The list also highlights Airgas’ 10-year average total return to investors of 19.4 percent per year, which ranked 42nd among all Fortune 500 companies. In 2013, Airgas delivered a total return of 24.7 percent to investors, according to Fortune.

“The Fortune 500 list includes some of the most successful and respected businesses in the country, and we are proud to be counted among them,” said Michael L. Molinini, Airgas’ President and Chief Executive Officer. “We are especially pleased to be recognized for our commitment to creating shareholder value over the long-term. Being ranked as one of the top 50 U.S. companies for total return to shareholders during the past decade is a testament to our strong execution of strategic growth initiatives, as well as the hard work and dedication of Airgas associates in serving our customers every day across the country.”

Airgas, founded in 1982 by Executive Chairman Peter McCausland, became a publicly traded company in 1986 and was added to the S&P 500 Index in 2009. Through more than 450 acquisitions, Airgas has become one of the largest industrial gas companies in the U.S. More than 16,000 associates work in approximately 1,100 locations, including branches, retail stores, gas fill plants, specialty gas labs, production facilities and distribution centers.

Airgas was last included in the Fortune 500 list in 2010. Complete results of the Fortune 500 appear in the June 16 issue of Fortune and are available online at fortune.com/fortune500. Fortune 500® is a registered trademark of the Fortune magazine division of Time Inc.