The largest user of hydrogen is the petroleum industry for converting crude oil into gasoline and hundreds of chemicals. No one sustained hydrogen burns in the 1937 Hindenburg accident. Seven million cubic feet of hydrogen, equal in volume to a structure three football fields in size and 49 ft. in height, burned in less than one minute. However, diesel fuel for the propulsion engines fell to the ground and continued to burn for many hours. If liquid hydrogen is spilled it will very rapidly evaporate, leaving no pollution or toxic residue.
Carbon is a valuable by-product of separating hydrogen from hydrocarbon compounds.
The hydrogen left over could be used in cars that clean the air of pollution caused by those vehicles using hydrocarbon fuels. Carbon is the most versatile of all elements. With it we can make materials to replace wood and steel. It is not rational to burn petrocarbons and deny future generations their right of access to fossil hydrocarbon reserves to make plastics, synthetic fabrics, lubricants, solvents, carbon-fiber products that are stronger than steel and countless other new products that are even now being developed. Hydrogen packs more chemical energy in a pound for pound comparison than with any other fuel.