Officials said two fire trucks had their lights and sirens running when they collided Wednesday afternoon in Monterey Park, sending one careening into a restaurant.
Monterey Park Fire Chief Jim Birrell said the trucks -- one from Monterey Park, the other from Alhambra -- were responding to a house fire in south Monterey Park when they crashed at the intersection of Emerson and Garfield avenues about 3:15 p.m.
Officials now say 15 people, including six firefighters, were hurt.
One person, described as a civilian who was inside Lu's Dumpling House, was critically injured, Birrell said. One firefighter suffered moderate injuries; the other injuries were described as minor.
Nine of the patients were taken to Los Angeles County-USC Medical Center, a hospital spokesman said. Six others were wheeled to Garfield Medical Center, about 100 yards away from the crash site.
What led to the crash remains unclear. CHP Officer Doris Peniche said the Alhambra ladder truck was traveling south on Garfield and the Monterey Park engine was heading east on Emerson.
It was the Monterey Park engine that came to rest inside the restaurant, with more than a third of the truck still inside Wednesday evening. Investigators began snapping pictures of the truck and the rubble piled around it.
"This is the first time I've witnessed an accident like this," Birrell said.
Christina Lee, who works at the nearby Monterey Park Florist, said she was helping a customer when they heard a loud boom.
She said all of the customers rushed outside to see what had happened and were stunned.
“It was really bad,” she said.
The California Highway Patrol's major accident team will lead the investigation into the crash. Officials said everything from the speed of the trucks to radio traffic would be reviewed.
Monterey Park Fire Capt. Matt Hallock said that even though his department's firefighters wear headsets that allow them to communicate with dispatchers and other first responders, it was "hard to say" if the firefighters would have been able to hear the other truck's sirens.
Alhambra Fire Chief Bill Walker said the three firefighters on his department's truck had experience ranging from one year to more than 20.
Officials said the investigation would last through the evening, and the truck would not be removed from the restaurant until it was deemed safe.
"Nothing moves until the investigation is complete," Walker said.