Leaking valve on oil pipeline spills nearly 70K gallons of oil in Jefferson County

A valve failure on an Enbridge Energy oil pipeline in Wisconsin caused a spill that dumped some 69,000 gallons of oil into the ground.

The spill happened on the morning of Nov. 11 about four miles east of the village of Cambridge, between Milwaukee and Madison, according to an accident report released this week by the U.S. Department of Transportation. It released 1,650 barrels of crude oil. One barrel contains 42 gallons of oil. 

The failed carbon steel valve was more than five decades old, according to federal data, having been installed in 1973. 

“Based on the current volume estimates and observed release rate prior to the repair,” the federal report states, “this flange was likely leaking for an extended period of time.”

The leak was identified that morning by field workers for Enbridge, who shut down the line and separated and disposed of the contaminated soil. A third party conducted soil sampling to confirm that the company had addressed the contamination.

The spill was “totally contained on operator-controlled property,” according to federal officials. The spill will be the subject of a long-term impact assessment and anticipated remediation estimated in the federal report to cost $890,456. With the cost of emergency response and pipeline repairs, the incident is expected to cost nearly $1.1 million.

There were no injuries reported in the incident. The company shut down the pipeline for about 10 hours after discovering the spill, according to federal data.

In a statement to WPR, Enbridge Energy said it estimated that about 60 percent of the spill, or 960 barrels, has been recovered so far.

“We are working with the Wisconsin Department of Natural Resources as cleanup and restoration proceed,” a company spokesperson said.

Environmental advocacy groups said the spill shows the risks involved in operating oil pipelines. This week the Bad River tribe and environmental groups filed a legal challenge to state permits for a 41-mile stretch of new Enbridge pipeline in northern Wisconsin. Tony Wilkin Gibart of Midwest Environmental Advocates, which was part of that effort, pointed out in a statement that the Jefferson County spill was discovered the same week the state DNR determined the risk of spills along northern Wisconsin’s Line 5 would be “low.” 

“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,” Wilkin Gibart said.