The common gasoline additive MTBE, which has been blamed for contaminating ground water, is turning up in fuel supplies in states where it is not required, says one researcher.

The common gasoline additive MTBE, which has been blamed for contaminating ground water, is turning up in fuel supplies in states where it is not required, a researcher said recently at the national meeting of the American Chemical Society, according to the AP. That means the entire country is potentially at risk of pollution, said Reynaldo D. Barreto, associate professor of chemistry at Purdue University North Central.

Barreto collected regular unleaded samples from more than 200 gasoline stations in Indiana, Illinois and Michigan - none of which are required to use MTBE. Basing his research on these samples, he found that more than 70 percent of the samples in all three states contained MTBE, and 25 percent of the total samples contained significant amounts - over 500 parts per million. Forty percent of the gas stations sampled in Indiana had a significant amount of MTBE. "It has so permeated the fuel distribution system that it is a potential threat in areas where it is not in use,'' Barreto said, according to the news agency.

Barreto said the most likely source of MTBE is tanker trucks, storage facilities and pipes that once held gasoline containing MTBE. He said he believes the only way to prevent further spread is to completely ban the additive.