The sprawling /*Sunoco refinery*/ in South Philadelphia is one of fifty in the country using a potentially deadly chemical called hydrofluoric acid, or HF.
/*ABC News*/ reports the industry's own worst case scenario shows an accidental release of HF could sicken or kill 1.3 million people within 8 miles of the refinery.
James Jamison knows all about the dangers.
"I knew right then that something was going wrong," he tells Action News.
Jamison was an iron worker doing a welding job for a subcontractor at the Sunoco refinery two years ago. An acid vaporizer leaked deadly HF into the air.
"This dark cloud came over me and I couldn't breathe," he said. "The first thing I thought about was, like survival, you know. I thought about my family and my kids."
Jamison says he can't work, and can't play very long with his young sons anymore, suffering from lung damage that requires constant therapy.
"It went from my nose, all the way down to my chest and my stomach and it just settled there," he said. "And it was just so intense, so painful. It's something I never experienced in my life."
Federal inspectors looked into the accident and later issued these four serious safety citations, noting a 36-year history of leaks and maintenance problems. Jamison and four co-workers have filed a lawsuit against Sunoco. Their lawyers say they were sent into an unsafe environment without warning.
"They went to work to do their job," said attorney Brian Fritz. "Sunoco didn't do theirs. And, as a result, James and his co-workers' lives have been changed forever."
Sunoco says it can't comment on the lawsuit. But the company issued a statement about HF, saying the company "has invested $200 million dollars in improving the safety and reliability of the equipment involved in the use and storage of hydrofluoric acid."
Click to see an interactive map from ABC News on refineries that use HF.