It seems like a wilderness paradise, replete with mule deer, bald eagles, and foxes — but Colorado’s Rocky Mountain Arsenal is also a Cold War relic contaminated by years of chemical weapons production. The 27-square-mile patch of land just 10 miles outside of Denver bears the paradoxical dual designation of National Wildlife Refuge and Superfund site. Cleanup of the area, which once produced and stored mustard gas, sarin, and other deadly chemicals, is expected to cost $2.2 billion; the ultimate goal is the restoration, by 2011, of the high-plains wetland and the construction of an urban wildlife center. As recently as October 2000, crews discovered 10 nerve-gas “bomblets” on the site, each containing liquid sarin and an explosive charge. Public access to the area was immediately restricted, but could open again as early as late summer.