NTSB says rocks under Enbridge pipeline likely cause of oil leak in Illinois

ROMEOVILLE, Ill. - Rocks lodged beneath the Romeoville pipeline were the likely cause of the two-inch hole that led to the pipeline oil spill here, officials from the National Transportation Safety Board said on Sept. 16.
During a conference call with reporters, Matt Nicholson of the NTSB said the 40-year-old, 34-inch Enbridge Line 6A did not appear to suffer from corrosion or cracking, but that more analysis is needed at the agency's lab in Virginia.
Nicholson described the hole as a puncture, perhaps aggravated by a
leaking water line buried just a half-foot below the oil pipeline.