The federal government and the oil industry are financing the study of possible health hazards associated with an additive required to be mixed into gasoline during winter months in 39 urban areas, including Los Angeles.
Consumers, public interest advocates and environmentalists say the substance--methyl tertiary butyl ether, or MTBE--causes headaches and nausea.
So far, however, there is no scientific basis for the fear, says the U.S. Environmental Protection Agency, which is funding a Rutgers University study along with producers of the additive and the American Petroleum Assn.
The federal Centers for Disease Control and Prevention is also investigating reports of health problems.
Some concern has also been raised that MTBE could be a low-level, cancer-causing agent over long exposure.
Though the EPA says studies so far show little likelihood of this, the agency is investigating.
Consumer complaints of nausea and headaches from gasoline containing 15% MTBE began last fall in Fairbanks and Anchorage, Alaska, and have surfaced more recently in Missoula, Mont., and parts of Colorado and New Jersey.
"I have seen customers gagging and turning away" at gasoline stations in Southern California, commuter Paul Christensen said on Friday.
The EPA and Arco Chemical Co., the world's largest maker of the substance, say that a decade's experience with the additive has shown no such harmful effects. And the new research should answer any remaining questions before the additive is required next year.
"This (Rutgers) test program is well underway," said William S. Whitney, business manager for oxygenated fuels at Philadelphia-based Arco Chemical.
The study will be finished by August, Whitney said, "so this should be understood before the program begins next fall. . . . The only reason we haven't addressed this health issue before is because we haven't observed it."
The 1990 federal Clean Air Act required additives such as MTBE to be put in gasolines beginning Nov. 1, 1992.
Such additives, known as oxygenates, alter the combustion of gasoline to reduce an automobile's emission of carbon monoxide.
Winter weather, with its temperature inversions and slower auto engine warm-up, increases the output of carbon monoxide, which can be harmful, particularly to people with existing respiratory ailments.
The so-called "winter gas" season ended Jan. 31 for California cities. In some other states, the requirement runs until March 31.
An Arco spokesman said all MTBE gasoline was likely out of station tank systems within days after the season ended because it had been diluted by conventional gas.
But the two additives now available--MTBE and ethanol, a grain alcohol usually made from corn--could have their own adverse health effects, some environmentalists and consumers worry.
During combustion, both create formaldehyde.
Richard D. Wilson, director of the EPA's office of mobile air pollution sources, sees the MTBE issue muddled by factors beyond science.
"People will blame anything new for anything that happens to their cars," said Wilson, noting that an identical "winter gasoline" program has been in place in such cities as Denver in past winters without any health complaints.
Wilson said that when Alaska Gov. Walter J. Hickel stopped distribution of MTBE gasoline in December in response to complaints and consumer demonstrations, the health complaints dropped off immediately--even though the gasoline was still being sold for several days.
Many at the EPA suspect that public turmoil over the 15-cent-a-gallon hike in gas prices for MTBE gasoline, higher than in the Lower 48 states, encouraged consumers to see health effects that may have no connection to the fuel.
"The truth is we just don't know," Wilson said.
Deborah Gordon, a chemical engineer and senior transportation analyst with the Union of Concerned Scientists, isn't surprised at the reports of nausea and headaches.
"Formaldehyde is the stuff they used in the old gangster movies, when they they came up behind you and put a rag over your face," Gordon said Friday.
Arizona and some other western states have long used oxygenates in their fuels, Gordon said, "and when I was lecturing there several years ago, I heard people say, 'We have had isolated instances of people fainting and getting nauseous, blacking out.' "
Gordon suspects that people may be more affected by the concentrations that can accumulate around service stations.
But the EPA, the MTBE industry and others say that formaldehyde is formed in such minute quantities that any health effects are unlikely.
"I wouldn't see it as significant," said Jay A. Young, a chemistry safety and health consultant in Silver Spring, Md., who does research for various federal agencies. "If I were a gasoline attendant, I would be much more concerned about the vapors of benzene and the hydrocarbons themselves than formaldehyde.
"Formaldehyde simply does not cause nausea," Young added, "and long before you suffered a headache your eyes would be tearing to where you couldn't stand it."