By Kenneth W. Fent, Ph.D., CIH, Gavin P. Horn, Ph.D., and Sean DeCrane | Fire Protection Engineering
USE OF FLAME RETARDANTS
structure fires present different risks to firefighters than structure
fires from several decades ago, due in part to the amount of synthetic
materials used in U.S. households. 1 These synthetic materials tend to be highly flammable and produce large volumes of smoke and effluent.2
Flame retardants have been added to many flammable household products
over the last 40 years, primarily to meet the California open flame
standard (TB 117) adopted in 1975.3 The TB 117 open flame
test was conducted on bare filling materials (e.g., foam). Consequently,
adding flame retardants to filling materials became a primary means of
meeting the standard.3
effectiveness of flame retardants at slowing the progression of a fire
depends on a number of factors, including the amount of flame retardants
used in the product, flammability of the fabric or other covering
around the product, orientation of the product relative to the ignition
source, and type of ignition source.4-8 In general,
flammability standards have not fully accounted for these variables and
have mainly tested two ignition sources (i.e., small open flame and
smoldering cigarette), even though several other types of ignition
sources have been indicated in fatal fires involving upholstered
furniture.8 Consequently, the fire safety benefits of adding
flame retardants to consumer products to meet these standards has come
under scrutiny.8 Recently, new flammability standards have
been adopted or proposed – including a revision to TB 117 – that allow
for other ways to reduce flammability beyond the addition of flame
retardants, such as incorporating barrier materials into the product.9-12
The National Fire Protection Association is also exploring the
development of flammability standards that are more representative of
to 2005, the most commonly used flame retardants— at least in
furnishings—were polybrominated diphenyl ethers (PBDEs) and tris
(1,3-dichloro-2-propyl) phosphate (TDCPP).14,15 Manufacture and import of PBDEs was phased out between 2003 and 2013,16 and several producers have committed to stop using TDCPP in favor of less hazardous alternatives.14
However, products containing these flame retardants will remain inside
structures for decades to come while they are gradually replaced by
products containing alternative flame retardants or products that meet
flammability standards by other means. While scientists have some
understanding of the biological absorption, distribution, and toxicity
associated with PBDEs, they are generally less familiar with the
alternative flame retardants currently being used, which include
brominated, chlorinated, chlorinated phosphorus, and mineral compounds.17
the two leading health concerns for the fire service are cancer and
cardiovascular disease. Sudden cardiac deaths have accounted for 42% of
the on-duty deaths in the last five years,18 and several
studies have indicated that firefighters have an increased risk of
several cancers compared to the general population.19 A NIOSH
cohort study of 30,000 career firefighters employed from 1950 to 2009
found an excessive risk of digestive, oral, pharyngeal, and laryngeal
cancers, as well as mesothelioma, when compared to non-firefighters.20
In addition to individual firefighters’ personal risk factors,
occupational factors may increase the risk of these negative health
outcomes. Occupational factors include physical exertion, heat stress,
and chemical exposure.
combustion will produce hundreds if not thousands of chemicals. These
combustion byproducts will often include known carcinogens (e.g.,
benzene, benzo[a]pyrene, formaldehyde) and chemicals that can affect the
cardiovascular system (e.g., carbon monoxide, hydrogen cyanide, and
fine particulate). Fate and transport of PBDEs during fires is not well
understood, but some of the compounds are expected to be released
unaltered into the fire building or as thermal decomposition products
such as brominated-dioxins, furans, or acid gases.
