BEIJING — A suspected dust explosion at an automotive parts factory that supplies General Motors killed at least 69 people in eastern China and injured more than 180 others, most with severe burns, state media reported Sunday.

It was China’s most serious industrial disaster since a fire at a poultry plant killed 119 people in June last year, and again highlighted workplace safety that remains a concern.

Saturday morning’s explosion occurred when more than 200 workers were on the site of the factory, which is in an industrial zone in the city of Kunshan, officials from the city said at a news conference.

State broadcaster CCTV showed footage of large plumes of thick, black smoke rising from the plant, and news websites posted photos of the dead or injured being lifted onto the back of large trucks, their bodies black, presumably from burns or soot.

Some survivors sat on wooden cargo platforms on the road outside the factory or were carried to ambulances, their clothes apparently burned off and their skin exposed.

The explosion occurred at 7:37 a.m. at a workshop in the factory, which polishes wheel hubs. Rescuers pulled out 44 bodies at the site, and 25 other people died at a hospital, officials said. At least 187 people were injured.

A preliminary investigation showed that the blast was likely a dust explosion, the official Xinhua News Agency reported.

A dust explosion is caused by the fast combustion of particles suspended in air in an enclosed space. The particles could include dust or powdered metals such as aluminum. They would have to come into contact with a spark, such as fire, an overheated surface or electrical discharge from machinery.

The Kunshan factory is operated by the Kunshan Zhongrong Metal Products Co. Its core business is electroplating aluminum alloy wheel hubs, and it supplies GM and other companies, the company’s website says.

Police took away five senior Zhongrong executives to assist in the investigation, officials said, without providing details.