An Ohio power plant on Monday became the first utility to go on trial over government accusations it has caused smog and health problems as far away as the Northeast.

The Justice Department has accused 51 utilities in the Midwest and South of rebuilding old power plants without installing state-of-the-art pollution controls required under the Clean Air Act.

The lawsuit against FirstEnergy Corp.'s W.H. Sammis plant, near Steubenville in eastern Ohio, is the first involving a utility to go to trial. The government said FirstEnergy did not install appropriate pollution controls when it did work on the Sammis plant between 1984 and 1998.

"They should have considered the implications of what they were doing. They didn't and that's why we're here today," Jon Mueller, a Justice Department lawyer, told U.S. District Judge Edmund Sargus in his opening statement.

FirstEnergy argued that the work at the plant along the Ohio River was routine maintenance that did not require the additional pollution controls.

"The work did not cause or result in an emission increase," said Mason Evans, an attorney with FirstEnergy.

The government said pollution from plants in the Midwest and South winds up in Northeastern states where it causes acid rain, smog and health problems such as respiratory and heart problems.

In November, the Bush administration announced it was easing clean air rules, saying they deterred companies from implementing projects that would increase energy efficiency and decrease air pollution.