I am sure many of you watched the Jan. 16 ?60 Minutes? report on the use of MTBE in gasoline and its widespread contamination of groundwater supplies. The American Water Works Association was quick to respond to the program, immediately calling for action from EPA and the Clinton Administration.
Despite its benefits as a gasoline additive, MTBE leaking from underground tanks has seeped into drinking water wells in a number of communities around the country. Santa Monica, Calif., for instance, lost 80 percent of its local groundwater supply as a result of MTBE contamination in 1996. The city must now spend $3.3 million annually to buy alternative water supplies. It has been estimated the city would need to spend $150 million to remediate the local groundwater.
AWWA estimates that costs to water utilities nationwide to prevent, clean up and treat water supplies contaminated with MTBE could run more than $1 billion.
EPA recently issued a drinking water advisory to water suppliers for keeping MTBE levels in the range of 20-40 ppb or lower to prevent taste and odor problems and to protect against potential health effects. EPA has included MTBE on a list of contaminants (the Contaminant Candidate List) that may require regulation based on their known or anticipated occurrence in public drinking water systems.
Several class action lawsuits have been filed over the contamination of drinking water supplies by MTBE. One of the most recent was a suit filed in New York Supreme Court on Jan. 14. It calls for the testing of New York state residents? well water and the clean-up of potentially thousands of wells statewide.
The Clean Air Act of 1990 requires that the gasoline sold in areas where smog levels are at their highest ? including Los Angeles, New York and Philadelphia ? use an oxygenate to burn fuel more efficiently. To comply with the oxygenate requirement, many gasoline producers have added MTBE to gasoline, although other additives produce similar improvements in air quality.
MTBE (methyl tertiary-butyl ether) is made from methanol and a by-product of the oil refining process. Today, annual U.S. production of MTBE exceeds 4.5 billion gallons. Concerns about the hydrophilic properties of the additive have been raised for years.
In July 1999, a Blue Ribbon panel of experts compiled by EPA issued a report that recommended strengthening existing programs to reduce MTBE contamination of drinking water supplies. Several states, including California and New York, have already begun taking steps to reduce or phase out MTBE use.
Roughly 300,000 barrels of MTBE are used every day in the United States. The additive is a suspected carcinogen with a repugnant odor and taste that can render water undrinkable even in small concentrations. MTBE biodegrades rapidly in surface water and other places where it is exposed to a significant amount of oxygen, but studies by UC Davis and the EPA have shown that it can persist in deeper water for several years, traveling underground from place to place well after the source of the pollution is cut off.
The MTBE predicament could be costly for oil and gas companies who are already being held responsible for some of the pollution. Estimates for cleaning up MTBE are around $1 million per well, because current cleanup technologies for the chemical are limited.
A number of energy companies, including Shell Oil, are responding to the threat of more legal challenges by sponsoring research into microbial treatment ? the cheapest MTBE remediation technology currently available.
Other methods of cleanup are significantly more expensive and include absorption using activated carbon, photo-oxidation using ultra violet light, and chemical oxidation using substances like hydrogen peroxide. Because of the financial and technological hurdles, many contaminated areas have yet to be cleaned up ? and are instead simply sectioned off to reduce spreading until more cost-effective treatments are found.
