CHICAGO, IL Environmental Systems Design, Inc. (ESD), an international leader in the design of high performance buildings, mission critical facilities, workplaces, and health, science and education environments, is celebrating its 50th anniversary.

From humble beginnings, ESD has grown to $50 million a year in revenues, with nearly 300 employees. Working in more than 30 states, the firm boasts Fortune 500 clients nationwide and is engaged in high-profile projects internationally. Now one of the biggest engineering firms in the country, with offices in Dallas, Texas, and San Francisco, California, along with one in Abu Dhabi, UAE, ESD has been involved with three of the seven tallest buildings in the world. In 2016, thanks to its close relationship with Adrian Smith + Gordon Gill Architecture, ESD added AS+GG's PositivEnergy Practice Studio to the fold.

While the war in Vietnam and race riots filled the headlines 50 years ago, a tiny engineering firm opened in Chicago, Illinois, attracting little notice. Hem Gupta -- an engineer who grew up without electricity or running water in India -- had worked successfully for many years at Perkins & Will. Still, his entrepreneurial zeal remained unfulfilled. He chose to launch Environmental Service Design, Inc. in July 1967. Hem, along with architect Jack Train - who had worked with him at Skidmore, Owings & Merrill on the landmark Inland Steel Building - contributed $25,000 in start-up capital. Situated in the second-biggest city in the United States, ESD opened shop but would it survive?

Starting with its first major project - the Chicago Board of Trade - there is hardly a building in Chicago's Loop ESD has not touched. Possessing expertise in mechanical, electrical, plumbing, technology and other services, its best work needs to go unseen to allow architectural excellence to shine. Though Hem Gupta passed away earlier this year at 85, ESD is still family-owned, as second-generation leader and CEO Raj Gupta steers the Chicago-based company into the future.

"I'm proud of what has been accomplished by my Dad and many others," Gupta said. "I'm also really excited about is what can be accomplished in the future in areas that didn't even exist when we started. Changes in government regulations, technology and more are influencing the design of buildings inside and out. That makes the specialization we bring more valuable than ever."