MTBE heroes

Townsend Letter for Doctors and Patients,  Jan, 2005  by Rose Marie Williams

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What is MTBE?

MTBE (methyl tertiary-butyl ether) is a chemical compound manufactured by the chemical reaction of methanol (derived from natural gas) and isobutylene (a by-product of petroleum refining). It is one of a group of chemicals commonly known as "oxygenates" because they raise the oxygen content of gasoline. In 1999 average US production of MTBE was more than 200,000 barrels per day, used as a fuel additive for motor gasoline. At room temperature MTBE is a volatile, flammable, colorless liquid that dissolves quickly in water. This last property has led to excessive water contamination throughout our country. (1,2)

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Since 1979 MTBE has been used in gasoline at low levels as a replacement for lead. As of 1992, MTBE has been used at higher concentrations in some gasoline to fulfill the oxygenate requirements set by Congress in 1990 as part of the Clean Air Act Amendments. MTBE is added to reformulated gasoline, oxygenated fuel, and premium grades of unleaded gasoline. Oxygen helps gasoline burn more completely, reducing harmful tailpipe emissions from motor vehicles. (1,3)

The United States Environmental Protection Agency (EPA) recognizes that even with the best controls there will always be equipment failures and installation mistakes that release fuel contaminants into the environment. Additional contamination comes from automobile and tanker truck accidents, gasoline spills, and drips during refueling of cars, lawnmowers, tractors and other machines, plus leaks from pipelines and storage tanks. (3)

MTBE in Drinking Water

MTBE dissolves easily in water and does not "cling" to soil very well. It migrates faster and farther than other gasoline components. MTBE does not degrade easily, and is considered a persistent pollutant. Once it has contaminated a drinking water source, MTBE is very costly to remediate. Because of MTBE's high water solubility and extensive use, it is showing up in ground water throughout the country. Initially, MTBE-contaminated water was considered offensive due to bad taste and odor, but more insidious problems appear to be its negative impact on health. (4)

Early research of the health effects of MTBE focused on inhalation of the chemical. Cancers and non-cancerous health effects resulted in animals inhaling high concentrations of MTBE. EPA claims limited data exists on human health risks associated with MTBE ingestion, but concludes that MTBE is a potential human carcinogen at high doses. EPA's current drinking water advisory document indicates there is a small likelihood that MTBE in drinking water would cause adverse health effects at concentrations between 20 and 40 parts per billion (ppb). However, since there is insufficient research on human health risks, EPA's assurances may not be reliable. High levels of MTBE in drinking water may smell, or taste like turpentine. (4)

Anyone interested in having their water tested, can call the EPA Safe Drinking Water Hotline (800-426-4791) to get a list of qualified labs in their state, or call National Testing Labs in Cleveland, Ohio (800-458-3330).

Health Effects

Humans, pets and livestock can be exposed to MTBE through ingestion, direct contact, or from breathing vapors in drinking water. Inhalation of MTBE also occurs when showering or bathing with contaminated water. Immediate health effects associated with MTBE exposure include headaches, dizziness, eye irritation, nose and throat burning, and nausea. (5,6)

In long-term studies with rats, MTBE caused lymphoma, as well as liver, testicular and kidney tumors from inhaling or ingesting the contaminant. Though adequate research of health effects on humans is lacking, the New York State Department of Health believes, "The animal data support concerns about the carcinogenic potential of MTBE in humans." (2)

Prior to the announcement in August 1999 of West Nile Virus being responsible for the deaths of some elderly residents in New York City, an epidemic of animal deaths occurred in the tri-state area, including thousands of birds, rodents, reptiles and some horses. A connection to West Nile Virus and pesticides was posed as a possible cause.

An article by Jim West in the July 2002, TLfDP, postulates a different theory. Mr. West makes a case for MTBE as a major risk factor in the wildlife deaths, most of which occurred near airports with excessive air pollution containing the gasoline additive, MTBE. While industry and some government representatives claim "MTBE is a good thing for the air environment, critics claim it actually raises ozone levels and increases photochemical smog." (7)

Leaking storage tanks from gasoline stations have polluted water supplies all across the nation. Thousands of individuals have been ingesting, bathing, and washing their clothes with MTBE-contaminated water from municipal sources and private wells. Local health departments have been very slow to test water, and even slower in assisting communities or individuals with remediation procedures. Boiling water does not rid it of MTBE. Instead, heat converts the chemical into formaldehyde and acetone, the vapors of which should not be inhaled for an extended period of time. (8) Cooking with MTBE-contaminated water provides a double route of exposure--inhalation and ingestion.