Bridgman S
Industrial and Community Health Research Centre, Department of Postgraduate Medicine, University of Keele, UK.
J Epidemiol Community Health. 2001 Dec;55(12):921-7. doi: 10.1136/jech.55.12.921.
A factory fire in Tranmere, Merseyside, England, deposited asbestos containing fallout in an urban area. There was considerable community anxiety for months after the incident. Therefore an assessment of the long term health risks of this acute environmental incident were requested by the local health authority.
The facts of the incident were gathered and appraised from unpublished and press reports, involved personnel, and further analysis of material collected at the time of the incident. The literature on the long term health risks of asbestos was reviewed, and combined with evidence on asbestos exposure to estimate community health risk.
Risk was almost entirely from exposure to fire fallout of chrysotile in asbestos bitumen paper covering the factory roof. Amosite was only detected in a few samples and in trace amounts. The number of people who lived in the area of fallout was 16 000 to 48 000. From a non-threshold model with assumptions likely to overestimate risk, the lung cancer risk is estimated to be undetectably small. Risk of mesothelioma from chrysotile exposure, and risks of lung cancer and mesothelioma from amosite exposure were based on observational studies and were estimated to be even lower than that of lung cancer risk from chrysotile exposure. Academically, there are assumptions that while reasonable cannot be proven, for example, the validity of extrapolating observed risk from much higher exposures to lower exposures, estimates of individual exposure, and that there is no threshold for asbestos to cause cancer.
The author is unaware of a similar study on long term health risks in a community exposed to asbestos in a fire. It is concluded that, using methods that do not underestimate risk, risk is undetectably small. Practical lessons from this methodology and approach to health risk assessment are discussed.
英国默西塞德郡特兰米尔的一家工厂发生火灾，含有石棉的沉降物落在市区。事件发生后的数月里，社区民众忧心忡忡。因此，当地卫生部门要求对这起急性环境事件的长期健康风险进行评估。
从未发表的报告、新闻报道、相关人员处收集并评估事件详情，并对事件发生时收集的材料进行进一步分析。查阅了有关石棉长期健康风险的文献，并结合石棉暴露证据来估计社区健康风险。
风险几乎完全来自于接触覆盖工厂屋顶的石棉沥青纸中温石棉的火灾沉降物。仅在少数样本中检测到微量铁石棉。受沉降物影响地区的居民人数为16000至48000人。根据一个可能高估风险的无阈值模型，估计肺癌风险极小，难以察觉。温石棉暴露导致间皮瘤的风险，以及铁石棉暴露导致肺癌和间皮瘤的风险是基于观察性研究得出的，估计甚至低于温石棉暴露导致肺癌的风险。在学术上，存在一些虽合理但无法证实的假设，例如，将从高得多的暴露水平观察到的风险外推至低暴露水平的有效性、个体暴露估计，以及石棉致癌不存在阈值。
作者不知道有类似的关于火灾中接触石棉的社区长期健康风险的研究。结论是，使用不低估风险的方法，风险极小，难以察觉。讨论了这种健康风险评估方法和途径的实际经验教训。
