WASHINGTON (AP) — The U.S. Environmental Protection Agency has tightened standards for the nation's landfills to reduce emissions of methane and other harmful air pollutants.

EPA estimates the new rules announced Friday as part of President Obama's Climate Action Plan will reduce methane from decomposing household waste by about 480,000 tons a year by 2025.

Landfills rank as the third-largest human-related source of methane, a potent greenhouse gas that contributes to global warming at 25 times the rate of an equivalent amount of carbon dioxide. Landfills also emit such toxic gasses as benzene, toluene and vinyl chloride.

EPA says implementing the new standards will cost about $55 million over the next decade.

A spokeswoman for the Solid Waste Association of North America said the industry group is studying the new standards before responding.