Glycol based runway deicers are generally made from monoethylene glycol and diethylene glycol. Both are moderately toxic.
Aircraft de-icers - typically type II - are based on monopropylene glycol, which is not classed as toxic and is used in phamaceutical preparations.
However, all de-icers contain additives, some of which may be toxic. Methanol is a component of automotive de-icers and is certainly toxic.