MMT, Déjà Vu and national security

Abstract The Ethyl Corporation, the manufacturer of the gasoline additive tetraethyl lead, has developed a new anti‐knock agent, MMT, methylcyclo‐pentadienyl manganese tricarbonyl, an organic derivative of manganese. Ethyl has already used international free trade laws to force MMT on a reluctant Canadian government, and the Corporation appears to be attempting to market MMT in the United States. These efforts are eerily similar to the events that took place 80 years ago when Ethyl successfully introduced tetraethyl lead to the American market. The tetraethyl lead story began in 1922, when the Ethyl Corporation began commercial manufacture of this organic lead compound [Rosner and Markowitz, 1985]. Despite concerns about its health hazards, manufacture of tetraethyl lead was justified on the grounds that it was essential for the production of high‐octane gasoline for high‐compression engines. A few months after Ethyl began producing tetraethyl lead, 80% of the chemical workers at its plant in Bayway, New Jersey began hallucinating, some developed acute convulsions, and five died. Others were left permanently psychotic. A brief moratorium was imposed on production. But after a hasty study by a compliant U.S. Public Health Service, the chemical was declared safe, plant conditions were improved and the additive was put back into gasoline [Rosner and Markowitz, 1985]. At peak production in the 1970's, more than 200,000 tons of tetraethyl lead were produced annually in the United States [National Academy of Sciences, 1972]. Vast amounts of this lead were released into the environment from the tailpipes of cars, trucks and buses. Widespread contamination of dust, soils, surface water, and the food chain resulted. For many years the hazards of this contamination to public health went unrecognized. Several generations of American children unknowingly suffered loss of intelligence and alteration of behavior on the result of subclinical lead poisoning. The health, welfare and security of the nation were diminished [Hertzman and Keating, 2000]. In the 1970's, after 50 years had elapsed, scientists and regulators came to realize that lead from automobile exhaust was getting into the brains of American children to cause neurodevelopment impairment [Needleman et al., 1979; Bellinger et al., 1987; Dietrich et al., 1991; McMichael et al., 1998; Wasserman et al., 1997]. This chronic impairment was shown to increase the number of children with mental retardation, to reduce the number of truly gifted children and to increase the number of adolescents with a propensity to violence and criminal behavior [Needleman et al., 1990; Needleman et al., 1996]. As a consequence of these findings, tetraethyl lead was phased out from gasoline in this country‐one of the most important public health actions in the last three decades. As a direct consequence of this action, the level of lead in Americans' blood has declined by over 90% [CDC, 1997]. The national intelligence has increased [Schwartz et al., 1985]. Propensity for violent and criminal behavior has diminished. MMT, like tetraethyl lead, is a neurological toxin that can cause agitation and convulsions, as well as pulmonary damage [Penney et al., 1995]. In 1994, the EPA attempted to block the manufacture of MMT in the United States citing it as a potential health hazard. But in October of that year, a Federal Appeals Court in Washington, DC ruled on narrow technical grounds that MMT was not covered by a regulation that required fuel additives to be tested before they could be sold. The Court ruled that the Ethyl Corporation could test the additive while selling it and set no deadline for completion of such testing. In essence, the Court stated that the chemical was to be considered innocent until proven guilty. A much wiser approach to the management of MMT would have invoked the precautionary principle [Goldstein, 1999]. The precautionary principle would argue that a chemical such as MMT with potentially serious and irreversible health hazards should be considered dangerous until proven innocent. Application of the precautionary principle would require extensive testing of MMT prior to its use and would demand explicit debate about the wisdom of releasing this potentially dangerous material to the American environment. A decision to market MMT has the potential to be a disaster for public health. MMT poses potential hazards of unknown magnitude for mechanics, gas station workers, other workers and members of the public who might come into contact occupationally or environmentally with fuel containing MMT. Manganese, the metal that would be released to the environment by the combustion of MMT in gasoline engines, is also a well‐known neurotoxin [Rom, 1983]. Industrial workers exposed to manganese such as miners and welders, are at risk of manganism, a disease of the central nervous system characterized by tremors similar to those of Parkinson's disease. Mental deterioration can result. A range of toxicity is seen in many workers exposed occupationally to manganese that extends from devastating impairment at higher levels of exposure to more subtle aberrations at lower levels [Lucchini et al., 1985]. The consequences of widespread exposure of Americans of all ages, including workers, pregnant women and children to manganese from MMT are virtually unknown. The potential for injury to the nervous system has never been independently assessed. The Ethyl Corporation asserts that MMT is safe, but Ethyl's claims do not withstand scientific scrutiny. As the report in this issue of the Journal by Zayed demonstrates, systematic studies of the effects of manganese at low levels in humans are lacking in Canada as well as elsewhere [Zayed, 2001]. Infants and young children are especially vulnerable to neurotoxicants in the environment [NAS, 1992]. They live and play close to the ground where fumes from tailpipes settle. The cells in young brains are growing, developing and continually changing throughout the early years of life. These processes are delicate and easily disrupted by environmental toxins. The effects of early exposure to a toxic substance such as manganese could be evident immediately, or could become manifest only years or decades later [NAS, 1992]. The possible long‐term consequences of widespread early exposure to manganese have not been examined. It makes no sense for our society to violate the precautionary principle and to experiment again with the introduction of a potentially neurotoxic material to the nation's gasoline supply. The intelligence of our population is a critical foundation of our national wealth [Hertzman and Keating, 2000], and thus of our security. It is not unreasonable to argue that the exposure of the American population to MMT and manganese could constitute a potentially grave threat to our national security. The United States cannot afford a repeat of the tetraethyl lead tragedy. Sincerely, Philip J. Landrigan, MD, MSc Chairman, Department of Community and Preventive Medicine

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