Yesterday the U.S. Environmental Protection Agency announced a record $4.6 billion settlement with American Electric Power in a lawsuit brought by eight northeastern states and a number of environmental advocacy groups. The Ohio-based company also agreed to install pollution controls in order to reduce air pollution coming from its facilities, including coal-burning plants in Virginia, West Virginia and Kentucky.

"Less air pollution from power plants means fewer cases of asthma and other respiratory illnesses," said Granta Nakayama, assistant administrator for EPA's enforcement and compliance assurance program.

It's true that the settlement reached with the company will allow millions of people to breathe cleaner air. But it also raises a question: What will the company do with the additional coal combustion waste collected after installing more effective emissions controls?

The EPA currently does not regulate coal combustion waste as hazardous waste, and this lack of regulation is creating serious environmental problems. Across the South and the nation, coal combustion waste landfills and surface impoundments have released to the environmental toxic chemicals and metals including arsenic, lead and cadmium at levels dangerous to human health. At least 23 states including Texas, Virginia, North Carolina and South Carolina have poisoned surface or groundwater supplies from the improper disposal of coal ash. As we reported last month, the agency recently released a draft risk assessment on coal combustion waste disposal that found unlined coal ash waste ponds pose a cancer risk 900 times above what the government considers acceptable.

Environmental advocacy groups have been urging EPA to begin regulating coal combustion waste as hazardous waste, and the agency is now accepting public comments on the matter. The AEP settlement and the additional waste the company's cleanup efforts will create highlight the importance of addressing this environmental hazard soon.