BISMARCK, N.D. (AP) — Electronic monitoring equipment failed to detect a pipeline rupture that spewed more than 176,000 gallons of crude oil into a North Dakota creek, the pipeline's operator said Monday. It's not yet clear why the monitoring equipment didn't detect the leak, Wendy Owen, a spokeswoman for Casper, Wyoming-based True Cos., which operates the Belle Fourche Pipeline, said. Though crews have been working around the clock to deal with the Tesoro Corp. pipeline break, which happened in a wheat field in September 2013, less than a third of the 840,000 gallons that spilled has been recovered — or ever will be, North Dakota Health Department environmental scientist Bill Suess said. Suess said the spill migrated about almost 6 miles from the spill site along Ash Coulee Creek, and it fouled an unknown amount of private and U.S. Forest Service land along the waterway. The creek feeds into the Little Missouri River, but Seuss said it appears no oil got that far and that no drinking water sources were threatened. The creek was free-flowing when the spill occurred but has since frozen over. The Tesoro spill was not far from where oil was first discovered in North Dakota in 1951.The Texas-based company and federal regulators have said a lightning strike may have caused the 2013 rupture in the pipeline, which runs from Tioga to a rail facility outside of Columbus, near the Canadian border. "We have several working theories and the investigation is ongoing."  BISMARCK, N.D. (AP) — A company with a history of oil field-related spills in North Dakota and Montana is being hampered by winter weather in its cleanup of a "significant" pipeline break that leaked crude oil into a tributary of the Little Missouri River in western North Dakota, a regulator said Thursday. The 32,000-gallon spill temporarily shut down water supplies in the downstream community of Glendive, Montana, after oil was detected in the city's water treatment system. The 6-inch steel Belle Fourche Pipeline is mostly underground but was built above ground where it crosses Ash Coulee Creek, Suess said. Owen said the pipeline was built in the 1980s and is used to gather oil from nearby oil wells to a collection point. "Anytime you have cold temperatures, it's going to hinder cleanup and the investigation," Suess said. True Cos. operates at least three pipeline companies with a combined 1,648 miles of line in Montana, North Dakota and Wyoming, according to information the companies submitted to federal regulators. Since 2006, the companies have reported 36 spills totaling 320,000 gallons of petroleum products, most of which was never recovered. Kevin Pranis, a spokesman for the Laborers District Council of Minnesota and North Dakota, which represents some workers building the disputed four-state, $3.8 billion Dakota Access Pipeline, said Thursday that regulators need to provide better oversight of the True Cos. This month's pipeline break in Belfield, which belched an estimated 176,000 gallons of oil into a creek that feeds into the Little Missouri River, a tributary of the Missouri River, really rankled her. Dallas-based pipeline company Energy Transfer Partners says the Dakota Access pipeline would include safeguards such as leak detection equipment and that workers monitoring the pipeline remotely in Texas could close valves within three minutes if a breach is detected. ___ 
 
 Associated Press writer Matthew Brown in Billings, Montana, contributed to this report.
– Three years and three months later, a massive oil spill in North Dakota still isn't fully cleaned up. The company responsible hasn't even set a date for completion. Though crews have been working around the clock to deal with the Tesoro Corp. pipeline break, which happened in a wheat field in September 2013, less than a third of the 840,000 gallons that spilled has been recovered. While the nearest home was a half-mile away and the state said no water sources were contaminated and no wildlife hurt, one of the largest onshore oil spills recorded in the US serves for some as a cautionary example, especially given a recent pipeline break in Belfield, about 150 miles south, and ongoing debates over the four-state Dakota Access pipeline. Texas-based company Tesoro and federal regulators have said a lightning strike may have caused the 2013 rupture in the pipeline, which runs from Tioga to a rail facility outside of Columbus, near the Canadian border. The cleanup has cost Tesoro more than $49 million to date and is expected to top $60 million, according to recent filings to the state. Crews have had to dig as deep as 50 feet to remove hundreds of thousands of tons of oil-tainted soil, North Dakota Health Department environmental scientist Bill Suess says. The company has now switched to special equipment that cooks hydrocarbons from crude-soaked soil in a process called thermal desorption before putting it back in place. Landowners, not the monitoring equipment in place, discovered both the Tesoro and Belfield breaks, reports the AP.