Rescuers search for survivors at the site of a boiler explosion in a local hospital in Changzhi, North China's Shanxi province, Aug 20, 2011. [Photo/cnr.cn]

TAIYUAN - 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 Friday, local authorities said.

A person was killed instantly when a boiler exploded at about 4 pm at the Chengqu Hospital in Changzhi, Shanxi Province, and two others died while being rushed to the emergency room, the city government announced in a statement.

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, the statement said.