From human error to ball lightning, there are different versions regarding how the fireworks warehouses near Elin Pelin caught fire. According to security expert Milen Ivanov, incidents of this kind leave enough traces behind for an expert assessment to be made.

• Air quality in the vicinity of the burning fireworks warehouse near Elin Pelin is normal
• One killed in the explosion at the fireworks warehouses near Elin Pelin
• UPDATED: Fireworks warehouse complex near Sofia bursts into flames; urgent evacuation ordered

In an interview with Nova TV the expert commented that the explosive material in the warehouse is not fast burning. He explained that black powder, which is the main raw material that goes into the making of fireworks, burns slowly and can produce a powerful explosion in confined spaces. If the other warehouse in the area is affected there will be a powerful blast but nothing more can be done except wait and hope there will be no new explosions, he said.

Meanwhile, Nikolay Nikolov, former director of the Fire Safety and Civil Protection Chief Directorate said for public service TV BNT that any intervention on site can only take place once the people in charge are convinced the danger to firefighters, the rescue teams and the military is passed.