MarkWest operates a large natural gas processing plant in Chartiers Township (Washington County), PA. In the past few years they doubled the size of the plant. Apparently the installation of more new equipment due to go online yesterday didn’t go as planned. Characterizing it as “several events,” automated safety equipment kicked in and burned off (or flared) propane at the plant–resulting in smoke that could be seen for miles.
The (scant) known details of what happened yesterday at the Chariters processing plant: