Wyoming’s Department of Environmental Quality (DEQ) on Thursday finalized new standards aimed at reducing emissions from new and modified oil and natural gas facilities in the state.

The rules, which go into effect Feb. 1, would require oil and gas companies to check new facilities regularly for harmful emissions of smog and methane, including leaking natural gas that deprives the state of royalty and tax revenues. The standards incorporate successful requirements implemented three years ago in the state’s Upper Green River Basin (UGRB).

Most new drilling in Wyoming occurs outside of the UGRB and will be subject to the new standards, but 75% of the state’s existing oil and gas wells would not be covered by the new standards.

“These standards only apply to wells that are new or modified,” a DEQ official said. “We have similar requirements for existing wells in the UGRB, which is a nonattainment area, but we have no plans currently to spread these requirements to existing wells statewide.”

DEQ’s decision “is an important step toward comprehensive statewide emissions reduction rules, and comes in the wake of federal attempts to weaken our nation’s pollution standards for new and modified wells,” said Jon Goldstein, regulatory and legislative affairs director for the Environmental Defense Fund (EDF).

EDF officials have pledged to work with the state and the new incoming administration on implementing the new standards. Goldstein said that oil and gas companies support the standards because they are “proven, affordable ways to reduce pollution and stop energy waste.”

John Robitaille, vice president with the Petroleum Association of Wyoming, said his members are supportive of the new DEQ standards.