Silver Bow Creek/Butte Area, Montana
One of the largest Superfund sites, the Silver Bow Creek/Butte area features more than 500 underground mines and four open-pit mines, including the Berkeley Pit (pictured) with its ancillary tailings ponds, waste dumps and acid leach pads. This pit — which has since been flooded with acidic, metal-contaminated water — might just be the pit from hell. The water contains so much dissolved metal that materials can be mined directly from the water. In 1995, a flock of migrating snow geese died in the Berkeley Pit. Necropsies found the acid water had eaten away at esophageal tissue and damaged internal organs.
The area, designated a Superfund site in 1983, has become such a symbol for toxicity that it has been turned into a tourist attraction.
A water treatment plant now stands along the pit, capable of treating 5 million gallons of water per day. Even so, it's a race against time, as the water level is expected to reach the natural water table by 2020, which means mine water will spill into the local groundwater.