NFPA Journal - Fall 2022 - 29

Many of these complications arise from the simple fact
more PFAS chemical at or above the minimum
reporting threshold.
The pervasive nature of the chemicals
has impacted the health of humans and
wildlife alike, according to government
and university studies conducted around
the world. In 2007, researchers tested
blood serum samples from about 2,100
" I have retired
colleagues whose
attitude I would
describe as outright
fear. For those of
us who essentially
bathed in it for
decades, I'm concerned
about what exactly
I've been exposed to. "
people from across the US and found that
more than 98 percent of the samples had
detectible levels of PFAS. According to
the Agency for Toxic Substances and Disease
Registry, exposure to elevated levels
of PFAS could cause increased cancer risk
and other health issues in humans. Some
of the non-cancer health problems with
suspected links to PFAS include elevated
cholesterol, thyroid disease, liver and kidney
damage, effects on fertility and low
birth weight, and immune suppression, according
to various studies.
" We all thought it was completely safe-
the warnings I read through the years said
don't drink it and don't get it in your eyes
because it stings, but it was not something
we would suit up for or take any extraordinary
precautions around, " said Jeremy
Souza, a longtime firefighter and former
deputy fire chief at T. F. Green International
Airport in Providence, Rhode Island.
Years ago, Souza and other firefighters
used the AFFF solution for a variety of applications,
including as an all-purpose
degreaser. " Now I have retired colleagues
whose attitude I would describe as outright
fear. For those of us who essentially
bathed in it for decades, I'm concerned
about what exactly I've been exposed to. "
-J.R.
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 to 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 coauthored the 2020
Research Foundation report. (Back's work won that year's
Foundation Medal, awarded to the project that best exemplifies
the 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 the 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 hose line handler back to
survey the foam blanket for holes and watch for reflash. "
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NFPA Journal - Fall 2022

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