There was no "agent" put on the vehicles or pers. It was purely notional. However mistakes could have been made with the decontamination drills, for example........
For vehicle wash, it was a chlorine solution that was used in the slurry, (the sluryy machine I believe was a 4CMBG unique piece of equipment) a standard ingredient that was common at the time. Of course who knows what the dilution was, (-% Chlorine to water) and we probably never will know. It is very powerfull stuff and was chemically similar to swimming pool "shock treatment" There is a standard measurment for the mixture. But HAZMAT awareness was not high on anyone's priority list back then.
As far as the respirators go, they used to rinse them in bleach provided by the flying kitchens. This would cause the burning on the face when sweat was introduced. This practice was stopped due to the fact that it degraded the composite rubber of the mask and eventually rendered the elasticized fabric useless. This caused an unacceptable expense, as base clothing stores would have to replace them. (Not because of soldier discomfort). Soap and water would get rid of the training agent quite nicely. So who decided on the bleach...?? After all, in the event of an actuall chemical attack the mask would be destroyed after its usefull life cycle and a new one would be issued. (I can imagine the headache this would cause to the SQMS/CQMS)
Nothing but water and soap should have been used for personal decontam. Who knows if mistakes were made???? I can see that happening, and one could certainly lose eyelashes with a bleach or clorine mix. Of course we should all know the effects of a chlorine gas on the body. (WWI) If the mixture for vehicles was accidentally/ inadvertently used on personnel even in its weakened state, could have dramatic effects on ones respiratory tract and nervous system. But, soldiers would have known immediately.
Long term effects................Beats me. I guess we need an expert. As L.W. stated, I cannot recall anyone suffering from any negative symptoms in 'A' Squadron or the Regt. Of course we Armoured folks did supplement our blood content with a type of antifreeze. We could have been immune >

I am not trying to pull theories out of thin air, I was a NBC Operator/ Supervisor and have background knowledge from my time with the Joint NBCD Coy.
However this is just my 2cents worth as an armchair critic now.
Would the military be involved in a coverup? I don't think so. Would they admit to a mistake even if they had some proof? I don't think so...............
Very thought provoking though Tom.........