ver.di ist Germanys larges trade union. They were head on the subject in 2009 and 2010 and then not very actively involved in the following years. Since summer 2015 fume events and aerotoxic syndrome is again one of their no one priorities. They published the check list (in German) below in January 2016, intended for crew but also passengers may find it helpful.

toxin free travel on toxin free aircraft