I filled up one day a few years ago - I noticed my truck was sluggish - stopped on the way home and it was difficult to start, but it did. The next morning the truck would not start and there was quite a bit of white smoke.  I called the station - they said thier delivery guy put a small amount of diesel in one of the gas tanks.  The truck needed new O2 sensors and it was as good as new.  They paid for the repairs and sent a gift card.