The blast took place during repairs to a fifth-floor sanitary inspection room at the State Research Centre of Virology and Biotechnology – usually known as Vector – in Koltsovo, in the Novosibirsk region of Siberia, the centre said on Monday. The site housed biological weapons research during the Soviet era and is now one of Russia’s main disease research centres.
One worker suffered third-degree burns after the blast, which blew out the glass in the building. A fire covering 30 square metres was later extinguished.
Russian authorities insisted that the room where the explosion occurred was holding no biohazardous substances and that no structural damage was caused.
The smallpox virus survives in two places on Earth: at Vector and at another high-security laboratory, at the US Centre for Disease Control in Atlanta.
In 2004, a researcher died at the laboratory complex after accidentally pricking herself with a needle carrying the Ebola virus.
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