The aerosol spray can—used for many years to apply everything from deodorant to paint to insecticides--dates back to 1926, when Norwegian inventor Eric Rotheim discovered that a product could be contained in and sprayed from an aluminum can injected with gas or liquid to build pressure. In 1939, American Julian S. Kahn received a patent for a disposable spray can, but the product remained largely undeveloped,even after Lyle David Goodhue,credited as the inventor of the spray can,earned a patent for a refillable aerosol spray can in 1941. A breakthrough came in 1949 when Bronx machine shop proprietor Robert H. Abplanalp developed a cheap, efficient valve that facilitated widespread use of the can. The propellants in aerosol spray cans--usually liquified gases such as hydrocarbons,carbon dioxide,or nitrous oxide--are mixed with the contents of the can and pressure-sealed for eventual release through a valve. Although products...