Threads like this importantly increase awareness and need to be kept on track. I regret that until now I had not really taken much notice of exactly what contaminant it was in the bleed air that it has been argued has caused death and disablement for too long amongst aircrew. I had previously assumed it was a problem with only a few aircraft types like BAe146. Evidently not so.
So I've just stumbled upon the following paper which discusses methods for measuring the risk of the same contaminant exposure to ground staff and technicians who are not even breathing bleed air but spend a lot of time in close proximity to the engines and/or the lubricants which routinely contain sometimes quite surprising levels of the toxic components (sometimes as high as 5%):
Exposure to airborne organophosphates originating from hydraulic and turbine oils among aviation technicians and loaders
The paper also touches upon the purpose of the presence of these dodgy compounds in the first place which very simply put would appear to increase engine life perhaps a bit like lots of added lead (Pb) once did routinely in car fuel until the practice was severely curtailed. I appreciate that jet turbines are far more difficult to protect from wear than car engines, and I apologise if I have linked to an already well publicised paper known in these parts ...