PacifiCorp’s Wyodak coal-fired power plant near Gillette and its Naughton coal-fired power plant near Kemmerer are in compliance with federal requirements to reduce pollutants that contribute to regional haze, according to a ruling by the Tenth Circuit Court of Appeals.
The Aug. 15 ruling, which sided with state and federal environmental regulators, settles two separate disputes that were combined into one case before the court.
The first was a dispute between the Wyoming Department of Environmental Quality and the U.S. Environmental Protection Agency over the state’s “implementation plan” to meet regional haze controls at Wyodak. EPA alleged the state’s plan was too lenient and didn’t meet federal guidelines. But the court sided with the state, ruling the EPA overstepped its authority where the state has discretion to determine compliance methods — particularly for coal plants with a capacity to generate less than 750 megawatts of power.
The Wyodak plant has a maximum generation capacity of about 335 megawatts.

The second matter was a challenge by conservation groups to force the EPA to insist on more stringent controls for the two remaining coal-burning units at Naughton. The court ruled against the petitioners, asserting that both EPA and the state had developed a plan that satisfies federal regional haze requirements.
Gov. Mark Gordon hailed the court’s decisions — particularly regarding Wyodak — as a “key court victory,” he said in a prepared statement. The state met federal regional haze regulations in a more cost-effective manner than proposed by the EPA, he added, and therefore spared Wyoming ratepayers an unnecessary expense.
“It is gratifying that the court recognized this example of federal overreach into what is the rightful domain of the State of Wyoming,” he said.
The court’s ruling is a disappointing setback, said Jenny Harbine, an attorney for Earthjustice’s Northern Rockies regional office who helped argue the case on behalf of conservation groups.
“It reflects a missed opportunity to gain some significant, immediate pollution reductions from the Wyodak and Naughton coal plants,” Harbine told WyoFile. “However, it’s not the end of the story.”
Regional haze
Both disputes stemmed from more than a decade of wrangling among multiple utilities, the state, EPA and several conservation groups. The parties were at odds over how Wyoming can best decrease visibility-reducing pollutants from coal plants to improve airsheds over specific federal lands in the region that fall under the 1999 Regional Haze Rule of the federal Clean Air Act.
Regional haze, in a regulatory context, is the degradation of visibility via human-caused emissions that diminish the characteristics and enjoyment of a landscape, according to EPA.

The federal Regional Haze Program focuses on reducing industrial emissions to help improve viewsheds, particularly in national parks and wilderness areas. For the Naughton plant, those include Yellowstone and Grand Teton national parks, as well as the Fitzpatrick, North Absaroka, Washakie and Teton wilderness areas. For Wyodak, they include the Badlands and Wind Cave national parks.
Wyoming and neighboring states are home to some of the nation’s most iconic national parks, and existing regional haze diminishes people’s experiences in those places and cuts down on return visits, said Ulla Reeves, clean air program director for the National Parks Conservation Association. “Wyoming’s pollution does not stay within its borders,” Reeves told WyoFile. “It’s traveling to many other states and places, including the Badlands and Wind Cave and Rocky Mountain [national parks].”
Particulate matter and nitrogen oxides are the primary coal plant emissions targeted by the federal regional haze effort. The pollutants also pose risks to human health and the environment.
Although regional haze authority lies with the EPA, participating states hold primacy over implementing it. In other words, EPA sets baseline or minimum standards and Wyoming DEQ works with federal permittees in the state about how to meet or exceed them.

Wyoming DEQ and the EPA spent the past 10 years hashing out disagreements and deals regarding Wyodak, Naughton and many other coal-fired power plants in the state — including Laramie River Station on the eastern border and Jim Bridger outside Rock Springs.
More wrangling to come
The federal regional haze program is intended to make continual improvements to visibility over national parks and wilderness areas. States are required to submit a new regional haze plan every 10 years.
The phase of the program addressed by the appellate court on Aug. 15 focused on “best available retrofit technology.” The EPA and participating states have already shifted to the next phase, which requires “reasonable progress goals.”
“States are supposed to be making reasonable progress toward reducing their haze pollution,” Reeves said. “So [EPA is] looking for kind of a continuous trajectory to make steady improvement in air quality over time for the parks.”
Wyoming DEQ submitted its draft plan for the next phase in the program in 2022.

