Class A and Class B Firefighting Foam

There are two major types of firefighting foam, Class A and Class B. Class A foams are used to extinguish fires caused by wood, paper, and brush. Class A foams generally do not contain per- and polyfluoroalkyl substances (also known as “PFAS”).

Class B firefighting foams are commercial surfactant solutions that have been (and continue to be) stored and used for fire suppression, fire training, and flammable vapor suppression at military installations and civilian facilities and airports, well as at petroleum refineries and bulk storage facilities, and chemical manufacturing plants and storage facilities. Additionally, local fire departments in communities have used and may maintain quantities of Class B firefighting foam in their inventories for use in training and emergency response.

Class B foams can be divided into two categories: fluorinated foams and fluorine-free foams. Fluorinated foams contain PFAS, and fluorine-free foams do not. Of the fluorinated foams, aqueous film forming foams or “AFFF” are the foams that contain varying amounts and mixtures of PFAS, and of the most concern to human health and the environment.

Class B Fluorine-Containing Firefighting Foams

AFFF foams have the potential to create an adverse environmental impact if released uncontrolled to the environment, particularly if the foam solutions reach drinking water sources, groundwater, or surface waters. PFAS contamination has been identified at many locations across New Hampshire where AFFF products were stored and/or discharged in multiple ways including but not limited to: through applications associated with fire or catastrophic events, system discharge or false activation, firefighter training, and system testing.

October 2, 2017, NHDES issued a letter to fire departments recommending that they voluntarily test on-site drinking water supply wells for PFAS. We are working with several fire departments that have identified PFAS contamination at their facilities to investigate the source(s) and extent of impacts, and develop a remedial action plan to address impacts as appropriate.

NH RSA 154:8-b Limiting Use of Class B Fluorine-Containing Firefighting Foams

During the 2019 legislative season, the NH Legislature adopted Senate Bill 257 relative to PFAS in firefighting foam and firefighter protective clothing. NH RSA 154:8-b includes requirements designed to reduce environmental contamination and to reduce the risk of public health impacts for firefighters and New Hampshire citizens. NH RSA 154:8-b prohibits foams containing PFAS for use in testing or training on or after January 1, 2020. NH RSA 154:8-b also bans manufacturers of Class B foams containing PFAS from knowingly selling or distributing these foams in the State of New Hampshire unless otherwise specifically exempt. Refer to the jointly issued Technical Bulletin by the Department of Safety and the Department of Environmental Services that includes Frequently Asked Questions.

If Class B firefighting foam containing PFAS is discharged, NH RSA 154:8-b requires the municipality of the fire department that discharges Class B foam containing PFAS to notify NHDES within 48 hours of making the discharge.

To report a discharge of Class B foams containing PFAS, contact Amy Doherty of the Waste Management Division, Hazardous Waste Remediation Bureau at 603.271.6542 or

NHDES AFFF Activities and Priorities

NHDES has several actions planned in order to support the firefighting community and comply with new legislation, including but not limited to the following:

  • Collaborate with the State Fire Marshal and conduct a state-wide survey of fire departments and their current inventory of Class B foams containing PFAS, and report results to the legislature by 12/31/2020.
  • Provide support to Fire Departments in selecting fluorine-foam alternatives.
  • Initiate a Class B foam take-back program on or before July 2021.
  • Provide technical support in identifying tools and resources for Fire Departments to better understand and implement best management practices for management, use, and disposal of Class B firefighting foam.
  • Once Class B firefighting foam has been discharged, work with the stakeholders to identify any impacted water supply wells and provide safe drinking water, investigate impacted media, and develop a plan to clean it up, as appropriate.

Additional Resources

 The Interstate Technology Regulatory Council (ITRC) Fact Sheet about Class B firefighting foam.