ALBUQUERQUE, N.M. (AP) -- Gov. Bill Richardson and Attorney General Gary King want the U.S. Environmental Protection Agency to ensure that a proposed coal-fired power plant in northwestern New Mexico has the best technology to deal with hazardous pollutants before construction on the plant can begin.

Under the federal Clean Air Act, the EPA has to review the Desert Rock Energy Project's maximum achievable control technology, or MACT, before work can start on 1,500-megawatt plant.

Richardson and King, however, are asking the EPA to make that determination as part of the air permitting process, though the agency is not legally required to.

"Doing so provides for enforceability of the MACT requirements while ensuring the compatibility of those requirements with the design parameters specified in the PSD (air) permit," they wrote in a joint letter to the EPA on Thursday.

The air permit would set limits for emissions such as sulfur dioxide, nitrogen oxides, carbon monoxide, particulates and lead emissions. The MACT determination would look at pollutants such as lead, arsenic and mercury.

Mary Uhl, bureau chief of the state Environment Department's Air Quality Bureau, said some hazardous pollutants, such as mercury, contain particulates that are covered under the air permit.

"If you don't tie the two together, you're getting an inaccurate or incomplete picture of the control technologies that will be put on the plant," she said.

An EPA spokeswoman in San Francisco, Margot Perez-Sullivan, said the agency has received the letter and will formally respond in a timely manner.

She said distinguishing the air permit and MACT processes "is the right way to do it." She declined to comment further.

Houston-based Sithe Global Power and the Dine Power Authority, an enterprise of the Navajo Nation, are partnering on the $3 billion Desert Rock plant to be built on tribal land south of Farmington.

The EPA has said it will issue a decision on the air permit by July 31 as part of a settlement of a lawsuit developers brought against the agency for delaying action on the permit.

Desert Rock proponents say the plant's technology would be cleaner and more efficient than that used in current coal-fired power plants.

"The reality is this power plant has the most advanced technology that you can have for a power plant," said Sithe spokesman Frank Maisano.

While the developers are touting the technology, the state said Sithe refuses to consider real advances that would combat global warming.

"It's premature to say this is the best technology out there because that is a determination EPA has to make," said Phil Sisneros, a spokesman for King.

Richardson and King are asking that the EPA acknowledge its obligation to make the MACT determination and identify the procedure it will follow.

If EPA does not complete the MACT determination before it acts on the air permit, the New Mexico officials want the EPA to reconsider the permit to incorporate any modifications that might be brought up in the MACT determination.

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