Author(s): Jesse Roman. Published on July 22, 2022.

The New Foam

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.


This article will appear in the Fall 2022 issue of NFPA Journal.

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.

SIDEBAR: The old foam worked, but at a potential cost to human health and the environment
• RESEARCH“Firefighting Foams: Fire Service Roadmap, a report from the Fire Protection Research Foundation

“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.”

Firefighters discharge foam onto a simulated crashed plane during a drill last year in Ankara, Turkey. For decades, AFFF has been a mainstay at airports around the world for its ability to quickly extinguish liquid fuel fires.  GETTY IMAGES 

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.


Many of these complications arise from the simple fact that these new foams lack fluorine, a critical component of how AFFF works to suppress liquid fuel fires. When water alone is used on a liquid fuel fire, it can spread and possibly even accelerate the blaze. But combining water and an AFFF concentrate of 3–6 percent creates a frothy mix of billions of tiny bubbles light enough to sit atop the burning fuel and dense enough to begin to smother it. The fluorine also contains a small electrical charge that repels the fuel like an opposing magnet, creating a microscopic layer between the bubbles and the surface of the fuel. As liquid slowly drains out of the bubbles, it is held at the surface by this charge and “forms a very thin layer that covers the fuel, holds the vapors down, and to some extent cools the fuel,” Souza said. Without the fluorine, the denser liquid sinks below the fuel and its burning vapors and is much less effective. 

Manufacturers and scientists have tried unsuccessfully for years to achieve a similar film layer without the PFAS-causing fluorine. “These fluorine-free foam products don’t make a film on the fuel like AFFF,” Back said. “They work simply by providing a physical barrier of bubbles that contains the fuel vapors and prevents them from mixing with oxygen. AFFF had two mechanisms to put out the fire; these new products only have one.”

That distinction has major implications for how the two foams perform. AFFF is extremely forgiving and versatile, able to put out fires in a single pass regardless of how aspirated, or foamy, the substance is coming through the hose. The new formulations, however, are highly dependent on what Back calls “foam quality,” meaning dense, highly aspirated bubbles. Even with a denser foam blanket, tests have shown that firefighters must discharge more fluorine-free foam on a liquid fuel fire to achieve the same results as AFFF. “AFFF also tends to be more forgiving when you’re trying to flow around obstructions in the fire field,” said Back, who conducted the fire tests and co-authored the 2020 Research Foundation report. (Back’s work won the 2020 Foundation Medal, awarded to the project that best exemplifies the Research Foundation’s fire safety mission.) The bottom line, he said, is that it takes roughly twice as long to put fires out with these new products compared to AFFF. 

The higher degree of aspiration that the new foams demand may require fire departments to invest in new hose nozzles. They will also need to retrain firefighters on how to extinguish liquid fuel fires, taking into account the limitations and properties of the new foams. During several of the large-scale fire tests, Back brought in firefighters who had never used fluorine-free foams to observe their tactics and note any challenges. In exercises involving kerosene-based fuels, which include jet fuel, the foam blanket that firefighters had laid down began to dissipate in spots around them as they advanced on the fire. “The fire spread to these holes,” Back told a rapt audience at the recent NFPA conference, as a video of the fire played. “The firefighters needed to take a step back, address the holes, and then keep going. Eventually, we decided to slide one hoseline handler back to survey the foam blanket for holes and watch for reflash.” 

Overall, Back characterized the firefighters’ initial performance as awkward. “They had no technique and they seemed to be constantly thinking about what they were doing,” he said. “The fires always got worse before they got better. But eventually, by the end of the week, they got the hang of it. The takeaway is that training is going to be key.” 

Other issues that have emerged wherever AFFF has been replaced include the disposal of remaining AFFF concentrate and the assessment of equipment that may be contaminated. Some states have offered to dispose of fire departments’ AFFF for free through takeback programs; departments that aren’t so fortunate must foot the disposal costs themselves, which can run up to $20 per gallon, Back said. Even departments that can easily offload their AFFF are still confronted with the thorny question of how to ensure their new foam isn’t tainted with residual AFFF.

“I worked with Los Angeles County to help transition their foam trucks to fluorine free, and one of the questions we couldn’t answer was how clean the existing tank has to be to make the transition,” said Hawthorne, a co-author of the Foundation’s roadmap report. “To this day there is still no regulatory number that has been agreed upon across the US. Do you wash it once or five times? That’s important because every time you wash out a 1,000-gallon foam tank, all that rinse water is contaminated and now you have to collect and dispose of 1,000 gallons of contaminated water. You can’t put it down the sewer drain. What do you do with it? Even that is still a question.”


In 2004, a study commissioned by a group called the Fire Fighting Foam Coalition estimated that there was roughly 10 million gallons of AFFF concentrate in the United States and its territories. About 10 percent of it belonged to municipal fire departments, the report found. The vast majority—more than 80 percent—resided on military bases, airports, and at gas and oil facilities. 

