ST. GEORGE — Opposition is mounting against a private company's plan to build a massive coal-fired power plant on 200 acres of federal land about 12 miles northwest of Mesquite, near Utah's border.

The proposed $1.2 billion Toquop Energy Project would generate 750 megawatts of electricity, enough to provide power to 75,000 homes in the Las Vegas and Phoenix area, according to the permit application filed by Sithe Global Power.

The company's original plan to build a natural gas-fired power plant changed to coal when gas prices escalated. A new environmental impact statement is now required, according to the Bureau of Land Management in Nevada.

Critics say the coal-fired plant would pollute the environment, contribute to global warming and create unnecessary health risks for residents of the region.

But Sithe Global Power spokesman Frank Maisano said the proposed plant would use the latest cleaning technology to prevent the drift of pollutants into Washington County. In addition, the company also signed a memorandum of understanding with the Nevada Division of Environmental Protection to make pollution control changes once the technology becomes commercially feasible.

But there are plenty of folks who don't believe that statement, or any others made by the privately held energy company.

Casey DeMoss Roberts, executive director of Global Health Inc., a St. George-based nonprofit group, said the power plant would ruin southern Utah's environment.

"If the Toquop coal plant is issued a permit, that will mean 50 to 60 years of pollution for southern Utah. Neither our residents nor our tourist economy can afford it," DeMoss Roberts said.

An online petition hosted by Citizens for Dixie's Future also seeks to have the coal-fired plant permit denied. So far, hundreds of people in Utah and Nevada have signed the petition, voicing concern for the future of the region's air quality if the plant is built.

"You claim your plant is 80 percent cleaner than all others?" writes Kris Neal of Washington County. "We don't want the 20 percent dirty air in our area."

Lin Alder, executive director of the citizen's group, said he plans to deliver the petition to BLM officials before the Dec. 11 public comment deadline on the project.

"The residents of Washington County have spoken very clearly through Vision Dixie," said Alder. "In that process, 'protecting air quality' ranked No. 1 among 16 options for government priorities."

The group's petition asks Utah Gov. Jon Huntsman Jr. and the Utah congressional delegation to put pressure on Nevada to deny the power plant permit.