Five students were injured in the accident, including one was taken to Advocate Illinois Masonic Medical Center with serious burns to his face and arms. Fire Department spokesman Larry Langford said three other students were taken to the hospital, while one declined.
"There was a small cooking class going on, and it was powered by a butane fuel source, a small butane fuel source," Chicago Fire Department Deputy Dist. Chief Patrick Brennan told WLS. "And, it seemed like it may have caught fire or heated up so much, that the product, which was just hot chocolate, let loose and burned some of the kids at school.
"I don't know if you'd call it an explosion," he added. "The product was possibly over-heated to the point it bubbled over, it splashed out."
"The school responded immediately," Chicago Board of Education officials said in a statement. "All students were evacuated from school for a short time until it was determined that they could return safely."
Officials said that safety crews extinguished the fire and that they were investigating the incident.