What caused explosion at Zagorsk Optical-Mechanical Plant in Russia? 

Defense Express explains what could be the cause of the explosion. 

A powerful blast shook the Zagorsk Optical-Mechanical Plant near Moscow's Sergiyev Posad today, August 9, at 10:40 a.m. 

The explosion caused substantial destruction, leveling multiple structures and shattering windows over a kilometer away. The toll stands at about fifty injured, one person died in hospital, more may be trapped under debris. 

Officially, the Russian authorities attribute the explosion to a "technological process violation" by the Pyro-Ross company, which rented space on the plant's premises. Notably, Pyro-Ross had licenses for handling ammunition, indicating the presence of artillery munitions on-site.

A video capturing the incident reveals a series of explosions culminating in the main detonation. While its quality hinders definitive conclusions, we can see the explosion's sequence.

In any case, the Kremlin has already identified the cause of the explosion as "violation of industrial safety requirements for hazardous production facilities, which resulted in a fire in the pyrotechnics warehouse." The Russian prosecutor's office has already opened a case under this article of the Russian Criminal Code.

“But in any case, we must recognize that Russia is great at putting explosive devices, like shells, directly in the center of a city, in the yard of a defense company that works with optics. Especially when there is high-precision and sensitive equipment for the production of optical devices,” the article notes.