Enterline P E
Environ Health Perspect. 1983 Oct;52:93-7. doi: 10.1289/ehp.835293.
The current standard for occupational exposure to asbestos is 2 fibers/cm3 averaged over an 8-hr day. A NIOSH/OSHA committee has recently concluded that the 2 fiber/cm3 standard is grossly inadequate to protect workers from asbestos-related disease, and that all levels of asbestos exposure studied thus far have demonstrated asbestos-related disease. The committee recommends that a 0.1 fiber/cm3 limit replace the current 2 fiber/cm3 standard on the grounds that this is the lowest level detectable with currently available analytical techniques. Thus a 0.1 fiber/cm3 limit is not based on epidemiological data but on the presumption that any level of exposure is disease producing. This paper addresses the question of whether it would be possible to detect health effects of exposure below the current 2 fiber/cm3 standard. Five studies are reviewed which provide evidence on the strength of the relationship between asbestos fiber exposure and lung cancer. Calculation of sample sizes needed to be 95% certain of detecting the kind of excess probably associated with exposure to 2 fibers/cm3 suggests that epidemiology is not likely to be useful in detecting lung cancer below the current standard. Some outcome measures other than lung cancer or clinical asbestosis will be needed if observations on humans are to be used as evidence for a lowering of the present standard.
目前职业接触石棉的标准是在8小时工作日内平均每立方厘米2根纤维。美国国家职业安全与健康研究所/职业安全与健康管理局的一个委员会最近得出结论，每立方厘米2根纤维的标准远远不足以保护工人免受与石棉相关的疾病侵害，而且迄今为止所研究的所有石棉接触水平都已证实会引发与石棉相关的疾病。该委员会建议用每立方厘米0.1根纤维的限值取代现行的每立方厘米2根纤维的标准，理由是这是目前可用分析技术能够检测到的最低水平。因此，每立方厘米0.1根纤维的限值并非基于流行病学数据，而是基于任何接触水平都会导致疾病的假设。本文探讨了是否有可能检测出低于现行每立方厘米2根纤维标准的接触所产生的健康影响这一问题。回顾了五项研究，这些研究为石棉纤维接触与肺癌之间关系的强度提供了证据。计算要95%确定能检测出可能与接触每立方厘米2根纤维相关的那种超额病例所需的样本量表明，流行病学在检测低于现行标准的肺癌方面可能并无用处。如果要将对人类的观察用作降低现行标准的证据，就需要一些除肺癌或临床石棉肺之外的其他结果指标。
