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Public Radio's Environmental News Magazine (follow us on Google News)

New at the Pumps: Manganese Gasoline

Air Date: Week of

The Environmental Protection Agency has not had time to assess it, and in the meantime the Ethyl Corporation is promoting its new product, the fuel additive M.M.T., derived from the metal manganese. Dan Grossman reports on the latest controversy at the gas pumps.


CURWOOD: This is Living on Earth. I'm Steve Curwood. After a 20-year phase-out, lead is finally gone from America's gasoline. Public health advocates are cheering. Low levels of lead poisoning have been linked to lowered intelligence, as well as increased learning disabilities, school dropout rates, and delinquency. But today another metal that's toxic to the nervous system, manganese, is in the process of being added to the nation's gasoline supply, and public health advocates are warning that, like lead, it may do more harm to your body than good for your car. Manganese is a cheap way to boost the octane rating and thereby boost the profits of refiners. The US Environmental Protection Agency is against it, but as Dan Grossman reports, a recent court ruling has overruled their objections.

GROSSMAN: Last New Year's Eve marked an important milestone. It was the last time gasoline containing the additive tetraethyl lead could be legally sold at gas stations in the US. Starting in the 1920s, lead was blended with gas to prevent premature combustion or knocking. But in 1970, concerned that lead would gum up auto emissions devices, law makers in Congress began a gradual phase-out of lead. the action also removed the largest source of human exposure to a major neurotoxin.

SILBERGELD: We now know that the use of lead in gasoline accounted for about, on average, 60% of the body's burden of lead for Americans and was a major contributor to the incidence of lead poisoning, particularly among children.

GROSSMAN: University of Maryland epidemiologist Ellen Silbergeld ranks the lead ban among the public health achievements of the century. But she worries that the lead story is being repeated all over. Last December the Ethyl Corporation, which originally produced tetraethyl lead, received approval to sell MMT, a gasoline additive containing another metal: manganese. The company boasts MMT will be just as good as lead for America's cars. Health experts like Dr. Silbergeld says the compound could be just as bad as lead for America's people.

SILBERGELD: Like lead, manganese is neurotoxic, and we know it causes clinical disease in people who are chronically exposed. Just as in 1925 when the government had to make a decision about whether lead could be added to gasoline, in 1995, when the government was confronted with the same challenge, there are significant gaps in our knowledge. And this time we have the chance to demand that these gaps be reasonably filled before we permit what is undeniably a dispersive use of a toxic metal that will never go away.

GROSSMAN: Dr. Silbergeld is a consultant to the Environmental Defense Fund. She and other researchers fear that just as in the case of lead, minute amounts of manganese dispersed in auto exhaust will gradually build up in human tissues, possibly with harmful results.

SILBERGELD: At relatively high levels, exposure to manganese causes damage to the lung and the nervous system. Its effects on the brain include psychosis and neuro-motor damage which progresses to a disabling tremor and loss of movement.

GROSSMAN: The effects of large doses of manganese are not in dispute. The question is, what happens when people are exposed to small doses? Chris Hicks, Ethyl's Vice President for Government Affairs, says the exhaust of cars burning fuel with MMT has too little manganese to be harmful.

HICKS: There are many things that we use in our daily life that are toxic at high exposure levels. Aspirin, for instance. Salt. Table salt is toxic at high exposure levels. But if you use it responsibly in small doses, aspirin or salt or MMT actually has a benefit to public health.

GROSSMAN: The benefit would come if MMT helped reduce pollutants that cause smog: a claim made by Ethyl, but which environmental regulators give little weight. More to the point, Mr. Hicks says studies in Canada where MMT has been used since 1977 show that auto exhaust does not substantially contribute to a person's intake of manganese.

HICKS: In a typical automobile gas tank, we're talking about adding one half of a teaspoon of MMT to achieve the benefits. And as our studies in Canada and elsewhere have repeatedly shown, the manganese that comes out of the tail pipe just does not add to the background levels. Manganese is part of your recommended daily intake from the FDA. Most vitamins that contain minerals have manganese in the tablets that are orders of magnitude higher than you would ever be exposed to here.

GROSSMAN: But Ethyl's critics say that's not the point. They're concerned that emissions from MMT gas could significantly raise the levels of manganese in the air, and that inhaling manganese could be more dangerous than eating it. Government scientists say the detailed studies needed to find out have yet to be done. The Environmental Protection Agency is so concerned about MMT, it sought to keep the additive off the market. But Ethyl sued, and last December the US Court of Appeals in Washington ruled the Agency didn't have authority to regulate the additive on health grounds. EPA Administrator Carol Browner says the Agency's hands are tied for now, but it may revisit the issue when further health tests are completed.

BROWNER: We're going to use every single authority to ensure that the kind of health research that we think should have been done on the front end is in fact done, and again if there is any evidence, we will move expeditiously to protect the public's health.

GROSSMAN: Ms. Browner says that could take years. And if there's one lesson she's learned from lead, it's that we should learn the effects of such substances before they go into widespread use, not after.

BROWNER: The bottom line for me is that in 1996 there is no reason that a product should go on the market without being subjected to comprehensive testing. The American people should not be turned into a laboratory.

GROSSMAN: Meanwhile, car companies also have questions. They are concerned that, like lead, MMT could cause trouble for pollution control equipment. And they're considering studies of their own to find out. A coalition of environmental and health groups, spearheaded by the Environmental Defense Fund, has asked oil refiners and gasoline suppliers to voluntarily refrain from using MMT. No major oil company has announced it will use the additive, but they aren't pledging they won't. Ethyl says gas containing MMT is already for sale at certain service stations, but it won't say which ones. Within a year and a half, the company plans to be producing nearly a million pounds a month for use in gas pumps nationwide. For Living on Earth, this is Daniel Grossman.



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