What may be the nation's largest spill of coal ash lay thick and largely untouched over hundreds of acres of land and waterways Wednesday after a dam broke this week, as officials and environmentalists argued over its potential toxicity.
Federal studies long have shown coal ash to contain significant quantities of heavy metals such as arsenic, lead and selenium, which can cause cancer and neurological problems. But with no official word on the dangers of the sludge in Tennessee, displaced residents spent Christmas Eve worried about their health and their property and wondering what to do.
The spill reignited a debate over whether the federal government should regulate coal ash as a hazardous material. Similar ponds and mounds of ash exist at hundreds of coal plants nationwide.