Tests of groundwater at two former firefighter training areas at the Madison airport have revealed hazardous chemicals known as PFAS at levels thousands of times higher than recommended health standards.
An environmental contractor hired by the Dane County Regional Airport found combined levels of two chemicals — PFOA and PFOS — at more than 68,000 parts per trillion in water collected from a site near Darwin Road, according to a report submitted last week to the Department of Natural Resources.
Samples taken from a site near Pearson Street found levels in excess of 20,000 ppt.
The Environmental Protection Agency recommends against consuming water with more than 70 ppt of PFOA and PFOS combined, while Wisconsin’s Department of Health has proposed a safe drinking water standard of 20 ppt for the two.
In June 2018, the DNR notified Dane County, the city of Madison and the Wisconsin Air National Guard that they share responsibility for the contamination at the two sites, which were known as “burn pits” used for firefighter training between the 1950s and 1980s.
Last year Mayor Satya Rhodes-Conway told the DNR the city should not be responsible for the burn pits, but the DNR maintains that the city provided firefighting services for Truax Field and owned the Darwin Road site until 1974, when the federal government required the use of PFAS foams at military bases.
The city announced the test results Tuesday after they were posted to the DNR’s spill database, saying “questions still remain about how the samples at these sites compare to surrounding areas, and how shallow groundwater moves around the site and toward Starkweather Creek.”
Previous tests have found high levels of PFAS in Starkweather Creek as well as in fish from the creek and Lake Monona, prompting health officials to warn against eating some fish.
The city also noted the samples were from “shallow groundwater that is separate from the deep aquifers” that municipal wells draw from.
Maria Powell, executive director of the Midwest Environmental Justice Organization, said the test results are not surprising but she is frustrated that cleanup has not begun.
“We point fingers and all this time goes by and it’s not cleaned up and it’s oozing into Starkweather Creek and people are eating the fish,” Powell said. “They could have tested it years ago.”
The Madison water utility, which has found some levels of PFAS in every well, shut down one well along East Washington Avenue last year when PFOS and PFOA levels reached 12 ppt. The utility has launched a $50,000 study of options to remove the PFAS, which it believes originated from the Wisconsin National Guard’s Truax Field.
This fall the city council approved $50,000 in the 2021 budget for “testing and planning at the Dane County Regional Airport, Air National Guard 115th Fighter Wing Base, and surrounding area.”
The Dane County Board last year approved $200,000 to address PFAS contamination at the airport.
The Wisconsin National Guard announced Tuesday that Truax Field has received authorization from the federal National Guard Bureau to begin evaluating the extent of contamination and the risk to human health, though the timeline for that evaluation has yet to be determined.
PFAS are a group of largely unregulated synthetic compounds found in firefighting foam as well as food packaging, non-stick cookware, water-resistant clothing, carpeting and other products that have been shown to increase the risk of cancer and other ailments. They are known as “forever chemicals” because they don’t break down in the environment.
They have been found in drinking water, groundwater, surface water, soil, sediments, air, fish and wildlife as well as human blood samples.
The airport burn pits are among more than 40 PFAS contamination sites being monitored by the DNR.
The Madison Fire Department last year stopped using fluorinated firefighting foam. The 115th Fighter Wing uses foam containing different types of PFAS for emergency firefighting but only tests it in an enclosed system.