BEIJING (AP) — The death toll in an explosion at a Chinese auto parts factory has risen to 75, as investigators fault poor safety measures and news reports reveal that workers had long complained of dangerous levels of dust at the facility.

Metal dust produced from polishing steel hubcaps ignited Saturday morning at the factory in the eastern Chinese city of Kunshan, causing an explosion that destroyed almost the entire roof of the plant, city officials said. More than 200 workers were at the factory at the time of the blast, China’s most serious industrial disaster since a fire at a poultry plant killed 119 people in June last year.