Emergency shutdown equipment worked well to contain an explosion at a natural gas compressor station in Susquehanna County, PA, late last month that blew a hole in the roof of the complex holding the engines, shaking homes as far as a half-mile away.
The late morning blast at the Lathrop compressor station sent black and gray clouds billowing from the building for several hours, but the damage ended up contained on the site and no one suffered an injury, said a spokeswoman for Williams Partners LP, which owns the Lathrop station.
As a result of the limited damage, Williams officials restarted station operations last week despite state regulators’ request the facility remain shut down during an investigation, the Department of Environmental Protection (DEP) said Wednesday.
Williams Partners turned on some of the seven compressor engines at the Lathrop station without permission Friday evening after the state denied the company’s request to begin operating in a limited capacity, regulators said.
The Springville Township station building and two of its engines suffered damage in the March 29 explosion when gas seeped into the building and ignited.
Williams said Wednesday 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, said Williams spokeswoman Helen Humphreys.
As the blast occurred, automated emergency shutdown procedures stopped gas from entering or leaving the compressors, limiting damage as much as possible.
“The emergency shutdown equipment did work properly to isolate and minimize the incident,” Humphreys said. “Emergency procedures were immediately activated. That included notifying local authorities and first responders, and evacuating all personnel.”
The Lathrop station pressurizes and dehydrates natural gas from Marcellus Shale wells in the county for transport through interstate pipelines, including the Tennessee and Transco, which bring the gas to market. Williams bought the station from Cabot Oil and Gas Corp. as part of a deal in 2010 that also included a second compressor station and 75 miles of the natural gas drilling company’s gathering pipelines.
Cabot called the incident a “flash fire, which extinguished itself immediately” and said it was moving approximately 365 million cubic feet of gas per day through the station before it shut down.
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, Connolly said. DEP has not yet determined if Williams will get a fine for the explosion or for disregarding the agency’s shutdown request.