An oil pipeline owned by troubled Canadian company Enbridge has been shut down after a leak was discovered near Grand Marsh, Wisconsin, on Friday afternoon. According to company estimates, more than 1,200 barrels of light crude oil destined for Chicago-area refineries had already leaked into a field in the five minutes between the initial drop in pressure and the pipe shutdown.

As of Sunday the company was rushing to clean up and repair the damage, and get the 300,000-plus barrels-per-day pipeline restarted, with plans to replace the damaged section Monday.

As of Sunday, the company was unable to say what had caused the spill in the 14-year-old, 24-inch pipe. The U.S. Pipeline and Hazardous Materials Safety Administration has begun an investigation, including metallurgical examination of the damaged pipe section. According to the same agency, all of the pooled oil has been cleaned up, and Enbridge representatives say that no surface waterways or drinking water supplies appear to have been endangered.

The spill is the worst for Enbridge since a 2010 disaster that spilled more than 800,000 gallons into the Kalamazoo River in Michigan. As recently as July 10, the National Transportation and Safety Board released its report on the investigation into that spill, sharply condemning the company for lax adherence to safety standards and poor handling of the pipeline rupture, which went 17 hours before it was reported. Enbridge was fined $3.7 million, and NTSB chair Debbie Hersman was quoted as comparing the company’s actions to the Keystone Kops.

Friday’s spill is not Enbridge’s first major incident in Wisconsin. In 2007, two spills in January and February--during the construction of a pipeline running parallel to the one that ruptured Friday--released about 176,000 gallons of crude oil onto farmland and roadway in Clark and Rusk counties. In the second spill, in which construction crews mistakenly struck the existing pipeline, oil that could not be removed seeped into the water table. At that time, it was one of the largest spills in state history.

Enbridge, which funnels about 400,000 gallons of crude oil through the state every day, recently proposed increasing the capacity of its pipelines by 40 percent. The expansion would involve no new pipeline, but rather upgrades to pumping systems to increase how much could flow through per day. The upgrade is part of a $3.2 billion project to increase the flow of oil from North Dakota and oil sands in western Canada.

Friday's spill is the second petroleum-based pipeline leak Wisconsin’s seen this July. On July 17, a leaking gasoline pipeline owned by West Shore Pipeline Co. was shut down, but only after an estimated 55,000 gallons of gasoline had already spilled in Jackson, in Washington County. Seven wells near the site have tested positive for benzene, a toxic substance in gasoline, and in one case nearly 300 times the federal limit of 5 parts per billion. Work crews are currently removing contaminated soil near the site, and the DNR estimates that monitoring could last months or years, depending on what further well testing turns up.

Christie Taylor

Contributor

Christie Taylor (@ctaylsaurus) covers science, environment, and, depending on the season, state politics for dane101. She verbs a lot of nouns, including rollerskates, radio, and Kurt Vonnegut. A Madison native, she's not sure she'll ever quite manage to leave Wisconsin, and that's just fine by her. Contact her at christie@dane101.com.