National Geographic : 2014 Dec
Superfund 137 Denver. During World War II the U.S. Army made mustard gas at the site, which is about the size of Manhattan, and later the nerve gas sarin; the Shell Chemical Company produced the pes- ticide dieldrin there. Waste was shunted into a basin that became a black hole of contamination. When Sherry Skipper first arrived at the site as a young biologist in the early 1990s, she would often don booties, respirators, and goggles to check on starlings she was using, like canaries in a coal mine, to monitor pollution. The birds fed on worms and burrowing insects that accumulated dieldrin. Skipper remembers one damp spring in particular when the earth- worms emerged—and birds that ate them fell out of trees, convulsing. “That’s never going to happen again,” she said one day last winter. The place is now a wildlife refuge, and Skipper was riding around it with its manager, David Lucas of the U.S. Fish and Wildlife Service. It’s a wholly altered landscape. The chemical facilities were razed between 1999 and 2003 and covered with a “biota barrier”—ground-up tarmac from the old Denver airport topped by four feet of soil—to keep animals from burrowing into the contamination. Native prairie grasses now whisk water away from it. On the refuge’s fringes, wells block the spread of polluted groundwater. New town houses have sprouted on the border. With the Denver skyline as a backdrop, we watched for bald eagles—up to 80 of them roost here during winter. There are bison, prairie dogs, and mule deer. People should never live on the site itself, Skipper said. But there’s an upside to that. “What are the chances,” Lucas said, “that there’d be 16,000 acres right here in the middle of Denver—undeveloped, for wildlife—if it wasn’t a Superfund site?” j MORE ONLINE ngm.com/more INTERACTIVE GRAPHIC Not in Your Backyard? Type an address or zip code to find out how many miles you live from the nearest Superfund site—or sites.