Minnesota State Fire Marshal Finding Triggers the PFAS Firefighting Foam Ban at Airports

Originally published in the November 2025 issue of Bench & Bar of Minnesota Environmental Law Update, Minnesota State Bar Association.

As explained below, on the basis of an August 2025 determination by the Minnesota State Fire Marshall, all airports in Minnesota must discontinue manufacture, sale, distribution, storage and use of PFAS-containing firefighting foams by January 1, 2026.

Starting in 2020, Minnesota began its transition away from using class B firefighting foams for testing and training purposes. Most legacy Class B foams contain intentionally added PFAS.

In 2023, the Minnesota Legislature updated the applicable firefighting foam statute (Minn. Stat. § 325F.072, subd. 3) to prohibit the use, manufacture, sale, and use of class B firefighting foam containing PFAS chemicals; however, the legislature granted an extended transition period for use at airports until the state fire marshal makes a determination that three criteria have been met. The three criteria are the following: (1) the Federal Aviation Administration (FAA) has provided policy guidance on the transition to fluorine-free firefighting foam; (2) a fluorine-free firefighting foam product is included in the FAA’s Qualified Product Database (QPD); and (3) a firefighting foam product included in the database under clause (2) is commercially available in quantities sufficient to reliably meet the requirements under Code of Federal Regulations, title 14, part 139. Until the state fire marshal made a determination that all three criteria were met, the operator of an airport using class B firefighting foam containing PFAS chemicals was required to, on or before December 31 each calendar year, submit a report to the state fire marshal regarding the status of the airport's conversion to class B firefighting foam products without intentionally added PFAS, the disposal of class B firefighting foam products with intentionally added PFAS, and an assessment of the factors listed above as applied to the airport.

After receiving a directive from Congress in December 2022, the FAA began to develop a transition plan to ensure the orderly transition from current aircraft fire fighting foam to a replacement firefighting foam. The FAA developed and published a transition plan on May 8, 2023. This transition plan satisfies criteria 1 of the factors to include in the state fire marshal’s determination.

As of July 23, 2025, there are four fluorine-free firefighting foam products listed on the FAA’s QPD from three different vendors. With at least one product included on the QPD, criteria 2 of the factors to include in the state fire marshal’s determination is satisfied.

To determine if criteria 3 was met, the Minnesota Department of Public Safety’s State Fire Marshal division (SFM) at the request of airport operators sent a standardized electronic form to collect the information required to be reported. The survey included a question on how many gallons of fluorine-free firefighting foam the airports had in current inventory and date of inventory. Additionally, airports were asked to provide the total gallons of PFAS-containing firefighting foam in inventory and the amount disposed of in 2024. The SFM emailed the electronic report to all airport operators, using a list provided by the Minnesota Department of Transportation Aeronautics Division. Sixty-five airports provided responses. The majority (87.5%) stated that they do not have equipment with PFAS or that their local fire department, who provides fire suppression protection for the airport, does not use PFAS-containing firefighting foams. The eight airports that reported using firefighting foams all stated they are either in process of transitioning to fluorine-free firefighting foams or have completed the transition. One airport (Duluth International Airport) completed the transition to fluorine-free firefighting foams in 2024. The Minnesota airports that indicated they are in the process of transitioning and their projected completion date include: Mankato Airport (projected completion date 7/1/2025); Minneapolis/St. Paul Airport (projected completion, end of fiscal year 2025); Range Regional Airport, Hibbing (projected completion date 9/30/2025); Rochester International Airport (projected completion, end of 2025); St. Cloud Regional Airport (projected completion, second quarter of 2025); Bemidji Regional Airport (projected completion date 9/30/2025); and Thief River Falls Regional Airport (projected completion 2025 if awarded a grant, 2026 if not). Based on the information from firefighting foam manufacturers and the reported amount of fluorine-free foam at Minnesota airports, criteria 3 of the factors to include in the state fire marshal’s determination is satisfied.

Using the relevant data discussed above, the state fire marshal has determined that all 3 criteria of Minn. Stat. § 325F.072, subd. 3 are satisfied and that airports can successfully and safely transition to fluorine-free firefighting foams in 2026. In a series of letters sent to Minnesota airports in late August 2025, State Fire Marshal and Director of Pipeline Safety Daniel Krier informed the airports of his determination and indicated they will have until December 31, 2025, to complete their transition and must discontinue manufacture, sale, distribution, storage and use of class B firefighting foams effective January 1, 2026.  Note, however, that the determination and deadlines do not apply to class B firefighting foams used in fixed firefighting systems in hangars at airports. Airport hangars are allowed to use class B firefighting foams until January 1, 2028, pursuant to Minnesota Legislature 2025 Special Session Chapter 1, Article 4, Section 21.