In November, the Natural Resources Defense Council petitioned the Consumer Product Safety Commission for an immediate ban on spray cans using freon (a DuPont tradename) and similar fluorocarbons as a propellant. NRDC cited growing scientific evidence that the gases released from aerosol cans are causing gradual deterioration of the ozone layer in the upper atmosphere. The ozone layer, about 10 to 20 miles up, shields the earth from ultraviolet radiation, a major cause of skin cancer. A study conducted by Dr. Michael McElroy of Harvard University predicted that if the use of freon continues at present rates, the ozone layer will be diminished by 10 percent within 15 years, and that as a result, the incidence of skin cancer will rise by 20 percent. By the year 2000, the study estimated, the ozone layer will have been reduced by 14 percent.

The fluorocarbons used in aerosol cans were originally thought to be ideal propellants, owing to their chemical stability. In the past five years, use of freon has increased some 15 percent per year, in spray cans of cosmetics, paints, and a variety of household products. In 1972, 1 1/2 billion aerosol cans of cosmetics were sold, and some 700 million cans of household products. One million tons of freon are released into the atmosphere each year. Recently, however, scientists discovered that at stratospheric levels, ultraviolet light causes fluorocarbons to break down, releasing free chlorine atoms that in turn break down the ozone. The Atomic Energy Commission has found fluorocarbons in the stratosphere from as far north as Greenland to as far south as Argentina. The sharp decrease in the ozone layer began in 1971, after 10 years in which the density of the gas increased. That increase is attributed to the 1963 ban on nuclear testing in the atmosphere.