It's the perfect opener to an apocalypse movie: An accident at a top-secret government bioweapons research facility. And it just happened in Russia. Sort of. Not really.

On Monday, a gas explosion occurred at Vector, the State Research Center of Virology and Biotechnology in the science town of Koltsovo, some 20 km (12 miles) from Novosibirsk, the third most populous city in Russia.

The research centre is one of only two places in the world allowed to retain stock of the Variola viruses that cause smallpox. The other one is a Centers for Disease Control and Prevention (CDC) facility in Atlanta.

According to independent Russian news agency Interfax, on 16 September a gas explosion started a fire on the fifth level of a Vector building. The resulting fire only burned an area of about 30 square metres (320 square ft) and injured one person, who was admitted to hospital.

The explosion wasn't linked to scientific endeavours, though - it occurred in a sanitary and disinfection area that was being renovated. The mayor of the science town, Nikolai Krasnikov, told Interfax that the location of the fire wasn't in active use and there were no biohazardous materials present.

Reports of the event are consistent across the board, as the local science town news service and the institute itself have confirmed the news. A federal investigation is underway to determine whether there was a breach of work safety requirements that may have led to the accident.

So, are people on the internet panicking now this news has reached the English-speaking world?

Absolutely. Especially amongst headlines using evocative "explosion rocks research facility" phrasing and a mistranslation that claims "all glass in the building was broken". In reality, Interfax only stated (in Russian) that some windows in the building were broken, without specifying how many.

Still, the confusion has led to mass panic on Twitter - hashtag 'bioweapons', anyone?

In reality, Vector - one of the leading research facilities in its field - is a huge centre across several buildings with over 1,600 staff members who work on numerous bioresearch projects that involve a lot more than just some smallpox vials.

The chances that the blast somehow let loose a plague onto the world seem exceedingly small - not to mention that if a dangerous vial cracked open in a fire, the microbes would, uh, burn. You know.

But it's not like the danger of bioterror is imaginary, either. Smallpox still looms as an extremely contagious, devastating ailment from the history books, a reputation that directly competes with its success story as the first-ever disease we eradicated from the face of our planet.

Understandably, the decision to hold on to the remaining Variola virus stocks for research purposes has been highly controversial, as is the DNA research investigating how to piece this virus together (um, can we not).

Besides, the news about a mysterious explosion at a Russian weapons testing site just last month is still fresh in everyone's memory, and there was a lot of confusion over the statements coming out at the time.

Added to that is Vector's historical reputation as a secretive, government-aligned bioweapons research institution established in 1974; the fact it also houses Ebola, bird flu, anthrax, and a bunch of other nasties; and that one time in 2004 a staff member at Vector died from accidentally injecting herself with Ebola.

However, the World Health Organisation (WHO) has only allowed Vector scientists to retain smallpox because they actually have a biosafety level 4 (that's the highest level there is) facility. The collaboration with WHO apparently involves a bunch of rules and biannual inspections, too.

So while it might feel concerning, it's highly unlikely this event was as disastrous as some people may lead you to believe. Maybe there was a relatively small gas explosion and a small localised fire that was quickly put out, and the biohazardous materials hosted at this top-level facility where nowhere near the site of the accident.

Or maybe there's a horde of misshapen virus-mutant zombies already shambling in the research centre's local area.

If the gas explosion at Vector really does start a smallpox pandemic, I guess I'll have to print out this article and eat it, but by that point it will probably be pretty low on anyone's priority list.