Mariner East 2: What are natural gas liquids, and what happens if they leak?

Susan Phillips

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Susan Phillips tells stories about the consequences of political decisions on people's every day lives. She has worked as a reporter for WHYY since 2004. Susan's coverage of the 2008 Presidential election resulted in a story on the front page of the New York Times. In 2010 she traveled to Haiti to cover the earthquake. That same year she produced an award-winning series on Pennsylvania's natural gas rush called "The Shale Game." She received a 2013 Alfred I. duPont-Columbia University Journalism Award for her work covering natural gas drilling in Pennsylvania. She has also won several Edward R. Murrow awards for her work with StateImpact. In 2013/14 she spent a year at MIT as a Knight Science Journalism Fellow. She has also been a Metcalf Fellow, an MBL Logan Science Journalism Fellow and reported from Marrakech on the 2016 climate talks as an International Reporting Project Fellow. A graduate of Columbia School of Journalism, she earned her Bachelor's degree in International Relations from George Washington University.
Tom Downing

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As part of the Digital Services Team, Tom designs websites using HTML, CSS, PHP and JavaScript and creates motion graphic animations to support a variety of projects for WITF. In his spare time, Tom enjoys photography, playing soccer, and hiking with his family.

The pipeline will carry volatile propane, ethane and butane, which has raised fears of many who live near it — even though explosions are rare. As part of StateImpact Pennsylvania’s “Mariner East 2: At what risk?” series, we put together this video to explain what those substances are and how they act both inside the pipeline and if they got out, and how you should respond if there’s a leak.

As part of the “Mariner East 2: At what risk?” series, this StateImpact Pennsylvania video examines the natural gas liquids that flow through the pipeline and what happens if they leak — something that could be caused by:

Welding failures
Material defects
Corrosion
Shifting land exposing the pipe

In 2017, about 1,000 gallons of natural gas liquids leaked from the Mariner East 1 in Morgantown, Berks County. It was discovered by a resident who noticed discolored grass. The leak did not result in an explosion.

In September 2018, a leak from a gathering line carrying a mixture of hydrocarbons including methane, ethane and butane resulted in an explosion, with one house burning to the ground. No one was injured.

The Mariner East 1 pipeline has experienced three leaks since 2014. Those leaks did not result in any explosions.