Is glycerin hazardous?

NO!

Glycerin is:

Non-Hazardous to Water (Water Hazard Class WGK:10)
Non-Toxic
Completely Biodegradable
Used worldwide as entered in the EINECS list of time-tested non-hazardous materials
Neither listed nor classified in given transport regulations for hazardous goods
Used in pharmaceutical and cosmetics industries as a substance vehicle & humidity stabilizer
Used in the food sector for rounding off taste & conservation