Cloud1 - if you want to ignore the potential and very real dangers of inhalation of organo-phosphates including TCP from very small quantities of such contaminants (as found in engine oil additives) then that is your choice.
However if you have ever met people who have had their life ruined by from such exposure you might think again. I would therefore suggest that you keep your ill informed thoughts to yourself rather than trying to influence people who may not know better. Blood testing does not harm - but may show that harm has been done. I would advocate it for all in such a position.