Kennedy S M, Chan-Yeung M, Marion S, Lea J, Teschke K
Department of Medicine, University of British Columbia, Vancouver, Canada.
Occup Environ Med. 1995 Mar;52(3):185-91. doi: 10.1136/oem.52.3.185.
To study exposure to cobalt and chromium in saw maintenance rooms and test respiratory health among saw filers at lumber mills. Hard-metal lung disease is associated with cobalt in the manufacture of tungsten carbide tools; recently it has also been reported among tool maintenance workers. Lumber mills often use saws tipped with tungsten carbide or with a newer alloy, stellite (containing more cobalt, as well as chromium).
A cross sectional study of 118 saw filers at eight lumber mills was carried out that included a standardised questionnaire, spirometry, personal air sampling, and examination of tasks every 10 minutes (by observation). Comparison data were from a study of bus mechanics tested with similar methods.
Cobalt exposure was associated with tungsten carbide grinding but not with stellite grinding. Chromium exposure was associated mainly with stellite welding. Saw filers had a twofold increase in phlegm and wheeze (P < 0.01) and a threefold increase in cough, phlegm, and wheeze related to work (P < 0.001), but no increase in breathlessness. Stellite welding was associated with a significant increase in nasal symptoms and cough related to work and a small decrease in airflow (forced expiratory volume in one second/forced vital capacity (FEV1/FVC%), P < 0.05). Saw filers wet grinding with tungsten carbide had significant reductions in forced expiratory lung volumes (FEV1 and FVC, P < 0.05) and were significantly more likely to have FEV1 and FVC values in the abnormal range. Cobalt exposure (in wet grinding) and duration of work that involved tungsten carbide grinding were both associated with significant reductions in FEV1 and FVC. Average cobalt exposures in this study were about 5 micrograms/m3, well below the currently accepted permissible concentration, which suggests that the current workplace limit for cobalt may be too high.
研究木材厂锯片维修室中钴和铬的暴露情况，并检测锯片锉磨工的呼吸健康状况。硬质合金肺病与碳化钨工具制造过程中的钴有关；最近，工具维修工人中也有相关报道。木材厂经常使用碳化钨锯片或一种新型合金司太立合金锯片（含更多钴以及铬）。
对8家木材厂的118名锯片锉磨工进行了一项横断面研究，包括一份标准化问卷、肺功能测定、个人空气采样以及每10分钟对工作任务的观察。对照数据来自一项采用类似方法检测的公交机械师研究。
钴暴露与碳化钨磨削有关，但与司太立合金磨削无关。铬暴露主要与司太立合金焊接有关。锯片锉磨工咳痰和喘息增加了两倍（P < 0.01），与工作相关的咳嗽、咳痰和喘息增加了三倍（P < 0.001），但呼吸困难无增加。司太立合金焊接与与工作相关的鼻部症状和咳嗽显著增加以及气流轻度下降（一秒用力呼气容积/用力肺活量（FEV1/FVC%），P < 0.05）有关。使用碳化钨进行湿磨的锯片锉磨工用力呼气肺容积（FEV1和FVC）显著降低（P < 0.05），且FEV1和FVC值处于异常范围的可能性显著更高。钴暴露（在湿磨中）以及涉及碳化钨磨削的工作时长均与FEV1和FVC的显著降低有关。本研究中的平均钴暴露约为5微克/立方米，远低于目前公认的允许浓度，这表明当前工作场所的钴限值可能过高。
