WASHINGTON -- The Bush administration next week will roll back clean air regulations and allow old, coal-fired power plants and oil refineries to emit more air pollution, an environmental activist group said today.

The Environmental Protection Agency is set to issue a final rule that would make it easier for industrial facilities to upgrade their plants without having to install expensive equipment to fight air pollution, the activist group said.

The new rule would allow facilities to avoid installing pollution controls when they replace equipment -- even if the upgrade increases pollution -- as long as the cost of the replacement equipment did not exceed 20 percent of the cost of what the EPA broadly defines as a "process unit," according to the Natural Resources Defense Council.

"Corporate polluters will now be able to spew even more harmful chemicals into our air, regardless of the fact that it will harm millions of Americans," said the NRDC, which obtained a leaked copy of the EPA's final rule.