China suffered its worst industrial accident for a year yesterday when an explosion killed at least 68 people and injured more than 120 at a factory that makes wheels for US carmakers.

The blast occurred at around 7.30am at Kunshan Zhongrong Metal Products Co in Kunshan city, about an hour's drive from Shanghai. An explosion ripped through a workshop and a preliminary investigation suggested it was triggered when a flame was lit in a dust-filled room. Several officials from the firm have since been detained, the government said.