Lead in the Air

True or false: lead-free gasoline is the best thing to come down the freeway since the V-8 engine. True, according to the oil companies that recently switched to unleaded or low-lead fuels and are promoting them as an antipollution measure. False, from the viewpoint of the Ethyl Corp., the nation's largest producer of lead additives for gasoline.

Shell, Esso, Chevron and Amoco make ambitious claims. Esso's Big Plus is touted as "the lowest-lead, highest-octane gasoline for the money," and Chevron boasts that its F-310 fuel will "reduce fuel consumption, improve performance and cut maintenance." Ethyl Corp., which pioneered the use of lead compound additives for autos in 1923 and saw its stock jump in the 1950s when Detroit moved to high-compression engines, contends that by taking the lead out of gasoline, oil companies will actually increase other forms of noxious automobile emissions.

Octane Loss. Specifically, charges Lawrence Blanchard Jr., Ethyl's executive vice president, nonlead gasolines will have to use larger amounts of the more combustible gasoline components called aromatics, which compensate for the loss of octane that results from the removal of lead. Without them, high-performance engines as presently designed would lose power and produce knocking. But, argues Blanchard, the burning of the aromatics emits toxic benzene and other chemicals, which react with sunlight to produce heavy smog.

While not disputing Blanchard's claims, critics argue that lead from car exhausts is indeed a serious problem. Dr. Henry A. Schroeder of Dartmouth Medical School last week cited lead and other heavy metals among the major killers in the rogues' gallery of polluting agents. Blanchard's retort is that the amount of lead absorbed by the body is only the equivalent of "one BB shot of lead inhaled by one man over a period of 70 years."

Despite Blanchard's BB-shot analogy, the fact remains that minute amounts of auto-exhaust lead, when added to the lead taken into the body from other sources, can cause serious injury and even death. Industrial wastes add lead to drinking water and children sometimes eat leaded paint peelings. Concentrations of only .8 parts per million can cause illness. Children are especially susceptible to lead poisoning because their toxicity level is only .6 p.p.m. Thus far, concentrations of .25 p.p.m. have been found in some residents of vehicle-clogged cities, where airborne lead is thickest. In New York City, a campaign is under way to reduce lead levels in the air by having cabs and city-owned cars switch to unleaded fuel.

Detroit Move. The presence of lead in gasoline poses still another hazard: the metal's residue clogs the antippllution devices that the automobile industry has developed for its next generation of cars. Hence Detroit favors lead removal as a means of meeting federal emission standards that are to take effect in the fall of 1974.

This approach still leaves the problems of octane loss and the new types of pollution that may be caused by lead substitutes. Organic Chemist Fausto Ramirez of the State University of New York at Stony Brook argues that they can be solved. The trick is to lower the compression ratio--the degree to which the mixture of oxygen and fuel is compressed within the engine cylinders. Lower compression reduces octane requirement, and emissions from the substitute additives can thus be kept within tolerable limits. Beginning with its 1971 models, Detroit is moving toward engines with lower compression ratios.

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