Three students were killed in an explosion occurred in the morning at a laboratory in Beijing Jiaotong University when they were conducting experiments on sewage treatment of landfill leachate, the Beijing Fire Department said on its official Weibo account. 

Video source: VCG

Fire fighters arrived at the scene soon after getting a call at around 9:30 am, and put out the fire an hour later, according to the official release. 

A student told the Beijing News that he heard three explosions when he was sitting in class before seeing flames from a nearby building.  

The explosion is still under investigation.

(Photo: Screenshot from the live broadcast of the firefighers' efforts to put out the fire by the Beijing News)

(Photos: Weibo)

(Compiled by Huang Jingjing)