As to the effects of chemicals, we were spraying Quela(spelling) birds in Tanzania in the mid eighties with a 206.
We wondered how we treated the pilot in the event of an accident resulting in him being covered in the stuff.
The answer came back Atropine!!!!!!!! Standard military injection for nerve gas poisoning.
Mind you when you saw the effects of the stuff on the birds it was easy to believe, not nice.
Somehow the passing of spraying, certainly in Europe is probably not to be mourned however there were some good times in the process.
The increacing costs of keeping up with the legislation and the increaced use of low tyre pressure ground vehicles made it largely uneconomic in the end.