Illegal operations at a gas station caused an explosion in a drainage pipe that killed two people in Yongshun county, Hunan province, local government said on Thursday.

The explosion also injured five others and destroyed the first floor of a hotel on Monday night.

The gas station has been closed and three people involved in the case have been detained by police, said a report from Xinhua.

According to the investigation by the government of Yongshun county, staff of the station did not follow rules when they transferred the gasoline from an oil tank.

As a result, the gasoline overflowed the oil tank and got into the urban drainage network, causing the explosion.