The U.S. Environmental Protection Agency on May 4 unveiled a draft rule to regulate coal ash, for the first time, under the Resource Conservation and Recovery Act. The proposal would require coal-fired powerplants to retrofit existing impoundments, which typically store ash in liquid form, with composite liners. It also would provide strong incentives to eventually close surface impoundments and shift to dry storage in landfills, EPA says. The new scrutiny follows a 2008 collapse of a Tennessee impoundment that spread ash over a 300-sq-mile area of land and water. Environmentalists claim contaminants in coal ash, such as mercury and arsenic, can leach into groundwater. But manufacturers of concrete say that fly ash has been recyled safely into concrete for years. EPA says it will retain an exemption for recycling and other “beneficial uses” of coal ash. The agency says it will accept public comment on the proposal for 90 days once it is published in the Federal Register.