Three people were killed and 17 others injured, two severely, after a blast ripped through a boiler room in a hospital in northern Chinese city of Changzhi, local authorities said Sunday. A person was killed instantly when a boiler exploded at Shanxi Province on Friday, and two others died while being rushed to the emergency room, China''s News Agency (Xinhua) reported. The injured people are being treated at the hospital and all are described in stable condition. Online photos show that half of the boiler room was destroyed after the blast. Local authorities have launched an investigation into the cause of the accident.