Pennsylvania regulators used flawed methodology to conclude that air pollution from natural gas development doesn't cause health problems. The revelation has further eroded trust in an embattled state agency.

The news was first reported Monday by the Pittsburgh Post-Gazette. The paper cited court documents that show how air quality studies conducted by the Department of Environmental Protection in 2010 and 2011 failed to analyze the health risks of 25 chemicals. The studies also didn't report some instances where high pollutant levels were detected.

The evidence came from statements of two DEP scientists who were deposed in a lawsuit.

Their depositions call into question the report's conclusion that the air sampling found no health risks from shale development.

The DEP "did not identify concentrations of any compound that would likely trigger air-related health issues associated with Marcellus Shale drilling activities," the study's executive summary said.

Two later DEP air sampling studies from 2011 used the same methodology. All three reports have been cited by Pennsylvania regulators and industry to support drilling activity.

"It's a really serious mess," said toxicologist David Brown of the Southwest Pennsylvania Environmental Health Project, which helps residents whose health may be impacted by natural gas development.

Brown has worked at various health agencies throughout his career, including the Centers for Disease Control and the Connecticut Department of Public Health, where he was chief of environmental epidemiology and occupational health.

"Probably the most important thing health and environmental agencies do is to maintain trust," he said. Now that the DEP has broken that trust, "I don't think it's fixable."

When InsideClimate News asked the DEP to comment, agency spokeswoman Morgan Wagner responded with a letter that the DEP sent to the Pittsburgh Post-Gazette on Wednesday. The letter criticizes the Post-Gazette article, but doesn't challenge its main finding about the data left out of the DEP reports.

The DEP has faced years of criticism for its handling of the Marcellus Shale boom.

"The gas industry is treated with kid gloves," said George Jugovic Jr., a former DEP official who is now chief counsel of the environmental group PennFuture. Jugovic said that leniency applies to both the current administration under Republican Governor Tom Corbett, and the previous administration of Democratic Governor Edward Rendell.

A July audit by Pennsylvania's Auditor General's office faulted the agency for poor communication with citizens, a lack of transparency and weak industry oversight on the issue of water protection from natural gas development .

Two months later, the Auditor General's office followed up with a separate document that warned citizens not to rely on data posted on DEP's website, because it often contains self-reported data from shale gas operators that aren't reviewed for accuracy.

Nadia Steinzor, eastern program coordinator of the environmental group Earthworks Oil and Gas Accountability Project, said the recent revelations about the DEP's air studies have made her even more skeptical of the agency's actions.

"They make me question DEP's ultimate motivations," she said. The next time the agency releases a study, "we and others have to take a really hard careful look at [the] methodologies they use."

A Series of Mistakes

Both of the DEP employees deposed, Linda Hreha and Nicholas Lazor, were involved in the studies. Their depositions, taken in Dec. 2013 and Jan. 2014, were filed as part of an air and water pollution case against drilling operator Range Resources.

The DEP has cited the flawed studies as recently as September 2014 in a lawsuit filed by citizens trying to block several gas wells near schools and homes in Middlesex Township. In response to the plaintiffs' concerns, the DEP wrote a letter that referenced its 2010 study, saying the "short-term, screening level air quality sampling initiative...did not identify concentrations of any compound that would be likely to trigger acute air emission-related health issues."

Range Resources, the company involved in the lawsuit that brought the depositions to light, lists the Pennsylvania studies (among others) to show how "air quality surrounding natural gas development...is safe."

The depositions reveal a series of mistakes made by the DEP. To begin with, the report's raw data show the agency detected high concentrations of certain chemicals—but those results weren't included in the final study released to the public. The DEP also failed to assess the potential health risks of 25 of the monitored chemicals.

In his deposition, Lazor said none of the DEP employees who prepared the 2010 report were trained in epidemiology, medicine, or environmental or occupational health. Although the agency consulted with an epidemiologist from the Pennsylvania Department of Health, the epidemiologist only saw a copy of the final report—not the raw data behind the study.

The DEP studies were criticized even before the depositions came to light. In 2011, the environmental group GASP (Group Against Smog and Pollution) noted that the DEP air monitoring instruments could only detect some pollutants at extremely high levels unlikely to be found in the atmosphere. In one case, the agency's minimum detection limit for nitrogen dioxide (NO 2 ) was 198 parts per billion—18 times higher than the state's average NO 2 concentration of 11 parts per billion.

Earthworks' Steinzor said the studies do have some value. They were—and still are—among the few studies conducted by regulatory agencies on the air impacts of shale development. Also, they ultimately convinced the DEP to do another long-term air quality study in the Marcellus. Those results have not been released to the public.

Brown, the Environmental Health Project scientist, said the latest news has seriously damaged the DEP's reputation in future work. "I don't know how an agency redeems credibility once they've lost it at this scale."