It's not running into burning buildings or dangling from ropes and all the stuff you see on TV. It's a career's worth of poor sleep habits, poor eating, subliminal stress and repeated exposure to toxins . In recent years, they have found that most cancers in Firemen are not inhaled but absorbed. Fire Departments world wide have REEEEALLY cracked down on Firemen washing their gear after EVERY fire. USED to be a "badge Of Honor" to have dirty gear. Now you are a FOOL if you do. Most Firefighter deaths happen around MY age because of years of bodily abuse. Sleep Apnea is common. High BP is a way of life. All the intangibles open the door for low immunity to all sorts of crap. I have had to set a LOT of people straight when I get eye rolls about being retired at 55.