While the amount of AFFF at petroleum facilities has likely been greatly reduced since then, large quantities remain at airports and military installations, which are still required by federal standards to use AFFF. Much of this fluorinated foam resides inside fixed suppression systems, which sit at the ready to discharge thousands of gallons of foam to protect key infrastructure including aircraft hangers, fuel storage tanks, and refueling stations in the event of a fire. 

To the US military, the nation’s largest user of AFFF, the performance differences between AFFF and fluorine-free foam can be significant. When a pool of jet fuel is burning on an aircraft carrier loaded with highly explosive military ordinance, there’s no room for uncertainty. The same goes for the Federal Aviation Administration (FAA), which is charged with keeping millions of air travelers safe at the nearly 20,000 private and public airports the agency oversees.

For decades, the US Department of Defense has set its own performance specification standards for firefighting foams on its bases, referred to as MIL-SPEC. Since 2017, the DoD has spent at least $28 million on funding research to identify fluorine-free foams that can pass MIL-SPEC performance tests, which includes being able to extinguish a fuel fire in less than 30 seconds. To this point, not one of the dozens of new foams has managed to pass each part of the rigorous test, and as a result, no FAA-regulated airports or military facilities have yet abandoned AFFF.


But that will soon change. As part of the National Defense Authorization Act passed by Congress in late 2019, the US Navy is required to publish a new military specification for a fluorine-free foam by the end of January 2023 and is required to make a full transition to fluorine-free firefighting foams by October 2024. Congress had imposed earlier mandates on the FAA to transition airports to fluorine-free foams by October 2021, but that deadline was missed. The new MIL-SPEC regulations now being written will pave the way for both airports and military bases to make the switch, which by all accounts will be a massive undertaking requiring a significant investment. According to a report to Congress last October, the military still has about 3 million gallons of AFFF concentrate remaining at its facilities, and it is estimated that civilian airports have at least three times that.

Although the military has yet to officially approve a fluorine-free foam for use at its facilities, there are now a few dozen products that have passed performance tests developed by credible testing and approval authorities, such as UL. Of the 70 or so fluorine-free foam products now on the market, about half have credible approvals/listings, according to the Research Foundation’s roadmap report.

The NFPA standards that address foam suppression—including NFPA 11, Standard for Low-, Medium-, and High-Expansion Foam, and NFPA 30, Flammable and Combustible Liquids Code, as well as NFPA’s suite of standards for the protection of airfield and airport facilities—focus mainly on hardware and do not stipulate which type of foam can or should be used. As such, little has changed so far in NFPA 11 regarding the transition to fluorine-free foam, other than adding information about the new foams in the Annex, said Back, who is a member of the technical committee. Since the new foam concentrates are still undergoing testing, there hasn’t yet been a need for significant changes to the design or protection strategies outlined in NFPA 11 for fixed-system foam application.

“The testing data seem to suggest that you’re probably still OK using these new products in legacy systems in many applications, as long as you go through the right process of getting it approved for that application,” Back said. An important caveat to that, however, is that the new foams have not yet been tested by a major real-world event. If a catastrophic incident did reveal flaws in how well the new foams perform within existing system designs, it would likely result in the technical committee revisiting those design parameters, Back said.

But this does not mean that facilities can simply replace the existing AFFF concentrate in their fixed systems with a fluorine-free foam. In fact, the experience of facilities that have made the switch suggests an array of new challenges and considerations. 

As with fire departments, the first problem facilities face is figuring out which new foams will meet their needs. Whereas AFFF is a one-size-fits-all solution that can put out most fuel fires the same way every time, the effectiveness of a fluorine-free foam depends on myriad factors, including the type of fuel being protected, the depth and temperature of the fuel, and more. Those factors inform which foam concentrate is used, which in turn dictates the necessary equipment and discharge devices, Souza said. “It becomes really specific to the application,” he said. “You can’t do anything until you answer the question of which concentrate you’ll use, and everything else flows from that.” 

Once the concentrate is selected, the engineering work is only just beginning. For one thing, the AFFF in the jars on Souza’s mantle have a viscosity similar to water. By comparison, some fluorine-free concentrates are so thick that you could turn a glass of it upside down and none would spill out. Others have a consistency more like ketchup or Jell-O. “The existing equipment is not calibrated correctly to handle that,” Souza said. “I wish we could say to users, ‘here are the new bubbles, put it in your system and it will work.’ But it’s way more complicated than that.”

All of those issues were in play on a project Souza led recently to design and install a new fluorine-free fixed foam system at Nantucket Memorial Airport in Massachusetts, one of the first such undertakings at an airport in the US. The viscosity problem, coupled with other factors including the increased densities and application rates required for the new foams to work, were engineering challenges that weren’t cheap to solve. Virtually every part of the foam system that protected the airport’s fuel storage and transfer area had to be replaced, a scenario that’s likely indicative of what most airfield facilities will face.

“As we started digging into what it would require to switch to a fluorine-free system, it just snowballed from the engineering standpoint,” Souza said. “Pretty much every airport is completely freaking out about how they are going to get this foam thing taken care of.” 

