Although gasoline additive MTBE is now being mandated in fuel sold all over the United States to reduce harmful emissions, leading scientists agree that, in reality, the only thing it is reducing is the amount of green stuff in consumers’ pocketbooks.
Dr. Joel Kauffman, professor of chemistry at the Philadelphia College of Pharmacy and Science, says MTBE seems to have little or no effect in reducing carbon monoxide emissions. The reason? No oxygenate can clean the air, according to Kauffman, because cars are now equipped with oxygen sensors and catalytic converters that regulate the amount of oxygen that mixes with fuel in the engine.
“There’s no way that an oxygenate can fool a modern engine into burning cleaner,” Kauffman said.
Kauffman added that with oxygenated gasoline, people are now paying more money for gas because oxygen, which engines naturally take freely from the air, is now being added to gasoline at a cost to the consumer. He also stated that the increase in oxygen in fuel is what is causing the decrease in gas mileage because less of what you fill up with is actually gasoline.
Worse yet, says Dr. Myron Mehlman, editor of the journal Toxicology and Industrial Health, MTBE does not help clean the air.
“There is no evidence that MTBE is helpful to the environment,” he states unequivocally.
So why has the federal government approved the use of MTBE? The Environmental Protection Agency oxygenate sees things differently.
“MTBE is not supposed to clean the air,” says Dave Kortum, group manager in the Environmental Protection Agency’s Department of Fuels and Energy. “We would prefer that there was no MTBE in the air – just carbon, oxygen, nitrogen and carbon dioxide which is what the air is made of, but adding MTBE to gasoline would be changing the composition of gasoline in such a way that NOx [nitrogen oxides] emission and VOC [volatile organic compounds] emissions are positively effected, and that does help the air.”
Kortum concedes that the issue of reduced carbon monoxide emissions, which is supposed to be a function of MTBE in reformulated gasoline, is one in which there is currently a lot of disagreement.
And there’s plenty of disagreement from the experts. Kaufman, for instance, says MTBE is actually increasing NOx emissions making it harder for cars to pass smog checks and, thus, costing the consumer more to get their cars fixed. Kauffman also said that MTBE itself is a VOC which, when mixed with NOx, helps produce ground-level ozone.
Dr. Peter Joseph, professor of Radiologic Physics at the University of Pennsylvania School of Medicine, says federal and state governments are missing the point by mandating oxygenates such as MTBE.
“I really think that CO [carbon monoxide] is being greatly exaggerated in terms of its ability to do harm at its present level,” he said, adding he thinks something else, possibly formic acid, which he believes may actually be produced from fuels with MTBE, is the real problem. Formic acid is known to be extremely irritating to the respiratory system.
The EPA’s Kortum also concedes that MTBE is leeching into the water supply as many critics have charged.
“We recognize that’s a real problem, and a lot has to be done there to address this problem,” he said.
Dr. Nachman Brautbar, a clinical toxicologist and editor of International Journal of Occupational Medicine, emphasized the seriousness of MTBE in water and stated that MTBE shouldn’t be used in gasoline at all because of the adverse health effects when it does get into the water.
“If it gets into the water and people drink the water, there is an increased risk of cancer,” he said.
And that’s just the start of the health concerns over MTBE. Brautbar, Mehlman, and other scientists believe that it is a probable carcinogen. Kortum, although not willing to concede that it is carcinogenic to humans, did say the EPA believes the evidence shows it is carcinogenic to animals.
Mehlman, however, says there is plenty of evidence to suggest MTBE is a human carcinogen.
“MTBE causes cancers in many organs and tissues of two species of experimental animals,” he said. “These cancers are identical to those caused by exposures at the same doses as benzene, vinyl chloride, and 1,3-butadiene, which are known human carcinogens. My opinion is supported by the general agreement among experts in chemical carcinogens that a substance which causes cancer in significant numbers of experimental animals in well-conducted assays poses a presumptive carcinogenic risk to some humans, even in the absence of confirmatory experimental data.”
Besides Mehlman’s statement about MTBE being a probable carcinogen, MTBE is also a member of the hazardous air pollutants list as is stated by the 1990 Clean Air Act’s own air toxics program.
Until 1979 when MTBE was first used in the U.S. as an octane booster, Joseph says there was a decrease in asthma-related deaths. According to data that he has researched, it has increased parallel to the use of MTBE since 1979. Joseph also says EPA studies regarding asthma and MTBE are incomplete.
The EPA’s Kortum disagrees. He said conclusions about MTBE having adverse effects for asthmatics are not supported by the facts and that such a suggestion is like comparing apples and oranges.
“Over the past several years, the budget deficit of the United States has decreased substantially as MTBE use has increased,” Kortum said. “Therefore, the use of MTBE causes a decrease in the U.S. budget deficit. That’s ridiculous, and that’s the sort of argument that is being used here.”
Joseph scoffs at the analogy.
“Of course it’s ridiculous … because there’s no conceivable way in which MTBE and the deficit are related,” Joseph said. “We all know that. However, there is a very logical way in which MTBE could be related to asthma, namely, if it is producing formic acid in the air – and formic acid affects the respiratory system – then there is the connection.”
In California, where MTBE is mandated in all gasoline sold, an executive summary from state Senator Richard Mountjoy states that MTBE can increase engine wear and internal rust and corrosion. A Chevron technical bulletin also stated, “Elastomers in fuel system seals and hoses may shrink, swell, or lose strength when exposed to RFG [reformulated gasoline]. This creates the potential for fuel leaks.”
Kortum, in response to this, agreed that some cars will have problems with MTBE. But he also stated that most new car engines are made with a type of elastomer that is compatible with MTBE. He later added, however, that people should be cautious.
Kortum said that although the EPA is aware that MTBE had to be further researched, it should not be banned.
“The way Congress wrote the Clean Air Act and the way the agency implements it is that things that are already in the marketplace [such as MTBE] – we’ll make you do testing on those things,” Kortum said. “If the testing turns out to be bad, we have the authority to control the use of, or perhaps even remove them, from the market place.” He also added that the EPA is in the process of requiring users and producers of MTBE to do extensive studies on the chemical.
