"I was shocked. I didn't know it was that serious. Everybody just kind of shrugged it off. When we were going back to class, everyone was saying it wasn't a drill and everybody just said 'what happened,'" said student Alexis Hendon.
Hendon was just outside the classroom where the explosion happened during lunchtime. She heard a "pop" but thought nothing of it.
"They were cooking Korean barbeque, and one of the canisters popped or something exploded," said Hendon.
School district officials said the lunchtime event was a fundraiser for UNICEF, hosted by the senior English class. Dozens of students were said to be inside the classroom at the time with some teachers.
"This was lunchtime, at 12:46 p.m., so it's their lunch period. Often the high schools have club activities going on. They're raising money. They're doing a variety of fundraising activities and this was one such activity," said Tammy Kahn of the Torrance Unified School District.
In all, 10 students were injured and transported to Little Company of Mary Hospital, Harbor-UCLA Medical Center and Torrance Memorial Medical Center. Four of the students had serious burns.
All of the victims sustained injuries to their hands, faces and necks, which are areas of particular concern.
"Hands obviously, we want to make sure they heal correctly, so we want to make sure our patients get to the appropriate facilities and appropriate hospitals. Obviously the neck and the face, anytime you get a burn there, we're concerned with airway involvement," said Tad Friedman of the Torrance Fire Department.
Three dozen emergency responders arrived on campus after receiving reports of the explosion.
School officials said they notified the parents of the injured students immediately. They also contacted the parents of all the students at North High School.
"Why were they actually cooking inside the classroom? Because it seems like if they were going to sell food, it should've been cooked before it was brought here," said parent Mignon Washington.