AEROTOXICITY..?? Do You Have It?

[bushpig]

I have known of fumes to have entered the cabin of a King Air to the extent that the aircraft had to be depressurised and landed at "nearest suitable" etc. If that contamination were happening to a less extent ie seepage or small amounts of fumes coming from residual in the lines and slightly leaky seals that would also make its way into the cabin.
It would be less noticeable and detectable by human detection means (sense of smell) than when there is a complete failure of some description but it is still not good, in the short term for safety and in the long term for health.
The point of mentioning recirculated air is that it stays there, is recirculated and most likely added to by more coming in. It has also been heated.
Oil used in turbine engines, although harmless enough in appearance, feel and smell is highly toxic and carcinogenic.
In the past I have noticed those carbon monoxide? detectors in aircraft that look to be years old anyway and thought to myself ...well that's all well and good but this is a turbine aircraft and it won't necessarily do much good here...and... what is that slightly oily smell in here anyway?
The subject was raised and I am merely adding my two bobs worth as a subject worth attention. Single pilot in a high performance aircraft at F290 is not the time to find out you have contaminated air. Neither is it good to know (or maybe not know) that your working environment is contaminated even if it is gradual or only a small amount and I suspect that many of them are.