For decades, aqueous film forming foam, or AFFF, has been the gold standard for extinguishing dangerous liquid fuel fires. Now, with AFFF being rapidly phased out and new firefighting foams being developed, the fire protection world braces for what’s next.


ON THE MANTLE IN HIS HOME OFFICE, beside antique fire alarm boxes, model fire trucks, and old fire helmets, Jeremy Souza once kept a collection of slightly stranger mementos: about a dozen jars filled with various amber liquids.

For years, as a firefighter and later deputy fire chief at T.F. Green Airport in Providence, Rhode Island, Souza would lug the jars to trainings for new firefighters. He’d pass the jars around and explain how the liquid inside, a chemical substance called aqueous film forming foam, or AFFF, worked to extinguish liquid fuel fires and even perform other feats of magic around the fire house.

“Back in the day at the airport, we used this stuff for just about everything short of brushing our teeth,” said Souza, who is now an engineer specializing in foam suppression systems at Code Red Consultants, a Massachusetts-based fire safety company. “AFFF is a wonderful degreaser. Take a half gallon of AFFF concentrate, throw it on a garage floor and hose it down, and the stain is gone. I would say that is more of an airport thing—municipal fire departments would never have dealt with quantities of foam like that. But we had loads of it.”

For a certain generation of specialized firefighters tasked with protecting airfields, oil and gas facilities, and military installations, Souza’s experience is probably relatable. For nearly six decades, AFFF has been as indispensable to their jobs as water is for structural firefighters, owing to its unique ability to quickly snuff out even the nastiest liquid fuel fire under a blanket of chemical bubbles. In the dangerous scenarios that can play out when large stores of fuel are threatened by fire, AFFF’s qualities as a fast and reliable suppression agent have literally been a lifesaver.


And yet, there is now near-universal agreement among health officials, environmental scientists, governments, and even firefighters that AFFF must go, preferably as soon as possible. 

Citing mounting evidence that the chemicals present in AFFF—known as per- and polyfluoroalkyl substances, or PFAS—are potentially damaging to the planet and to human health (see “The PFAS Problem”), there has been rapid movement around the world to limit or ban their use. In 2021 alone, the number of US states that banned or severely limited AFFF went from just a handful to at least 15, and legislation is pending in at least five other states to do the same. The US military, which helped develop AFFF in the 1960s, has announced plans to stop using it by October 2024, and the Federal Aviation Administration intends to follow suit at thousands of airports across the country. Several European countries have already stopped using AFFF, and in February the European Chemicals Agency proposed an outright ban on the manufacture, use, and export of AFFF for the entirety of the European Union.

“We can all allude to how good AFFF has been for us, but AFFF is going away. If you are still dwelling on that point, then you are behind,” Casey Grant, executive director of the research and engineering firm DSRAE LLC, told a room full of fire protection professionals during a presentation in June at the NFPA Conference & Expo in Boston. “There is no doubt that this issue is full of questions and complications for all of us, but we have to face the fact that this transition is happening.”

For Souza, the transition is happening in more ways than one. Late last year, he received a call from researchers who were looking for old samples of AFFF to study how its compounds break down over time. Some of the specimens on Souza’s mantle dated back nearly two decades, and he even had the original lot numbers from the manufacturer. “Apparently, I was the only fruit loop who thought that somebody might need these at some point,” he said. “So I handed over my collection and all the information I had.”

Others, however, may find the move away from AFFF to be a bit more complicated. For fire protection officials, many of whom are squeezed between fast-approaching government bans on AFFF and the continued need to quickly extinguish dangerous liquid-fuel fires, the transition raises two major questions: What will replace AFFF, and what will the transition look like?


For more than a decade, foam manufacturers have been working on possible replacements for AFFF. There are now dozens of foam products on the market that claim to be made without fluorine, a key ingredient in AFFF that is also a source of PFAS. Extensive testing by the Fire Protection Research Foundation, the US Department of Defense, and the petroleum industry research group LASTFIRE has shown that many of these new products can be effective at extinguishing liquid fuel fires under the right conditions. 

Unlike AFFF, however, the effectiveness of fluorine-free foam comes with a lot of caveats and complexities, said Jerry Back, a researcher at Jensen Hughes. Over the last five years, Back has conducted hundreds of fire tests on the capabilities of fluorine-free foams. “These fluorine-free foams are not a drop-in replacement for AFFF; they are new products with different characteristics and use different methods for putting out the fire,” Back told me in an interview this summer. Although the new foams perform “reasonably well,” their different properties mean that “the transition from AFFF is going to be much more complicated than you would initially believe,” he said. 

Recognizing an urgent need for guidance, the Fire Protection Research Foundation has released two seminal reports since 2020 on the topic, both co-authored by Back. The latest, “Firefighting Foams: Fire Service Roadmap,” published in June, aims to help fire departments understand the considerations for choosing a foam to replace AFFF, as well as the numerous factors, including new training and equipment, that will go along with it.

Those decisions will be critical, because testing conducted by the Research Foundation has shown that the performance of new fluorine-free foams can vary dramatically depending on factors such as the manufacturer, the type of fuel burning, how aspirated the foam is, the discharge devices used, and the techniques and tactics of the firefighters during the incident. Even when those factors align perfectly, Back said, it can still take twice as much foam and twice as long to extinguish a liquid fuel fire as it does with AFFF. “Because of the variables, one of the things that we emphasize in the roadmap document is that the end user, independent of who it is, is going to need to do their homework,” he added.

Those layers of complexity make the transition question difficult to answer, according to experts like Edward Hawthorne, the recently retired global emergency response manager for Shell Oil.

“The body of work that Jerry and the Research Foundation have done, as well as work by the Department of Defense and LASTFIRE, make me confident that we have agents that can put out spill fires and fires in liquid fuel tanks,” said Hawthorne, who is also an assistant fire chief in Texas. “I believe that the new foams are ready for prime time. Now we have to make sure the end users are ready for prime time, too.”  

Although much of the industry is bullish on the potential of the new foams, swapping out the old for the new will likely come with a steep learning curve and additional costs. Choosing which fluorine-free foam to use among the myriad options available is just the first step for fire departments. After that comes a plethora of other issues, such as how to dispose of the old AFFF, how to decontaminate old equipment, what new equipment might be necessary, and what new tactics and trainings need to be developed.