By NBC News Staff WriterNEW YORK — For the third year in a row, San Diego firefighters are battling a massive blaze at a helicopter landing site in northern California.

Fire officials say the fire started on the aircraft hangar and is burning with “exhaustive” use of water and smoke alarms.

The fire is burning under a runway and a helicopter hangar at the San Diego International Airport, a fire department spokesman said.

The cause of the fire is under investigation, San Diegans fire chief John Gulland said.

More: Firefighters say there are no injuries reported.

The helicopter is being inspected.