Out of the chimney

You should be coming out of the chimney as steam and carbon dioxide. All ready to feed the plants that fed you. Unfortunately your cremation will produce lots of nasty pollutants too. Mercury (from your fillings), carbon monoxide, hydrogen chloride, and smoke.



To keep you from polluting the environment the products of your cremation go into a second chamber where a secondary burner burns off any remaining gases and smoke particles. Your gases might even go through filter bags to clean them further. However, no system is perfect, you still might manage to puff brown smoke out of the chimney for a couple of minutes.