I do this on cast iron. Never on Teflon. You can use an oven thermocouple to measure the temp of your pan as you heat it without oil. If you do it once,and com

I do this on cast iron. Never on Teflon. You can use an oven thermocouple to measure the temp of your pan as you heat it without oil. If you do it once,and compare with the temps that are dangerous(you could see it on Internet) you will never do it again, as you will realize how fast temp goes up and how easy is to manufacture C8 with your pan. Water acts as a limit of temperature, when it is wet it can't go higher than 100 Celsius(locally, it can in the parts of the pan that are dry). But once all water is gone, it goes hot incredibly fast. Oil does the same but with higher temperature than water, with way higher boiling pressure. If someone does this mistake in one of my Teflon pans, I just throw it away. I never trust pans that are not mine. Obviously, when you see smoke in the oil it is not good either. By the way most of my pans are ceramic or cast iron.