PFAS may linger at Marengo fire site

Besides petroleum products that have leaked from a Marengo explosion site, state regulators also are worried about toxic chemicals from foam used to fight the Dec. 8 blaze.

More than 20 Iowa fire departments responded to the explosion and fire, which injured up to 15 people and caused an evacuation of houses near the C6-Zero plant.

One or more of the departments brought drums of firefighting foam that may be aqueous film-forming foam, a product used for decades to suppress liquid fuel fires. That foam is being phased out because it contains per- and polyfluoroalkyl substances — or PFAS, commonly called “forever chemicals” — that are harmful to humans and animals.

“We used 2,000 gallons of foam from several different fire departments,” Iowa County Emergency Management Coordinator Josh Humphrey said. “For these big commercial fires like this, you get what you get when you call for help. We’re not faulting anybody.”

The Iowa Department of Natural Resources on Jan. 6 took water and soil samples near the site to test for PFAS, Humphrey said. Results are expected back later this month.

Barrels of leftover foam at the site, now surrounded by inky black water, also will have to be disposed of safely.

The Iowa City Fire Department helped battle the C6-Zero fire, but did not bring firefighting foam, Chief Scott Lyon told The Gazette. Without foam, fighting a fuel-based fire is very difficult, he said.

“Without a surfactant agent, putting this type of fire out is next to impossible,” he said. “Without an extinguishing agent, your options are to let it burn out or use copious amounts of water, which makes the petroleum product spread exponentially farther.”

Lyon said the firefighting community is looking for PFAS-free alternatives to the aqueous foam, but so far options are limited.

The Iowa DNR has prohibited fire departments in the state from buying new foam as of January 2022, Humphrey said.

The Eastern Iowa Airport has been negotiating with a couple who lives near the airport whose drinking water well is contaminated with PFAS, which may be linked to firefighting foam used at the airport since the 1960s.

However, PFAS also have been found in many other substances, including clothing, carpet, cleaning products, plastic and paint.

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