Organophosphates are particularly dangerous and action needs to be taken to deal with the engine oil systems or filter bleed air effectively on those aircraft at risk. The effects of ingestion of these toxins has in the past caused legislation to protect farmers from sheep dips and the use of these toxins in nerve agents is hardly reassuring to airline crews.
I was fortunate throughout my flying career to fly types where oxygen use was mandatory for the duration of flight although airmix settings allowed one to whiff the fumes occasionally. I would want to use oxygen if I flew an at risk aircraft regularly.
Unfortunately, the elimination of risk is going to cost a fortune - watch the bean counters try to bury this issue.