Most cars are manufacturer-approved to run on up to ten percent ethanol blended with gasoline. Flex fuel vehicles can run on up to 85 percent. But the Environmental Protection Agency is looking into whether 20 or 30 percent ethanol-blended gasoline meets Clear Air Act standards.

At issue, according to this story in the Aberdeen (SD) News, is that so-called blender pumps “are marked for use by flex fuel vehicles only. However, they operate the same way as regular gasoline pumps, so customers with non-flex fuel vehicles are able to put higher blends of ethanol than are deemed acceptable into their vehicles.”

There are very few stations in the country offering multiple ethanol blends at a pump and the EPA question has already caused them to be shut down in South Dakota until the issue is resolved.