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Press Release

PUC Investigation of Mariner East 1 Pipeline Incident in Chester County Shifts to Geological Testing

Published on 1/25/2019

Filed under: Gas

HARRISBURG – A safety investigation by the Pennsylvania Public Utility Commission’s (PUC’s) independent Bureau of Investigation and Enforcement (I&E) – which includes the PUC’s Pipeline Safety Division – regarding Mariner East 1 (ME1) pipeline, operated by Sunoco Pipeline LP, a/k/a Energy Transfer Partners (SPLP), has now shifted to detailed geological surveys around a “sinkhole” that developed last Sunday along Lisa Drive, in West Whiteland Township, Chester County.

  • Geophysical surveys around the Lisa Drive site are scheduled to begin tomorrow (Saturday, Jan. 26), and will be closely monitored by pipeline safety engineers from the PUC and geophysical consultants. Work on-site to prepare for the surveys began today.
  • The testing, which will be used to evaluate underground conditions, is expected to take several days to complete.
  • I&E pipeline safety engineers and geophysical consultants will be on-site monitoring the collection of geophysical data.
  • Results of the testing will be shared with I&E’s engineers and I&E’s geophysical consultants for independent analysis and review. 
  • Additionally, PUC engineers and geophysical consultants have been working with municipal officials and SPLP to monitor and track stormwater flow around the incident site, including investigation of storm drains in the area.
  • Analysis of testing results and information from the ongoing safety engineering investigation will be used by I&E as a basis for data-driven discussions about next steps at the Lisa Drive site, along with any other work that I&E believes is necessary.

As noted in previous PUC updates:

  • The ME1 pipeline has been shut down since Jan. 21, meaning no product is flowing in this pipeline anywhere in Pennsylvania, and a 44-mile section of pipeline around the Lisa Drive site has been isolated and purged.
  • SPLP is not permitted to resume the transportation of product through ME1 until approval is received from I&E. 
  • I&E pipeline safety engineers and geologists continue to monitor all work at the Lisa Drive site and remain in constant contact with SPLP regarding their activities involving ME1.

As the independent investigation and enforcement bureau of the PUC, I&E has the authority to bring enforcement action, seek emergency orders from the Commission or take other steps to ensure public safety, should circumstances change or based on the finding of the investigation.

The Pennsylvania Public Utility Commission balances the needs of consumers and utilities; ensures safe and reliable utility service at reasonable rates; protects the public interest; educates consumers to make independent and informed utility choices; furthers economic development; and fosters new technologies and competitive markets in an environmentally sound manner.

For recent news releases and video of select Commission proceedings or more information about the PUC, visit our website at Follow the PUC on Twitter – @PA_PUC for all things utility. “Like” PA Public Utility Commission” on Facebook for easy access to information on electric shopping.

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