i worked in a lab one summer where i handled phenol all the time. now that's scary ass shit. i also worked with hydrofluoric acid on a regular basis, which has an interesting property. if you spill it on your skin, it doesn't react with your skin, muscle or fat tissue right away, but instead absorbs through the flesh until it reaches the bone, which it reacts to much quicker. so it basically dissolves your bones... crazy. you could spill it on yourself and not even notice until you start to die. i've also worked with all the other common acids and bases like hydrochloric, sulfuric, nitric acids and bases like concentrated sodium hydroxide. one time i came close to liquid oxygen, but never actually had to handle it.