BILLINGS, Mont., July 29 (UPI) -- Less than 3 percent of the observed sections of the Yellowstone River in Montana downstream from a pipeline break are heavily affected by oil, the EPA said.
Exxon Mobil reported that around 1,000 barrels of crude oil spilled July 1 into the Yellowstone River from its 12-inch Silvertip pipeline near Billings, Mont.
The U.S. Environmental Protection Agency in a statement last week said crews were "finding numerous, heavily oiled flood debris piles at various locations along the shoreline and on the islands."
In its latest update on survey operations along the Yellowstone River, the EPA said it found 2.7 percent of the first 10 miles of river downstream from the pipeline break were heavily affected by oil. Less than 1 percent of the next 18 miles were observed to have heavy oil impacts, the agency said in a statement.
Because of the amount of oil-soaked debris left when floodwaters along the Yellowstone River receded, the response includes nearly 900 personnel engaged in remediation and assessment efforts.
The EPA said it had to airlift some equipment into areas previously inaccessible.
"This has accelerated cleanup efforts and will enable contaminated debris piles to be removed more effectively," the agency said.
Though Silvertip had carried heavy crude oil from tar sands projects in Alberta, Canada, the pipeline was carrying conventional crude at the site of the spill, Exxon said.
