LAS VEGAS (AP) – An American Indian tribe living in the shadow of a coal-fired power plant outside Las Vegas is heading a legal push for more stringent emissions and air quality standards for the facility.

The Moapa Band of Paiute Indians, National Parks Conservation Association and Sierra Club is asking the 9th U.S. Circuit Court of Appeals in San Francisco to order the federal Environmental Protection Agency to beef up standards approved in August for the Reid Gardner Generating Station.

“Everything we’ve done so far, we’ve ended up with nothing,” William Anderson, chairman of the 320-person tribe, said Monday.

Anderson said he’s seen friends and neighbors sickened by soot, chemicals and ash waste produced by the three-unit, 557-megawatt plant built in the mid-1960s. Health officials have not verified those complaints because sample sizes of health studies are small.

EPA spokesman Mike Ardito in San Francisco said the federal agency could not comment on the legal case.

NV Energy Inc. officials didn’t immediately comment Monday. The publicly traded company has said the plant complies with federal and state laws, and provides enough electricity to power 335,000 Nevada households. It calls Reid Gardner a key component of a group of generating stations providing reliable electricity at a stable price for customers.

The EPA Clean Air Act standard adopted Aug. 23 didn’t address health concerns. It placed limits on emissions of nitrogen oxide, sulfur dioxide and fine particles blamed for regional haze in areas such as Grand Canyon, Joshua Tree and Zion national parks.

Anderson argued that a court order requiring installation of expensive pollution control measures could prompt NV Energy, the state’s dominant electric utility, to shut down the plant.

“We’ve advocated, we’ve gone to regulators, we’re building commercial-scale solar, but still the coal pollution and illness are here,” Anderson said. “We’ve seen coal at Reid Gardner become too costly to make economic sense, but still NV Energy doesn’t retire a plant that’s almost 50 years old.”

Conservationists spent years fighting a similar battle before Southern California Edison shuttered a 1,580-megawatt coal plant in December 2005 that opened in 1971 near the Colorado River resort town of Laughlin, about 100 miles south of Las Vegas. The plant’s distinctive 500-foot smokestack was imploded in March 2011.

The EPA issued its rules on the Reid Gardner facility just two weeks after U.S. Sen. Harry Reid, D-Nev., joined Moapa tribe members and the environmentalists calling for the plant to be closed.

Bill Corcoran, regional director of the Sierra Club’s “Beyond Coal” campaign, previously submitted to the Nevada state Public Utilities Commission a report that found closing the plant would save NV Energy and its ratepayers $59 million.

The commission is expected to issue a report this year on a company request to extend the lifespan of the plant. It is named for a former energy company employee not related to the U.S. Senate majority leader.

The appellate filing seeking more stringent air standards was submitted Friday and is being handled by Earthjustice, a San Francisco-based non-profit public interest law firm.

It asks the court to force the EPA to require NV Energy to upgrade to best-available emissions controls – called selective catalytic reduction – instead of using less-expensive measures.

“Cleanup of this old, dirty power plant is long overdue,” said Suma Peesapati, the Earthjustice attorney handling the case. “What the EPA has proposed does not protect the neighboring community of the Moapa Paiutes or the iconic beauty of the Grand Canyon.”