The dataset is available on Kaggle. The dataset covers the years 2000 to 2015.
Histograms showing age distribution for the fatalities. The first histogram has 10 bins, the second has 20 bins.
I was surprised at the age distribution, in my mind firefighters are younger - it is a physically demanding job. My next step was to investigate if the causes of death might be different for younger and older firefighters. I divided the data into two sub groups, under 40, 40 and over.
Causes of death for fire fighters under 40 years old:
Vehicle Collision 100
Causes of death for fire fighters 40 years old and above:
Vehicle Collision 105
It is perhaps not surprising that Stress/Overexertion is a major cause of death of those who were 40 or older. Vehicle collision appears to be a major source of fatalities across both age groups. If I were responsible for health and safety in US fire departments I think I would want to investigate this further. I imagine vehicle collisions being a risk for police officers but not for fire fighters.
343 firefighters are listed as dying on Sep 11, 2001.