I've ridden that Fireball more times than I can even count, at two different locations including OHSF. It looked like that "pod" of four seats just disintegrated right when the upswing started. I won't jump to conclusions on the root cause of this failure, although at least on the exterior those groups of seats seem to be all Fiberglass, so the video seemingly showing at least one individual seat falling away doesn't surprise me considering the violence of the failure.
Local reports still at one fatality, 5 critical and two stable. News conference with OSP, Ohio Agri, and the governor ended a little while ago. Governor ordered all rides closed around 9 pending re-inspection, they had apparently continued to operate, even nearby rides, for at least an hour after the incident which was at 7-something PM. Midway was originally scheduled to operate until 11