Oil and gas facilities have faced similar engineering challenges, Hawthorne said. Larger companies such as Shell, Chevron, Exxon, and BP have conducted extensive studies on the performance of fluorine-free foams and are either in the process of converting their AFFF systems or have already done so. “Some of the hardware needs to be recalibrated, some of it needs to be replaced. It’s the same kinds of questions with the storage tanks and fire trucks,” said Hawthorne, noting that municipal fire departments may also need to replace or recalibrate fire pumps on trucks that carry foam. The new hardware and specifications have also meant that the workers who service and maintain the equipment need to be retrained, as do any firefighters that work at the site. That involves rewriting training manuals and reworking operating procedures, Hawthorne added.

The petroleum industry has long relied on AFFF to snuff out fires at facilities worldwide, on both land and sea. Here, firefighters in the United Kingdom spray foam onto oil storage tanks during a fire at a depot on the outskirts of London.  GETTY IMAGES 

There is also the lingering issue of how to inform and educate outside firefighters and contractors about the new foams and systems. Many oil and gas facilities do not employ a full-time fire department onsite and rely instead on local municipal fire departments to assist during an incident. 

“I may have a terminal that is going to switch out the foam to fluorine free, but the municipal fire department I’m working with is still using AFFF,” Hawthorne said. “If you just spent a lot of money to replace the AFFF, you don’t want your mutual aid partners to come in and contaminate your facilities if you have a fire, so we have to work with them to figure out how to handle that. The petroleum industry is still grappling with that challenge across the world, from Rotterdam to Singapore to New York.”


Though numerous petroleum facilities and some fire departments have already made moves to replace AFFF, a large percentage remain reluctant to do so. Back estimates that roughly 20 percent of the petroleum industry has made the switch, but little data is publicly available to confirm the actual number. “I think the rest of the industry is still playing a wait-and-see game just to see whether the products get a little bit better,” he said. 

One issue consistently raised by experts is what is referred to as “transition regret.” Since the early 2000s, the industry has moved through a number of different AFFF formulations, with each eventually phased out due to health and environmental concerns. Although fluorine-free foams may not contain PFAS, nobody can say yet with certainty that the chemicals they do contain won’t eventually be found to be hazardous in other ways. “Nobody wants to transition to fluorine free and then in three or four years have to transition again,” Hawthorne said. “A large refinery might have 20,000 to 40,000 gallons of foam concentrate, so replacing all of that is no small matter.”

Municipal fire departments must consider numerous factors as they determine when and how they might switch to fluorine-free foam. In states where AFFF has been banned or restricted, the movement has been swifter as the sunset date for AFFF approaches. Resources, department size, and what types of facilities a department protects are all factors that likely contribute to how well-informed individual fire departments are on the foam issue, Hawthorne said. 

“Big-city departments like Chicago, LA, Atlanta, New York—particularly the more progressive ones that also have airports to protect—are probably actively engaged in this transition,” Hawthorne said. “When you look at smaller departments, which are the vast majority of fire departments in US, I think we would find they are either unaware, or are aware and not sure what to do. That was the whole purpose of the Foundation’s roadmap report—to provide those fire departments with a guide for how to do it.”

There is reason to believe that the Foundation’s guidance document could become very important very soon. Many experts like Hawthorne believe that the effort to replace AFFF is going to shift into high gear as soon as the new fluorine-free military specifications are published early next year. The first fluorine-free foams that the military officially approves will likely trigger large purchases by the US government and high-profile airports, which will signal to hesitant petroleum facilities and fire departments that it is time to move forward. “When that happens, fire departments all over US are going to say ‘we now have foams that we can use,’ and will start to make the jump to fluorine free,” Hawthorne predicts. New firefighter protocols and training, along with updated equipment and other key changes, will need to follow soon after, experts say. 

Acknowledging that the journey has only just begun, the Research Foundation has applied for additional funding to continue its efforts to keep stakeholders informed. The proposed new project will aim to generate recommended best practices and tactics guidance for firefighters using the new fluorine-free foams. The results could help inform badly needed new training programs for departments across the world as they make the transition away from AFFF.
Ongoing research will also be vital, Back said, to stay on top of changes as foam technology continues to evolve. “We’ve done hundreds of fire performance tests over the past five years on the various capabilities of these products and there is no question that the manufacturers are tweaking their formulations and making them significantly better as we go,” he said. Some manufacturers even claim to have developed fluorine-free foam concentrates with low enough viscosities to work with minimal changes to existing infrastructure.

Regardless of the final capabilities of new-generation foams, it will matter little if facilities managers don’t spec the right foam or if firefighters aren’t adequately trained to use it. Hawthorne, Back, and others believe that the new foams are good enough as currently formulated to handle whatever situation is on the other end of the 911 call. Now it’s up to the safety community to get ready.

JESSE ROMAN is senior editor at NFPA Journal. Top Photograph Courtesy of Gerald Back