Digging in several sites I have found a press report in "Die Welt" from 2010 and one in "Der Spiegel" from 2011. Here the links - unfortunately only in German - couldnīt find the English version.
"Es gibt weniger giftige Alternativen" - Nachrichten Welt Print - Wissen - DIE WELT
and
DER SPIEGEL*9/2011 - Gestank alter Socken
Especially the interview in "Die Welt" is interesting since the scientist interviewed already in the mid 50`s performed a study on the tocix potential of TCP. He found that there is in fact no tolerance value acceptable because of the damage even smallest amounts of that chemical does to nerve tracts.
To avoid further possible poisoning of crews and passengers there seems to be only two possibilities.
Nr. 1 Avoid usage of TCP in Jet Engine Oil at all, use a safe substitute
or
Nr. 2 Copy Boeings recent decision to delete bleed air from air supply in
airliners and use seperate compressors and filters, like they did in the new
B 787.