(KRON) -- Four people were injured in a boat crash near Rock Island in the Richmond Marina on Saturday night, San Francisco Fire officials said. Just after 8:30 p.m., fire crews responded to a request for assistance from the Coast Guard involving a boat crash with four people on board in shallow wa ter. "Crews located the vessel perched on top of a jetty-style rock structure in the water with four adults with serious to moderate injuries," officials said. One of the injured adults was airlifted to a trauma center. The other three were transported by ground to a hospital for treatment. Officials have not confirmed the condition of the injured parties. It is unclear what led to the crash. ...read more read less