Solid carbon dioxide (C02 snow) used for therapeutic refrigeration. Solid C02 has a temperature of 80°C below zero. Its application to the skin for 1 to 2 sec causes superficial frostbite; 4 to 5 sec, a blister; 10 to 15 sec, superficial necrosis; and 15 to 45 sec, ulceration. It is used mostly for removal of certain nevi and warts, occasionally for telangiectasia.