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Press Release

Wyoming & Kansas Refiners Agree to Settle Clean Air Act Violations

For Immediate Release
Office of Public Affairs

WASHINGTON—Two petroleum refiners have agreed in separate settlements to spend a total of more than $141 million in new air pollution controls at three refineries in Kansas and Wyoming, Justice Department and U.S. Environmental Protection Agency (EPA) announced today.  The settlements are expected to reduce harmful emissions by 7,000 tons per year.

Frontier Refining and Frontier El Dorado Refining (Frontier) have agreed to pay a civil penalty of $1.23 million and spend approximately $127 million in pollution control upgrades for alleged violations at its refineries in Cheyenne, Wyo., and El Dorado, Kan.   Wyoming Refining Co. (WRC) has agreed to pay a civil penalty of $150,000 and spend approximately $14 million in similar upgrades for alleged violations at its Newcastle, Wyo., refinery.

The state of Wyoming joined the federal government in the agreement with WRC.  Both the states of Wyoming and Kansas joined the federal government in the agreement with Frontier.

The three refineries are required to install advanced control technologies that, when fully implemented, will reduce annual emissions of sulfur dioxide by approximately 3,775 tons, nitrogen oxide by approximately 2,100 tons and other pollutants by approximately 1,200 tons.  The refineries have a combined production capacity of approximately 168,000 barrels per day.

In addition, each refinery will upgrade leak-detection and repair practices to reduce harmful emissions from pumps and valves, implement programs to minimize the number and severity of flaring events and adopt new strategies for ensuring continued compliance with benzene waste requirements under the Clean Air Act.  Flaring, the process by which byproduct-gas from the refining process is burned off, can cause respiratory problems and exacerbate asthma.

As part of the settlement, Frontier agreed to implement environmentally-beneficial projects valued at more than $1.3 million, including several projects at its refineries to reduce volatile organic compound (VOC) emissions by installing dome covers on refinery storage tanks.  VOC’s are a prime ingredient in the formation of smog.  

“Today’s agreements will bring three important refineries, two in Wyoming and one in Kansas, into compliance with the Clean Air Act,” said John C. Cruden, Acting Assistant Attorney General for the Justice Department’s Environment and Natural Resources Division. “The settlements, done in coordination with the states of Wyoming and Kansas, require new pollution controls, reduce significant amounts of air pollutants, secure sizeable penalties, and will ultimately benefit the environment and impacted communities.”

“Today’s settlements demonstrate EPA's continuing efforts to reduce emissions of nitrogen oxide and sulfur dioxide, which are the largest sources of pollution from refineries,” said Catherine McCabe, Acting Assistant Administrator for EPA’s Office of Enforcement and Compliance Assurance. “Nitrogen oxide and sulfur dioxide can cause severe respiratory problems and contribute to childhood asthma, smog and haze, as well as other health and environmental effects.”

The settlement requires Frontier to correct deficiencies in the refinery's risk management program that were identified during a 2006 EPA inspection. These deficiencies included overdue inspections and tests of storage vessels containing toxic and flammable substances. 

Under the Clean Air Act, facilities that handle large amounts of chemicals are required to develop a risk management program, which assesses the hazards associated with dangerous chemicals.  The program must include an accident prevention program and an emergency response plan to deal with accidental releases. 

Today’s agreements are the latest in a series of comprehensive, company-wide settlements under an EPA initiative to reduce air pollution from refineries nationwide.    With today’s settlements, 99 refineries operating in 29 states, or 88 percent of the nation’s refining capacity, have agreed to federally-enforceable judicial consent decrees that will significantly reduce emissions and achieve compliance with the Clean Air Act.

The consent decrees, lodged today in the U.S. District Courts in Kansas and Wyoming, are subject to a 30-day public comment period and approval by the federal court.   Copies of the consent decrees are available on the Department of Justice Web site at:

Updated April 4, 2024

Press Release Number: 09-105