Toner is over 85% plastic. There are no special precautions for handling or disposal. In my experience, nobody ever got sick from toner. Two people (in 25 years) mentioned headaches from the ozone created by a photo copier. This was from high volume color copiers, which used corona wires. Small printers mostly use charge rollers which don't generate ozone. The few that do use corona wires would only have a tiny fraction of the output of those large production copiers.