A fire in an independently-built house that killed 12 people last December in Shantou, Guangdong province, has been attributed to the owner's improper use of mosquito-repellent incense, according to the National Fire and Rescue Administration.

Speaking at a news conference in Beijing on Tuesday morning, Wang Tianrui, deputy director of fire prevention and supervision with the administration, described the fire as devastating, given that all of the victims came from a single family. He said that a special task force established by the Guangdong provincial government is still investigating the case.

According to Wang, the building had five floors. The first floor housed a hardware store, which illegally stored a quantity of highly flammable items beyond its approved business scope, including polyurethane foam sealant, spray paint, butane canisters for portable stoves, and lithium batteries, he said.

The upper floors were home to 20 people from four generations of the family. Opposing staircases rain on either side of the building from the first floor all the way to the fifth. With the first floor acting as a tinder box and the staircases acting as chimneys, the structure had all the conditions for a fire accident to occur, Wang said.

The deputy director urged owners of independently-built houses used for business operations to comply with the law and meet fire safety requirements.