methyl tertiary butyl ether (mtbe) has been found in the Midwest region of the us even though it is not used there, shows a recent research. mtbe, which is a gasoline additive, is said to be carcinogenic and has been known to contaminate groundwater. It was found in 70 per cent of the gasoline samples taken from more than 200 sites in Indiana, Illinois and Michigan. " mtbe is not supposed to be there,' said Reynaldo Barreto of Purdue University, who did the research. According to him, the most likely sources of mtbe in the Midwest is tankers, storage tanks and pipelines that once carried gasoline containing the additive.

Meanwhile, an investigation by The San Francisco Chronicle shows that mtbe is leaking from nearly 1,200 underground tank sites in California and this threatens the drinking water supply of millions. During the investigation, more than 2,500 public drinking water systems that serve 90 per cent of California's population were tested for the presence of mtbe . Of the 8,311 groundwater sources sampled, 48 contained the additive. mtbe was also found in 26 of the 595 surfacewater sources tested. Statewide, Los Angeles county has the greatest number of leaking tanks, with 16 centered in Santa Monica, Glendale and Burbank, followed by eight each in San Diego county and El Dorado county.