Explosion at Russian lab that holds smallpox samples

There's been an explosion and fire at the Russian State Centre for Research on Virology and Biotechnology (Vector), a facility near Novosibirsk in Siberia that happens to hold live samples of smallpox. Vector officials say there's currently no risk of contamination. Vector and the US Centers for Disease Control and Prevention are the only two approved labs known to hold live samples of smallpox. The World Health Organization certified the eradication of smallpox in 1980 thanks to a global immunization effort. However, concern remains that the deadly virus could still be used as a bioweapon. From CNN:

In its statement, Vector said that no biohazard material was being stored in the room where the explosion took place. The city's mayor also insisted that the incident does not pose any biological or any other threat to the local population, according to TASS...

Dr. Joseph Kam, Honorary Clinical Associate Professor at the Stanley Ho Centre for Emerging Infectious Diseases (CEID) told CNN that rules for storing viruses are very strict and highly dangerous diseases such as Ebola and smallpox would be stored in the highest "Level 4" laboratory.

Access to the samples would be limited, special containers are used and the storage mechanism is different from other laboratories, Kam said.

He added that while fire would be hot enough to destroy viruses, an explosion could risk spreading the virus and there would be a danger of infecting those in the room or contaminating the immediate area.