Fuels and Society - MTBE Pollution

William Kovarik
Radford University
and
Matthew E. Hermes
Kennesaw State University

Fuels and Society C: 12. Methyl t-Butyl Ether (MTBE) Pollution

13. Corporate/Govt. Decisions - 1990's

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MTBE:

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Another octane boosting additive is a form of manganese known as M.M.T. (for methylcyclopentadienyl manganese tricarbonyl) manufactured by the Ethyl Corp., the company that originally produced tetraethyl lead.

Ethyl argues that MMT helps the environment because, without it, oil companies have to employ a more intensive refining process that consumes slightly more crude oil to produce a given quantity of gasoline. There is also some evidence that MMT reduces auto emissions of nitrogen oxides.

Ethyl's assertions that MMT is safe do not withstand scientific scrutiny, according to Herbert Needleman. Laboratory studies show that manganese crosses the placenta and retards growth in fetal rodents. When inserted into the brain cells of rats, it disturbs the normal functioning of the cells. Ethyl claims that MMT has been used safely in Canada for 19 years. But no systematic studies of manganese in humans have been done in Canada or elsewhere.

Children are more vulnerable than adults to most neurotoxins, Needleman says, and the effects of MMT -- learning disabilities and behavioral problems -- could show up years later. Based on historical experience with leaded gasoline, Needleman says Ethyl should be made to prove MMT is safe rather than being allowed to put its product on the market until is proven unsafe.

Opinions of the Greater Boston Physicians for Social Responsibilities

Note, as of April 11, 2001, the Ethyl Corporation pages that are indexed to state Ethyl's position on MMT are not accessible.

Status of MTBE

Methyl tertiary butyl ether (MTBE) has been added in relatively low concentrations to increase octane ratings in premium grade fuels since the late 1970's. Since the early 1990's MTBE has been added up to 15 percent to enhance gasoline combustion and reduce tailpipe emissions. Gasoline producers are required to add a chemical that aids in combustion by increasing available oxygen to certain reformulated gasolines to reduce air pollution, especially carbon monoxide. MTBE is the most commonly added material, used in more than 80 percent of oxygenated fuels. MTBE is credited with contributing to significant reductions in carbon monoxide and ozone levels in many of these areas.

Chemical Toxicity: The measurement of chemical toxicity is often done be obtaining the LD50 - the concentration of a substance that is fatal to one-half of a test animal group. But toxicity, its measurement and the establishment of exposure standards is a complex activity. See Toxicity for a discussion of and references to critical information on chemical toxicity.

Water contaminated by MTBE has become a cause for major public concern and increasing controversy. MTBE readily dissolves in water, can move rapidly through soils and aquifers, is resistant to microbial decomposition and is difficult to remove in water treatment. The US Environmental Protection Agency (USEPA) has classified MTBE as a potential human carcinogen.

Finally, MTBE can give water an unpleasant taste and odor. Californians spearhead the concerns that MTBE will contaminate drinking water supplies. On March 25,1999 California Governor Gray Davis issued an Executive Order "...for the removal of MTBE from gasoline no later than December 31, 2002."

Surface-water MTBE concentrations in California have been reported up to 12 µg/L in water bodies where powered craft are used. California urban storm runoff samples generally has been less than 2 µg/L but higher concentrations have been reported in heavily urbanized parts of the New York Metropolitan area.

Ground water used as a drinking water source in the Santa Monica area has been reported with MTBE concentrations of more than 600 µg/L. This has been traced to leaking underground gasoline storage facilities. MTBE concentrations greater than 30 µg/L usually can be attributed to a leaking tank or pipeline facility.

MTBE accounts for about 30 per cent of global demand for methanol, and California alone represents 6 per cent of world demand.

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