BILLINGS, Mont. (AP) - A second large oil spill into Montana's Yellowstone River in less than four years is reviving questions about oversight of the nation's aging pipeline infrastructure.
Investigators and company officials on Wednesday tried to determine the cause of the 40,000-gallon spill that has contaminated downstream water supplies in the city of Glendive.
Sen. Jon Tester says Saturday's spill from the decades-old Poplar Pipeline was avoidable.
He says more inspections are needed and older pipelines should face stricter safety standards.
The spill comes as Republicans and some Democrats, including Tester, want the Obama administration to approve TransCanada's Keystone XL pipeline from Canada to the Gulf.
Keystone would cross the Yellowstone roughly 20 miles upstream of the Poplar Pipeline spill.