Firefighters might face a higher risk of brain cancers caused by exposure to chemicals in fire extinguishers, a new small-scale study says.

Veteran firefighters appear to have a higher risk of brain tumors called gliomas, which can be caused by gene mutations linked to flame retardant chemicals called haloalkanes, researchers reported in a study published March 10 in the journal Cancer. 

Previous studies have highlighted a mutational pattern, or “signature” in gliomas linked to haloalkane exposure, researchers said.

“In these data, we confirm detection of this signature in a cohort of individuals likely highly exposed to haloalkanes, i.e., long-term firefighters,” a team led by senior researcher Dr. Elizabeth Claus, director of medical research at the Yale University School of Public Health, wrote.

Gliomas are the most common type of brain cancer, researchers said in background notes. About one-third of all brain tumors are gliomas, according to Johns Hopkins Medicine.

For the study, researchers found 17 firefighters with gliomas participating in a University of California-San Francisco study of adults with this form of brain tumor. The firefighters had been on the job for an average of 22 years.

They compared the tumors of the firefighters with 18 other participants in the brain tumor study who worked in other fields. 

“As firefighters have exposure to such chemical agents, we examined mutational signatures in glioma brain tumors diagnosed in persons who worked as firefighters versus those who did not,” Claus said in a journal news release.

The firefighters’ brain tumors were indeed more likely to carry the haloalkane-associated mutational signature, especially if they’d been firefighters for many years, researchers explained.

Among the non-firefighters, the haloalkane tumor signature was more likely in jobs that also could involve exposure to the chemical, such as car painting and machine maintenance, researchers noted.

“Our study provides preliminary data but will need confirmation in a larger data set and across a wider range of occupations,” Claus said.

“Identifying exposure to such mutational agents is important to inform public health intervention strategies and pinpoint occupational hazards that may be avoidable,” she concluded.