Water supplies affected by last Saturday’s crude oil spill of up to 50,000 gallons along the Yellowstone River in Montana were deemed to be meeting federal safe drinking water standards as of Friday, the state Department of Environmental Quality (DEQ) said.

Original estimates of the size of the spill were revised downward to 40,000 gallons, state officials said while reporting that the water treatment plant for the town of Glendive, MT, about seven miles downstream from the spill at a river crossing (see Shale Daily, Jan. 20), was “decontaminated and the main distribution lines flushed through the city’s fire hydrants.

“Flushing of the system throughout homes and businesses is under way, and residents have received instructions,” DEQ said Friday. “The municipal water delivery system now meets standards as set by the federal Clean Water Act.”

Glendive, with a population of slightly more than 5,000, draws its drinking water from an intake structure about 14 feet under the surface of the Yellowstone River. Early testing indicated the presence of volatile organic compounds (VOC), specifically benzene, and as a result, residents were alerted to not use water for cooking purposes, and the water system was monitored.

DEQ also confirmed Friday that the 12-inch diameter pipeline crossing the river and operated by Dallas-based Bridger Pipeline Co. was carrying primarily Bakken crude oil at the time of the release last Saturday morning (Jan. 17).

As of Friday, product sheen had been observed on the river beyond Sidney, MT, about 50 miles northeast of Glendive near the border with North Dakota. No other communities draw water supplies from the Yellowstone River downstream of the release, DEQ officials said

The pipeline was shut down within an hour of the spill being detected by a pressure drop, according to Bridger Vice President Tad True as quoted in local news media last Monday. A spokesperson did not immediately respond to multiple inquiries from NGI‘s Shale Daily.

This is the first significant spill in Montana since an ExxonMobil Corp. pipeline broke in south-central Montana near Laurel in July 2011, releasing 63,000 gallons of crude along an 85-mile stretch of the Yellowstone River. ExxonMobil is facing several millions of dollars in state and federal fines related to that spill.