By J.F. Meils and Julie Depenbrock, CAPITAL NEWS SERVICE

Maryland Gov. Larry Hogan announced a lawsuit Wednesday against the federal Environmental Protection Agency for failing to enforce limits on air-pollution control at 19 mostly coal-fired power plants in five states upwind of Maryland.

"We want the EPA to step in and make sure provisions of the Clean Air Act are followed," said Ben Grumbles, Maryland's secretary of the environment. "This is necessary to protect air quality and the Chesapeake Bay."

The 19 plants have installed "smog controls," according to the Maryland Department of the Environment. "But they're not always running them when they should be," Grumbles said. About one-third of the nitrogen that ends up in bay waters comes from "air sources," according to the EPA, which did not respond to multiple requests for comments by press time.

The original petition to the EPA requesting that the agency regulate the plants -- in Ohio, Kentucky, Pennsylvania, Indiana and West Virginia -- was filed by the MDE in November. The EPA granted itself a six-month extension on the original 60-day deadline. By July, the agency still had not responded to the petition. The Hogan administration and MDE contend the power plants in question have not "effectively" operated their pollution control systems during the summer months, also known as "ozone season," and some have not used their pollution control systems at all.

Although most parent companies of the power plants cited in the Maryland petition did not respond to requests for comment by deadline, the Tennessee Valley Authority, which operates Paradise, a coal-fired plant in Kentucky, challenged Maryland officials' claims.

"We do have emissions controls. They run when the plant is operating," said Jim Hopson,TVA's manager of public relations, who said he was not aware of the Maryland lawsuit. "They reduce sulfur dioxide and nitrous dioxide levels in excess of 90 percent and they eliminate particulate matter...All of our plants have those."

The EPA defines the ozone season for Maryland and all the states named in the EPA petition as April through October, with the exception of Indiana, whose ozone season is April through September. Ozone levels are believed to be at their worst during the summer on sunny, hot days, particularly in urban environments, according to the EPA. "Pollution from out-of-state power plants also harms our in-state streams, rivers and the Chesapeake Bay," said Jon Mueller, vice president of litigation at the Chesapeake Bay Foundation, which plans to file a similar lawsuit with partners in the coming weeks. "Studies show nitrogen oxides from coal plant emissions degrade our water, and harm our fish and other aquatic life."