The documents may have evidence of residual plutonium contamination and other ongoing environmental dangers.
The wildlife refuge's past as a Superfund site has caused concern among environmental groups.
Congressman Jared Polis asked the federal government to keep Rocky Flats National Wildlife Refuge closed. Fish and Wildlife plans to open the refuge regardless.
The buffer zone surrounding the former trigger manufacturing site was turned into a refuge that the government intends to allow trail access to.
A retired professor claims he has evidence of plutonium particles contaminating the refuge. Government lawyers counter that the EPA has since determined the area was safe.
The town of Superior asked a federal judge to keep the U.S. Fish and Wildlife Service from opening Rocky Flats National Wildlife Refuge
A U.S. official harshly criticized a Colorado health officer who questioned the safety of a former nuclear weapons plant that was converted into a wildlife refuge.
The area, set to open to the public this summer, is one of the few nature spaces within 30 miles of Denver.
Five environmental groups are seeking a court injunction to halt construction of hiking and biking trails at the Rocky Flats Wildlife Refuge.