LA firefighters put out massive blazes. Now they worry that cancer might be smoldering inside them

(CNN) — Pacific Palisades was burning to ash.

“As far as the eye could see, homes were on fire, everywhere,” said firefighter Joseph Field, 50, who’s been with the Los Angeles Fire Department for more than 25 years. “Nothing I’ve ever seen was like it was that night.”

Field, manning a 10-inch hose line, dropped a curtain of water on a house that hadn’t caught fire – yet.

Seven feet away, the neighboring home was going up in smoke.

Even with goggles, the irritants in the smoke made his eyes feel like he’d been wiping them with sandpaper.

“You’re using basically a cloth hood to kind of help a little bit, but you’re taking in a lot of smoke,” Field said. “You’re just eating it. You’re constantly eating it.”

At one point, he had to back out and find a pocket of cleaner air on a porch.

“I could not breathe, and I was trying to catch my breath and coughing,” he said.

The wind was so strong that the hose water streamed only about 2 feet before blowing right back on him.

“Finally, you just start to lose it. [The fire] starts to get into the house, despite your best efforts,” he recalled.

Field helped fight the fires for seven days in a row, went home for a day and then came back for eight more days.

“We’re not used to getting our butts kicked on a fire,” he said. “This fire, for the most part, kicked all our butts.”

The Palisades Fire in Los Angeles in January ranks as the second-most destructive wildfire in Southern California history, with more than 23,000 acres and 5,000 structures burned. So many structures burned simultaneously, with so many unknown contents: plastics in furniture, batteries in cars.

Now, Field wonders what might be smoldering inside him.

“A lot of guys say it’s probably a lot – couple years off our life – with the amount of stuff we took in,” he said. “You can only take in so much bad stuff.”

Field is among 300 firefighters who are participating in a study to monitor their exposure to cancer-causing chemicals after the LA fires.

Researchers with the Wildfire Conservancy and the University of Arizona have collected blood and urine samples from firefighters with the California Department of Forestry and Fire Protection, the LA Fire Department and other smaller departments. They’ve also collected contaminant-absorbing wristbands the firefighters wore to measure their exposures.

The samples are being tested for carcinogens associated with wildfires that burn into urban areas.

The first set of preliminary results from the ongoing investigation found that 42 firefighters who worked the LA fires had significantly higher concentrations of certain chemicals called PFAS in their blood. It is not clear whether these changes will be linked with health problems, according to the researchers. Also, an analysis of heavy metal exposures shows elevated levels of key metals, including chromium, arsenic and cobalt.

Separately, a US Centers for Disease Control and Prevention study released in February found a brief 110-fold increase in air lead levels during the LA fires. The health effects from these exposures are not well-understood, the agency said, noting that many of the buildings affected were built before 1978, when lead paint was still commonly used.

At peak, more than 6,000 firefighters worked the Palisades incident.

“These are 9/11-scale exposure events for firefighters,” said Matt Rahn, executive director of the Wildfire Conservancy.

Exposure to carcinogens in the aftermath of the September 11, 2001, attacks has been linked to heightened risk of cancer. According to the New York City Fire Department, 3,500 firefighters have cancer related to their work in the World Trade Center.

“We need to understand better as to the air and the soil and the water contamination that are specific to LA,” Dr. Kari Nadeau, chair of the Department of Environmental Health at the Harvard T.H. Chan School of Public Health, said in January during a public health discussion about the smoke. “I don’t want to say that anything is the same as LA, because LA will be LA.”

A mixture of toxicants

Two-thirds of firefighters die from job-related cancer, according to the International Association of Firefighters.

“It’s a pretty stark statistic, but it’s the reality of what we deal with in the fire service as a result of our occupational exposures,” said Derek Urwin, the association’s chief science adviser. “Any exposure to products of combustion increase cancer risk, and [the Los Angeles fires] were obviously quite substantial exposures.”

Wildland firefighters are also regularly exposed to carcinogens; at least 29 have been linked to this type of fire, according to a 2024 study by US Forest Service researchers.

Wildland firefighters who battle blazes that spread into urban areas are exposed to even more hazardous emissions from the burning of both natural and human-made fuels.

Then, after the initial incident, these firefighters encounter “off-gassing,” the release of harmful gases from everything that combusted in the rubble, which can last days or even weeks.

All of this makes the Southern California fires, with their mixture of toxicants, more complicated than either wildland or structure fires, according to Jooyeon Hwang, an associate professor and occupational health researcher at UTHealth Houston who has researched the health risks to firefighters from wildfire smoke.

“We really do not understand fully yet about the long-term effects of these exposures to the carcinogens,” she said. “We definitely need more studies.”

It can take decades for cancer to develop after exposure to carcinogens, Hwang said.

“Let’s say you are exposed to these carcinogens at age 20. Then, maybe 40 or age 50, you might find those cancers,” she said.

Interventions to reduce cancer risk

In addition to helping firefighters understand and predict their cancer risk, the Wildfire Conservancy is studying interventions that can be put in place now.

It’s not feasible for wildland firefighters to wear full-face respirators with filter cartridges and battery packs while hiking with 40-plus pounds of gear in terrible conditions, so they may have only a bandana or shroud to protect their airways.

“That’s not a respiratory protection device. It’s letting everything through except big chunks of ash,” Rahn said.

Plus, the respirator cartridges aren’t certified to protect against the type of smoke encountered by these firefighters. Even high-quality N95 masks become unusable very rapidly.

“All the cartridges that are out there are certified and tested against single-gas challenges,” Urwin said. “The issue with smoke is, it’s an extraordinarily complex mixture of many, many, many, many gases. And the issue with just relying on a respirator is, we don’t know how effective they are against smoke exposures, if at all.”

For the past year, conservancy researchers have been conducting field tests to evaluate the effectiveness and functionality of different types of respiratory devices. They want to consider firefighters with stubble and sunscreen and ash and soot and smoke and sweat.

The conservancy is also investigating clothing that contains an added barrier to filter out tiny particles. In lab tests, researchers have seen up to a 95% reduction in skin contamination from firefighting with the use of these clothes.

When Field came home after the first seven days of fighting the Palisades Fire, he soaked his brush coat in a bucket of water and detergent.

“It looked like oil, sludge,” he said. “All those carcinogens, get ‘em off you.”

When he got some downtime recently, he took a drive through the Pacific Palisades, back to another street of homes that his team had showered with water.

“There were homes that, if we had not put a stand on those homes, they definitely would have burned down, and if those homes burned down, they would have burned a lot more homes,” he said. “We actually did save a number of homes.”

That, he said, was good to see.

He’s not focusing on whether the cost of saving those homes might mean cancer down the line.

“I don’t try to build too much into stuff like that,” he said. “When I’m faced with that kind of stuff, then that’s another story, and I’ll deal with it when that happens.”

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