Malignant pleural mesothelioma in US automotive mechanics: Reported vs expected number of cases from 1975 to 2007

The Production of Corporate Research to Manufacture Doubt About the Health Hazards of Products: An Overview of the Exponent Bakelite® Simulation Study

Although corporate sponsorship of research does not necessarily lead to biased results, in some industries, it has resulted in the publication of inaccurate and misleading data. Some companies have hired scientific consulting firms to retrospectively calculate exposures to hazardous products during use that are no longer manufactured or sold. As an example, this paper reviews one such study-a litigation-generated study of Union Carbide Corporation's asbestos-containing product, Bakelite®. This analysis is based on previously secret documents, produced as a result of litigation. The study generated asbestos fiber exposure measurements which resulted in underestimates of actual exposures to create doubt about the hazards associated with manufacture and manipulation of Bakelite®.

Review of refractory ceramic fiber (RCF) toxicity, epidemiology and occupational exposure

This literature review on refractory ceramic fibers (RCF) summarizes relevant information on manufacturing, processing, applications, occupational exposure, toxicology and epidemiology studies. Rodent toxicology studies conducted in the 1980s showed that RCF caused fibrosis, lung cancer and mesothelioma. Interpretation of these studies was difficult for various reasons (e.g. overload in chronic inhalation bioassays), but spurred the development of a comprehensive product stewardship program under EPA and later OSHA oversight. Epidemiology studies (both morbidity and mortality) were undertaken to learn more about possible health effects resulting from occupational exposure. No chronic animal bioassay studies on RCF have been conducted since the 1980s. The results of the ongoing epidemiology studies confirm that occupational exposure to RCF is associated with the development of pleural plaques and minor decrements in lung function, but no interstitial fibrosis or incremental lung cancer. Evidence supporting a finding that urinary tumors are associated with RCF exposure remains, but is weaker. One reported, but unconfirmed, mesothelioma was found in an individual with prior occupational asbestos exposure. An elevated SMR for leukemia was found, but was absent in the highly exposed group and has not been observed in studies of other mineral fibers. The industry will continue the product stewardship program including the mortality study.

Recent Scientific Evidence Regarding Asbestos Use and Health Consequences of Asbestos Exposure

To justify the continuous use of two million tons of asbestos every year, it has been argued that a safe/controlled use can be achieved. The aim of this review was to identify recent scientific studies that present empirical evidence of: 1) health consequences resulting from past asbestos exposures and 2) current asbestos exposures resulting from asbestos use. Articles with evidence that could support or reject the safe/controlled use argument were also identified. A total of 155 articles were included in the review, and 87 % showed adverse asbestos health consequences or high asbestos exposures. Regarding the safe/controlled use, 44 articles were identified, and 82 % had evidence suggesting that the safe/controlled use is not being achieved. A large percentage of articles with evidence that support the safe/controlled use argument have a conflict of interest declared. Most of the evidence was developed in high-income countries and in countries that have already banned asbestos.

Residual fibre lung burden among patients with pleural mesothelioma who have been occupationally exposed to asbestos

OBJECTIVES

To evaluate the lungs asbestos fibres concentration in participants with malignant pleural mesothelioma (MPM) who have been occupationally exposed.

METHODS

The lung samples were obtained from pleuropneumonectomies or autopsies of 271 male MPMs. The lung samples were examined through scanning electron microscopy. Retrospective assessment was used to assess for asbestos exposure. This study includes 248 MPMs with an occupational exposure defined as either 'definite' or 'probable' or 'possible'.

RESULTS

The participants had finished working in asbestos exposure conditions more than 20 years ago (on average 26.1±11.0 years). The fibre burden resulted with a geometric mean equal to 2.0 (95% CI 1.6 to 2.4) million fibres per gram of dry lung tissue. The burden was higher among participants employed in asbestos textiles industry and in shipyards with insulation material, if compared with construction workers or non-asbestos textile workers or participants working in chemicals or as auto mechanics. 91.3% of MPMs had a detectable amount of amphibole fibres. A strong lung clearance capability was evident among workers exposed to chrysotile fibres. Owing to that, the 1997 Helsinki Criteria for occupational exposure were reached in <35% of cases among participant working in construction, in metallurgical industry, in chemical or textile industry and among those performing brake repair activities.

CONCLUSIONS

The MPM cases are now occurring in Italy in participants who ceased occupational asbestos exposure decades before the analysis. A large majority still shows a residual content of amphibole fibres, but given the lung clearance capability, attribution to occupational exposure cannot rely only on fibres detection.

Withdrawn: The production of corporate research to manufacture doubt about the health hazards of products: an overview of the Exponent Bakelite™ simulation study

Withdrawal statement Egilman DS. The production of corporate research to manufacture doubt about the health hazards of products: an overview of the Exponent Bakelite™ simulation study. International Journal of Occupational and Environmental Health. 2016;22(1):18–26. DOI: 10.1080/10773525.2015.1123379. This content has been removed by the publishers.

Electron microscopy remains the gold standard for the diagnosis of epithelial malignant mesothelioma: a case study

This is a case of idiopathic epithelial malignant mesothelioma in a 47-year-old mechanic. The advent of a large battery of immunochemical markers has provided new tools for the diagnosis of mesothelioma in recent years; however, immunostaining can often be misleading or inconsistent, as demonstrated in this case. This report highlights the lasting utility of electron microscopy in the diagnosis of mesothelioma. Ultrastructural features of epithelial mesothelioma were discernable using electron microscopy even on somewhat poorly preserved chest wall biopsy specimens from paraffin blocks. These images, combined with immunostains and a fiber analysis from the lungs, allowed for a final diagnosis of a non-asbestos-related malignant epithelial mesothelioma in this patient.