MTBE in Our Drinking Water

MTBE is the acronym for Methyl-tertiary-butyl-ether, a gasoline additive widely used in North America to help cut us down on air pollution. Way back in 1987, an Environmental Protection Agency memo warned, "Known cases of drinking water contamination [by MTBE] have been reported in four states, affecting 20,000 people. It's possible that this problem could rapidly mushroom due to leaking underground storage tanks. The problem of groundwater contamination will increase as the proportion of MTBE in gasoline increases." That was before the Clean Air Act became law in 1990, at which time most gasoline companies began adding about one cup of MTBE per gallon of gas. Recently a State of California paper entitled “Public Health Goal for Methyl-tertiary-butyl-ether in Drinking Water” maintained that since 1997 it has become the second most heavily produced chemical in the United States (approximately 16 gallons per person per year!). Not surprisingly, says 60 Minutes’ Steve Kroft, this has led to MTBE’s becoming America’s second most common water contaminant. Couple that fact with two others—MTBE’s high toxicity and its obstinacy to groundwater management—and you have serious cause for concern.

Just how toxic is MTBE? According to 60 Minutes, the single cup of MTBE found in every gallon of gasoline is enough to contaminate 5 million gallons of water, making them undrinkable and making MTBE it one of the most toxic contaminants around. A study done in Italy showed that laboratory animals ingesting high doses of MTBE had high incidence of leukemia, testicular cancer and lymphoma. But, unfortunately, MTBE has not been adequately tested for its long-term human health effects in humans. This may explain why, at the time of the program’s airing in 1999, there were no requirements for either local or municipal governments to test their water for the presence of MTBE contamination. Since 1996, the State of California has named 10,000 sites where groundwater is contaminated by MTBE. And the contaminant has been found in groundwater in 49 states, including many major cities—Dallas, Atlanta, Denver, Las Vegas, to name a few—and even idyllic recreational areas like California’s South Lake Tahoe.

In fact, the fear exists in some circles that our MTBE problem is already unmanageable. What gives rise to this fear is the contaminant’s combined water solubility and long life. MTBE is more water-soluble than nearly anything else in gasoline and so, says director of the Environmental and Occupational Health Sciences Institute in New Jersey, toxicologist Dr. Bernard Goldstein, it moves very quickly into groundwater in the case of a gasoline spill. Furthermore, MTBE doesn't break down. Dr. Peter Garrett of the Maine Department of Environmental Protection states that "MTBE moved further and faster in groundwater and was more difficult to clean up than any other contaminate in gasoline." Craig Perkins, director of public works for the city of Santa Monica concurs: "What we found was that it was behaving much differently than contaminants we had tracked in the past… moving through the groundwater into the wells much more quickly.” In one Santa Monica well, the MTBE level doubled in a single week.

Where does this leave us? Bob Perciasepe, assistant administrator of the EPA told 60 Minutes "Any optimism anybody had that we could manage the potential problem has not come to fruition and—before this becomes a national crisis, before this gets worse—we need to change the way we make clean-burning gasoline." Although the EPA has responded to recent studies showing that it contaminates water supplies nationwide by saying it will move to ban the substance, such a move has yet to be made. That being so, when it comes to MTBE contamination and the purity of your drinking water supply, residents of most states and municipalities are left to fend for themselves. Certainly, anyone drinking well water in most regions ought to have their water checked regularly for MTBE or take the simple precaution of filtering their water for MTBE. Fortunately, the manufacture of filters designed to remove MTBE by such reputable companies as Doulton USA puts protecting ourselves against this contaminant within the reach of most North American consumers.

© Robert E. Freeman 2005