrower is not delivered on the date of this Amendment, such Foreign Borrower shall not be permitted to request (nor shall the Foreign Currency Lenders have any obligation to lend to such Foreign Borrower) Foreign Currency
Loans under the Credit Agreement until such time as such documentation has been delivered.

[remainder of page
intentionally left blank]



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IN WITNESS WHEREOF, each of the parties hereto has caused a counterpart of this Amendment to
be duly executed and delivered and this Amendment shall be effective as of the date first above written.



|           |  |  |  |  |  |  |  |                                                                   |  |                              
|---------- |  |  |  |  |  |  |  | ----------------------------------------------------------------- |  | -----------------------------
|BORROWERS: |  |  |  |  |  |  |  | AIRGAS, INC.                                                     
|           |  |  |  |  | 
|           |  |  |  |  |  |  |  | By:                                                               |  | /s/ Joseph C. Sullivan       
|           |  |  |  |  |  |  |  | Name:                                                             |  | Joseph C. Sullivan           
|           |  |  |  |  |  |  |  | Title:                                                            |  | Vice President               
|           |  |  |  | 
|           |  |  |  |  |  |  |  | AIRGAS CANADA INC., as a Canadian Borrower and a Foreign Borrower
|           |  |  |  |  | 
|           |  |  |  |  |  |  |  | By:                                                               |  | /s/ Thomas M. Smyth          
|           |  |  |  |  |  |  |  | Name:                                                             |  | Thomas M. Smyth              
|           |  |  |  |  |  |  |  | Title:                                                            |  | Vice President               
|           |  |  |  | 
|           |  |  |  |  |  |  |  | RED-D-ARC LIMITED, as a Canadian Borrower and a Foreign Borrower 
|           |  |  |  |  | 
|           |  |  |  |  |  |  |  | By:                                                               |  | /s/ Thomas M. Smyth          
|           |  |  |  |  |  |  |  | Name:                                                             |  | Thomas M. Smyth              
|           |  |  |  |  |  |  |  | Title:                                                            |  | Vice President               
|           |  |  |  | 
|           |  |  |  |  |  |  |  | AIRGAS, S.A. DE C.V., as a Foreign Borrower                      
|           |  |  |  |  | 
|           |  |  |  |  |  |  |  | By:                                                               |  | /s/ Mario Adolfo Galvan Ordaz
|           |  |  |  |  |  |  |  | Name:                                                             |  | Mario Adolfo Galvan Ordaz    
|           |  |  |  |  |  |  |  | Title:                                                            |  | Attorney In Fact             
|           |  |  |  | 
|           |  |  |  |  |  |  |  | AIRGAS WEST, S.A. DE C.V., as a Foreign Borrower                 
|           |  |  |  |  | 
|           |  |  |  |  |  |  |  | By:                                                               |  | /s/ Joseph C. Sullivan       
|           |  |  |  |  |  |  |  | Name:                                                             |  | Joseph C. Sullivan           
|           |  |  |  |  |  |  |  | Title:                                                            |  | Vice President               
|           |  |  |  | 
|           |  |  |  |  |  |  |  | RED-D-ARC, S.A. DE C.V., as a Foreign Borrower                   
|           |  |  |  |  | 
|           |  |  |  |  |  |  |  | By:                                                               |  | /s/ Joseph C. Sullivan       
|           |  |  |  |  |  |  |  | Name:                                                             |  | Joseph C. Sullivan           
|           |  |  |  |  |  |  |  | Title:                                                            |  | Vice President               
|           |  |  |  | 
|           |  |  |  |  |  |  |  | RED-D-ARC (UK) LIMITED, as a Foreign Borrower                    
|           |  |  |  |  | 
|           |  |  |  |  |  |  |  | By:                                                               |  | /s/ Joseph C. Sullivan       
|           |  |  |  |  |  |  |  | Name:                                                             |  | Joseph C. Sullivan           
|           |  |  |  |  |  |  |  | Title:                                                            |  | Vice President               



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RED-D-ARC (NETHERLANDS) B.V., as a Foreign BorrowerBy:

