Guangzhou's government has launched a month-long safety inspection campaign across the city targeting factories, offices, residences and parking lots located 30 meters either side of an expressway.

The move is to prevent serious accidents like Friday's explosions, which killed at least 20 people and injured 31. The explosions were triggered by solvent oil that leaked from a rear-ended tanker truck.

The solvent oil flowed down to the drain under the Nangang section of a flyover along the Yanjiang Expressway, then caught fire and burned buildings and a container yard. The tanker truck was carrying 40 metric tons of solvent oil.