AUDIE CORNISH, HOST:
We're going to explore the noisy side of natural gas development. After the drilling and fracking, the workers and equipment are gone on. But compressor stations which are needed to push the gas through the pipelines can run for years, even decades. Marie Cusick of member station WITF reports.
MARIE CUSICK, BYLINE: Compressor station engines hum constantly, pulling and pushing gas out of wells. They're needed every 50 to 100 miles along pipelines to keep gas flowing. There are legitimate issues with how they affect air quality, but noise from the sites can also create problems.
Ian Vranich is a manager with Seneca Resources' midstream operations. He's standing in front of the company's compressor station in a forested part of north-central Pennsylvania. There are eight engine units here. Each looks sort of like a large shed with a giant fan on the end.
IAN VRANICH: Whenever the engine's running, we try to keep everything as contained to keep the noise contained inside the build so we're not, you know, passing that noise out into the open air environment.
CUSICK: Noise regulations around the country vary widely depending on where the compressor's located and what kind of pipeline it's attached to. Regulators typically put limits on decibel levels, but that metric only measures loudness. In Pennsylvania, both industry and environmental groups agree more nuanced rules are needed.
The state's Department of Conservation and Natural Resources - or DCNR, which manages public forest land - is working with Penn State University acoustics professor Tom Gabrielson to overhaul the agency's noise guidelines.
TOM GABRIELSON: The station operators aren't very happy with it. The DCNR people aren't very happy with it. It's probably a little too simplistic.
CUSICK: As Gabrielson explains, many other factors affect how noise is perceived, from its frequency to the topography of an area. For example, a hill could block nearby noise, but the sound can travel a long distance through a valley. Even the weather and the wind speed on a particular day can play a role. Gabrielson plays four sounds. All are about the same in terms of decibel level or loudness, but he points out they're widely different in terms of annoyance. He starts with rain and thunder...
(SOUNDBITE OF RAIN AND THUNDER)
CUSICK: ...Then a helicopter flying overhead.
(SOUNDBITE OF HELICOPTER)
CUSICK: Dogs barking.
(SOUNDBITE OF DOGS BARKING)
CUSICK: And birds chirping.
(SOUNDBITE OF BIRDS CHIRPING)
GABRIELSON: Some of the those I could sleep through easily. Some of them would wake me up.
CUSICK: Which brings us back to compressor stations. Paul Karpich lives near three of them in rural northeastern Pennsylvania. He can't always sleep through the sounds. Depending on the day, he can be irritated by the humming of a low frequency or the loudness of high decibels.
PAUL KARPICH: You know, you live in the country where I should just be hearing crickets and - but we hear that.
CUSICK: Mike Atchie is a spokesman for Williams, the company that operates the compressors near Karpich. He admits the facilities may exceed the county noise ordinances sometimes but says the company's tried to work with residents.
MIKE ATCHIE: We're a 100-year-old company, so we're not kind of a fly-by-night business looking to do something quickly here. We want to be a long-term neighbor in this community.
CUSICK: But Karpich doesn't think Williams has been a good neighbor. He's lived here for 32 years and is now thinking about moving.
KARPICH: They're here to stay, but I wish they would've done it in a friendlier way.
CUSICK: Since compressor stations can fall under so many different regulatory bodies, it's hard to find figures on how many there are across the country. The last time the U.S. Energy Information Administration counted in 2009, there were over 1,700. But more are being built all the time as the nation's natural gas production keeps soaring. For NPR News, I'm Marie Cusick.
CORNISH: This story comes to us from StateImpact Pennsylvania, a public media reporting project covering Pennsylvania's energy economy.
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