Characteristics and occupational risk assessment of occupational silica-dust and noise exposure in ferrous metal foundries in Ningbo, China

INTRODUCTION: To investigate the major existing occupational hazards and to assess the occupational health risks for ferrous metal foundries (FMFs) in Ningbo, China. METHODS: Unified questionnaires were formulated to investigate the information on the basic situations, occupational hazards, and occupational health management for 193 FMFs in Ningbo. Furthermore, we used the semi-quantitative risk assessment model, which was developed by the International Council on Mining and Metals (ICMM), to assess occupational health risks for 59 of 193 the FMFs. RESULTS: The casting process of FMFs in Ningbo was mainly divided into sand casting and investment casting, and silica-dust and noise were the major occupational hazards in both sand casting and investment casting foundries. Silica-dust mainly occurred in industries with such work as sand handling, modeling, falling sand, and sand cleaning, with the median of the permissible concentration-time weighted average (PC-TWA) was 0.80, 1.15, 3.52, 0.83 mg/m(3), respectively. The noise mainly existed in industries with such work as sand handling, core making, falling sand, sand cleaning, cutting and grinding, and smelting with median of PC-TWA was 81.72 dB(A), 82.93 dB(A), 90.75 dB(A), 80.18 dB(A), 90.05 dB(A), 82.70 dB(A), respectively. In addition, the results of the ICMM assessment model indicated that 100 and 98.7% of the jobs exposed to silica-dust and noise in 59 FMFs have an “intolerable risk” level of risks of causing pneumoconiosis and noise deaf, respectively. DISCUSSION: The hazard risk of silica-dust and noise is serious for FMFs in Ningbo. It is necessary to supervise enterprises to improve operating environmental conditions, accelerate the reduction of silica-dust and noise exposure risks, and promote the healthy and sustainable development of the foundry industry.