The Vector State Research Center of Virology and Biotechnology announced Monday that a gas tank erupted during repairs in a sanitary inspection room at its lab in Koltsovo, Novosibirsk region. One worker was hospitalized with burn injuries, the state-run TASS news agency reported .

An explosion has hit a disease research center in Siberia that houses strains of Ebola and smallpox, causing a fire and injuring one worker.

Vector, along with Russia’s consumer protection watchdog and the town’s mayor, were quick to stress that biohazard substances weren't present at the time of the blast and said the explosion does not pose a threat to the community.

“No work with biological materials was carried out in the building,” Vector said in an online statement.

Vector is one of two places on Earth known to store samples of the live smallpox virus. The other sample of the deadly pathogen is stored at the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta.

It completed trials of an Ebola vaccine earlier this year. A Vector researcher died there in 2004 after pricking herself with a needle carrying the virus, raising concerns about safety and secrecy.

A 2016 World Health Organization inspection said Vector met biosafety and biosecurity standards, but inspectors had “requested further work on some issues.”

The former head of Vector vanished in 2017 following accusations of fraud and a Soviet defector claimed in the early 1990s that smallpox strains were moved there for bioweapons research.