The U.S. Department of Interior said approval of Santee Cooper's proposed $1 billion coal-fired power plant needs to be put on hold until a comprehensive analysis is done of potential damage to the Cape Romain National Wildlife Refuge from mercury fallout and other air pollution that the plant would generate.

The department's Fish and Wildlife Service recommends that Santee Cooper abandon plans for a standard coal burning plant and possibly replace it with a modern coal gasification plant, a more expensive process that releases far less air pollution.

Only a few such plants are in operation in the world, but the wildlife service said more are being constructed in the U.S. and more are in planning stages as several states push to reduce air pollution and cut emissions that contribute to global warming.

Lonnie Carter, Santee Cooper's president and chief executive officer, told The Post and Courier in an earlier interview that the proposed plant is the only feasible way to supply the amount of electricity needed by 2012 and that without it, lights could go out. He called coal gasification too experimental to rely on, and that the proposed plant would be one of the nation's cleanest.

Laura Varn, the power company's head of communications and media relations, said Santee Cooper was aware of the interior department's comments and considers them to be part of the review and comment process on getting the plant approved. She said the company is pleased that interior gave the proposal such a thorough evaluation. Varn also said that today Santee Cooper will outline further steps it plans to take to reduce its dependence on coal and make nuclear and non-greenhouse producing fuels account for 40 percent of its power generation by 2020. Santee Cooper currently gets 13 percent of its electricity from nuclear, hydro and other power sources.

The state Department of Health and Environmental Control has issued a preliminary air pollution permit for the plant to be built in Florence County and will make a decision on whether to grant the permit after time for public comment is cut off in late January.

The Fish and Wildlife Service expressed its concerns about the plant in two letters obtained this week by The Post and Courier.

In a letter dated Sept. 11, Fish and Wildlife urged DHEC to make no decisions permitting any aspect of the plant until "a comprehensive and adequate review of the project and its affects to the environment, the atmosphere, and the quality of human life is conducted."

In a second letter, dated Oct. 3, the service said the project's air pollution emissions, particularly mercury and sulfur dioxide, pose threats to several state and federal wildlife sanctuaries, including the Cape Romain and Waccamaw national wildlife refuges.

The letter said much of South Carolina's coastal forest and the dune and marsh grasses in the Cape Romain refuge could be damaged by increased levels of acid rain due to the sulfur releases.

In addition, the letter urges DHEC to fully analyze the effects of increased mercury fallout from the plant into rivers already contaminated with enough mercury that the state warns people not to eat fish caught in some of the waters.

The Cape Romain refuge, 60 miles southeast of the proposed plant, is designated as a "Class 1" area under the U.S. Clean Air Act, which requires that such areas get additional air quality protection.

DHEC spokesman Thom Berry said the agency is preparing a response to the letters and plans to talk with Santee Cooper about conducting additional tests that only the company can do. Berry declined to elaborate on the response or the additional tests.

Mercury pollution from the proposed plant became a special concern for environmental groups and some residents in the Pee Dee region in late October when The Post and Courier revealed that it had conducted tests on people who eat fish from two of the most mercury contaminated rivers in the state. The newspaper discovered that nearly half of those tested had mercury levels exceeding the government's safety margin. Above that level, mercury can cause major health problems, including brain damage. DHEC has tested mercury levels in fish for decades but doesn't test people, preferring only to warn them to not eat or to limit the amount of certain fish they eat from the state's rivers and coastline.

On Thursday, four doctors from Florence County urged the state to begin testing people for mercury, especially people living in or near the so-called mercury triangle, an area between the Little Pee Dee and Lynches rivers, where fish have the highest mercury readings.

DHEC spokesman Adam Myrick said the agency is reviewing the doctors' request to test people.

Dr. Ken Kammer, one of the physicians, said in a statement, "The agency now knows, thanks to publicized laboratory findings, that citizens in this state have dangerously high levels of mercury in their bodies. Given mercury's toxic effects, this is a clear health problem."