Question: What is the most toxic gas and why?

Jordan Moir answered on 15 Jun 2018:

The most toxic gas I work with at my work is Liquid Nitrogen when it is released at room temperature and becomes a colourless gas when it boils at -192oc there is the risk of asphyxiation which means if there is a leak in the room where we store this and you enter it a few breaths of it can actually kill you as this replaces all the oxygen in the room so you are unable to breath. We use monitors and detection systems when working in this area to prevent this happening. It can also cause severe burns as it is so cold like frostbite.