Gaseous,
Seems to be you wearing the White coat,..... so Ethelene Glycol was, and I think still is a liquid used as a coolant in big A/c piston engines....It was also injected along with water into the fuel stream of the Rolls Royce Griffon engine when at full throttle and full supercharged boost to give I believe more bang to the fuel.
Then, if it is present in the 100LL of today, is this done for the same reason to make a Low Lead fuel more explosive upon compression/ignition, seems the more we dig the wider the hole is appearing! but I am sure we are near the answer, despite the Farmyard Experiments!
PeterR-B