Read the full article by Samuel Blackstone

“In 1970, innumerable gallons of toxic, chemical-laden firefighting foam started contaminating the grounds of Sioux Falls Regional Airport. Almost 50 years later, the city is now dealing with the consequences.

Today, 19 municipal wells sit dormant. Chemicals linked to cancer and other health maladies have contaminated 15 of those wells, including 10 with concentrations above what the Environmental Protection Agency deems safe. Foam use by the South Dakota Air National Guard and Sioux Falls Fire Department is the cause.

As city officials grapple with the well shutdowns — representing 28 percent of the city’s water production from the Big Sioux aquifer — it may soon face an even larger challenge when citizens begin to learn how long their drinking water was contaminated before it was detected and the wells taken offline. As that question looms, the contamination’s scope remains unclear…

About half of Sioux Falls’ drinking water demands — 7.73 billion gallons in 2017 — are met by the Big Sioux River, Big Sioux aquifer and Middle Skunk Creek aquifer. Before water drawn from those sources reaches residents, it’s routed to the city’s water purification plant just east of the airport.

In 2011 and 2012, treated water leaving the purification plant and heading to homes was sampled for chemicals within firefighting foam, known as per and polyfluoroalkyl substances (PFAS). The results, which the city received in 2013, showed PFAS but at levels below the EPA’s health advisory level, a baseline amount of exposure at which there are no expected adverse health risks…

In response to the detections, the city began testing all 69 municipal wells to identify the source. Every well with PFAS was shut down…

In 2014, the city tested for PFAS as part of an EPA-mandated water sampling program. In 2016, when the EPA dropped its advisory level to the current 70 parts per trillion threshold, it tested again. There were no detections in 2014 but low levels of PFOS were found in 2016.

More wells were subsequently shut off. Today, the 19 offline wells are no longer sampled, but water leaving the city’s purification plant is sampled monthly. No water samples have contained PFAS since 2016. In October 2016, three years after the first detection, the city acknowledged the contamination in a news release.

Mark Meyer, drinking water program administrator for the Department of Environment and Natural Resources (DENR), said the city notified his office in 2013. Since then, Meyer said, the city has managed the situation ‘as best they can.’ …

According to a 506-page report by a DOD-hired consultant, the Sioux Falls Fire Department was responsible for fire protection at the airport from 1970 to 1991. During that time, it used foam for firefighting and allowed it to ‘dissipate in the area’ during weekly tests and training.

In 1991, the South Dakota Air National Guard took over firefighting responsibilities and conducted foam tests and training primarily on its base near the southern end of the airport’s two runways. Countless gallons of foam — neither the city nor the Air Guard kept records of use — were released in the area before eventually emptying into the city’s sanitary sewer system. Though the city ceased accepting foam-water solution at its wastewater treatment plant in 2013, once PFAS is released into the environment, it never breaks down.

The DOD report identifies 12 locations where foam was presumably released as well as the results of well sampling at those locations. Of the 17 wells sampled for PFOA/PFOS, 12 had concentrations above the EPA level, including one well 3,500 times that level.

Results of the city’s municipal well sampling were not part of the base report and have not been disclosed by the city. But the report notes that municipal well 10 had PFAS concentrations 200 times the EPA level. City testing of a few private wells near the airport’s southern boundary found some PFAS detections that were shared with well owners, Lubbers said. ”