The attack in Santa Ana occurred Thursday as several bystanders attempted to rescue a man in a wheelchair who was being stung repeatedly, the Los Angeles Times reported.
Responding firefighters said they found four victims in anaphylactic shock, a severe allergic reaction that can follow bee or wasp stings.
All the victims, including the man in the wheelchair who was stung more than 60 times, were suffering from nausea and having trouble breathing, Santa Ana Fire Capt. Steve Snyder said.
They were treated by paramedics at the scene, then taken to hospitals.
Their condition was not immediately available.
Several firefighters were stung on their faces but remained at the scene as bee experts removed the hive from some wooden pallets in an industrial area.
Firefighters closed off and evacuated a square block area, the Times reported.