The crash occurred at Marina Boulevard and Broderick Street, according to the fire department.
Coast Guard spokeswoman Lt. Lauren Kolumbic said the Coast Guard was notified of the incident at 1:15 p.m. after a small amount of what may have been transmission fluid from the vehicle leaked into the water, she said.
Kolumbic said the driver had apparently been traveling down Broderick Street and crashed into the wall, causing the front wheels to go over the wall. The vehicle did not go into the water, she said.
The Coast Guard dispatched a boat to the area as a precaution for any spill, but protective booms had already been placed into the water by the fire department and the harbormaster had already contained the fluid using absorbent material, Kolumbic said.
The cause of the crash and the condition of the hospitalized driver were not immediately known.
