CMU Study Finds New Forever Chemicals in Firefighters After Fires
Heidi Opdyke
- Associate Dean of Marketing and Communications, MCS
- Email opdyke@andrew.cmu.edu
- Phone 412-268-9982
Forever chemicals are so prevalent in consumer goods that they can be detected in nearly everyone. But firefighters are exposed to these complex chemical compounds, also called PFAS (per- andpolyfluoroalkyl substances), more frequently than the general population. There are thousands of different kinds of PFAS, and they’re found in foam used to put out fires and in protective firefighting gear.
Carnegie Mellon University’s Carrie McDonough, an associate professor in the Mellon College of Science Department of Chemistry, studies how the human body deals with forever chemicals.
In a new study, McDonough’s lab took blood samples from 33 firefighters in the City of Tucson, Arizona, within two days of a fire or fire-related event. They found that firefighters had significantly higher levels of two novel PFAS that people are not typically tested for.
Why did you want to look at PFAS levels in firefighters in the aftermath of a fire?
CM: A large portion of the forever chemicals in everyone’s blood is unexplained —and my lab has the instrumentation to look for PFAS beyond what’s typical or expected. For that reason, we’ve been really interested in what can be found beyond the compounds that we know about. I’ve worked with firefighters before and studied the residual markers of aqueous firefighting foams (AFFFs) in blood. PFAS in these foams and other products break down to common PFAS, which makes it hard to trace them back to a specific source with blood tests every few years.
We wanted to know if there are PFAS that are present within the hours after a fire that could give us clues about specific exposures that we could use to identify exposure sources. We also wanted to better understand the difference in health effects in firefighters compared to the general population.
What kind of fires and response roles led to these exposures?
CM: There are different variables that can impact a firefighter’s exposure: what they’re actually doing in the fire, how long they’re in the fire and the kind of fire — like automobile, business or home. All these factors affect what kinds of things are burning that they’re exposed to and sometimes what gear they wear, which could also be a PFAS exposure. In our study, firefighters were tested after six different fires, including one or two automobile fires, at least one house fire, and several fires in schools, offices or businesses. I definitely think future work should look at how specific firefighting activities are linked to PFAS exposure.
What did the study reveal?
CM: When we started this study, we knew that what we’re looking for has to be something that’s flying under the radar: a chemical compound that might have a lower half life in the body, or transforms in a way that is impossible to capture in later testing. We kind of knew whatever PFAS firefighters are exposed to via these fire events isn’t going to be a compound that’s on our traditional lists of chemicals to test for.
The post-fire samples allowed us to see what might have happened during one instance of exposure that could contribute to long-term exposure. When we looked at the targeted chemicals, we didn’t see any that were elevated directly after a fire. We did see two or three that were above what the general population typically has in their blood, though the reasons for these elevated exposures aren’t fully understood.
We did see two novel chemicals that were significantly elevated in blood after fires. Neither are PFAS that have been studied before, so there’s no information on sources of exposure or potential health effects. Getting these immediate samples that are associated with a specific exposure event allows us to see a chemical signature of the exposures that they’re getting, that is then invisible once you look at blood a few months or years on.
What do we know about how the body reacts to the novel PFAS that you observed?
CM: We don’t know much about those PFAS yet. But it’s really important to capture those exposures because those PFAS could be having serious effects.
How will this study inform your research on PFAS in firefighters moving forward?
CM: This study really magnifies how little we know about this stuff. It’s such a weird gap in knowledge — we know firefighting is dangerous and that they’re exposed to harmful chemicals, but we don’t know the specifics of how things burn or what happens when you’re exposed to these chemicals over and over again. There are questions there that concern me.
Now that we have these results, we’re starting to do more and more of these immediate sampling studies.
I have a student, Kiran Ali (a Ph.D. student in the Department of Chemistry), who has been developing a method for urine testing over the past two years. It’s much easier to get people to do a urine sample than to have to get a phlebotomist to draw blood. So, if we can start to monitor shorter-lived exposures in urine, then that gives us another piece of information about these chemicals and understand whether exposure means every time that you go into a fire or every time you wear your gear.
How do you think this research will impact firefighters’ health in the future?
CM: It’s well established that firefighters are at greater risk of several diseases, including multiple types of cancer, and that this is linked to chemical exposures. This research gives us new information on poorly studied chemicals that firefighters may be continually exposed to during fire response, but that don’t stick around in the blood long-term. More information about the health effects of these chemicals can help to improve clinical guidance and preventive care for firefighters. Also, by uncovering the identity of these chemicals, we’re a step closer to identifying their sources. Knowing more about specific exposures faced by firefighters and where they come from can help improve efforts to reduce their exposure.
This interview has been condensed for length and clarity.
