Warning that skin cancer will rise rapidly if the use of fluorocarbon propellants continues to rise and weaken the earth's ozone shield, the National Academy of Sciences yesterday suggested that the United States put a tax on them and set up a quota system to limit their use.
In a 392-page report to the Environmental Protection Agency, the NAS noted that nonessential uses, such as cans, already have been banned.It did not recommend extension of that ban because most of the remaining uses are too important. The chemicals are still used in refrigeration and air conditioning, in metal cleaning and drying and as blowing agents to make most of the flexible cushions for furniture.
"In eliminating the nonessential uses, the United States has dropped to where it now generates less than half the world's fluorocarbons," said Princeton University's Dr. John W. Tukey, chairman of the committee that wrote the report for the NAS. "If we could get the rest of the world to adopt the same ban, we might be able to make things a little better."
But Tukey said that even if the entire world banned the spray can propellants, so many important uses for the chemicals have sprung up that emissions of fluorocarbons to the atmosphere would equal today's levels in less than 10 years.
The NAS did not recommend regulatory actions against the fluorocarbons, mostly because EPA did not ask it to do so. Instead, it drew up a range of options such as taxes, quotas and alternate chemicals, to cut down on the use of fluorocarbons.
If worldwide use of the chemicals, technically called chlorofluorocarbons, continues at today's rates, the NAS said, enough of these indestructible compounds will rise into the stratosphere to eat away by the end of the next century nearly 20 percent of the ozone that protects the Earth from the sun's most damaging ultraviolet light.
The ultraviolet breaks up the chlorofluorocarbons into chlorine and fluorine. The former attacks the ozone -- oxygen molecules containing three atoms instead of the usual two -- and breaks it apart. While evidence so far suggests this attack has not yet begun in earnest, the NAS believes enough fluorocarbon will reach the stratosphere in the next few years to begin shrinking the ozone layer.
"The chlorofluorocarbons accumulate slowly and their products accumulate slowly," Princeton's Dr. Tukey said in sending the academy's report to the EPA. "If our calculations are correct, we should see half their ultimate effect in 30 years.
The academy said that in the United States alone, a 16.5 percent reduction in ozone would result in "several hundred thousand" more cases of a rarely fatal skin cancer each year and "several thousand" new cases of an often-fatal skin cancer called melanoma. An estimated 13,600 new cases of melanoma were predicted for 1979, as well as 4,300 deaths.
"The melanoma rate is going up in the U.S., where it hits young, indoor professional people," said Harvard University's Dr. Thomas B. Fitzpatrick. "It is increasing faster than any other cancer except lung, apparently because people are exposing themselves to the sun a lot more."
To cut down the use of chlorofluorocarbons, the NAS suggested that the United States immediately begin to look at their use in flexible plastic foams, metal cleaning and drying and sterilizing medical instruments, and seek to replace them with other chemicals.