A solid form of carbon dioxide, CO₂, which finds its largest application as a cooling agent in the transportation of perishables. It is nontoxic and noncorrosive and sublimes directly from a solid to a gas, leaving no residue. At atmospheric pressure it sublimes at −109.6°F (−78.7°C), absorbing its latent heat of 246.4 Btu/lb (573.1 kilojoules/kg). Including sensible heat absorption, the cooling effect per pound (kilogram) of dry ice is approximately 270 Btu (628.0 kJ) at storage temperatures above 15°F (−9°C) and 250 Btu (581.5 kJ) at lower temperatures. Slabs of dry ice can easily be cut and used in shipping containers for frozen foods, in refrigerated trucks, and as a supplemental cooling agent in refrigerator cars.