I grew up loading for my dad between ages 13 and 18. In the 70s. There was typically plenty to do between loads with prepping next load, refilling water tank from well, accepting jobs from farmers, occasionally having one stop by to pay (which required looking up the work, finding the bill and writing a receipt), receiving chemical shipments and unloading. Farmers delivering their own chemicals which needed marked/segregated from other chemical. Selling chemicals to other farmers. There was always equipment to maintain and service such as pumps, motors, augers, trucks, etc. If nothing else, just picking up and cleaning up empty containers, packaging, etc took time as well. During defoliating season, it Was not uncommon to have a coule hundred 5 gallon cans of defoliant.
Dad was also an A&P so there were frequently other planes to work on.
Dad opted to retire from ag work rather than have my brother and me continue on. We both fly recreationally but didn't pursue it professionally. An established ag pilot can make a pretty good living.
I once made up a list of all the chemicals to which I as directly exposed to loading and flagging not to mention living around. It was pretty extensive. Dad died of old age, asleep in his bed with some 10,000+ ag hours. My brother and I have experienced no health issues attributable to chemical exposure thus far. My 22year Army career took a hell of a bigger toll on my body so far. Still, we could both be sitting on a proverbial time bomb.
I do know of two of my dad's contemporaries did die of cancer, but they were older when it happened. Don't know if any causal relation was established, but it is possible. Maybe it was from saccharine or smoking (one did, one didn't).
I knew only one ag pilot during this period killed in a crash, though a few balled planes up. Knew more folks who died in non-ag aviation accidents.