GOLDEN, Colo. — Rocky Flats National Refuge is more than 5,000 acres of wild animals, wetlands and grasslands, with some of the best views of the Flatirons.

But the land, about 20 miles northwest of Denver, is notorious for its past.

“I’m so concerned,” Elizabeth Panzer said. “My major concern is disturbing the soil.”

That soil sits near what was a plant that made triggers for nuclear weapons for 37 years. It closed in 1989 and was cleaned up in 2005.

Numerous government studies say the refuge and area around it are safe.

But many people inside a Rocky Flats Stewardship Council meeting on Monday disagree.

“My son has a very rare cancer,” Panzer said. “Heart cancer. And we don’t know how he got it. And we don’t know if the causation is from the Rocky Flats contaminants.”

Panzer and her family have lived in the Five Parks neighborhood just south of the refuge for about 10 years.

She and others are worried that when the federal government opens 20 miles of hiking and biking trails on the refuge in the summer, it could make people sick.

“I’m concerned. I believe in it,” Elaine McNeely said. “There’s too much sickness. There were many people in our neighborhood that were sick.”

That includes McNeely’s husband Brian, who died from the same and rare cancer that Panzer’s son has, cardio angiosarcoma.

The Department of Energy’s site manager for Rocky Flats, Scott Surovchak, said there was nothing to concern him about the levels of nuclear and other contaminants at the refuge.

“I’m out there all the time,” Surovchak said. “My folks are out there all the time. If I was concerned about it, we wouldn’t be doing that.”