One night in early September, a critical piece of natural gas infrastructure temporarily blew its stack.

By the time a resident heard the racket, dialed 911 and workers responded, the Harmony compressor station in rural northeastern Pennsylvania had spewed more than twice as much natural gas into the air as a typical compressor station does in a year.

Yet the Sept. 2 leak was not made public by any state agency or by the company itself. The Associated Press learned of it during a review of calls to the U.S. Coast Guard’s National Response Center hotline for discharges of oil, chemicals and other substances.

County emergency management officials found out the same way — about a week after the fact. They said the station’s operator, Detroit-based DTE Energy, should have notified them at the time of the release so they could’ve taken steps to make sure residents were out of harm’s way.

“If it’s something like this that’s larger, we definitely need to know about it,” said Robert Thatcher Jr., coordinator of the Susquehanna County Emergency Management Agency. “I don’t know why they didn’t contact us. That’s a question that DTE needs to answer.”

Company spokesman Pete Ternes didn’t offer a direct response but said: “DTE has a strong track record of following all state and federal regulations.” He said that as a matter of courtesy, the company notifies the county agency of planned releases in case emergency officials get 911 calls from the public. On occasion, unplanned releases have been called in, also as a courtesy, he said.

State regulations require operators of compressor stations to “immediately” alert county emergency officials when there’s an “imminent and substantial danger to the public health and safety.”

The company might not have seen the methane release as a serious situation that warranted public notice, as the nearest residence is more than a half-mile away. There was no explosion and no one was hurt.

When Thatcher found out about the release and called DTE, “They said it was a minor leak, less than two hours,” he recalled. “We questioned them: ‘Did you notify the residents, did you reach out to them?’ They said no.”

The National Response Center log of the gas release said a “technician was called to the site, the emergency stop button was pushed, pilot was replaced and unit was put back into service.”

Compressor stations help get natural gas to market by pressurizing it for movement along the pipeline network.

Environmental groups and some residents have long expressed concern over air quality and safety. Residents who live downwind of compressor stations have complained of headaches, breathing trouble or other health problems they blame on air emissions from the compressors.

In 2012, an explosion at a compressor station about 35 miles (56.32 kilometers) from the DTE facility sent black smoke into the air and shook nearby trailer homes, but caused no injuries.

DTE said the release at its Harmony station was caused by a failing pilot on a discharge valve, which triggered a release valve.

“The system worked as designed, preventing a buildup of gas in the building and mitigating any safety concerns,” Ternes, the company spokesman, said in an email.

DTE reported the release to the U.S. Pipeline and Hazardous Materials Safety Administration and to the Pennsylvania Department of Environmental Protection.

“Under DEP regulations, the operator would have also needed to alert the county emergency management agencies,” said DEP spokesman Neil Shader. “Notification to residents nearby would fall to the county,” with DEP assistance if necessary.

The release did not prompt a state investigation. That’s because methane emissions aren’t currently covered by the operating permit for compressor stations.

The DEP is developing a new permit as part of Democratic Gov. Tom Wolf’s pledge to require the natural gas industry to reduce emissions. It would require operators to use “best available technology” to detect and plug leaks of methane, a powerful greenhouse gas that contributes to global warming.

The industry says it’s already taken steps to sharply reduce methane emissions. According to an emissions inventory released by DEP last month, the average compressor station released 97.5 tons of methane in 2015, down from nearly 107 tons in 2014, though experts say the actual amount is likely far higher because fugitive emissions are so difficult to quantify.

By comparison, DTE’s Harmony station leaked more than 200 tons of methane in the span of a couple hours.


Associated Press reporter Michael Biesecker contributed to this report from Washington.