The Pennsylvania Department of Environmental Protection (DEP) has indicated that it could advance federal recommendations for reducing smog-forming volatile organic compounds (VOC) for the oil and natural gas industry as a way to better address methane emissions from existing sources in the state.

The agency has previously said it would work with, or even enhance, the control technique guidelines (CTG) for addressing VOCs that were issued by the U.S. Environmental Protection Agency (EPA) late last year to curb emissions from existing oil and gas sources. But it gave the clearest indication yet in a recent presentation before the state Air Quality Technical Advisory Committee that it would likely move forward with the federal guidelines.

While regulators are still in the early stages of establishing regulations for existing industry sources, implementing the federal guidelines would lead to a “collateral reduction of methane emissions,” the agency said. DEP officials said during the meeting that they’ve yet to make a final decision and stressed that nothing is set in stone. However, the agency’s presentation hinged almost entirely on the federal guidelines.

The CTGs are not legally required, but they are designed to help states address VOC emissions from covered oil and gas sources and submit plans for meeting the national standards for ground-level ozone.

The guidelines include recommendations for reducing VOC emissions from a range of equipment and processes used in the upstream and midstream sectors, including storage tanks, compressor stations, and pneumatic controllers and pumps. If the guidelines are advanced in Pennsylvania, existing well sites, processing plants, compressors and pigging stations could be affected.

DEP has been considering regulations for existing sources as part of Gov. Tom Wolf’s plans to reduce industry emissions. A general permit for unconventional well sites and revisions to the general permit for midstream facilities to better address methane emissions from new sites are set to be finalized and issued before the end of March.

The industry has already taken aim at some of the mitigation measures, contending state officials haven’t acknowledged the strides operators have made in voluntarily reducing emissions, and expressing dissatisfaction over the agency’s use of permits to establish a threshold for and to regulate methane emissions.

DEP has until October to submit implementation plans to the federal government to deal with existing industry emissions. The EPA has set an implementation deadline of January 2021.

VOCs, which play a significant role in forming ozone and fine particulates, are generated by vehicles, power plants and industrial activities. The federal government has said the oil and natural gas industry is the largest emitter.

According to DEP’s latest air emissions inventory, while several industry pollutants dropped considerably year/year, both methane emissions and volatile organic compounds from unconventional natural gas wells and midstream facilities increased in 2015. There were 10,109 unconventional wells on record last year, according to the latest annual report.