The Russian city of Dzerzhinsk declared a state of emergency after multiple blasts rocked an explosives factory here on Saturday authorities said.
Videos shared on social media showed that three explosions at a TNT production plant sent massive plumes of smoke over the city. The first explosion soon triggered two other blasts at the same facility at 11:45 am (local time), before spreading to another building nearby, Russia Today reported.
Dzerzhinsk officials have also launched a criminal inquiry in the blast that injured at least 20 people, on suspicion of a breach of industrial safety rules.
The Ministry of Emergency Situations further stated that the fire is currently spread over a 100 square meter area. The strength of the explosion smashed glass three kilometres away.
The TNT factory, which manufactures and stores explosives and ammunition, suffered a third blast since last year. Last August, five workers were killed in an explosion at the site, and in April an explosion destroyed a one-story building but caused no injuries.