The owners of nearly two dozen coal-burning (search) power plants could face lawsuits from the Environmental Protection Agency for clean air violations stemming from plant expansions or improvements, according to agency officials and documents.

The EPA (search) and the Justice Department are considering actions against operators of 22 plants for alleged violations of a regulation that the Bush administration has been trying to scale back and make less burdensome to industry.

The rule requires utilities to install additional pollution controls when making expansions or improvements that result in more emissions (search). Utilities have argued the rule has been abused by regulators targeting routine, needed maintenance.

No decision on whether to file the lawsuits has been made but at least 14 of the cases have been turned over to the Justice Department for possible action, said an EPA official, speaking on condition of anonymity because the cases are pending.

Some cases may be settled before going to court or possibly dropped, the EPA official and industry sources said.

A list of the utilities being targeted was obtained by The Associated Press.

The enforcement agenda represents five years of preparation by EPA staff to identify alleged clean air violations under the so-called "new source review" requirements of the Clean Air Act. Among the targets are some of the country's largest utilities.

Neither the EPA nor the Justice Department would confirm or deny on the record the pending enforcement actions.

"We will not discuss ongoing enforcement investigations," said EPA spokeswoman Cynthia Bergman.

Justice spokesman Blaine Rethmeier said the department had no comment on pending cases, but he added, "We are vigorously prosecuting all the (new source review) cases" before the department.

The Clinton administration brought nine cases involving 51 power plants under the rule, and another six cases had been filed since then, even as the Bush administration has sought to make the regulation less stringent. Seven of those 15 cases have been settled.

The new wave of enforcement cases involve power plants across the country from New York to North Carolina, Florida and Mississippi, as well as Indiana, Michigan, Colorado, California and Oregon, among other states.

Among them are plants owned by the federally owned Tennessee Valley Authority; Atlanta-based Southern Co. subsidiaries Gulf Power in Florida and Mississippi Power; Pacific Gas & Electric in California; and PacificCorp in Oregon.

Another eight cases are still under review at the EPA. These include possible actions against Michigan-based Consumers Energy, Indian Power and Light and Westar Energy in Kansas, Northern Indiana Public Service Corp. and Minnesota-based Xcel Energy, according to the EPA list and agency officials.

The enforcement cases involve regulations that have been strongly criticized by the White House and have been the target of an intensive overhaul within the EPA because of arguments by industry that they have hindered plant maintenance, expansion and efficiency.

In December, a federal appeals court blocked the Bush administration's planned changes in the "new source review" rules until a lawsuit filed by more than a dozen states challenging the changes can be fully considered.

In the meantime, EPA Administrator Mike Leavitt has said he favors vigorously prosecuting violators of the rules, including cases filed by the Clinton administration as well as any new cases that have merit.

Scott Segal, a spokesman for the Electric Reliability Coordinating Council, a utility group, said a decision to pursue these new cases "creates more uncertainty" and will further prompt utilities to put off needed maintenance and efficiency improvements for fear of lawsuits.

But environmentalists have criticized the EPA for not adequately enforcing the regulations, which they argue would significantly reduce smokestack emissions if aggressively enforced.

"We have 150 million people exposed to unhealthy air in the country. Yet these utilities are being allowed to circumvent their clean air obligations," said William Becker, executive director of two associations that represent state and local air pollution control officials.