The Aug. 30 blast at the Xinxin Firework Plant in Inner Mongolia also injured three people and destroyed 50 workshops.

Two owners of the plant in Sijiazi township were each given five-year terms, while the safety manager was given four years, Xinhua said.

Three other workers were sentenced to between three and three-and-a-half years, it said.

The report did not give details of any of the charges but said a violation of safety regulations was blamed for the incident, which occurred when workers were weighing and mixing ingredients for fireworks.

Accidents in Chinese factories are common, with thousands dying every year in part because of lax enforcement of safety rules.

Fireworks factories, many of them illegal, are notoriously unsafe. -- AP