Additive wars

Aug. 9, 2002
Automakers last month said they are worried that US refiners may expand their use of the octane-enhancer MMT.

Maureen Lorenzetti

Automakers last month said they are worried that US refiners may expand their use of the octane-enhancer MMT.
MMT, known by chemists as methylcyclopentadienyl manganese tricarbonyl, is a manganese-based fuel additive used often in Canada but rarely in the US.
Complying with a 1996 court order, the US Environmental Protection Agency allowed MMT back in the US conventional gasoline market after a 2-decade absence. Automakers said a new multiyear, $8 million study shows MMT can increase smog, reduce fuel economy, increase greenhouse gas emissions, and cause low-emission vehicles to fail hydrocarbon-emission standards. Automakers compiled data from 14 vehicle models built by six manufacturers.
Richmond-based Ethyl Corp., MMT's sole manufacturer, denies that its product aggravates air pollution.
"The automobile industry has been presenting the same story for 25 years. In every case, scientists have found serious flaws in their test program data and have determined MMT does not harm the emission control system," said Ethyl.

US not the focus
Ethyl also rejected automakers' claims that the company wants to flood the US with MMT.
According to EPA, about 0.02% of the US gasoline supply contains MMT. By comparison, methyl tertiary butyl ether, an oxygenate often used to meet reformulated gasoline guidelines, is in up to 50% of all US gasoline.
MTBE first gained prominence in the 1980s as a safe alternative to lead, Ethyl's primary product before EPA phased it out when there was growing evidence that high exposures could cause serious health problems.
Ironically, MTBE may now be phased out because of environmental concerns surrounding groundwater contamination; but unlike with lead, EPA does not have data showing extended exposures cause long-term health issues.

MTBE role
Ethyl officials say it is "premature" to speculate whether an MTBE phaseout plan before Congress will help sell more MMT.
Given that Congress will likely mandate fuel ethanol, it's unlikely Ethyl will realize immediate benefits from MTBE's woes. Ethanol boosts octane like MMT does, but gasoline suppliers get a tax break for using the alcohol.
Longer-term MMT use could grow if EPA sharply narrows fuel specifications to reduce other "bad actors" in gasoline or diesel that either exacerbate tailpipe emissions or are carcinogenic.
"It would depend on the overall sulfur reduction, aromatics and benzene reductions, and what impact the driveability index would have on the overall octane pool," Ethyl said.
Meanwhile, Ethyl is looking overseas.
"Our biggest growth opportunity will be in developing countries, where leaded gasoline is in the process of phasing out and there is a need for low-cost, environmentally safe alternatives," Ethyl said.
Ethyl also recognizes EPA is sympathetic to environmentalists' assertions that MMT is chemically similar enough to lead to incur almost identical health problems. Ethyl must furnish EPA with detailed data on possible health risks in 2004. EPA then, barring a rewrite of the Clean Air Act, could ban or phase out MMT.