The highway patrol is on the scene of a multi-vehicle pileup west of Defiance on U.S. 24.   Traffic is blocked-off in both directions on route 24, somewhere between state routes 127 and 49, near the Defiance-Paulding County line.   A dense freezing fog has hit that area; and likely was a factor in this crash.  A number of rescue squads were sent to the scene.   More details are expected later this morning.