The death toll from Wednesday’s blast at an explosives factory in northwestern Bulgaria could be as high as 15, according to unofficial estimates.

State-run Bulgarian National Radio reported on Thursday morning that the site of the explosion at the factory near the village of Gorni Lom could be inspected by rescue teams no earlier than 24 hours after the last secondary blast which is said to have occurred around 21.45 local time.

Neither Caretaker Interior Minister Yordan Bakalov,nor the ministry’s Chief Secretary Svetlozar Lazarov could say how many people have been at the site at the time of the blast.

Nikolay Nikolov, head of the National Fire Service, and the factory’s owner Valeri Mitkov, who have also arrived in Gorni Lom, in Vidin region, also were unable to say what the number of victims could be.

Mitkov also said he could not speculate what the reason for the blast might have been. According to unofficial estimates, there were around 10 tonnes of highly explosive ammonite at the storage facilities of the factory at the time of the blast.

The explosion left three women injured.

Nikolov told BNR that three volunteers are awaiting the green light to enter the site of the blast to look for survivors.

He added drone planes and remote controlled bomb-defusing robot will be used to search the area. Population won’t be evacuated from the village.

In February 2010, an explosion and a huge fire at the privately-owned Midzhur factory near the village of Gorni Lom left four people injured and destroyed two units of the factory.

According to Bakalov, the latest overall inspection of the explosives and ammunition factory carried out 15 days ago had found irregularities. He didn’t elaborate.