Two trains collided in Chatsworth.
The death toll would reach 25. More than five times that were injured.
Peering through a home's chain-link fence, first responders saw fire licking twisted metal.
Soon they brought order to the chaos with color-coded tarps: red for the most severely injured, yellow for the moderately injured and green for the least injured.
The story, however, starts 30 years ago, some 80 miles to the south, in Newport Beach, where the Fire Department and Hoag Hospital staff developed a system of sorting patients based on who needed care most. They called it START: Simple Triage and Rapid Treatment.
In 1983, Newport Beach firefighters conducted a drill involving high school students with fake injuries simulating a mass casualty bus accident.
Firefighters invited Hoag staff to participate and make suggestions on improving their response, according to Dr. Greg Super, Hoag's medical director of emergency services at the time.
What started as an afternoon's excursion became several months' worth of work and collaboration between the department and hospital, according to Costa Mesa interim Fire Chief Tom Arnold.
"It was a collaboration that married their world of medicine and our world of the application of that medicine," said Arnold, then a Newport fire captain.
The responses to multiple-victim disasters before START were impractical, requiring paramedics to make diagnosis while in the field, said Super, one of START's developers.
Sometimes emergency crews treated the first people they found, neglecting those who urgently needed care but were out of sight.
"It was pretty chaotic, and that's when this thing came around," said Dr. Carl Schultz, UC Irvine's director of disaster medical services.
In analyzing other incidents, including a plane crash in the Everglades, the collapse of a balcony onto a dance floor in the Midwest and a subway fire in London, the team gained a better understanding of what's known as mass-casualty incidents.
"What we learned was in those kinds of situations, about a third of the people affected were dead on the scene and about a third of the people didn't have any significant injuries," Super said.
With START, rescuers first ask those who can walk to go to a designated area, which enables a quick assessment of the severity of injuries. If victims are able to move and obey commands, they are likely not in dire need of care.
Rescuers can then go to the more critically injured, checking pulses and breathing and assessing them for head injuries. Each person is then assigned a color: green, yellow, red or black — the latter for the dead or dying.
A veteran rescuer can evaluate someone in as little as 15 to 20 seconds, Schultz said.
Some START protocols are counterintuitive. For instance, rescuers don't stabilize the necks of those who are not breathing before clearing the airway.