“We feel that it is another terrible plan,” Reeves said. “They have not [proposed requiring] any new pollution controls from any of the coal-fired power plants. Jim Bridger, Dave Johnston, Laramie River Station, Wyodak — along with a whole host of mines — they all still [emit] regional haze pollution that should be cleaned up.”
Harbine of EarthJustice said the EPA should learn from the previous phase of the regional haze effort that resulted in many delays and shortcomings to reduce more regional haze emissions.
“Congress did not give states or the industry the option of simply not complying by not reducing their haze-causing emissions,” Harbine said. “I fear that that might be what the industry is after.”
For its part, PacifiCorp, which operates as Rocky Mountain Power in Wyoming, has signaled a shift from fossil fuels to more renewable energy resources — a move that will likely forego some investments to scrub haze-contributing emissions from its existing power facilities.
The utility plans to convert its remaining coal-fired units at Naughton to natural gas in 2026. A row with EPA in 2022 nearly resulted in a partial, forced closure of the Jim Bridger plant due to the utility’s failure to add haze pollution controls. The utility later promised to operate two of four coal-burning units there at lower capacities in order to emit fewer regional haze pollutants, then convert the units to natural gas in 2024.
Preparations are already underway to convert the units, the company said.
PacifiCorp, however, plans to continue burning coal at Wyodak beyond 2030. It plans to comply with regional haze efforts by installing selective non-catalytic reduction scrubbers at the plant in 2026.
Reeves said the National Parks Conservation Association will continue to push for more regional haze reductions, including at natural gas-fired facilities, cement plants, mines and other industrial emitters in Wyoming.
“There’s still an opportunity for Wyoming to do the right thing,” she said. “There is still plenty of opportunity for EPA to make defensible determinations that require Wyoming to clean up the many sources of haze pollution that are still uncontrolled.”
I grew up in Gillette from 1970 to 1983. Wyodak was always visible from my elementary school unless it was a hazy day. The haze was not caused by Wyodak. Haze is caused by high humidity and smoke. When forest fires in other states west of Gillette occurred, the visibility of Wyodak was reduced. Haze occurs from high humidity and the visibility-reducing effects of haze are increased with the presence of forest fire smoke in the air. Almost zero smoke comes out of the exhaust of the coal-fired scrubbers on Wyodak. The emissions are mostly water vapor and the highly necessary compound for photosynthesis, carbon dioxide. The water vapor emitted by Wyodak is a sight to see when it is released into the atmosphere and the dew point temperature is high enough to cause a cloud to form. The cloud quickly dissipates and turns into water vapor after it reaches an altitude of around 100 feet or less. Sometimes photographers, who want the best shot of using the cloud as a sensational propaganda picture to portray it as smoke and pollution will position their camera from underneath the cloud. The best time of day to get this angle is at dawn or dusk; however, a talented photographer can get the desired picture as long as the sun is above the could the camera is below the cloud and the backlight is blocked from the cloud, making it appear as dark smoke. These types of photos can be used to sensationalize a claim that the coal plant is a mass polluter and is responsible for causing haze and pollution. This summer the haze was caused by Canadian Wildfires and fires in more western states. Hopefully these conservation groups will not try to blame the haze this summer on Wyodak.
The haze at Yellowstone and Teton national parks has nothing to do with these two power plants due to their location to the parks!! Maybe the conservationists ought to look to the west coast where there conservation efforts have created massive fuels for wild fires!!!
Well, this is not good news. Cheering means more pollution and we need to be moving forward, not backwards
I have an image of the Wyoming emissions being spun like wool from the haze. The spun wool rises to knit itself with other global emissions, thickening the atmospheric blanket that bakes our children’s world. I am so angry that a man like the Gov., trained at Middlebury with access to all the climate science of UW researchers, invokes a talking point about Federal overreach to celebrate Wyoming’s capacity to sell it soul, promoting emissions that lead in only one direction: hotter. Who throws another blanket on a febrile infant as a congratulatory gesture for local leadership? Is it really that hard to imagine ourselves as the people who shoulder the responsibility to cool it? We need everyone on board, now, for rapid transition.
Tick tock, planet Earth
bravo !