If we're talking pure elements at room temperature, people can die from extended contact/eating/breathing beryllium, fluorine, phosphorous, hlorine, chromium, cobalt, arsenic, cadmium, antimony, cesium, mercury, thallium, lead, bismuth, polonium, radium, thorium, uranium, plutonium, and americium. That doesn't even count all of the heavier than air gases that will kill you in a couple of deep breaths. People are very squishy and prone to getting injured by things.