studies demonstrate that relatively high doses of PBDEs (i.e., >100x
the levels found in the general population) can cause adverse effects
on the thyroid, liver, and immune system, as well as neurobehavioral and
developmental alterations.21 Certain congeners also appear to be carcinogenic in animals.21 Dioxins and furans appear to produce similar health effects as PBDEs in animals.22
An alarming characteristic of PBDEs is that they are highly persistent,
fat soluble, and can bioaccumulate in the body. PBDEs, dioxins, and
furans have biological half-lives ranging from several days to years.21-24 Most alternative flame retardants are not persistent and can be excreted from the body within hours or a few days.25 However, animal studies suggest that some of these alternative flame retardants can also produce adverse health effects.26,27
EXPOSURE IN FIREFIGHTERS
are just beginning to understand the magnitude and composition of
occupational exposure to flame retardants in firefighters. It is
reasonable to expect flame retardants or their combustion byproducts to
be released during structure fires, resulting in an increased risk of
exposure for firefighters. Two studies have characterized PBDE exposures
in California firefighters; both found elevated levels of a variety of
PBDEs in serum compared to the general population.28,29 In
the most recent study, cleaning turnout gear was associated with reduced
serum levels of certain PBDE congeners, while interior fire suppression
within the last month was associated with elevated serum levels of
PBDEs.28 In a related study, investigators found
substantially higher levels of deca-BDE in dust in firehouses compared
to dust in California homes, possibly due to the tracking of
contamination from a fire incident to the firehouse.30 In
addition to PBDEs, metabolites of a variety of chlorinated and
brominated dioxins and furans were also detected in firefighters’ serum.29
firefighters could inhale flame retardants, dioxins, and furans during
periods of the response when they are not wearing SCBA. For example,
firefighters do not always wear SCBA during exterior operations
(deploying hose, forcible entry, outside vent) or during overhaul
operations. Firefighters’ PPE ensembles could also become contaminated
with these compounds and then transferred to the skin. A number of
studies have characterized contamination on PPE ensembles, focusing
primarily on PAHs, heavy metals, phthalates, and VOCs.31-34
Retired turnout gear was recently evaluated for a variety of
contaminants, and PBDEs were among the most abundant compounds measured.35Because
some flame retardants, dioxins, and furans are highly persistent, they
could accumulate on gear over time and transfer to the skin of
firefighters where they may be dermally absorbed or ingested. Studies
suggest that dioxins and furans may be more readily absorbed through
skin than PBDEs.22,36
possible exposure pathway is from the particulate and vapors produced
during a fire that may penetrate or permeate the protective barriers of
the turnout gear and directly contact the skin. Studies have
demonstrated that neck and hands are particularly vulnerable to this
exposure pathway.33,37 The current knowledge base on chemical
exposures during firefighting suggests that incident commanders may
need to consider the potential for chemical exposures when making
risk-versus-benefit tactical decisions during a fire response.
studies suggest that firefighters have higher biomarker levels of
certain flame retardants than the general U.S. population.28,29
Additional studies are currently underway to determine the predominant
exposure pathway, route of absorption, and biological levels of flame
retardants, dioxins, and furans in firefighters before and after
suppressing modern structure fires. Also, a Department of Homeland
Security (DHS) Fire Prevention & Safety (FP&S)-funded study was
initiated in June 2015. Questions that need to be answered include:
Are the levels of exposures in firefighters capable of causing adverse health effects?
How long do systemic exposures from the fireground remain with the firefighter (i.e., half-life)?
How much contamination can be expected on PPE ensembles following a fire response?
effective are gross decontamination or laundering procedures at
reducing PPE contamination levels and subsequent biological uptake in
How effective are simple skin cleaning procedures at reducing dermal absorption?
Can firefighters’ tactical choices reduce their exposure to flame retardants?
these questions is essential to provide evidence-based guidance for
protecting firefighters. Additional studies are needed to determine the
most effective ways to reduce the ignitability or flammability of
consumer products that balance fire safety with downstream chemical
exposure and toxicity.
WHAT CAN FIREFIGHTERS DO TO PROTECT THEMSELVES
can take measures now to reduce their exposure to combustion
byproducts, which in turn should minimize their exposure to flame
retardants, dioxins, and furans. These measures include wearing SCBA for
all phases of a response; active avoidance of the smoke plume when on
the fireground; routine laundering of turnout coat, trousers, and hoods;
and washing hands and neck and showering after doffing PPE ensembles.
Some departments have initiated programs where firefighters can exchange
their dirty hoods for laundered hoods prior to leaving the scene.
Firefighters also should avoid transporting their PPE ensembles using
personal vehicles or storing their PPE ensembles in living areas.
Standard operating procedures that include the placement of exhaust fans
at the doorways of the structure after knockdown and prior to overhaul
operations also should be considered to reduce post-fire airborne
concentrations of contaminants.
W. Fent is with the National Institute for Occupational Safety and
Health, Gavin P. Horn is with the University of Illinois at
Urbana-Champaign, and Sean DeCrane is with the Cleveland Division of
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The Society of Fire Protection Engineers (SFPE) is a professional society for fire protection engineering established in 1950 and incorporated as an independent organization in 1971. It is the professional society representing those practicing the field of fire protection engineering. The Society has over 5,000 members and 100+ chapters, including many student chapters worldwide.