AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 39:434±435 (2001)

Editorial

MMT, DeÂjaÁ Vu and National Security

The Ethyl Corporation, the manufacturer of the gaso-

line additive tetraethyl lead, has developed a new anti-knock

agent, MMT, methylcyclo-pentadienyl manganese tricarbo-

nyl, 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 sstory 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 justi®ed 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 ®ve 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 1970s, 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 contamina-

tion 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 1970s, 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 ®ndings,

tetraethyl lead was phased out from gasoline in this

countryÐone 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 regu-

lation 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 ir-

reversible 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,

ß 2001Wiley-Liss, Inc.

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 Amer-

icans 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 scienti®c 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 im-

mediately, 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 pre-

cautionary principle and to experiment again with the intro-

duction 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 unreason-

able 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, MSc, MD

Chairman, Department of Community

and Preventive Medicine

REFERENCES

Bellinger D, Leviton A, Watermaux C, Needleman HL, Rabinowitz M.1987. Longitudinal analyses of prenatal and postnatal lead exposureand early cognitive development. N Engl J Med 316:1037±1043.

Centers of Disease Control and Prevention. 1997. Update: blood leadlevelsÐUnited States, 1991±1994. MMWR 46:11±146.

Dietrich KN, Succop Pa, Berger O, Hammond P, Bornschein RL. 1991.Lead exposure and cognitive development of urban preschool children:the Cincinnati lead study cohort at age 4 years. Neurotoxicol Teratol13:203±211.

Goldstein BD. 1999. Editorial. The precautionary principle andscienti®c research are not antithetical. Env Health Persp 107(12):594±595.

Hertzman C, Keating DP. 1999. Developmental Health and the Wealthof Nations: social, biological and educational dynamics. New York:Guilford Press.

Lucchini R, Selis L, Folli D, Apostoli P, Mutti A, Vanoni O, Iregren A,Alessio L. 1995. Neurobehavioral effects of manganese in workersfrom a ferroalloy plant after temporary cessation of exposure. Scand JWork Environ Health 21:143±149.

McMichael AJ, Baghurst PA, Wigg NR, Vimpani GV, Robertson EF,Roberts RJ. 1988. Port Pine cohort study: environmental exposure tolead and children's abilities at four years. N Engl J Med 319:468±475.

National Academy of Sciences. 1972. Lead: airborne lead inperspective. Washington DC: National Academy Press.

National Academy of Sciences. 1992. Environmental Neurotoxicol-ogy. Washington DC: National Academy Press.

National Academy of Sciences. 1993. Pesticides in the Diets of Infants& Children. Washington DC: National Academy Press.

Needleman HL, Gunnoe C, Leviton A, Reed R, Peresie H, Maher C,Barrett P. 1979. De®cits in psychologic and classroom performance ofchildren with elevated dentine lead levels. N Engl J Med 300:689±695.

Needleman HL, Schell A, Bellinger D, Allred E. 1990. The long-termeffects of exposure to low dose of lead in childhood: an 11-year follow-up report. N Engl J Med 322:83±88.

Needleman HL, Riess JA, Tobin MJ, Biesecker GE, Greenhouse JB.1996. Bone lead levels and delinquent behavior. JAMA 275:363±369.

Penney DA, Hogberg K, Traiger GJ, Hanzzik RP. 1985. The acutetoxicity of cyclopentadienyl manganese tricarbonyl in the rat.Toxicology 34:341±347.

Rom WN. 1983. Chromium, manganese, nickel and other elements. In:Rom WN, editor. Environmental and Occupational Medicine. Boston:Little, Brown and Company, p 493±510.

Rosner D, Markowitz G. 1985. A Gift of God? The public healthcontroversy over leaded gasoline during the 1920s. Am J Pub Health75:344±352.

Schwartz J, Pitcher H, Levin R, Ostro B, Nichols AL. 1985. Costs andbene®ts of reducing lead in gasoline: ®nal regulatory impact analysis.EPA-230/05-85/006. Washington DC.

Wasserman GA, Liu X, Lolacono NJ, Factor-Litvak P, Kline JK,Popovac D, Morina N, Mustabegovic A, Vrenezi N, Capuni-Paracka S,Lekic V, Preteni-Redjepi E, Hadzialjevic S, Slavkovich V, GrazianoJH. 1997. Lead exposure and intelligence in 7-year-old children: theYugoslavia prospective study. Environ Health Perspect 105:956±962.

Zayed J. 2001. Use of MMT in Canadian gasoline: health andenvironment issues. Am J Ind Med 39:426±433 (this issue).

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