> The most frequent hydrocarbon bond is the CH2–CH2, as in PE (Figure S1B). Although the molecular details of wax biodegradation require further investigation, it seems likely that the C–C single bond of these aliphatic compounds is one of the targets of digestion.
Which seems to imply methylene(o) as the byproduct?
Also burning plastic releases more than just CO2:
> The most dangerous emissions can be caused by burning plastics containing organoch- lor-based substances like PVC. When such plastics are burned, harmful quantities of dioxins, a group of highly toxic chemicals are emitted. Dioxins are the most toxic to the human organisms. (i)
(o) https://en.m.wikipedia.org/wiki/Methylene_(compound)
(i) http://www.wecf.eu/cms/download/2004-2005/homeburning_plasti...