A huge explosion at a factory in the city of Kunshan, in East China’s Jiangsu Province has killed at least 68 people and injured 187 others.

44 of the victims were killed at the scene while 24 others died at hospital. Among those injured, 137 have been transferred to hospitals in the nearby cities of Suzhou, Shanghai, Wuxi and Nantong. Authorities said Saturday morning’s blast happened at a factory that makes wheel hubs for cars.

A preliminary investigation has suggested that the explosion was caused by negligence, after a flame was lit in a dust-filled room, which triggered the blast. Two managers from the company that operates the factory have been detained by police. The Zhongrong Metal Products Company has 450 employees and specializes in aluminium processing. It’s also a designated supplier for US auto giant General Motors.