Deadly Danger In a Spray Can

By MICHAEL D. LEMONICK

When they were first synthesized in the late 1920s, chlorofluorocarbons (CFCs % for short) seemed too good to be true. These remarkable chemicals, consisting of chlorine, fluorine and carbon atoms, are nontoxic and inert, meaning they do not combine easily with other substances. Because they vaporize at low temperatures, CFCs are perfect as coolants in refrigerators and propellant gases for spray cans. Since CFCs are good insulators, they are standard ingredients in plastic-foam materials like Styrofoam. Best of all, the most commonly used CFCs are simple, and therefore cheap, to manufacture.

There is only one problem. When they escape into the atmosphere, most CFCs are murder on the environment. Each CFC molecule is 20,000 times as efficient at trapping heat as is a molecule of CO2. So CFCs increase the greenhouse effect far out of proportion to their concentration in the air.

A more immediate concern is that the chlorine released when CFC molecules break up destroys ozone molecules. The ozone layer, located in the stratosphere, between 10 and 30 miles up, is vital to the well being of plants and animals. Ozone molecules, which consist of three oxygen atoms, absorb most of the ultraviolet radiation that comes from the sun. And ultraviolet is extremely dangerous to life on earth.

The small amount that does get through to the earth's surface inflicts plenty of damage: besides causing sunburn, the rays have been linked to cataracts and weakened immune systems in humans and other animals. Ultraviolet light carries enough energy to damage DNA and thus disrupt the workings of cells, which is why excessive exposure to sunlight is thought to be the primary cause of some skin cancers.

When scientists first warned in the 1970s that CFCs could attack ozone, the U.S. responded by banning their use in spray cans. (Manufacturers switched to such environmentally benign substitutes as butane, the chemical burned in cigarette lighters.) But the rest of the world continued to use CFC-based aerosol cans, and overall CFC production kept growing. The threat became far clearer in 1985, when researchers reported a "hole" in the ozone layer over Antarctica. Although the size of the hole varies with the seasons and weather patterns, at times Antarctic ozone has been depleted by as much as 50% in some spots. As a result of this disturbing development, 24 nations, including the U.S. and the Soviet Union, met in Montreal two summers ago and agreed to cut back on CFCs. The so-called Montreal Protocol is designed to achieve a 35% net reduction in worldwide CFC production by 1999.

That is not good enough, however. The same stability that makes CFCs so safe in industrial use makes them extremely long-lived: some of the CFCs released today will still be in the atmosphere a century from now. Moreover, each atom of chlorine liberated from a CFC can break up as many as 100,000 molecules of ozone.

For that reason, governments should ensure the careful handling and recycling of the CFCs now in use. Said Senator Albert Gore of Tennessee: "Much of what reaches the atmosphere is not coming from industrial sources. It's things like sloppy handling of hamburger containers." When plastic-foam burger holders are broken, the CFCs trapped inside escape. Discarded refrigerators release CFCs as well, and, noted Gore, a significant part of the U.S. contribution to CFC emissions comes from "draining automobile air conditioners and leaving the stuff in pans where it boils off." Such release of CFCs could be prevented if consumers and businesses were offered cash incentives to return broken-down air conditioners and refrigerators to auto and appliance dealers. Then the units could be sent back to the manufacturers so that the CFCs could be reused.

While recycling will help, the only sure way to save the ozone is a complete ban on CFC manufacture, which should be phased out over the next five years. Fortunately, as the Montreal Protocol demonstrates, banning CFCs will be far simpler than reducing other dangerous gases. "The CFC producers are a small club of countries," said Brice Lalonde, France's Environment Secretary. But a ban could admittedly be economically disruptive to the entire world: the annual market for CFCs is some $2.2 billion. The Soviet Union, which is a heavy user of CFCs, will have a particularly tough time phasing out the chemicals. "I agree with the ban in principle," said Vladimir Sakharov, a member of the Soviet State Committee for Environmental Protection, "but in practice it will be extremely difficult. Our economy is not as flexible as others."

To make the transition easier, chemical companies are working hard to find practical substitutes for CFCs. The most promising approach so far is to use CFC family members that are chemically altered to make them less dangerous to the environment. The chlorine-free substance HFC-134a, for example, is most likely to be used in refrigeration devices.

The major drawback to CFC substitutes is the high cost of making them. It may be that until better manufacturing techniques are developed, consumers will have to pay more for affected products. The prospect is not a pleasant one, but it is a small price to pay for curbing the greenhouse effect and saving the life-preserving ozone layer.