Veterans who served at secret base say it made them sick, but they can't get aid because the government won't acknowledge they were there

In the mid-1980s, Air Force technician Mark Ely's job was to inspect secretly obtained Soviet fighter jets. 

The work, carried out in hidden hangers known as hush houses, was part of a classified mission in the Nevada desert, 140 miles outside of Las Vegas at the Tonopah Test Range — sometimes referred to as Area 52. The mission was so under wraps that Ely said he had to sign a non-disclosure agreement.

"Upholding the national interest was more important than my own life," Ely told CBS News, and that's not just talk.

Ely was in his 20s and physically fit when he was working at the secret base. Now 63 and living in Naperville, Illinois, he's confronting life-threatening consequences from the radiation he says he was exposed to.

For decades, the U.S. government conducted nuclear bomb tests near Area 52. According to a 1975 federal environmental assessment, those tests scattered toxic radioactive material nearby.  

"It scarred my lungs. I got cysts on my liver. ... I started having lipomas, tumors inside my body I had to remove. My lining in my bladder was shed," he said.

All these years later, his service records include many assignments, but not the mission inside Tonopah Test Range, meaning he can't prove he was ever there. 

"There's a slogan that people say: 'Deny deny until you die.' Kind of true here," Ely told CBS News.

Dave Crete says he also worked as a military police officer at the same site. He now has breathing issues, including chronic bronchitis, and he had to have a tumor removed from his back.

He spent the last eight years tracking down hundreds of other veterans who worked at Area 52 and said he's seen "all kinds of cancers."

While the government's 1975 assessment acknowledged toxic chemicals in the area, it said that stopping work ran "against the national interest," and the "costs... are small and reasonable for the benefits received."

Other government employees who were stationed in the same area, mainly from the Department of Energy, have been aided by $25.7 billion in federal assistance, according to publicly available statistics from the Department of Labor. But those benefits don't apply to Air Force veterans like Ely and Crete.

"It makes me incredibly mad and it hurts me too because they're supposed to have my back," Ely said. "I had theirs and I want them to have mine."

When contacted for comment, the Department of Defense confirmed Ely and Crete served, but would not say where.