Santee Cooper may have to close older coal-fired power plants — including some generating units in Moncks Corner — because of a new federal crackdown on toxic mercury pollutants, The State newspaper reported today.

Also at risk is a power generator in Conway under a rule that took effect Wednesday.

"There is a good chance it is going to mean we need to close some of our generating units," said Mollie Gore, a spokeswoman for state-owned Santee Cooper.

Gore told The State on Wednesday that it would not be worth the cost of installing modern pollution-control equipment at some of the state-owned utility's older coal-fired plants. She noted that the most likely candidates for closure would be the Grainger power station in Conway and some units at the Jefferies plant in Moncks Corner.

She added: "We can't really answer questions about the impact on our other coal-fired units ... until we've had a little more time to look at it, although we do expect compliance will be very expensive, and unfortunately our customers will end up footing the bill."