Part 2: Doing science while the fire is still raging
This is the second installment of a special report on firefighter health risks. Part 1 appeared in Cosmos Weekly #37 on 14 January.
The Australian Firefighters’ Health Study gathered data from across nearly 40 years but only looked at health impacts retrospectively, well after fires had occurred. Other studies have put boots on the ground while the fires are still burning.
In May 2016, a Canadian team of epidemiologists managed to set up a long-term health study of firefighters within a few days of a wildfire sparking.
The fire began near Fort McMurray, a regional town in northern Alberta. About 80,000 people live in the town, but since it’s a hub for the petroleum industry, tens of thousands more live in work camps in the surrounding area.
The fire raged out of control for a full two months, spreading across 580,000 hectares and two provinces, forcing nearly 90,000 people to evacuate. It wasn’t fully extinguished until a year later in August 2017. At the fire’s peak, 2000 firefighters were battling the blaze every single day.
Epidemiologist Professor Nicola Cherry and colleagues at the University of Alberta in Edmonton immediately mobilised. They secured seed funding and headed north within days.
“The whole area of the fire was not open to researchers, so we started by looking at firefighters when they came back from the fires,” says Cherry.
“We didn’t actually get into the township of Fort McMurray until about three months after the fire… At that point, we did recruit the firefighters from the town who had been involved as well.
“In fact, we went to 13 different fire services, met with [firefighters] face-to-face, talked about what had happened to them and took various measurements.”
The team were also flown into fire areas by oil and gas companies, who run their own fire services, in order to take measurements of firefighters. These included testing lung function, taking blood and urine samples, and performing mental health clinical assessments.
They followed up with questionnaires, which not only sought to find out whether firefighters had any physical or mental health symptoms, but also tried to gather exposure data – when firefighters had been at the fire front, what part of the fire they had fought, how long they had been working, what tasks they had been doing, and the protective gear they wore.
Further follow-up questionnaires were sent over several years to firefighters from 82 fire services across Alberta who had been deployed to the Fort McMurray fire.
“We linked that to data we got from our environmental measures of smoke and so on, so we were able to… get a really quite good estimate of exposure,” Cherry says.
Around 1000 firefighters completed the questionnaires. One hundred and seventy were screened for respiratory health effects and 192 for mental health effects. According to Cherry, this is quite a large sample for detailed clinical assessments.
Previously, the biggest cohort of firefighters studied had been those of New York City in the wake of the 9/11 terrorist attacks.
“We based our assessment on what they had done,” Cherry says. “But they weren’t so much looking at the effects of smoke… When the twin towers collapsed there was an enormous amount of dust generated, and that’s really what was affecting the lungs of the firefighters.”
In Cherry’s study, clinical interviews were undertaken more than 42 months after the fire, making it nearly a five-year-long study. While the New York study is still going and is the longest of this type, Cherry’s still stands as one of the longest-running in the world.
The study found that firefighters were more likely to develop asthma, and the likelihood is related to their smoke exposure. It also revealed decreases in lung function related to exposure, both from self-reported symptoms and clinical assessments such as CT scans of the chest. Thickening of bronchial walls was also found.
The firefighters at Fort McMurray fought fires both in town and in the surrounding forest, allowing Cherry’s team to study firefighters tackling different environments and exposures. The results of health effects were more similar than expected.
“The lung damage, for example, was the same,” Cherry says. “It’s not so surprising because they were, in theory, all working at the interface between town [and forest]. With some structural firefighters you may have got very high exposures to chemicals in a broad sense when they went to fight fires in basements in the town.”
Many wildland firefighters were exposed to many of these same chemicals, but only during this particular fire, which was close to a town.
“In general, the exposures [between firefighting populations] are very different,” Cherry says. “The health hazards for wildland firefighters are very different than those for structural firefighters, and haven’t really had the same attention.
“Almost all evidence is for structural firefighters. There’s really rather little evidence for lung damage, for example – for chronic respiratory damage in firefighters who are working in towns, wearing proper breathing apparatus, going in for short periods and then other crews take over, under controlled conditions.
“Whereas in these wild situations where you’ve got massive fires that burn for days, and you don’t have proper respiratory protection… there haven’t been many studies.
“But both our study and the New York one – and a couple of other smaller ones – do see respiratory damage under those circumstances.”
Cherry adds that there’s not much data about seasonal workers or volunteers – firefighters who only work for a few months but come back year after year.
“We’re trying to get that evidence but it doesn’t really exist at the moment,” she says. “We do observe over the course of a fire season that lung function tends to decrease, we assume from the smoke, but we don’t really know anything about long-term health effects.”
Right now, Cherry’s group is working with Alberta’s wildland firefighter services to study personnel outside of emergencies, which would provide a baseline for a health study when a major wildfire occurs.
This is particularly relevant to Australia, as the vast majority of our bushfire defense comes from seasonal and volunteer firefighters.
What do these studies teach us?
“We are dependent on firefighters to protect our property and our livelihoods,” Cherry says.
“You want the same people coming back year after year after year; if you were having to recruit new people every year because people dropped out due to their health, or because they felt people didn’t care about the health – you would soon run out of volunteers.”
Studies like these are therefore crucial to protect the health of firefighters into the future, leading to insights about how to reduce risks.
For example, Cherry’s study revealed that firefighters are exposed to carcinogenic polyaromatic hydrocarbons from smoke through the skin.
“Skin hygiene isn’t thought to be the first priority,” she says. “But that’s one of the lessons that I think that we’ve been able to provide fire services: however chaotic, you’ve got to provide clean clothes, showers, opportunities to protect the skin from absorbing carcinogens.”
She adds that throughout much of North America, wildland firefighters don’t use much respiratory protection, but their study highlights the importance of such protective gear.
“Another lesson that came out from the Fort McMurray fire was that very little respiratory protection was worn for a number of reasons, one of which is that there were fire services from all over the province,” she explains. “They all used different sorts of respiratory protection, and the spares for one group didn’t fit the other one.”
Having a standard issue of respiratory protection, she says, is a simple but key recommendation.
The study also demonstrated that firefighters with rapidly rotating shifts did much better than people who worked long and repeated shifts.
Monash University’s Associate Professor Deborah Glass adds that these long-term studies are important for firefighters to be compensated for any health impacts, providing data to show that cancer and mortality may be directly related to their work.
In Australia, Glass says, this research, “provides evidence for regulators to make decisions”.
“I’m pretty sure that all states and territories now have signed up to what’s called presumptive legislation, so if a firefighter gets one of a certain list of cancers, and they’ve served for more than usually 10 years as a firefighter, they’re automatically compensated,” she explains. “They don’t have to go through seeking proof on an individual basis.”
The International Agency for Research on Cancer is currently revisiting their monograph on cancer and firefighting, because several further studies have been published since 2010. Glass is part of a working group preparing the new IARC monograph, chairing the exposure subcommittee. It will be finalised in June 2022.
But firefighters still need science’s attention, Glass believes.
“We rely on them,” she says. “They’re incredibly brave. They risk their lives looking after us, so I think we should look after them.”