I am surprised nobody has mentioned this report so far.. Credit to BBC news website.
BBC News - A cleaner future in the air?
Ref: I've never had any problems.....etc, about 30 years ago I took an interest in the un-willingness of MAFF (Ministry of Agriculture, Fisheries and Food) as it then was, to strive for any conclusions or further any definitive research into the OP/sheep-dip problems in the face of statistics showing the increasing numbers of farmers experiencing physical/mental/suicidal problems. Leaving out of the equation any possible pressures by the Agro-chemical industry, they were aided in their inertia by those users who would say - 'bunch of whingers, I've been gargling with/bathing in this stuff without any ill-effects for fifty years' while at the same time previously sane, upstanding, hard-working farmers who used OP sheep-dips were shooting/hanging themselves for no apparent reason.
As mentioned, it's a lottery who gets affected (in aviation and, previously ((before the banning of OP sheep-dips)), in agriculture) and who does not.