/s/ Joseph C. SullivanName:

Joseph C. SullivanTitle:

Vice PresidentAIRGAS SAKHALIN Limited Liability Company, as a Foreign BorrowerBy:

/s/ Joseph C. SullivanName:

Joseph C. SullivanTitle:

Vice President




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|                    |  |  |  |  |  |                                           |  |                    
|------------------- |  |  |  |  |  | ----------------------------------------- |  | -------------------
|U.S. SUBSIDIARY     |  |  |  |  |  |                                           |  |                    
|GUARANTORS:         |  |  |  |  |  | AIRGAS-EAST, INC.                        
|                    |  |  |  |  |  | AIRGAS-GREAT LAKES, INC.                 
|                    |  |  |  |  |  | AIRGAS-MID AMERICA, INC.                 
|                    |  |  |  |  |  | AIRGAS-NORTH CENTRAL, INC.               
|                    |  |  |  |  |  | AIRGAS-SOUTH, INC.                       
|                    |  |  |  |  |  | AIRGAS-INTERMOUNTAIN, INC.               
|                    |  |  |  |  |  | AIRGAS-MID SOUTH, INC.                   
|                    |  |  |  |  |  | AIRGAS-NORPAC, INC.                      
|                    |  |  |  |  |  | AIRGAS-NORTHERN CALIFORNIA & NEVADA, INC.
|                    |  |  |  |  |  | AIRGAS-SOUTHWEST, INC.                   
|                    |  |  |  |  |  | AIRGAS-WEST, INC.                        
|                    |  |  |  |  |  | AIRGAS-SAFETY, INC.                      
|                    |  |  |  |  |  | AIRGAS CARBONIC, INC.                    
|                    |  |  |  |  |  | AIRGAS SPECIALTY GASES, INC.             
|                    |  |  |  |  |  | NITROUS OXIDE CORP.                      
|                    |  |  |  |  |  | RED-D-ARC, INC.                          
|                    |  |  |  |  |  | AIRGAS DATA, LLC                         
|                    |  |  |  |  |  | MISSOURI RIVER HOLDINGS, INC.            
|                    |  |  |  |  |  | AIRGAS INVESTMENTS, INC.                 
|                    |  |  |  |  |  | AIRGAS SPECIALTY PRODUCTS, INC.          
|                    |  |  |  |  |  | WORLDWIDE WELDING, INC.,                 
|                    |  |  |  |  |  | AIRGAS MERCHANT HOLDINGS, INC.           
|                    |  |  |  |  |  | AIRGAS MERCHANT GASES, LLC,              
|                    |  |  |  |  |  | NATIONAL WELDERS SUPPLY COMPANY, INC.    
|                    |  |  |  | 
|                    |  |  |  |  |  | By:                                       |  | /s/ Thomas M. Smyth
|                    |  |  |  |  |  | Name:                                     |  | Thomas M. Smyth    
|                    |  |  |  |  |  | Title:                                    |  | Vice President     
|CANADIAN SUBSIDIARY |  |  |  |  |  |                                           |  |                    
|GUARANTORS:         |  |  |  |  |  | AIRGAS, S.A. DE C.V.                     
|                    |  |  |  |  |  | RED-D-ARC, S.A. DE C.V.                  
|                    |  |  |  |  |  | AIRGAS WEST, S.A. DE C.V.                
|                    |  |  |  |  |  | RED-D-ARC (UK) LIMITED                   
|                    |  |  |  |  |  | RED-D-ARC (NETHERLANDS) B.V.             
|                    |  |  |  |  |  | By:                                       |  |                    
|                    |  |  |  |  |  | Name:                                     |  |                    
|                    |  |  |  |  |  | Title:                                    |  |                    



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|            |  |  |  |  |  |                        |  |                         
|----------- |  |  |  |  |  | ---------------------- |  | ------------------------
|U.S. AGENT: |  |  |  |  |  | BANK OF AMERICA, N.A.,
|            |  |  |  | 
|            |  |  |  |  |  | By:                    |  | /s/ Bridgett J. Manduk  
|            |  |  |  |  |  | Name:                  |  | Bridgett J. Manduk      
|            |  |  |  |  |  | Title:                 |  | Assistant Vice President



