Exxon Mobil Corp. is challenging $1.7 million in proposed penalties from federal safety regulators who faulted the oil company over a 63,000-gallon crude oil spill into the Yellowstone River.
In documents released by the government Monday, Exxon attorneys contend the company responded appropriately to warnings that its 12-inch Silvertip pipeline was endangered by erosion along the Yellowstone.
They say Exxon took precautions, including checking the 20-year-old line to make sure it still was buried beneath the riverbed. Floodwaters exposed the line and caused it to break in July, 2011.
The spill contaminated 70 miles of riverbank, killing fish and wildlife and prompting Exxon to spend $135 million on cleanup and repair work.
The U.S. Department of Transportation has scheduled a July 17 hearing on the alleged safety violations.