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, the U.S. Environmental Protection Agency and the Justice Department announced Tuesday.

The settlements are expected to reduce harmful emissions by 7,000 tons annually.

Frontier Refining agreed to pay a civil penalty of $1.23 million and spend about $127 million in pollution control upgrades for alleged violations at its refineries in Cheyenne and in El Dorado, Kan.

Wyoming Refining Co. agreed to pay a civil penalty of $150,000 and spend about $14 million in similar upgrades for alleged violations at its refinery in Newcastle.

"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.

As part of the settlement, Frontier agreed to spend more than $1.3 million on pollution control upgrades, including dome covers on refinery storage tanks to reduce volatile organic compound emissions. VOCs are prime ingredients in the formation of smog.

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

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.

"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," Cruden said.