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|                |  |  |  |                         |  |                  
|--------------- |  |  |  | ----------------------- |  | -----------------
|CANADIAN AGENT: |  |  |  | THE BANK OF NOVA SCOTIA
|                |  |  | 
|                |  |  |  | By:                     |  | /s/ James J. Rhee
|                |  |  |  | Name:                   |  | James J. Rhee    
|                |  |  |  | Title:                  |  | Director         
|                |  |  | 
|                |  |  |  | By:                     |  | /s/ Vik Sidhu    
|                |  |  |  | Name:                   |  | Vik Sidhu        
|                |  |  |  | Title:                  |  | Associate        



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|         |  |  |  |  |  |                                                                                             |  |                                  
|-------- |  |  |  |  |  | ------------------------------------------------------------------------------------------- |  | ---------------------------------
|LENDERS: |  |  |  |  |  | BANK OF AMERICA, N.A.                                                                      
|         |  |  |  | 
|         |  |  |  |  |  | By:                                                                                         |  | /s/ Edwin B. Cox, Jr.            
|         |  |  |  |  |  | Name:                                                                                       |  | Edwin B. Cox, Jr.                
|         |  |  |  |  |  | Title:                                                                                      |  | Senior Vice President            
|         |  |  | 
|         |  |  |  |  |  | BANK OF AMERICA, N.A. (CANADA BRANCH)                                                      
|         |  |  |  | 
|         |  |  |  |  |  | By:                                                                                         |  | /s/ Medina Sales de Andrade      
|         |  |  |  |  |  | Name:                                                                                       |  | Medina Sales de Andrade          
|         |  |  |  |  |  | Title:                                                                                      |  | Vice President                   
|         |  |  | 
|         |  |  |  |  |  | BANK OF AMERICA MEXICO, S.A. INSTITUCION DE
BANCA MULTIPLE GRUPO FINANCIERO BANK OF AMERICA
|         |  |  |  | 
|         |  |  |  |  |  | By:                                                                                         |  | /s/ Jose Gomez                   
|         |  |  |  |  |  | Name:                                                                                       |  | Jose Gomez        Gerzido Obregan
|         |  |  |  |  |  | Title:                                                                                      |  | Attorney In Fact                 
|         |  |  |  | 
|         |  |  |  |  |  | By:                                                                                         |  | /s/ Gerzido Obregan              
|         |  |  |  |  |  | Name:                                                                                       |  | Gerzido Obregan                  
|         |  |  |  |  |  | Title:                                                                                      |  | Attorney In Fact                 



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THE BANK OF NEW YORK MELLONBy:

/s/ William M. FeathersName:

William M. FeathersTitle:

Vice President




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THE BANK OF TOKYO-MITSUBISHIUFJ, LTD., NY BRANCHBy:

/s/ Maria FerradasName:

Maria FerradasTitle:

Authorized Signatory




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JPMORGAN CHASE BANK, N.A.By:

/s/ James A. KnightName:

James A. KnightTitle:

Vice PresidentJPMORGAN CHASE BANK, N.A., TORONTOBy:

/s/ Steve VoightName:

Steve VoightTitle:

Senior Vice PresidentJ.P. MORGAN EUROPE LIMITEDBy:

/s/ Alastair A. StevensonName:

Alastair A. StevensonTitle:

Managing DirectorBANCO J.P. MORGAN, S.A.INSTITUCION DE BANCAMULTIPLE J.P. MORGAN GRUPO FINANCIEROBy:

/s/ Raul Freyre PorroName:

Raul Freyre PorroTittle:

Vice President




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WACHOVIA BANK, N.A.By:

/s/ Anne SheahanName:

Anne SheahanTitle:

Vice President




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PNC BANK NABy:

/s/ Meredith JermannName:

Meredith JermannTitle:

Vice President




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THE BANK OF NOVA SCOTIABy:

/s/ Timothy P. FinneranName:

