Pennsylvania's natural gas compressor stations will have to meet tighter air pollution standards under a mandate from the state environmental agency.
The Department of Environmental Protection said Thursday its revised permit for compressor stations requires a 75- to 93-percent reduction in air emissions for the largest, most common types of engines used to power the facilities, which pressurize natural gas taken from the Marcellus Shale formation for movement along pipelines.
Environmental groups and some residents have expressed concern over air quality as more compressor stations are permitted and built. Residents who live downwind have complained of headaches, breathing trouble or other health problems they blame on air emissions from the compressors.
The new DEP permit imposes stricter limits on volatile organic compounds, formaldehyde, nitrogen oxides and carbon emissions. The agency also announced it will accept public comment on a separate plan to reduce wellhead emissions.
"The steps we are taking now mean far lower emissions at well sites and more efficient compressor stations, resulting in cleaner air as development, production and transmission take place," DEP Secretary Michael Krancer said in a statement. "DEP's effective and robust oversight will deliver on the promise of cleaner air from the increased use of natural gas."
The Marcellus Shale Coalition, an industry group, said it supported the new standards. The revised permit will "further leverage technologies that continue to reduce our industry's footprint," said coalition president Kathryn Klaber.
Pennsylvania has more than 400 compressor stations, including older stations that handle natural gas produced from conventional wells.
DEP has been criticized by environmental groups over rules that govern when it treats compressor stations as individual, minor sources of pollution and when it groups them together with related natural gas facilities like wells and pipelines, for purposes of aggregating their air emissions. Major sources of pollution are subject to stricter controls.
State Rep. Jesse White, a Democrat from Washington County, said Thursday's announcement "totally ignores the real problem, which is that DEP refuses to aggregate emissions results. So if there are 10 compressors right next to one another, DEP monitors emissions of each one separately, even though the combined emissions of all 10 are coming in through your kitchen window."
Krancer has called the aggregation rules a "practical, common-sense and legally sound approach" used by many other oil- and gas-producing states.