Authorities said a mattress caught fire just after 5 p.m. Tuesday at bedroom in a home in the 5400-block of South Hermitage Avenue in the Back of the Yards neighborhood.
As firefighters worked to knock down the flames, police said an 11-year-old boy was injured in the fire.
He suffered burns to his hand, chest and both legs and was transported to Comer Children's Hospital in critical condition.
CFD said the mattress was ignited by an open flame.