Office of Occupational Medicine and Nursing, Directorate of Technical Support and Emergency Management, Occupational Safety and Health Administration, Washington, District of Columbia, USA.
Appleton Area Office, Occupational Safety and Health Administration, Appleton, Wisconsin, USA.
Am J Ind Med. 2021 Nov;64(11):915-923. doi: 10.1002/ajim.23284. Epub 2021 Aug 14.
Workers exposed to metalworking fluids (MWF) can develop respiratory illnesses including hypersensitivity pneumonitis (HP). These respiratory manifestations are likely due to microbial contamination of aerosolized MWF. This paper reports a cluster of HP and respiratory symptoms at a manufacturing plant where MWF and workplace air were contaminated with bacterial endotoxin despite frequent negative bacterial cultures of MWF.
A pulmonologist assessed and treated three workers with respiratory symptoms. The Occupational Safety and Health Administration (OSHA) inspected the plant. OSHA's investigation included bacterial culture of MWF, measurement of endotoxin concentrations in MWF and workplace air, review of the employer's fluid management program, and distribution of a cross-sectional symptom questionnaire.
Three workers had biopsy-confirmed HP. In addition, 30.8% of questionnaire respondents reported work-related respiratory symptoms. OSHA detected endotoxin levels as high as 92,000 endotoxin units (EU)/ml in MWF and 3200 EU/m in air. Endotoxin concentrations and risk of MWF inhalation were highest near an unenclosed multistation computer numerical control machine. A contractor had tested this machine's MWF for bacterial growth weekly during the preceding three years, and most (96.0%) of those tests were negative.
Contaminated MWF can cause severe occupational lung disease even if microorganisms do not grow in fluid cultures. Endotoxin testing can increase the sensitivity of detection of microbial contamination. However, employers should not rely solely upon MWF testing data to protect workers. Medical surveillance and meticulous source control, such as engineering controls to suppress MWF mist and prevent its inhalation, can reduce the likelihood of respiratory disease.
接触金属加工液（MWF）的工人可能会患上呼吸道疾病，包括过敏性肺炎（HP）。这些呼吸道表现可能是由于雾化 MWF 中的微生物污染。本文报道了一家制造工厂的 HP 和呼吸道症状集群，尽管 MWF 的频繁阴性细菌培养，但 MWF 和工作场所空气受到细菌内毒素污染。
一位肺病专家评估并治疗了三名有呼吸道症状的工人。职业安全与健康管理局（OSHA）对工厂进行了检查。OSHA 的调查包括 MWF 的细菌培养、MWF 和工作场所空气中内毒素浓度的测量、雇主的液体管理计划审查以及横断面症状问卷的分发。
三名工人的活检证实为 HP。此外，30.8%的问卷受访者报告有与工作相关的呼吸道症状。OSHA 在 MWF 中检测到高达 92,000 内毒素单位（EU）/毫升和空气中 3200 EU/m 的内毒素水平。在未封闭的多工位数控机床附近，内毒素浓度和 MWF 吸入风险最高。一名承包商在过去三年中每周对这台机器的 MWF 进行细菌生长测试，其中大多数（96.0%）测试为阴性。
即使 MWF 培养物中未生长微生物，受污染的 MWF 也可能导致严重的职业性肺部疾病。内毒素检测可以提高微生物污染检测的灵敏度。然而，雇主不应仅依赖 MWF 测试数据来保护工人。医疗监测和细致的源头控制，例如抑制 MWF 雾并防止其吸入的工程控制，可以降低呼吸道疾病的可能性。
