BILLINGS, Mont., July 20 (UPI) -- The EPA said it found "numerous" piles of oil-soaked debris along the Yellowstone River as floodwater levels recede in Montana.

The 12-inch Silvertip oil pipeline crossing under the Yellowstone River near Billings, Mont., ruptured July 1, dumping around 1,000 barrels of crude oil into the river, pipeline owner Exxon Mobil said.


Flooding along the Yellowstone River hampered much of the initial cleanup effort. The Environmental Protection Agency said it was getting better access to the area as water levels decline.

"We are finding numerous, heavily oiled flood debris piles at various locations along the shoreline and on the islands," the EPA said in a statement.

The agency said it was evaluating each debris pile to assess appropriate remediation methods.

Montana Gov. Brian Schweitzer has pressed Exxon on what type of crude oil was in the pipeline. The company acknowledged that Silvertip had carried oil from tar sands in Canada but said that wasn't what spilled into the Yellowstone River.

"The crude in the line at the point of the incident was a blend of crudes from Wyoming," a spokeswoman for Exxon said in a written statement to United Press International.