ALBUQUERQUE, N.M. (AP) – Federal regulators' decision to require more pollution controls at a coal-fired power plant that serves customers throughout the Southwest amounts to a “burdensome” mandate that could affect the Navajo Nation, the tribe's president said in a letter released Friday.

Navajo President Ben Shelly used the letter to the U.S. Environmental Protection Agency to outline the tribe's concerns over the agency's recent decision to require the San Juan Generating Station to install top-of-the-line emission-cutting technology.

In making the decision, the EPA rejected the state of New Mexico's plan for curbing haze-causing pollutants at the plant.

The state and the plant's operator, Public Service Company of New Mexico, are appealing the decision. They argue that the agency overlooked the state's plan and that the federal plan would result in similar improvements but at a much higher cost.

Shelly said the tribe, which spans parts of New Mexico, Arizona and Utah, supports the state and PNM's efforts to seek a stay in the case.

The Navajo Nation also disagrees with the EPA that its plan would not have an adverse effect on the tribe.

“The issuance of a finding that EPA's enormously burdensome decision has no impact upon the economic health of the Navajo Nation merely because the plant is located on non-tribal lands ignores the reality of the culture, geography and economics of the Four Corners area,” Shelly said in the letter.

Regional EPA officials did not immediately respond to a request for comment.

Shelly pointed to filings in the case that show portions of the workforce at the power plant and the coal mine that feeds it are tribal members. In fact, the power plant employs 85 Native Americans, and the adjacent mine employees another 635 Native Americans.

Shelly's chief of staff, Sherrick Roanhorse, said the tribe has already had several meetings with the EPA regarding the regional haze plan for the plant.

While the tribe is hopeful that industry can reduce emissions within a reasonable timetable, Roanhorse said it should be done with the least amount of economic impact as possible.

He added that the Navajo Nation considers itself a neighbor of Farmington, Aztec and Bloomfield, and that the plant and mine are important to the entire community.

“Our concern is to protect existing jobs within the area. Our concern is the families who depend on the plant for income,” he said.

Pat Themig, PNM vice president of generation, welcomed the Navajos' support. He said it was clear, as Shelly's letter notes, that New Mexico's plan for limiting emissions would meet federal standards and improve visibility while considering the economic implications for the region.

PNM has estimated the EPA mandate will cost the plant's owners $750 million to $1 billion, although environmental groups dispute those numbers.

Environmentalists and health groups support the EPA. They have argued that the state's plan would reduce 20 percent of the plant's nitrogen oxide emissions, compared with 80 percent under the EPA plan.

–––

Follow Susan Montoya Bryan on Twitter: http://www.twitter.com/susanmbryanNM