In explosions like those in Elin Pelin, it is always very difficult to determine the real cause. The last such case I remember was from Muglizh in the Arsenal workshops, where again there were very loud explosions, and the owner's son also died in the fire. The conclusion of the experts after such an incident is very often the same due to the lack of evidence due to the strong explosion, which is “human error”. He said this on the air of “Good morning, Europe” the national security expert Prof. Nikolay Radulov.
In his words, the requirements for having concrete walls around the premises in such warehouses are for ammunition warehouses, not for those where fireworks are stored.
„Usually in such fires and explosions, unless they are intentional, the conclusion is one and usually "human error" and is attributed to the one who died“, Prof. Radulov also pointed out.