The federal government is encouraging farmers to spread a chalky waste from coal-fired power plants on their fields to loosen and fertilize soil even as it considers regulating coal wastes for the first time.

The material is produced by power plant "scrubbers" that remove acid-rain-causing sulfur dioxide from plant emissions. A synthetic form of the mineral gypsum, it also contains mercury, arsenic, lead and other heavy metals.

But don't worry, the Environmental Protection Agency says those toxic metals occur in only tiny amounts that pose no threat to crops, surface water or people. Whew!