Skip to Content

Firefighting contaminants found in groundwater near site of MG&E substation explosion

MADISON (WKOW) — Firefighting foam with the contaminant PFAS was used to battle an electrical substation fire in Madison last July, and city officials are now analyzing the impact.

“We expect that there was probably some that went into the upper part of the groundwater, some that got into the lakes, it’s hard to contain it all,” Barrilleaux said.

However, she says it could have been much worse.

“If people are concerned that what happened at that site during that fire is going to have an immediate impact on their drinking water, that’s not the case,” Barrilleaux said.

This is according to data gathered by AECOM, a lab contracted by American Transmission Company, which is responsible for the substation, and released by the Wisconsin Department of Natural Resources on September 9.

It was only brought to the city’s attention Thursday, because of an apparent lack of communication.

On a quick glance, the data shows there was a large amount of PFAS detected in the soil and water near the substation.

Barrilleaux says you have to look deeper.

“When we look at those numbers, from our perspective, they’re not particularly high,” she said. “In most cases they’re surprisingly low.”

That’s because there are thousands of different types of PFAS that are commonly used to this day, but only two types that are most studied and most concerning and that have a recommended groundwater standard from the Wisconsin Department of Health Services.

Those two are PFOA and PFOS.

The report found one location where they appeared in higher concentrations than a recently proposed standard by the Department of Health Services of 20 parts per trillion (ppt).

PFOA was found at 24 ppt, and PFOS at 31 ppt.

That location was right next to the explosion where a burned power pole had to be removed, creating a hole in the ground that filled with water.

At three separate locations where storm water drains into the Yahara River and Lake Monona, PFOA was found at around 5 ppt and PFOS was found as high as 18 ppt.

The report also found a seemingly alarming amount of another type of PFAS called 6:2 FTS at that same power pole location, at 4900 ppt.

According to a report from the National Association for Surface Fishing from March of 2019, 6:2 FTS is considered dangerous in concentrations of 60,000 times higher, or 300 parts per million.

Barrilleaux said while the city is very concerned that firefighting foam with PFAS was used to fight a major fire, and could have seeped into surface groundwater and Lake Monona, efforts were made to mitigate the amount released to the environment.

Something that she says didn’t happen at Truax Air Field, where the city’s concerns mainly lie.

“In that situation you have firefighting training that was going on on the base for years with no effort for containment, with no remediation that has happened so far,” Barilleaux said. “We know that levels have been found in ground water on the base as high as 40,000 ppt.”

While she says the city doesn’t know for sure if that contamination fed into Well 15, they shut it down just to be safe.

“We didn’t shut down that well because we knew that water to be unsafe, we shut it down and took it offline because we had a concern, and don’t have enough information about what we found there,” she said.

Barrilleaux says the city still has more questions for the DNR about the new data, but it shouldn’t be nearly as bad as the concerns at Truax.

27 News contacted the DNR for more information about the report.

Francisco Almenara

Reporter, WKOW

Skip to content