A damaged Susquehanna County natural gas compressor station restarted operations last week despite state regulators' request the facility remain shut down during an investigation, the Department of Environmental Protection said Wednesday.

Williams Partners turned on some of the seven compressor engines at the Lathrop station without permission after the state denied the company's request to begin operating in a limited capacity, regulators said.

The Springville Twp. station building and two of its engines were damaged in an explosion on March 29 when gas seeped into the building and ignited.

Williams said Wednesday that it began flowing gas through the system the day after the explosion once a state fire marshal and a structural engineer completed inspections of the site and the company's own inspection found the equipment was safe to turn on incrementally.

The "misunderstanding" was procedural and never compromised the safety of the site, which was investigated and ensured before any engines were restarted, Williams spokeswoman Helen Humphreys said. It was not clear whether the state needed to issue formal stop or start orders before the company could resume operations, she said.

A DEP spokeswoman said the agency's advice not to run the station was clear and officials are disappointed with the company.

"The DEP made a request to Williams on Thursday and we advised them on Friday to continue to stand down at the site until we got an engineer to come out and inspect the compressor station and until we received a final report from them," DEP spokeswoman Colleen Connolly said. "Williams chose to not honor that request."

DEP engineers and a supervisor first discovered some engines running during an inspection at 9 a.m. Monday and found that they were working properly and appeared to be in compliance with their permits, she said. An emissions test on Tuesday confirmed that the engines were satisfying their permit limits.

Regulators do not plan to issue an enforcement order now, Ms. Connolly said. DEP has not yet determined if Williams will be fined for the explosion or for disregarding the agency's shutdown request.

The lack of an enforcement action disturbed a state environmental organization that has pushed for stronger air pollution controls.

"DEP has the authority and the obligation to halt all operations at the Lathrop station until the incident has been properly evaluated," said Joseph O. Minott, director and chief counsel of the Clean Air Council. "We insist that DEP stand up for residents and demand that operations at this station stop until they have performed a comprehensive investigation of the incident and have reported back to the local residents."

Earlier this week, Ms. Connolly mistakenly characterized a verbal report and answers to specific questions that Williams conveyed to DEP on Monday as the company's written investigation report, which has not yet been submitted. State regulators asked Williams on Tuesday to produce a detailed report outlining the cause of the explosion within five days.

Preliminary conversations between the company and state regulators indicate a valve on one of the compressors was accidentally left open during maintenance work, which allowed gas to gather in the building. Alarms and automatic shut-off procedures triggered by the buildup of gas prompted workers to evacuate safely before the explosion.

The blast tore part of the roof off the building and damaged two engines, knocking one out of service, Ms. Connolly said. The fire that continued to burn after the blast was fed by oil in one of the engines.

Williams is currently operating six of the seven engines it is permitted to run at the site, Ms. Humphreys said, and the volume of gas passing through the station is close to normal levels. Before the fire, the station processed about 365 million cubic feet of gas per day.

Along with DEP inspectors, the state Public Utility Commission has had inspectors on site since the day of the explosion, PUC spokeswoman Jennifer Kocher said.

Under a new state law, the commission has safety jurisdiction over some natural gas pipelines and compressor stations tied to natural gas wells in the state, but not those in the most rural areas - places with 10 or fewer homes within a 220-yard radius of a facility. The PUC is still examining whether it has oversight authority for the Lathrop station.

"We may not be able to take any enforcement actions based upon the location," Ms. Kocher said, "but we do want to be on site to look at the safety of it no matter what."

Contact the writer: llegere@timesshamrock.com

An article in Saturday's paper included the wrong date for when engines were restarted at the Lathrop compressor station in Springville Twp., Susquehanna County after an explosion. Dehydration units and other equipment began running on Friday, March 30. Engines began running on Sunday, April 1.