Peril from Superplastics?

Microscopic carbon fibers pose a threat

The new super lightweight, super strong materials are here. Made of plastics reinforced by extremely thin strands of carbon, they are already being used in everything from aircraft parts to golf clubs and tennis racquets. Industry planners also have their eyes on hundreds of other products that could benefit from the versatile materials. But now warning flags have been raised about a troublesome effect of the fibers in the superplastics. Federal officials are so concerned that they have quietly ordered a high-level inter-agency study to decide how to reduce the potential hazard.

Because the new composite materials can be formed into almost any shape, are extremely strong and durable, and weigh far less than metals of comparable strength, a ready market was available when they first appeared in the 1960s. The aircraft industry began using new composites for helicopter blades, turbojet fans and many other components--first plastics containing boron fibers. Then manufacturers began turning to fibers made of carbon or graphite (another form of carbon), which were less expensive and more versatile than the boron variety.

Almost immediately the first sign of trouble appeared. When the fine, nearly microscopic carbon fibers escape into the air--either during their manufacture or when the composite material is purposely or accidentally incinerated--they can settle on electrical equipment with disastrous results: carbon fibers are good conductors of electricity and thus can cause short circuits, arcing and sometimes fire. According to a recent NASA study, there have been more than a dozen such incidents since 1970 in industrial plants producing or using the fibers. As use of the composites increases, careless disposal and burning of wastes could release enough fibers into the air to short out air conditioners, TV sets, radios and even large power generating systems.

Such mischievous effects have not escaped the attention of military authorities who in classified studies have noted that a cloud of carbon fibers could be used, for instance, to incapacitate electrical equipment over wide areas--as well as knock out enemy radar. Because some 350 tons of carbon fibers are now produced annually in the U.S. and abroad, the Carter Administration ordered that much of the NASA study be made public. It also directed several agencies under the auspices of the Department of Commerce to look into the matter further.

There is every reason for a thorough inquiry. U.S. automakers, especially Ford, are stepping up their investigation of these materials as an alternative to steel in a new generation of lighter cars that will burn less fuel. Ford President Lee Iacocca says that the composites will cut by 600 kg. (1,300 lbs.) the weight of a prototype car planned for 1979.

What worries scientists is that, in the future, burning of waste materials by manufacturers, fires caused by aircraft and auto accidents, and incineration of discarded products could sharply increase the amount of carbon fibers in the atmosphere, threatening electrical equipment.

Government officials have no plans to ban the extremely valuable material. But they, as well as industry scientists, are looking for safe ways to handle, shield and dispose of the composites. Says a Government spokesman: "Properly handled, these materials can be very useful. We want to make sure, however, that their use is fully understood."

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