Objective To explore the applicability of commonly used occupational health risk assessment models in the dynamic risk assessment of mercury in a thermometer manufacturing company.
Methods In December 2019 and October 2020, an occupational health site survey and testing was conducted on a thermometer manufacturer to assess the occupational health risks of mercury and compare the risk ratio before(2019) and after(2020) renovation of occupational protective facilities, using the United States Environmental Protection Agency(EPA) risk assessment guidelines, the Singapore Ministry of Manpower(MOM) semi-quantitative risk assessment method for chemical substance occupational exposure, the International Council on Mining and Metals(ICMM) quantitative assessment method, and the GBZ/T 229.2-2010 "Classification of Occupational Hazards in the Workplace Part 2: Chemicals".
Results In 2019, the mercury concentrations at 75%(9/12) of work positions were higher than the national OEL. The EPA and ICMM quantitative risk assessment methods showed that the risks were mainly unacceptable, while the MOM method showed that the risks were primarily high. The hazard classification method showed that the work positions in the triangular thermometer production area were classified as severe hazard work, and 33% of the work positions in other areas were categorized as moderate hazard work. After the renovation of the protective facility in 2020, the mercury concentrations at all work positions meet the requirements of China's occupational health standards. The risk ratios shown by the MOM, ICMM, and operational hazard classification in 2020 significantly decreased compared to the 2019 risk levels(P < 0.05), while the risk ratio shown by the EPA model showed no statistically significant difference(P>0.05).
Conclusions The applicability of the MOM, ICMM, and GBZ/T 229.2-2010 are suitable for dynamic assessment of occupational health risks of mercury in this thermometer manufacturing enterprise.