What Can Be Done About Environmental and Health Concerns Around PFAS in Firefighting Foam?

TECHNOLOGY TODAY | BY DANIEL J. CHO

For decades, aqueous film-forming foam (AFFF) has been a firefighter’s friend, prized for its ability to spread rapidly across the surface of most hydrocarbon fuels, providing dramatic fire knockdown. AFFF has stopped a lot of fires, saved a lot of buildings, and protected a lot of lives.

But now, there are safety concerns associated with one of the key ingredients in AFFF that provides its fire suppressing punch. This risk is from per- and polyfluoroalkyl substances, collectively known as PFAS, a group of manufactured chemicals that have been used in a wide range of products for more than 50 years.

• Understanding the Impact of PFAS in the Fire Service
• Hacking Your PFAS Exposure
• Researcher Responds to Claims About PFAS, Firefighter PPE
• Stop Wearing Your Gear: A Call for Change in Firefighting Practices

PFAS show up in fire stations in many places:

• In breathable outerwear clothing.
• On nonstick frying pans in the kitchen.
• In pizza boxes and hamburger wrappers in the trash.
• In vehicles, tanks, and other places that AFFF is stored.

PFAS are often called “forever chemicals” because their molecules are persistent and will not easily break down. This, ironically, is one reason PFAS are such key ingredients in firefighting foams—PFAS molecules include combinations of carbon and fluorine, which is one of the strongest chemical bonds known to science. This makes the foam able to survive the high temperatures of a fire without breaking down so it can do its fire suppression work.

But those same strong molecular bonds make PFAS difficult for the human body to clear once they are ingested. The fact that PFAS “bio-accumulate” in the body has put them in the regulatory crosshairs of many environmental scientists, including some at the U.S. Environmental Protection Agency (EPA). There is growing concern about health impacts, even at low concentrations measured in the parts per trillion range.

There are hundreds of types of PFAS, but regulators’ primary concerns are around two specific types of legacy PFAS—perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), which were the most used in AFFF and in consumer products.

The EPA is updating the list of chemicals subject to toxic chemical release reporting under the Emergency Planning and Community Right-to-Know Act and the Pollution Prevention Act. This action updates the regulations to identify seven per- and polyfluoroalkyl substances (PFAS) that must be reported as described in the National Defense Authorization Act for Fiscal Year 2020. This rule, published in the Federal Register on May 17, 2024, went into effect June 17, 2024.¹

The EPA says that peer-reviewed studies have found that exposure to PFAS may lead to the following:

• Reproductive effects such as decreased fertility or increased high blood pressure in pregnant women.
• Developmental effects or delays in children, including low birth weight, accelerated puberty, bone variations, and behavioral changes.
• Increased risk of some cancers, including prostate, kidney, and testicular cancers.
• Reduced ability of the body’s immune system to fight infections, including reduced vaccine response.
• Interference with the body’s natural hormones.
• Increased cholesterol levels and risk of obesity.

PFAS Implications for Firefighting

There are three main areas in which PFAS is causing concern among the firefighting community:

1. Employee health and safety: Any product that is of concern at levels that can barely be detected by the latest sensory equipment—in parts per trillion—is something that is of health and safety concern. This can include firefighters breathing in PFAS-containing spray or foam or ingesting it through the digestive system. Yet, there are no clear guidelines on this matter.
2. Current firefighting systems: AFFF has become a firehall staple because it works. Currently, there are only experimental, nonfluorine foam products that might act as a replacement. Leaders in the firefighting community will need to carry on a balancing act in years to come—limiting employee exposure to potentially hazardous materials while retaining effectiveness in firefighting. But there will be increasing pressure to remove any PFAS-containing materials from the premises, possibly using one of several new technologies for destroying the PFAS molecule so it breaks into harmless molecules and atoms. Some waste-disposal companies offer services to destroy PFAS-containing materials.
3. Impacts at fire training sites: PFAS hot spots can develop at fire training sites, where large amounts of AFFF may have soaked into the ground, possibly contaminating groundwater, which then spreads widely. Many nearby residents are concerned about potential risks to their well water supply.

Three Emerging Technologies for Destroying PFAS

Here are three of the methods for PFAS destruction that have been tried at bench and pilot scale. Fewer have been developed to be ready for commercial use.

1. Plasma: This technology destroys PFAS molecules by harnessing the fourth state of matter, plasma. Within the plasma vortex reactor, a voltage gradient is applied between two electrodes. This creates an electric field that strips electrons from the inflowing gas molecules, creating charged ions and releasing a plasma discharge. The ions, which are charged particles, and the high-energy electrons are highly chemically reactive and can break down PFAS molecules (Figure 1).

Figure 1. Disposing of PFAS with No Waste

Plasma vortex is one of the technologies experts are using to destroy PFAS molecules in substances like AFFF. The figure above shows a powerful method of disposing of PFAS efficiently and quickly. This unit is capable of destroying PFAS with no waste. (Figure 1 courtesy of Onvector LLC.)

1. Supercritical water oxidation (SCWO, pronounced “squo”): Water above 705°F and pressure of 221.1 bar is considered “supercritical,” a special state where chemical oxidation processes are accelerated. It may be that SCWO will prove to be a practical way to destroy PFAS by breaking the strong carbon-fluorine bonds and decomposing the material into a nontoxic waste stream. Like many technologies for destroying PFAS, it has been shown to work, but the hard work will be showing that it can do this reliably and cost-effectively.
2. Electrochemical (EC) oxidation: This is a water treatment technology that uses electrical currents passed through a solution, such as PFAS-containing water, to oxidize pollutants. Advantages of EC oxidation include the following:
   • Low energy costs.
   • Operation at ambient conditions.
   • The ability to be in a mobile unit.
   • No requirement for chemical oxidants as additives.

Limitations of this technology include difficulty to scale up to commercial volumes and the potential generation of toxic byproducts.

Class B fire suppressants (AFFF) were developed by scientific innovators and introduced to the military and to firefighters to extinguish fires involving flammable liquids and gases. The intent was surely to empower and to protect our first responders and those who defend the nation in putting out some of the most dangerous types of fires. But ironically, over time, clinical research has begun to show that the innovative PFAS chemicals that were supposed to protect are also causing harm.

The best that scientists and engineers can do for our first responders is continue to innovate and develop cost-effective technologies that remove PFAS from the environment. We need to destroy these forever chemicals so they no longer cause harm to humans, especially to the very people whose jobs are to protect the rest of us.

REFERENCE

1. “Implementing Statutory Addition of Certain Per- and Polyfluoroalkyl Substances (PFAS) to the Toxics Release Inventory Beginning with Reporting Year 2024.” Federal Register, 17 May 2024, bit.ly/4cEMYRb.

DANIEL J. CHO is a graduate of Harvard University and CEO and founder of Onvector LLC.