The Navajo and Hopi tribes joined forces to oppose the proposed closure of a coal-fired power plant in northern Arizona.
Leaders said Thursday that keeping the Navajo Generating Station in full operation benefits the tribes and state because it is an important economic driver.
The Navajo Generating Station is near Page and employs 500 people, mostly Navajo.
The federal Environmental Protection Agency announced in 2014 that the plant could either shut down one of its three 750-megawatt units or reduce power generation by an equal amount by 2020 to cut haze-causing pollution at places like the Grand Canyon. Additional emission control equipment would be needed by 2030 on the two remaining units.
The Navajo Nation says it has a task force that meets with SRP officials to discuss other solutions.