A late-night explosion ignited a fire at the Sunoco-owned Marcus Hook refinery along the border of US states Delaware and Pennsylvania on 17 May.
It was reported that the blast in the ethylene unit of the refinery could be felt for miles and resulted in flames shooting high into the late-night sky. No one was injured.
The Marcus Hook refinery is the second largest in the North-eastern US, capable of processing 178,000 barrels a day. The 82-acre refinery is Sunocos biggest refinery and the seventh largest in the United States.