The largest study of firefighter-related cancer is expected to soon top 50,000 volunteer enrollees.
Growth has been strong over the last year despite a great deal of uncertainty last spring over the future of the ambitious effort.
In April 2025, the National Firefighter Registry for Cancer was shut down indefinitely in the wake of massive Trump administration layoffs at the Department of Health and Human Services.
Firefighters and their advocates pushed back and, by May 2025, the registration portal for the registry came back online.
Since then, enrollment has surged in what is now far and away the largest study of its kind. As of the last update on Friday, May 22, 49,461 current and former firefighters — including this reporter — had registered.
"We are seeing a sustained rate of about 2,000 new participants each month," said Kenny Fent, a research industrial hygienist at the National Institute of Occupational Safety and Health who oversees the registry.
Asked to explain the steep and steady growth, Fent said "more and more firefighters — whether they're career or volunteer or structural or wildland — are recognizing that this is an issue in their profession."
Cancer risk among wildland firefighters is particularly understudied, Fent has previously told the Mountain West News Bureau. Over 20% of enrollees have wildland experience, according to the registry's online portal.
"We can just learn so much by having this large and diverse population of firefighters that we can follow over time," Fent said.
Brian Fennessy, the inaugural chief of the Department of Interior's new U.S. Wildland Fire Service, recently told the Mountain West News Bureau that "cancer awareness and prevention … are the very top of my priorities."
Before taking that job, Fennessy was chief of the Orange County Fire Authority, which is recognized as one of just two California Gold Helmet Departments, a distinction given to fire departments where at least half, or 300, of their firefighters have enrolled. He said he was one of the first registry enrollees.
"The registry was created to build the kind of concrete, reliable data that can meaningfully inform how we protect the health of our workforce — what exposures matter, what interventions work, and where we can improve safety measures," he said. "That research will shape policy and practice for years to come."
"I enrolled because I believe in that work, and I encourage other firefighters to consider doing the same," he added.
Kenny Fent with the National Firefighter Registry for Cancer said that having someone with those perspectives at the top of the Wildland Fire Service is "enormous."
"I also think — because he's in such a powerful leadership position — that it could have ripple effects throughout the fire service," Fent added.
This story was produced by the Mountain West News Bureau, a collaboration between Boise State Public Radio, Wyoming Public Media, Nevada Public Radio, KUNR in Nevada, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio and KJZZ in Arizona as well as NPR, with support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
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