CLEARWATER — The driver of the boat that hit a Clearwater Ferry, killing one person and injuring several others Sunday night, showed no signs of impairment during a sobriety test, but investigators are working to determine whether to charge him with leaving the scene of a crash, officials said Monday.

The Clearwater Fire and Rescue Department declared the crash a "mass casualty incident" due to the number of injuries.

The ferry was carrying 45 people when it was struck near a bridge in Clearwater, Fla. Ten other people were injured, the authorities said.