Research over the past couple decades has reported some mixed results about the relationship between firefighting and cancer, which has been used to argue against supporting firefighters who contract the disease. Recent research that has reviewed and combined data from previous studies, weighing the studies based on the size of the sample, has found increased risks for several different types of cancer.
NIOSH also just completed a largescale cohort study combining data from Philadelphia, Chicago and San Francisco fire departments looking at risk, which confirmed many of the previous results and added an increased risk for malignant mesothelioma.