Food Supply Update: March 2000
MTBE: Concern or Crisis for U.S. Drinking Water?
Copyright©2000 by Geri Guidetti
In the last issue of the Food Supply Update a few weeks ago, I promised you additional information on MTBE (methyl tertiary butyl ether) contamination et drinking water, lakes and aquifers in the U.S. In this Update I will provide some background on the use history of this chemical with links to original documents. It is my hope that this information will help you assess what potential impact it may have on you and your family, today and in the future, and what technologies are currently available to treat contaminated water on the community and home levels.
Though local or regional water contamination events from accidental sewage, chemical or oil spills have received national news coverage from time to time, none of these accidents has anywhere near the breadth and depth of potential impact on the nation as MTBE does. Until CBS's 60 Minutes journalist, Steve Kroff, said on national television on January 16th, "…Even the government now says that we're facing a national crisis if something isn't done to stop MTBE from leaking into our drinking water…", there was little national concern. This is changing, but first, some history.
Since the late 1970s, MTBE was used in low concentrations in premium gasoline to increase octane ratings. In 1990, The Federal Reformulated Gasoline Program was created as part of the Clean Air Act Amendments and implemented in 1995. Congress mandated the use of reformulated gasoline (RFG), that is, gasoline mixed with other chemicals, to attain 2 percent oxygen by weight in those areas of the country with the worst ozone and smog problems. The Act requires "wintertime oxyfuel" to contain 2.7 percent oxygen by weight. In winter, most metropolitan areas can use ethanol to meet oxygenation needs, as volatility of ethanol is not as much of an issue in cold weather, but MTBE is the oxygenate of choice in over 85 percent, and ethanol in 8 percent, of all reformulated gasoline today. You can access the final report of the Environmental Protection Agency's Blue Ribbon Panel on Oxygenates in Gasoline, "Achieving Clean Air and Clean Water" at http://www.epa.gov/swerust1/MTbe/index.htm.
As of March, 1999, gasoline reformulated with MTBE has been used in 19 states and 32 regions of the U.S. to meet Federal clean air standards. The Federal government does not specify which oxygenate must be used, but only that dean air standards be met. According to industry data through the fall of 1999, MTBE is used at the rate of about one gallon of pure MTBE for every ten gallons of reformulated gasoline used in the U.S., or 10 percent of every tank. In California it is closer to 11 percent. On a more personal level, if your region is using this oxygenate, every time you fill up at your local gas station, you'll get about nine gallons of gasoline and one of MTBE for every ten gallons you buy. Remember, that's every time you fill up. Now multiply that times the numbers of gallons of gas used in this country every day, by every person who fills his/her tank with gasoline and you'll likely find the magnitude of this consumption difficult to conceptualize.
According to the State of California's March 1999 paper, "Public Health Goal For Methyl Tertiary Butyl Ether (MTBE) in Drinking Water", MTBE was the eighteenth most produced chemical in the U.S. in 1994. In 1995, it was twelfth, and in 1997, MTBE was the second most produced chemical in the country! Californians use more than 13.7 billion gallons of gasoline a year, not counting diesel fuel. At 11 percent MTBE in California's gasoline mix, that's 1.5 billion gallons of pure MTBE bought, trucked over highways, stored in underground tanks, sold, and finally burned in vehicles in California alone each year! Nationally, it's about 4.5 billion gallons a year.
Now, the good news about the widespread use of MTBE is that it does what oxygenates are supposed to do. It boosts octane, improves combustion efficiency, and promotes the more complete burning of gasoline. It has significantly reduced the levels of carbon monoxide and ozone released as gasoline combustion by-products. There is no doubt about it: reformulated gasoline has decreased-often more than expected-dangerous pollutants in our cities, but what is really tough about the MTBE contamination issue is that this chemical also has a dark side.