Timothy P. FinneranTitle:

Managing Director




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NATIONAL CITY BANKBy:

/s/ Debra W. RiefnerName:

Debra W. RiefnerTitle:

Senior Vice President




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BANK OF OKLAHOMA, N.A.By:Name:Title:




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BANK OF HAWAIIBy:

/s/ Marc AdelbergerName:

Marc AdelbergerTitle:

Vice President




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CALYON, NEW YORK BRANCHBy:

/s/ Yuri MuzichenkiName:

Yuri MuzichenkoTitle:

DirectorBy:

/s/ Mike MadnickName:

Mike MadnickTitle:

Managing Director




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GOLDMAN SACHS CREDIT PARTNERS L.P.By:

/s/ Andrew CaditzName:

Andrew CaditzTitle:

Authorized Signatory




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MIZUHO CORPORATE BANK, LTD.By:Name:Title:




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SUMITOMO MITSUI BANKING CORP.,NEW YORKBy:

/s/ David A. BuckName:

David A. BuckTitle:

Senior Vice President




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BRANCH BANKING AND TRUST CO.By:

/s/ Troy R. WeaverName:

Troy R. WeaverTitle:

Senior Vice President




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BANK LEUMI USABy:

/s/ Joung Hee HongName:

Joung Hee HongTitle:

First Vice President




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BARCLAYS BANK PLCBy:

/s/ Douglas BerneggerName:

Douglas BerneggerTitle:

Director




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CITIZENS BANKBy:Name:Title:




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SUNTRUST BANKBy:

/s/ Mark A. FlatinName:

Mark A. FlatinTitle:

Managing Director




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BAYERISCHE LANDESBANK,NEW YORK BRANCHBy:

/s/ Stuart SchulmanName:

Stuart SchulmanTitle:

Senior Vice PresidentBy:

/s/ Georgina Fiordalisi, CFAName:

Georgina Fiordalisi, CFATitle:

Vice President




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COMMERZBANK AG, NEW YORK ANDGRAND CAYMAN BRANCHESBy:Name:Title:




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FIFTH THIRD BANKBy:

/s/ Randolph J. StiererName:

Randolph J. StiererTitle:

Vice President




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FORTIS CAPITAL CORP.By:

/s/ John W. DeeganName:

John W. DeeganTitle:

Director &Group HeadBy:

/s/ John SpillaneName:

John SpillaneTitle:

Vice President




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HSBC BANK USA, NATIONAL ASSOCIATIONBy:

/s/ Collen GlackinName:

Colleen GlackinTitle:

Vice President




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WELLS FARGO BANK, NATIONAL ASSOCIATIONBy:

/s/ James R. BednarkName:

James R. BednarkTitle:

Senior Vice President




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REGIONS BANKBy:

/s/ David L. WallerName:

David L. WallerTitle:

Senior Vice President




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SOVEREIGN BANKBy:Name:Title:




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US BANK, NATIONAL ASSOCIATIONBy:

/s/ Michael P. DickmanName:

Michael P. DickmanTitle:

Vice PresidentBy:

/s/ Kenneth FielerName:

Kenneth FielerTitle:

Assistant Vice President




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COMERICA BANKBy:

/s/ Liesl EckhardtName:

Liesl EckhardtTitle:

Assistant Vice President




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NORTH FORK BANKBy:Name:Title:




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PEOPLES BANKBy:Name:Title:




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CHANG HWA COMMERCIAL BANK, LTD.,NEW YORK BRANCHBy:

/s/ Jim C.Y. ChenName:

Jim C.Y.ChenTitle:

Vice President & General Manager




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CHINATRUSTBy:Name:Title:




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E. SUN COMMERCIAL BANK., LTD.LOS ANGELES BRANCHBy:

/s/ Edward ChenName:

Edward ChenTitle:

Vice President & Deputy General Manager




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HUA NAN COMMERCIAL BANK, LTD.NEW YORK AGENCYBy:Name:Title:




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BANK OF CHINABy:

/s/ William W. SmithName:

William W. SmithTitle:

Deputy General Manager