Let's play a little game. We'll name several risk factors faced by an air tanker pilot in the course of a typical mission, and you lump all the risks together and figure out how much physical danger this job entails.
Risk #1: You rev up the airplane's engine(s) and take off. Anytime you leave the relatively safe confines of terra firma, you run the risk of not coming back...in one piece.
Risk #2: You're likely flying for many hours at a time, which means the fatigue factor might start to creep in.
Risk #3: You're probably flying in the same airspace as other air tankers, a spotter plane or two, perhaps a few helicopters, and maybe even a huge C-130 that can drop mucho water or retardant at one time.
Risk #4: Since you're flying over a fire, you'll face decreased visibility from haze or smoke. Sometimes really dense smoke. This means it might be difficult to see other aircraft, trees...or even mountains.
Finally, Risk #5: Fires can spread incredibly fast even in moderate wind conditions. If you're flying in southern California, you might encounter the dreaded Santa Ana winds that can scream through the canyons at fifty miles per hour or more, with gusts over a hundred. In south Texas, you'll see straight-line winds howling across the flatlands, hurling airborne embers, and creating unpredictable updrafts and downdrafts. We probably don't have to tell you that flying an airplane in these conditions will be a tad difficult.
Oh, and all of these risk factors? Yeah, they happen at the same time. Have fun with that.