Torrance police said the crash happened at Torrance Boulevard and Madrona Avenue at about 1:40 p.m.
A speeding truck approaching Madrona Avenue from westbound Torrance Boulevard tried to take the turn, but was going too fast, according to police.
Officials said the truck hit a tree, then four to five vehicles and a power pole before becoming fully engulfed in flames.
Video sent to ABC7 by Jamie Vassar using the hashtag #abc7eyewitness showed several off-duty firefighters rushing towards the scene to help.
Vassar told ABC7 that Torrance firefighters were setting up their spaghetti dinner fundraiser at the nearby Ken Miller Recreation Center when they saw the flames and that's when they jumped into action.
"Well over ten of us ran out there, close to 20 of us," Torrance firefighter Tim McAfee recalled. "It was interesting to see a bunch of men in aprons running to help people, but it's just a natural instinct."
But the truck was quickly engulfed in flames and the driver was killed, police stated.
"The vehicle was fully involved in fire. There was nothing we could for anybody that was inside," Torrance firefighter Joe Fewell said. "So the guys peeled off and started working on other patients that were in the other vehicles. A lot of us just worked on getting people removed from the area."
There were no other significant, according to officials.
All lanes of traffic approaching the intersection were closed as police investigated the cause of the crash.