Objective To assess the health risks of workers exposed to low concentration of benzene, and to provide a basis for occupational health management of benzene enterprises.
Methods A simple random sampling method was used to select three enterprises from 1 133 manufacturing enterprises registered with low-concentration benzene exposure in Ningbo. From March to September in 2016 and 2017, the usage of raw and auxiliary materials, distribution of benzene-exposed workstations, exposure mode, exposure time, protective measures, occupational health management, and benzene concentrations were investigated and detected. EPA inhalation risk models were used to assess the carcinogenic risks and non-carcinogenic hazard quotients (HQs) of the workers exposed to low concentration of benzene.
Results Protective facilities were installed in the benzene-involved workstations of the three enterprises, workers in the benzene-involved workstations did not properly wear personal respiratory protective equipment, and occupational health management system was not thoroughly implemented. The highest short-term concentration of benzene in the three enterprises was 6.79 mg/m3, and the 8h time weighted average concentration was 0.34-1.40mg/m3, which were within the occupational exposure limits of benzene in China. The risks were (0.023-1.800)×10-4, which partly exceeded the limit of 1×10-4; the HQs were from 2.83 to 10.65, which exceeded the limit of 1.
Conclusion Workers' long-term exposure to low concentration of benzene poses a health risk.
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