DNR orders Enbridge to test groundwater, additional soil after 2019 underground petroleum leak near Fort Atkinson

Enbridge Inc.'s Superior terminal in Superior, Wis.

The Wisconsin Department of Natural Resources is requiring a Canadian oil company to continue testing soil around the site of a 2019 pipeline leak to find the extent of contamination. 

The DNR has directed Enbridge Energy to conduct an additional soil investigation to determine the extent of contamination from the leak, investigate how far contamination may have spread through the groundwater in the area, determine whether the leaked compound could have traveled along the outside of the pipeline, to sample all wells within 1,200 feet of the leak and to assess the vapor risk within buildings on the site.

The DNR directed that a plan for the additional investigation be submitted within 60 days of March 31. 

Line 13, also known as the Southern Lights Pipeline, starts in Manhattan, Ill., and runs through Wisconsin and Minnesota, delivering products to Enbridge’s Edmonton terminal in Alberta, Canada, according to the company’s website.

The line transports 180,000 barrels per day of petroleum diluent, which is used to dilute heavy oils for easier transportation. 

The spill took place near Fort Atkinson, near the intersection of Blackhawk Island Road and Westphal Lane, close to both the Rock River and Lake Koshkonong. The leak took place on a 68-acre parcel of land that is home to Lines 6, 14, 13 and 61, according to DNR records. 

According to a report from Enbridge, a whistle alarm alerted the company to the leak on April 26, 2019. After that, samples were collected from around the site to determine where the leak was coming from. It wasn’t until May 17 that the leak was identified as coming from a faulty elbow joint and stopped. The valve was replaced on June 2. 

The company continued to excavate the site and test soil and nearby wells for contamination, but the leak was not reported to the DNR until July 31, 2020, more than a year after the spill occurred. In November, the company reached the conclusion that 29 to 33 barrels of diluent were released into the ground. 

During testing, 27 soil borings were taken and 27 temporary monitoring wells were installed and sampled, in addition to eight permanent monitoring wells. Enbridge also sampled the nearest potable well. Most of the shallow soil has been removed from the site, and the impacted groundwater appears to be limited to within 250 feet of where the leak occurred, DNR documents show. 

Steve Martin, a supervisor for the DNR’s remediation and redevelopment program, said most of the additional testing is being asked for out of an abundance of caution. The DNR wants to ensure that no nearby homeowners or businesses are in danger from anything moving through the soil or groundwater. 

He said the department expects to get a plan back from Enbridge quickly, and will expedite its approval so work can start. Some of the requests the DNR made of the company are already underway, such as drinking well sampling. The data gathered through all of the testing of water and soil will then determine how much remediation still needs to be done, such as removing additional soil around the leak site. 

Residents in the area are still concerned, especially because the spill wasn’t reported to the state for more than a year and that many people weren’t aware it took place until the last few weeks. 

Among those concerned is Ronni Monroe, a resident in the area and a local organizer over concerns surrounding the pipelines running through the community. She’s been working for years to keep residents informed about the pipelines and was shocked to learn about the spill and has been poring over reports of the spill since. She’s glad the DNR is requiring more testing. 

“It’ll be interesting to see what results come from this,” she said. “It will put residents in a better place to know what’s going on.” 

She hopes to see more accountability from Enbridge in the future, too. It was unacceptable to Monroe to find out that the company waited for more than a year to report the spill. 

“If there’s one lesson, it’s to be transparent, to be honest,” she said. “Hopefully we’ll see that.” 

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Jefferson County Board member Anita Martin said the additional testing is an important step in the process of learning about the contamination and its potential impacts on people. The Board will also be hearing more about the spill at upcoming meetings on April 23 and May 19, which she hopes will include some of the new monitoring results. 

“This situation is complicated, multi-faceted, and raises many questions,” she said. 

Enbridge is monitoring the site, said Juli Kellner, a communications staff member for the company, and working with the DNR and local homeowners as remediation continues. 

Laura Schulte can be reached at leschulte@jrn.com and on Twitter at @SchulteLaura