Oil spill led to factory blast that killed 25

Poor facilities, lax management and under-qualified workers may all have played a role in the chemical factory blast in Hebei province that killed 25 people and injured 46, according to a preliminary investigation.

The investigation's findings, released by the State Administration of Work Safety on its website on Tuesday afternoon, said that 25 people were killed in the accident and four were still missing, a sharp increase from the 17 casualties announced on Feb 29. There were no updates to the list of injured, which remains at 46 people. On Feb 28, a blast ripped through the Keeper Chemical Factory in Zhaoxian county, Hebei province, razing the three-story building. The explosion also seriously damaged other buildings at the site and shattered the windows of houses up to two kilometers away.

The investigation found that a heat transfer oil spill under one of the three chemical reactors inside the factory caused a fire that heated the ammonium nitrate and guanidine nitrate in the reactor. Both compounds are used to make explosives and explode at high temperatures.