A gas explosion caused a fire on Monday at the Vector Institute biological research facility in Siberia.
Scientists at the University of Alberta have managed to recreate a relative of the deadly smallpox virus.
A US government scientist discovered the forgotten vials at a research center near Washington.
Health officials will be meeting next week to decide if the virus should be destroyed once and for all.
A microbiology professor who helped eradicate smallpox has claimed we will be extinct within only 100 years.