Malignant mesothelioma in thermoelectric power plant workers in Italy

Our plain-English summary of Malignant mesothelioma in thermoelectric power plant workers in Italy, by P. Crosignani, F. Forastiere, G. Petrelli, et al (American Journal of Industrial Medicine, 1995).

The study

• Authors: P. Crosignani, F. Forastiere, G. Petrelli, E. Merler, E. Chellini, N. Pupp, S. Donelli, G. Magarotto, E. Rotondo, C. Perucci
• Journal: American Journal of Industrial Medicine
• Published: 1995;27(4):573-6
• Type of article: Case report
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Asbestos has been widely used in Italian thermoelectric power plants and instances of exposure to workers have been documented in a variety of jobs. Preventive measures were put into effect only in the late 1970s. We report here on four mesothelioma cases among workers of three Italian power plants where cohort studies were carried out, and on three additional cases recorded by a systematic survey carried out on this neoplasm in Tuscany. When the data of the cohorts sources are merged, a significant excess of lung cancer is also evident. Even without a quantitative assessment of exposure, this report shows the importance of asbestos risk in thermal power plants. The risk appears not to be restricted to any particular category of workers.

In plain English

This brief communication described seven cases of malignant mesothelioma among former workers of Italian thermoelectric power plants, where asbestos insulated boilers, pipes and turbines. The cases were listed as pleural, and all were microscopically confirmed. Four cases were known to physicians at three power plants that had earlier cohort studies. Three more came from a mesothelioma survey in Tuscany. The workers held a range of jobs, including insulator, maintenance worker, cleaner and clerk. Two cases came from two cohorts totalling 1,577 people. Assuming follow-up to the end of 1992 with no losses or deaths, the authors estimated 0.15 expected cases among workers 20 or more years past first exposure, against two observed. Merging lung cancer results from the three earlier Italian cohorts gave 19 deaths observed against 11.72 expected (standardized mortality ratio 1.62, 90% confidence interval 1.06-2.38). The authors noted that other respiratory carcinogens, such as polycyclic aromatic hydrocarbons, were also present at the plants. The authors concluded that asbestos exposure poses a serious health risk to workers in a variety of jobs at these plants. They said their case search was not exhaustive, and exposure was not measured quantitatively.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Brief communication: case series of mesothelioma cases, with a rough estimate of expected cases and a merging of lung cancer results from three earlier cohort studies
• Who was studied: Seven former workers of thermoelectric power plants in Italy with pleural mesothelioma. Four were known to plant physicians at three power plants where cohort studies had been carried out, and three were found in the file of a mesothelioma survey in Tuscany. All except case 3 were directly employed by the Italian National Board of Electricity (ENEL).
• Exposure: Asbestos used for insulating surfaces in contact with high-temperature steam (boilers, pipes, turbines) and in anti-flame barriers for electric wire bundles. Exposure occurred when lagging material was removed during checkups or repairs. Until the late 1970s, removal was done by hand without wetting or vacuum cleaning. Fiber type is not stated. Jobs included handling asbestos insulation objects, maintenance involving lagging removal, insulator, cleaner, and a clerk who spent time in polluted areas.
• Main results:
  • All seven cases were microscopically confirmed. The table lists them as pleural mesothelioma cases.
  • The cases covered various jobs. One case worked directly as an insulator, one as a cleaner in an environment reported to be polluted by asbestos, and one was a clerk who did not handle asbestos-containing materials but spent part of the working time in polluted areas of the plant.
  • Two cases (cases 1 and 2) belonged to two cohorts comprising 1,577 individuals. Among workers with 20 or more years since first exposure, the expected number of mesothelioma cases was estimated at 0.15, against two observed. The estimate assumed follow-up to the end of 1992 without losses or deaths and used Lombardy Cancer Registry mortality rates for 1976-1987.
  • Except perhaps for case 4, there was no evidence of occupational asbestos exposure in previous jobs. The authors considered the cases attributable to work in the power plants.
  • Merging lung cancer results from three earlier Italian cohort studies of ENEL workers gave 19 deaths observed against 11.72 expected, a standardized mortality ratio of 1.62 (90% confidence interval 1.06-2.38). The separate cohorts had shown non-significant or modest excesses: 5 vs 2.83, 8 vs 4.50, and 6 vs 4.39.
• The authors' conclusion: The authors concluded that the mesothelioma cases, together with the evidence of increased lung cancer risk, indicate that asbestos exposure poses a serious health risk to workers in a variety of jobs at traditional thermoelectric power plants, not only insulators.
• Limitations the authors state:
  • The case search was not exhaustive. The Tuscany surveillance system probably covers only part of mesothelioma cases, and other cases are likely among workers of other power plants.
  • There was no quantitative assessment of exposure.
  • Exposure to other respiratory carcinogens, such as polycyclic aromatic hydrocarbons, also occurred in this setting, which is relevant to the lung cancer finding.
  • The expected number of mesothelioma cases was an approximation that assumed follow-up to the end of 1992 without any losses or deaths.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma, Power plants and utilities.

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Mesothelioma, Neoplasm, Lung Cancer.

Related studies

• Mortality among workers in the geothermal power plants at Larderello, Italy — E. Pira, M. Turbiglio, et al. (1999)
• Asbestos related health hazards among power plant workers — Y. Lerman, A. Finkelstein, et al. (1990)
• Extrapulmonary neoplasms among asbestos-exposed power plant workers — I.G. Ron, H. Ron, et al. (1999)
• Occupational exposures during routine activities in coal-fueled power plants — M.J. Bird, D.L. MacIntosh, et al. (2004)
• Occupational exposure to asbestos during renovation of oil-shale fuelled power plants in Estonia — M. Kangur (2007)
• Exposure to airborne asbestos in thermal power plants in Mongolia — N. Damiran, E.K. Silbergeld, et al. (2015)

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