Two weeks' ago he was suspended from his job following a "fracas with a BBC producer." It was alleged that Clarkson had "punched" a colleague in a disagreement about the food provided for his evening meal.
On Wednesday, Hall confirmed that "A member of staff – who is a completely innocent party—took himself to Accident and Emergency (the emergency room of a hospital) after a physical altercation accompanied by sustained and prolonged verbal abuse of an extreme nature."
Clarkson has a track record of controversial behavior. He was criticized after a video was leaked that appeared to show him saying an offensive racist word.
The presenter himself had said that the BBC would sack him if he made "one more offensive remark, anywhere, at any time."
On Thursday, Hall said: "For me, a line has been crossed. There cannot be one rule for one and one rule for another dictated by either rank, or public relations and commercial considerations."
Hall added the BBC would look to renew Top Gear in 2016.
"This will be a big challenge and there is no point in pretending otherwise," he said.