There was a mushroom cloud over Panyu in Guangzhou this morning after an explosion at a construction site. No casualties were reported, Guangzhou Daily said on its microblog.

The mushroom cloud, courtesy of Sina Weibo

12 firetrucks and 78 firefighters were deployed after the explosion shortly after 8 a.m. The fire was under control within an hour.

Although there were no casualties, parents of students at the nearby Clifford International School are worried about the pollution.

The cause of the explosion is being investigated. Investigators are particularly keen to know what foam insulation material was being used on the site.