The cause of a freight train derailment and crash in Bulgaria last Saturday which killed seven people is still being investigated. A day of national mourning was held on Monday following the incident near the town of Hatrino, about 380 kilometres north east of the capital Sofia.

Twelve of the train’s tanks, carrying propylene, a very volatile and highly flammable gas, derailed at the village’s rail station. One of the tanks struck a power line and exploded in flames, police said. Around 50 houses and buildings are said to have been demolished.

Full evacuation

The powerful blast flattened dozens of houses and public buildings, leaving people under the ruins. Officials ordered a full evacuation of the village so that the propylene can be safely removed. Around 200 firefighters were involved in putting out the fires and cooling the derailed tanks to avoid further blasts.

Accident investigators say they are still investigating what caused the train to derail.