China's work safety watchdog Monday issued a circular, requiring chemical sectors nationwide to take strict precautions against serious accidents.

The State Administration of Work Safety (SAWS) made a public notice of a recent blast in north China, saying the direct cause was due to improper operation that generated high temperature and TNT, which is highly explosive.

The SAWS also pointed out problems including disorder in management, inadequate training and improper layout of the plant.

On May 11, a blast occurred in a chemical workshop in Cangzhou in Hebei Province, in which five people were killed and 80 injured, including 14 seriously-wounded.

This month also witnessed other accidents relating to work safety.

On May 4, 33 people were poisoned or injured in an ammonia leak in a chemical plant in east China's Anhui province.

The following day, a colliery explosion claimed 20 lives and left 10 missing in northern Shanxi province.

The administration urged chemical plants nationwide to conduct prompt inspections on incipient fault.