Firefighters and Smoke: Health Research and What It Means

Wildland firefighters work long shifts near flames while breathing complex smoke. The smoke carries fine and ultrafine particles, polycyclic aromatic hydrocarbons (PAHs), and other chemicals. Those tiny particles, called PM2.5, can enter deep lung tissue and the bloodstream. Smoke exposure can cause coughing, tiredness, and short-term changes in lung function.

Research has found that occupational exposure as a firefighter is carcinogenic to humans (Group 1), and long-term risks have been modeled. One assessment estimated lung cancer mortality could increase by 8 percent to 43 percent across different career scenarios. A study of wildland-urban interface fires reported that 50 microRNAs changed in blood after exposure, which may point to biological pathways for disease.

Agencies have launched studies and registries to improve knowledge and protection. The NIOSH National Firefighter Registry for Cancer has been created to collect data from large numbers of firefighters, and by March 31 nearly 24,000 firefighters had enrolled. NIOSH field teams have measured lung function, heart markers, and other tests before and after fire seasons to follow health changes. Gear chemicals like PFAS have raised additional concerns, so departments are testing PFAS-free equipment while researchers track long-term outcomes.