FAQs: Science-Based Answers to Common Questions About AFFF

Firefighter carrying a rolled fire hose

Gathering facts about aqueous film-forming foam (AFFF) is necessary to understand the current health and environmental crisis caused by these fire suppressants. Anyone diagnosed with a disease or cancer following a career in firefighting or the military should know the truth, and not the myths and misconceptions, about firefighting foam.

Science-based answers to questions about the active ingredients in the foam and the characteristics of the chemical compounds help explain why AFFF is so dangerous, but unfortunately, FAQs cannot explain the negligence of the foams’ manufacturers. Thanks to dedicated researchers and truth-seekers, advocates for firefighters and their families can lean on chemical and biological evidence to tell the truth about AFFF.

What Is AFFF Made Of?

The active ingredients in aqueous film-forming foam are per- and polyfluoroalkyl substances (PFAS), a term describing industrial chemicals that contain a carbon chain and the element fluorine. These fluorosurfactants are responsible for the film-forming capabilities of the suppressants. Since the carbon-fluorine bond is one of the strongest in organic chemistry, foam made with these elements offers extreme strength and stability, and unfortunately, environmental persistence. 

Several other components in AFFF contribute to its performance:

  • Hydrocarbon Surfactants reduce the surface tension of the solution, allowing it to spread
  • Glycols control the viscosity and freezing point of the concentrate and boost the foaming capabilities
  • Foam Stabilizers help the foam stay intact
  • Polymers are optional, and used in alcohol-resistant foams and other iterations

What Does ‘Surfactant’ Mean Regarding AFFF?

AFFF contains surfactants, a contraction of ‘surface-active agents,’ that work by reducing the surface tension of a medium, increasing its wetting and dispersing capabilities. Each surfactant molecule features a hydrophilic (water-loving) head and hydrophobic (water-hating) tail. This duality is what makes PFAS products and substances resistant to heat, grease, and water, components present at nearly any fire.
The trouble with the composition of aqueous firefighting foams is that they contain hydrocarbon and fluorinated compounds. The fluorinated chemicals, PFAS, are added to improve the performance of the foam but their presence results in AFFF’s significant impact on the environment and human health.

What Are Alternatives to AFFF?

Fluorine-free foam is the most eco-conscious, effective alternative to AFFF because the chemical makeup of this suppressant lacks the hazardous fluorinated surfactants, yet still offers the blanketing barrier that makes firefighting foam effective.

Why Are PFAS Foams Difficult To Replace?

Aqueous film-forming foam made with PFAS is the only fire suppressant known to contain surfactants that simultaneously repel and attract oils and fats. The fluorosurfactant molecules in PFAS foam concentrate arrange themselves on top of a fuel’s surface to create a barrier (water film) between the foam and the fuel. The addition of fluorine offers advantages, including faster spread of the suppression and supreme stability, which are difficult to mimic with non-fluorinated formulas.

What Is the Difference Between How Fluorine-Free Foam and AFFF Work?

AFFF uses two methods to separate fuel from oxygen sources (a water barrier and a foam blanket), while fluorine-free foam uses only the foam blanket for suppression. Putting out a fire using fluorine-free foam may require greater quantities of the suppressant and more time, but this concentrate causes fewer environmental and health issues.

Frequently Asked Questions About AFFF and Health

AFFF and health consequences will forever be tied together, persisting as long as the chemicals themselves. Commonly asked questions and science-backed answers about the effects of AFFF on human health include:

Is AFFF Cancerous?

While AFFF itself is not scientifically classified as cancerous, the ingredients in the formulations are classified as carcinogens. Early versions of AFFF contain PFOS, or perfluorooctanesulfonic acid, a substance that the National Cancer Institute Working Group has classified as a possible human carcinogen, and PFOA, perfluorooctanoic acid, which was upgraded to human carcinogen.  

Does PFAS Stay in Your System Forever?

Though PFAS does leave the body eventually, the rate at which the elements decay is incredibly slow, and extreme half-lives have been observed in many cases. The Agency for Toxic Substances and Disease Registry reported that the estimated elimination-half-lives of PFAS in humans is 2 to 30+ years, depending on the compounds. This persistence in the body and the environment is how PFAS earned the moniker “forever chemicals.”

What Are the Health Risks of AFFF Exposure?

While the health risks of AFFF exposure are often summarized as ‘cancer-causing,’ the scientific answer for why these chemicals pose a danger to humans is that PFAS are endocrine disruptors, which are agents that mimic hormones and influence cancer development and progression.