Reference summary — not medical advice or a personal risk estimate.
Firefighting (occupational exposure)
Quick answer
Classified as Group 1 — carcinogenic to humans, based on sufficient evidence in humans. Breathed and on skin. Smoke, soot, and chemical byproducts of fires; occupational exposure throughout a firefighter's career.
Summary
Working as a firefighter is associated with multiple cancers due to combustion exposures.
Detail
IARC classified occupational exposure as a firefighter as Group 1 in 2022, with sufficient evidence for mesothelioma and bladder cancer, and limited evidence for several other cancers including colon, prostate, testis, melanoma and non-Hodgkin lymphoma.
What's not established
This classification is based on sufficient evidence in humans that this factor can cause cancer. It does not establish a safe exposure threshold, your personal risk, or how this factor's risk compares in size to other Group 1 agents — hazard classifications are not ranked by magnitude.
Regional relevance
global
Evidence sources
Every claim on this page traces back to one of these. Click through to read the primary document yourself.
Primary sources
IARC
IARC Monographs — Classifications by Cancer Site, Vols 1–140
Supporting sources
ACS
ACS — Known and Probable Human Carcinogens
NTP
NTP — Report on Carcinogens (US National Toxicology Program)
Last reviewed: October 2026
Official reference list
A government list some readers use alongside the primary evidence. Meyron is not affiliated with it. A chemical being listed does not by itself describe a risk from any particular product.
- California Prop 65 list
State of California's list of chemicals known to cause cancer or reproductive harm.