Explosion and fire break out at Russian lab known for housing deadly smallpox virus

Russian authorities said that no biological material was present in the lab at the time of the explosion.

(CNN)An explosion has caused a fire at a Russian biological research facility that's one of only two centers in the world known for housing samples of the smallpox virus.

The blast occurred Monday during repair work of a sanitary inspection room at the Russian State Centre for Research on Virology and Biotechnology, known as Vector, near the Russian city of Novosibirsk in Siberia, the center said in a statement.
One worker was injured in the incident and is being treated in intensive care for burns, Russia's TASS news agency reported.