"Toxic" Misapplications Elsewhere a member poses a question on toxicity. On the news and in the print media as well as online, there is a low din of ongoing concern over "toxic" this or "toxic" that. We would all do well to recall the chemist's axiom: "There are no toxic chemicals, only toxic levels." Not long ago, a woman died from drinking too much water to win a radio station contest. It's a wonder the EPA didn't order all companies selling bottled water to label water "Toxic" as a result. Then too breathing pure oxygen for a few days is generally fatal. It is for this very reason Navy frogmen don't take their rebreathers down below about 25 feet. Oxygen at pressure will kill you even quicker. So is oxygen, so immediately necessary for life, "toxic". Je pense que "non".