To be "fair" the oil additive tri cresyl phosphate (TCP) has never actually been used as a nerve gas itself - its "LD50" (ie the lethal dose required to kill 50% of a defined population sample in a defined time) is way too low for military use, but its close chemical cousins most definitely have been and its close proximity to them chemically makes it a substance to avoid at all costs.
The following links may be of interest, the better to inform us about just how nasty chemically organo phosphate esters actually are.
http://dspace.dsto.defence.gov.au/ds...ndle/1947/3349
http://en.wikipedia.org/wiki/Tricresylphosphate
http://en.wikipedia.org/wiki/Nerve_agent
For the record and in brief summary, there are two basic types of nerve gas; the G Series and the V Series.
The Gs were discovered and developed in Germany in the 30s and the Vs in England in the 50s. Both were accidental discoveries "found" in the pursuit of developing new and more effective insecticides.
The Vs are generally more toxic than the Gs.
Both function by interfering with nerve impulse transmission by blocking the action of the enzyme acteyl choline esterase at the nerve synapses or junctions.
Because of this systemic attack on the nervous system exposure to them can produce a bewildering variety of symptoms.
As ever I suspect that preventing oil contamination of bleed or any other kind of air being used in cabins will revolve around cost/benefit analysis but in my view the contamination has to stop. I further suspect that this will only happen after a few very expensive lawsuits.
Think asbestos.