I believe it is the law that stations selling gas containing ethanol must label the pumps as such. This does not, of course, guarantee that the station is obeying the law. The only way to be sure is to test it for yourself (it's easy; search the web if you don't know how).

Rotax does allow up to 10% ethanol now. I would avoid ethanol in my fuel if I could, but I don't have that option in Connecticut.