The agents informed the Wetzels that they were interested in their car, a 1986 Volkswagen Golf, that David Wetzel converted to run primarily from vegetable oil but also partly on diesel.

Wetzel uses recycled vegetable oil, which he picks up weekly from an organization that uses it for frying food at its dining facility.

"They told me I am required to have a license and am obligated to pay a motor fuel tax," David Wetzel recalled. "Mr. May also told me the tax would be retroactive."

Since the initial visit by the agents on Jan. 4, the Wetzels have been involved in a struggle with the Illinois Department of Revenue. The couple, who live on a fixed budget, have been asked to post a $2,500 bond and threatened with felony charges.

State Rep. Bob Flider, D-Mount Zion, also plans to support legislation favoring alternative fuels.

"I'm disappointed that the Illinois Department of Revenue would go after Mr. Wetzel," Flider said. "I don't think it is a situation that merits him being licensed and paying fees.

"The people at the department of revenue apparently feel they need to regulate him in some way. We want to make sure that he is as free as he can be to use vegetable oil.