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The invisible danger: Studying PAH exposure on the fireground and after the call

Study shows chemical exposure is higher while on-duty, and increased with the number of fires fought

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For this study, researchers focused on polycyclic aromatic hydrocarbons (PAHs), a group of chemicals created during fire events, such as when wood or other material is burned.

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Diana Rohlman, PhD, and Carolyn M. Poutasse, PhD

Firefighters face myriad hazards on any incident scene. The danger of a falling beam or collapsing floor are often visible or easy to predict. On the other hand, the release of chemicals during a fire is harder to see and harder to track. These invisible chemicals are thought to be part of the reason firefighters are more likely to get cancer or suffer other negative health effects.

In order to determine which chemicals firefighters are exposed to during their time on and off duty, a team of researchers from the Food Safety and Environmental Stewardship Program in the Department of Environmental and Molecular Toxicology at Oregon State University (OSU) and the Center for Fire, Rescue and EMS Health Research at the National Development Research Institutes – USA (NDRI-USA) joined forces to study individual exposures using silicon dog tags.

Tracking chemicals

Silicone passive samplers absorb chemicals from the air. The OSU team has previously used them to look at chemical exposures following hot tar roofing, living near unconventional natural gas drilling, and looking for associations between air pollution and asthma.

The silicone passive samplers allow researchers to look at very low levels of pollution – like what an individual firefighter might experience at a fire scene. Individuals wear the samplers during work activities to capture the chemicals to which the individual is exposed.

When the OSU team looked at samplers from over 150 people across three continents, they could identify unique individual patterns of exposure. In addition, the silicone passive samplers are very lightweight and unobtrusive (they can be worn like a dog tag on a chain around the neck, like a wristband, or even pinned to a shirt), and have no battery or maintenance requirements.

For this study, researchers focused on polycyclic aromatic hydrocarbons (PAHs), a group of chemicals created during fire events, such as when wood or other material is burned. The researchers looked at PAHs because these chemicals are associated with impaired lung health and with cancer. The passive samplers look like a dog tag and were worn around the neck. Firefighters wore one tag while on-shift and a second tag when they were off-shift.

The invisible danger

PAHs are hard to see. Many of them are in the soot on your turnout gear, but many more are in the air, invisible. This is why these chemicals can be difficult to study.

These chemicals are common indoor pollutants. During a fire, household objects – plastic toys, furniture, utensils, household pesticides, dyed textiles and items containing rubber and plastic components – may burn and release PAHs into the air.

There are hundreds of different kinds of PAHs, and we know firefighters are exposed to them. We do not know much about which PAHs firefighters are exposed to, nor the amount of each PAH. This study helped answer those questions.

We worked with two fire departments in the Kansas City metro area. Fifty-six firefighters signed up to be part of the study. Firefighters were either from one high-call or one low-call volume department.

After 30 days, each tag was analyzed for 63 different PAHs. We selected these 63 PAHs because they are commonly found in the environment or they are suspected to be more harmful than other PAHs.

Results and analysis

Our research showed that chemical exposure was higher while on-duty, and exposures increased with the number of fires fought.

The study had three major conclusions:

  1. We found 18 PAHs that have not been seen in firefighter studies before. Some of these are associated with adverse health concerns, such as lung and skin irritation, or increased cancer risk. This information will help researchers better understand how firefighter exposures are different from those of non-firefighters.
  2. Levels of PAHs were higher in the on-shift dog tags. This was true for firefighters at the high- and low-call volume department.
  3. Dog tags from the high-call volume department had higher levels of PAHs. The more fires fought, the higher their levels of PAHs.

The new PAHs identified, not previously associated with firefighters, is useful information. The research does not tell us if these chemicals are coming directly from activities associated with firefighting, but it provides more information to better understand the health impacts of firefighting on human. By figuring out the chemical “fingerprint” of firefighting, researchers can begin to focus on the PAHs that may be unique to firefighting. From there, researchers can work on reducing those exposures, or preventing them in the first place.

In good news, exposure to PAHs was reduced in firefighters who fought fewer fires or were off duty. The researchers still found PAHs in those dog tags, but this is not surprising. Research has identified PAHs in rural, urban and Indigenous communities, as well as in firefighters specifically. These chemicals are common in the environment, but researchers are interested in understanding the difference between levels that are common, versus levels above average.

Similarly, finding PAHs in the off-duty tags isn’t surprising. As we walk around, running errands, exercising, we are exposed to many different chemicals. It is difficult to compare the levels seen in this study to levels seen in the general public.

In general, the levels of PAHs in the off-duty tags were lower than in the on-duty tags. This is more evidence suggesting that while on duty, firefighters are exposed to more PAHs than they would be in their normal life. This may be due to actively fighting fires or exposure to contaminated gear. More studies in this area are ongoing.

Reducing risk by washing your gear

While this research and prior research shows that firefighters are exposed to potentially harmful PAHs, there are some simple ways to reduce exposure:

  • Always wear your PPE and SCBA. We know that PAHs are in the air and in our environment. Properly worn PPE and SCBA can prevent most PAHs from entering the body.
  • Clean your turnout gear. Traditions change with the times. Consider a new tradition of cleaning, or even changing, your gear after every fire, or at least with every shift.
  • Shower after fires and before going home. Showers can remove any small amounts of soot, debris or PAHs that might remain after you’ve been fighting fires. You do not want to track this stuff home. Soot and chemicals left on your clothes or body can transfer into your home. This means your family members could also be exposed.

To learn more, please visit the researcher’s website for more information about the study, and ways to reduce risks from PAH exposure.

Read the full report: Discovery of firefighter chemical exposures using military-style silicone dog tags.

About the Authors

Diana Rohlman, PhD, and Carolyn M. Poutasse, PhD, are researchers at Oregon State University in the College of Public Health and Human Sciences and the Department of Environmental and Molecular Toxicology.

This article references research conducted by a team of researchers from the Food Safety and Environmental Stewardship program at Oregon State University (Kim A. Anderson, PhD; Lane G. Tidwell, PhD; Peter D. Hoffman; Emily Bonner; Michael Barton) and the Center for Fire, Rescue and EMS Health Research at the National Development and Research Institutes – USA (Sara A. Jahnke, PhD; Walker SC Poston, MPH, PhD; Cristopher K. Haddock, PhD).

The Food Safety and Environmental Stewardship program at OSU is a chemistry laboratory specializing in passive sampling technology development and quantitative analysis of environmental samples.

The mission of the Center for Fire, Rescue, and EMS Health Research (CFREHR) is to understand and improve the health of first responders through systematic research and evaluation.

Note: Kim A. Anderson and Diana Rohlman, authors of this research, discloses a financial interest in MyExposome, Inc., which is marketing products related to the research being reported. The terms of this arrangement have been reviewed and approved by Oregon State University in accordance with its policy on research conflicts of interest. The authors have no other disclosures.