Organic chemicals (ethylene, propylene, and many others) have by far the highest energy requirements of all chemical sectors, accounting for about 49% of total industry energy use. More than 50% of energy consumed in organic chemicals manufacture is in the form of energy feedstocks (natural gas and LPG). Feedstocks also represent a large share of energy used in production of plastics and agricultural chemicals. Inorganic chemicals are made from ores, air, and water and thus require little or no feedstock energy. [MECS 1994]