There are two types of foam, they include:
- Foam on lakes, streams, and creeks
- Firefighting foam
Foam on lakes, streams, and creeks
Most foam observed in lakes or streams is naturally occurring, and not an indicator of pollution. Foam is created when air mixes with natural organic compounds, such as decomposing plant material. The mixing or agitation in lakes is commonly caused by wind and wave action; in streams, it may result from water flowing through rapids or over a dam.
PFAS can also sometimes cause foaming on surface waters. In Minnesota, foam containing PFAS has been found in surface water pathways in the east metropolitan area of the Twin Cities which is a known area of PFAS contamination in groundwater and surface waters that was traced back to four landfills or dump sites.
As part of the 2018 3M Settlement, the MPCA is looking at how a flood-control project from the late 80s, known as Project 1007, may be contributing to the movement of PFAS in the east metro area. More information about Project 1007 can be found at the Minnesota 3M Settlement website.
One sample of PFAS-containing foam was also encountered on Battle Creek in St. Paul. Battle Creek is being investigated further through MPCA’s superfund site assessment program and is not part of Project 1007.
If in doubt, stay out.
PFAS-containing foam on surface water does not pose a risk to human health if skin contact with foam is minor and infrequent. The Minnesota Department of Health (MDH) recommends:
- People and pets should avoid contact with foam on surface waters in this area.
- Wash skin that has come into contact with PFAS-containing foam with soap and water.
Class B firefighting foam – also known as Aqueous Film-Forming Foam (AFFF) – is designed to extinguish fuel or flammable liquid fires. Some AFFF formulations contain PFAS.
MDH and MPCA have evaluated places where PFAS may have been released to the environment, including fire training facilities where special PFAS foams were reportedly used, chrome plating plants, wastewater treatment plants, and landfills. Although PFAS have been detected at many of these locations, most do not pose a risk to public health.
In 2019, the Legislature passed a law requiring that any class B firefighting foam containing PFAS that is used on a fire must be reported to the State Fire Reporting System within 24 hours. Use of PFAS-containing firefighting foam for testing and training is generally prohibited. The law is set to take effect July 1, 2020.