The head of a middle school in northwestern Shaanxi Province was dismissed from his post after the death of 11 school girls from carbon monoxide poisoning on Tuesday.

An initial investigation showed Zhao Binghong, the former head of the Duiziliang Middle School in Dingbian County, was responsible for the incident, according to the Yulin City government.

Twelve fourth-grade girls were poisoned after using a charcoal heater to warm their dorm room on Monday night and early Tuesday. The oldest of them was only aged 11.

Eleven died at the hospital. The sole survivor was still being treated at the Dingbian County Hospital. A doctor said she was in stable condition.

Police said they believed a quilt fell on the stove during the night. It caught fire and then ignited coals being stored under one of the girl's beds. As the coals smoldered, the students were poisoned by gases.

A teacher, who asked to remain anonymous, told Xinhua that the room usually held 12 students. Heaters and charcoal were provided by the school.

Soon after the incident, the Ministry of Education ordered boarding schools across the country to conduct safety checks for carbon monoxide poisoning and fire risks.

(Xinhua News Agency December 4, 2008)