Excerpts from 12news.com:

Cancer is the leading cause of death among firefighters, according to the Centers for Disease Control and Prevention and a team of researchers in Arizona believes it might be because each fire they fight is changing how their genes work, making them more susceptible to cancer and other diseases.

Bryan Jeffries, President of the Professional Firefighters of Arizona was diagnosed with seminoma in 2019, saying that it’s the synthetic materials that are catching fire, exposing them to toxic chemicals.  Gear protects them from the heat of the fires, not from the chemicals.

Dr. Jeff Burgess and his team at the University of Arizona Mel and Enid Zuckerman College of Public Health have been trying to understand how firefighters are at such a high risk for cancers and other diseases. Their latest study, funded by FEMA, found that firefighters undergo DNA methylation, where genes change in their expression without changing their actual DNA sequence. When certain genes are turned on or off it can make people more at risk for things like cancer.

They worked with Tucson Fire Department and studied new recruits through their first few years of working, finding the more fires they went to or how long they spent fighting them added up. They found changes at 680 different places on the genome, many of those genes were related to cancers and other diseases. While it’s not clear if those specific changes will lead definitely to cancer, it’s a lead to understand exactly what does.

With the study taking place at the very beginning of a new recruit’s career, it highlights how quickly these changes happen, and how they can add up over years on the job.

While firefighters are continually working on decontamination of their gear and themselves, keeping gear exposed to the chemicals out of the cab and in a separate area of the firehouse, there’s still more that can be done with changing equipment and tactics.

The team at UArizona is already expanding the study, working with even more fire departments around the country to understand exactly what DNA methylation sites are affected in firefighters.