Exposure to Amosite-Containing Ceiling Boards in a Public School in Switzerland: A Case Study

Our plain-English summary of Exposure to Amosite-Containing Ceiling Boards in a Public School in Switzerland: A Case Study, by D. Vernez, O. Duperrex, H. Herrera, et al (International Journal of Environmental Research and Public Health, 2019).

The study

• Authors: D. Vernez, O. Duperrex, H. Herrera, V. Perret, I. Rossi, F. Regamey, M. Guillemin
• Journal: International Journal of Environmental Research and Public Health
• Published: 2019;16(24)
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The measurement of an airborne concentration in Amosite fibers above 5035 F/m3 in a school prompted a retrospective quantitative health risk assessment. Dose estimates were built using air measurements, laboratory experiments, previous exposure data, and interviews. A dose response model was adapted for amosite-only exposure and adjusted for the life expectancy and lung cancer incidence in the Swiss population. The average yearly concentrations found were 52-320 F/m3. The high concentration previously observed was not representative of the average exposure in the building. Overall, the risk estimates for the different populations of the school were low and in the range of 2 × 10-6 to 3 × 10-5 for mesothelioma and 4 × 10-7 to 8 × 10-6 for lung cancer. The results evidenced however that children have to be considered at higher risk when exposed to asbestos, and that the current reference method and target values are of limited use for amphibole-only exposures. This study confirmed that quantitative health risk assessments and participatory approaches are powerful tools to support public decisions and build constructive communication between exposed people, experts, and policy-makers.

In plain English

This retrospective risk assessment concerned a Swiss school whose ceiling boards contained about 1% amosite asbestos by mass. After a 2015 reading of 5035 fibers per cubic meter (F/m3) in one classroom, a working group including parent and teacher representatives estimated exposures for pupils, teachers and the janitor. The models used an amosite-specific potency factor for mesothelioma and an all-fiber factor for lung cancer. They were adjusted for Swiss life expectancy and, for lung cancer, Swiss lung cancer incidence. All 16 background samples were below detection limits. Estimated average yearly concentrations were 52 to 320 F/m3. Estimated whole-life excess risks ranged from 1.8 × 10−6 (teachers, average scenario) to 2.97 × 10−5 (janitor, pessimistic) for mesothelioma, and from 3.0 × 10−7 to 8.3 × 10−6, in the same groups, for lung cancer. A risk of 1 × 10−6 means one extra death per million people exposed. Pupils' mesothelioma risk was three times teachers' in the average scenario. The authors judged the risks very low, concluded children should be considered at higher risk, and found current limits and the reference method of limited use for amphibole fibers. They noted that measurements were few and recent and that low-dose extrapolation is uncertain.

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: Retrospective quantitative health risk assessment (case study) of one school building
• Who was studied: Three groups who regularly used the asbestos-containing part of a Swiss school (main building built 1972 and 1976): pupils aged 6 to 15 (an estimated over 3000 between 1972 and 2015, exact number unknown), teachers (survey answered by 47 of 77) and the janitor
• Exposure: Passive exposure to amosite from ceiling insulation boards (about 1% amosite by mass; no other asbestos fibers found), from background release during normal use and from events such as hitting, replacing or breaking boards, lamp replacement and fire remediation
• Main results:
  • Method: the mesothelioma model used a potency factor (KM) specific to amosite, 3.9 × 10−8, rather than a single value for all amphiboles
  • Method: the lung cancer model used the DECOS potency factor (KL) of 1.64 × 10−2, which applies to all fibers
  • Method: the lung cancer risk calculation was adjusted for Swiss life expectancy and Swiss lung cancer incidence (the mesothelioma calculation was also adjusted for Swiss life expectancy)
  • In April 2015, before the study, 5035 F/m3 of amosite was measured in one classroom
  • All 16 background air measurements were below the limit of detection (95 F/m3 for 8-hour sampling and 190 F/m3 for 4-hour sampling)
  • Monte Carlo simulation gave 75 F/m3 (geometric mean) as a reasonable upper estimate of the background concentration
  • Estimated average yearly exposure concentrations across the groups and scenarios ranged from 52 to 320 F/m3; the earlier high reading was judged not representative of average exposure
  • Lowest estimated whole-life excess risks (Table 3): teachers, average scenario (average yearly exposure 52 F/m3), 1.8 × 10−6 for mesothelioma and 3.0 × 10−7 for lung cancer
  • Highest estimated whole-life excess risks (Table 3): janitor, pessimistic scenario (average yearly exposure 320 F/m3), 2.97 × 10−5 for mesothelioma and 8.3 × 10−6 for lung cancer
  • An excess risk of 1 × 10−6 means one additional death per 1,000,000 people exposed
  • In the average scenario, the excess risk of mesothelioma for pupils was three times that of teachers under similar exposure conditions
  • The authors judged the risks to the building's occupants very low
  • For amosite alone or amphibole mixtures, the Swiss 10,000 F/m3 occupational limit matched only the upper range of risk accepted at work, and the 1000 F/m3 target was mostly above the range accepted for the general population
  • The origin of the 2015 peak measurement could not be determined
• The authors' conclusion: The authors concluded that children should be considered at higher risk when exposed to asbestos, and that the current reference method and target values are of limited use for amphibole-only exposures
• Limitations the authors state:
  • Exposure estimates rest on a limited number of recent measurements that may not represent past exposures
  • The dose-response models come from highly exposed adult workers, so extrapolating to low doses in the general population is uncertain
  • The adult-based model has limited predictive ability for younger children
  • Because no adequate measurements existed, the exposure from remediation after a 2008 classroom fire was assumed by the working group

Topics

The National Library of Medicine indexes this study under subjects our site covers: Amosite, Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Amosite, Life Expectancy, Lung Cancer, Mesothelioma, Amphibole Group.

Related studies

• Asbestos in New York City public school buildings--public policy: is there a scientific basis? — R. Wilson, A.M. Langer, et al. (1994)
• Airborne Asbestos Exposures from Warm Air Heating Systems in Schools — G.J. Burdett, K. Dewberry, et al. (2016)
• Final results from a 90-day quantitative inhalation toxicology study evaluating the dose-response and fate in the lung and pleura of chrysotile-containing brake dust compared to TiO2, chrysotile, crocidolite or amosite asbestos: Histopathological examination, confocal microscopy and collagen quantification of the lung and pleural cavity — D.M. Bernstein, B. Toth, et al. (2021)
• Airborne exposure concentrations during asbestos abatement of ceiling and wall plaster — J.H. Lange, K.W. Thomulka (2002)
• Airborne asbestos levels in school buildings in Italy — A. Campopiano, S. Casciardi, et al. (2004)
• Mesothelioma among employees with likely contact with in-place asbestos-containing building materials — H.A. Anderson, L.P. Hanrahan, et al. (1991)

Browse more research in International Journal of Environmental Research and Public Health, or return to medical research.