At least 85 people were injured in multiple blasts at a munitions factory in the Russian city of Dzerzhinsk on Saturday, Russian media reported.
Among those requiring medical attention were workers at the plant and residents of nearby houses, the regional health department told the Interfax news agency. Four people suffered severe injuries, 16 in total had to be hospitalized.
According to the authorities there have been no fatalities.
A total of 39 factory workers and 46 people living in the area had sought treatment.
Russian media showed a huge cloud of smoke and fire rising over the Kristall plant, which reportedly produces the explosive TNT and bombs for the military.
Five of the factory buildings were destroyed and residents were asked to keep their windows closed. The local authorities said, however, that there was no dangerous chemical smoke.
On Saturday afternoon, several hours after the explosions, the fires were put out. According to the authorities, there was no danger of further blasts.
According to the Ministry for Emergency Situations, an 800-square-meter area at the factory site had been on fire, and the fire had also spread to a nearby forest.
The cause was unknown, but Russian authorities started investigating possible violations of safety regulations at the site.
A national investigating committee dispatched staff from Moscow to Dzerzhinsk, located about 400 kilometers east of the capital.
Regional governor Gleb Nikitin called in an emergency committee meeting and was on his way to the site, Interfax reported. A state of emergency has been declared in the area.
Such severe accidents resulting in many deaths and injuries happen not infrequently in Russia. One reason is neglect of safety precautions and regulations.
Since 2014, almost a dozen blasts have occurred in explosives factories across Russia, the Tass news agency said. At the Kristall plant, one occurred two months ago.
At a different armament factory in Dzerzhinsk, five people died in August last year in an explosion.