BACKGROUND: High-level exposure to crystalline silica dust is the key factor in silicosis. Long-term exposure to low-level silica dust, for example, lower than that in occupational exposure limits, still needs to be studied for their risk of silicosis. METHODS: A total of 30 697 workers were included from a cohort in China. Low-level silica dust exposure was defined as those having a lifetime mean silica dust concentration equal to or under permissible exposure limits, including 0.05 mg/m RESULTS: Among those with average exposure level equal to or lower than 0.05 mg/m CONCLUSION: Long-term exposure to low-level silica dust is still associated with a higher risk of silicosis. Control measurements and personal protective equipment should be emphasised to protect the health of workers.