BEIJING - China on Wednesday arrested three managers of a Taiwanese-invested car parts factory where a massive explosion this month killed 75 people, state media said.
The blast at a wheel hub polishing workshop at Kunshan in the eastern province of Jiangsu also left more than 180 injured.
The Taiwanese-invested firm hit by the blast, Zhongrong Metal Products Co., manufactured parts for car companies including US giant General Motors.
A preliminary investigation showed the explosion was caused by the ignition of excessive dust from the production process, the state news agency Xinhua said.
"It was believed that there was a serious dereliction of duty behind the accident," it added.
Local prosecutors have approved the arrest of Zhongrong's chairman, its general manager and a manager in charge of safety, Xinhua said, citing authorities.
In China a formal arrest generally precedes a criminal trial, at which suspects are almost certain to be found guilty.
The country has a relatively poor industrial safety record. Some owners evade regulations to save money and pay off corrupt officials to look the other way.
US-based China Labor Watch, a workers' rights group, said proper measures could have prevented the accident.
"Safety measures like ventilation systems should have prevented such accumulation of dust particles," it said in a statement.
Dust suspended in the air in the right concentration can cause explosions, with even materials that do not normally burn in larger quantities becoming explosive in certain conditions.
Workplace accidents of all types killed nearly 70,000 people in China last year, its National Bureau of Statistics said.