An Enbridge Energy pipeline in Jefferson County spilled nearly 70,000 gallons of crude oil underground, according to federal officials.
The spill is Enbridge's worst in Wisconsin, surpassing a 2012 incident that spilled 50,000 gallons in Adams County.
A petroleum pipeline spill was first detected Nov. 11 in the town of Oakland during a routine inspection by an Enbridge technician, according to a recent accident report from the U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration.
The discharge happened on Line 6, which was built in 1968, and the pumping station was shut down and isolated, the report says. Following excavation of the area, the source of the spill was repaired and the station was returned to service.
Enbridge said in a statement Friday that the spill was due to a faulty connection on a pump transfer pipe.
The accident report states that the pipeline was "likely leaking for extended period of time." According to the Dec. 11 report, an estimated 1,650 barrels, or 69,300 gallons, has spilled.
The Canadian oil company said in its statement that soil removal is ongoing and it estimates about 60% of affected soil has been removed. "Enbridge immediately reported the release to state and federal regulators," the statement says. "We are working with the Wisconsin Department of Natural Resources as cleanup and restoration proceed."
The extent of the damage and whether any waterways were affected wasn't immediately clear Friday. The DNR said that it is working with Enbridge on the "investigation of degree and extent of impacts and cleanup of the reported release and will continue to do so."
Enbridge failed to report a spill in early 2019 for more than a year even though the company was well aware that a large amount of an oil substance had been released near Fort Atkinson, also in Jefferson County. The DNR said at the same time that Enbridge was in violation of the law and could face fines.
Midwest Environmental Advocates provides legal support for citizens who exercise their rights to protect natural resources, according to its website. The group's executive director, Tony Wilkin Gibart, said in a statement:
"The close to 70,000 gallons of leaking crude oil from Enbridge's Line 6 in Jefferson County shows why we have challenged DNR's approval of the Line 5 reroute and why we have specifically challenged DNR's conclusion that the risk of a Line 5 spill is small. The risks posed by Line 5 are not small. The harm this pipeline would cause to Wisconsin's waters and the climate is guaranteed to be significant and could be catastrophic.
"Consider that in the very same week that DNR issued permits for Line 5 based on its conclusion that the risk for a spill would be 'low,' DNR was investigating a significant oil leak on another Enbridge pipeline in Wisconsin.
"According to documents from the US Department of Transportation, the faulty segment on Line 6 in Jefferson County has a leak detection system, but that system failed to even detect the leak -- much less prevent tens of thousands of gallons of oil from contaminating surrounding land and water in Jefferson County.
"But again, in the very same week the Enbridge leak detection system failed in Jefferson County, DNR then gave its approval for the Line 5 reroute in part because 'continuous monitoring and control of Line 5 (would be) carried out by Enbridge.'
"DNR's reasoning for approving Line 5 defies common sense."