Airgas Added to S&P 500 Index

RADNOR, PA – September 8, 2009 — Airgas, Inc. (NYSE: ARG) today announced it has been added to the S&P 500 after the close of trading. Airgas is the largest U.S. distributor of industrial, medical, and specialty gases, and welding, safety, and related products.

“It is an honor to be included in this important index and a rewarding affirmation of the consistent growth strategies that have marked our 27-year history,” said Airgas Chairman and Chief Executive Officer Peter McCausland. “We play an essential role in the U.S. economy, with products and services that support customers in a broad array of industries such as manufacturing, energy, healthcare, research and life sciences, construction, transportation, and food and beverage. We are grateful to our shareholders and our hardworking, dedicated associates for their commitment to our success.”

Airgas was started by McCausland in 1982, generating $3 million of revenue in its first year. It has since made approximately 400 acquisitions, growing to more than $4 billion in annual revenues with more than 14,000 employees and 1,100 locations. The company has specifically been added to the S&P 500 GICS (Global Industry Classification Standard) Industrial Gases Sub-Industry Index

About Airgas, Inc.

Airgas, Inc. (NYSE: ARG), through its subsidiaries, is one of the nation's leading suppliers of industrial, medical and specialty gases, and hardgoods, such as welding equipment and related products. Airgas is a leading U.S. producer of atmospheric gases with 16 air separation plants, a leading producer of carbon dioxide, dry ice, and nitrous oxide, one of the largest U.S. suppliers of safety products, and a leading U.S. supplier of refrigerants, ammonia products, and process chemicals. Approximately 17,000 associates work in more than 1,100 locations, including branches, retail stores, gas fill plants, specialty gas labs, production facilities and distribution centers. Airgas also markets its products and services through e-Business, catalog and telesales channels. Its national scale and strong local presence offer a competitive edge to its diversified customer base. For more information, please visit www.airgas.com.

Investor Contact:

Joseph Marczely 610-263-8277

Media Contact:

Sarah Boxler 610-263-8260