Why do firefighters experience higher risks for cancer? A California researcher plans to find out.

Many Californians have seen firsthand how wildfire smoke makes living and breathing difficult. The short-term health impacts, ranging from asthma flare-up to irritation on parts of the body like the eyes and throat, are easy enough to understand. 

But experts say new research is necessary to understand the longer-term effects of regular exposure to smoke. 

“There has been a pretty strong body of literature focused on acute effects of wildfires and wildfire smoke,” said UC Davis Public Health Researcher Shehnaz Hussain. “When you start to think more about these long-term effects like cancer risks, there really is a very small [pool of] literature to date.”

Wildfire smoke impacts more Californians than ever, according to a new report

Hussain hopes to fill in that gap by studying cancer in firefighters. She recently received a $1.9 million state grant, which came as part of a larger effort to fund research around climate solutions in California. Studies show firefighters experience greater risks of getting cancer and Hussain said this work is a step towards better understanding why.

CapRadio sat down with Hussain to learn a little more about her plans and how this research might help us better understand the impacts of smoke on Californians as a whole. 

This interview has been edited for clarity and length.  

Interview highlights

How did you end up choosing this topic to focus on in your research? 

One of my roles is serving as one of the associate directors for our comprehensive cancer center at UC Davis. We have a very dedicated team that's focused on community outreach and engagement and education, and that team has conducted a series of conversations with the community to really learn from the various populations that live in and around Sacramento about what their greatest concerns are as they relate to cancer. 

Air pollution has come up over and over again in these community conversations. From a more personal perspective, having just moved up to Northern California a few years ago, you can't deny the impacts that our wildfire season has on everyone that lives in this community. I certainly have my own concerns about how I'm behaving and the exposures that I'm experiencing during wildfire season.

What do you hope to accomplish with this research? 

Our goal is really to look at the firefront where the firefighters work and begin to characterize the exposures that they come into contact with. We're also hoping to study firefighters themselves. Our approach is to enroll and engage with firefighters throughout California and study not just the fire exposures, but other potential risk factors for cancer that are related to their occupation in the hopes that we can identify these risks and work to mitigate them through interventions in the future.

Fire crews fight the Caldor Fire just south of Meyers, Calif. on Tuesday, Aug. 31, 2021.Andrew Nixon / CapRadio

Firefighting as a whole has been deemed carcinogenic — that's by the International Agency for Research on Cancer through a report that was published last year. There is plenty of data to suggest that it's not just the air or the exposures from wildfire emissions, but really it's other attributes of the occupation. The sleep disruption, the exposure to diesel exhaust, poor diet quality, things like that are occupational hazards in addition to the emissions from the smoke.

You’re also interested in studying the long-term impacts of regular exposure to wildfire smoke as a whole. Why are firefighters a good case study for that? 

Certainly, any signals that we identify in this highly exposed community of firefighters would probably be more acute and more easily discernible than studying a very large population that's exposed inconsistently … over long periods of time.

What do we know about the long-term impacts of wildfire smoke on a community? Or has that been a tough question to answer? 

It is a tough question to answer. The challenge when we're looking at environmental exposures and their association with cancer risk or cancer survivorship is that there's often a very long latency period or lag time from when an individual is exposed or chronically exposed to when that cancer appears. That creates a very large time and space in which we need to characterize that environmental exposure and link that to the cancer. It has been a very challenging question to address on the population level. 

That said, we've learned a lot from our basic scientists who study this in more controlled settings. We certainly can appreciate that there are carcinogens in wildfire emissions. Now, the challenge is to really understand the population influence of those exposures.

This is just one part of the big conversations we're having about climate change and its impacts on human beings. Is looking at these long-term impacts of wildfire smoke and other climate events still pretty new? 

There is increased focus on wanting to understand the impacts of climate change and climate events on cancer. Our state has invested funding in this, and at the national level, the National Cancer Institute has issued several calls for action related to studying the impacts of climate on cancer. I think we have a lot to learn and this is a field that is going to continue to grow as we deal with the ever-increasing challenges due to climate.