Overexposure to these chemicals can be a heath hazard. I know a young lady who runs a driving range & sprayed various products from a tank pulled by tractor. She developed serious problems from skin contact & inhalation. Not that you would ever be exposed in the amount she probably was but avoid skin contact & only spray when the wind is down.
My dad and I farm organically. Long story short, my dad in his 20's sprayed herbicide to beat heck. When my older sister was 18 Mo., she had a tumor the size of a grapefruit on her stomach. By the grace of God she lived, and is doing just fine today. He stopped spraying in 1989 and about 5-6 years ago we became organic. The difference is amazing in our health and the health of our animals. If my dad came on here, he could write a book, I'll keep him away though.
PS, this is the incredibly abbreviated version