In the United States, residents of Glendive, Montana, and surrounding areas are being told not to drink their tap water after the cancer-causing chemical benzene was detected following an oil spill. The warning comes days after up to 50,000 gallons of oil spilled into the Yellowstone River, and follows earlier assurances by state officials the spill posed no public safety threat. Glendive sits on the edge of the Bakken Shale, a top oil production site, and near the route of the proposed Keystone XL pipeline.