A radiographic survey of public school building maintenance and custodial employees

Our plain-English summary of A radiographic survey of public school building maintenance and custodial employees, by H.A. Anderson, L.P. Hanrahan, D.N. Higgins, et al (Environmental Research, 1992).

The study

• Authors: H.A. Anderson, L.P. Hanrahan, D.N. Higgins, P.G. Sarow
• Journal: Environmental Research
• Published: 1992;59(1):159-66
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Analyses of radiographs from a cohort of 457 school maintenance and custodial workers (90 had no employment other than at a school) demonstrated an increased prevalence of abnormalities consistent with asbestos-caused disease. Pleural abnormalities predominated (24 of 29). The abnormalities could not be explained by occupational asbestos exposures which may have occurred prior to school employment. Abnormality prevalence ranged from 1.7% among those with less than 10 years to 37% among those with 30 or more years of public school employment. Laborers and skilled tradesmen with more than 20 years of school employment had a higher prevalence of abnormality (40 and 28%) than the building engineers (14%). In order to ensure that future asbestos exposure and disease risk is minimized in buildings constructed with asbestos-containing materials (ACM), implementation of asbestos hazard identification and abatement must include a rigorous operations and maintenance program. Control of asbestos exposure from in-place ACM is a public health priority.

In plain English

This Wisconsin study reviewed chest X-rays from clinic surveys of current public school maintenance and custodial workers. Their buildings contained asbestos-containing materials, including pipe and boiler insulation, fireproofing and acoustical products. Of 494 eligible workers, 457 were analyzed, and 90 of them had worked only at the schools. An X-ray counted as abnormal only when two certified readers agreed. Overall, 29 of 457 workers (6.3%) had abnormalities consistent with asbestos-caused disease, mostly involving the pleura, the lining around the lungs (24 of 29). Prevalence rose with years of school employment, from 1.7% among those with under 10 years to 37.0% among those with 30 or more years. Among workers with more than 20 years, laborers (5 workers) had 40% abnormal, maintenance trades (25 workers) 28%, and building engineers 14%. Workers with earlier construction or silica-exposed jobs did not differ significantly from others. The authors concluded that school maintenance and custodial workers are at risk of asbestos-caused disease. They noted two gaps: no personal or area asbestos fiber measurements covering the relevant employment years were available, and nothing was known about nonparticipants.

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: Cross-sectional radiographic survey, based on medical records abstracted from two clinic screening surveys
• Who was studied: Current public school maintenance and custodial workers in Wisconsin. 494 were eligible; 10 declined, 1 had an unreadable X-ray, and 26 were excluded for missing age or employment data, leaving 457 analyzed. Of these, 90 had no employment other than at the schools. Survey years are not stated.
• Exposure: Asbestos-containing materials in public school buildings: thermal insulation on pipes and boilers, fireproofing, acoustical insulation, and miscellaneous materials such as floor tile. Exposure was measured as years of school employment. No fiber types or exposure measurements were reported.
• Main results:
  • 29 of 457 workers (6.3%) met the case definition: 8 had irregular small opacities (profusion 1/0 or greater) and 24 had pleural abnormalities, with 3 having both.
  • Prevalence of abnormalities increased with length of school employment (P less than 0.001): 1.7% for 1 to 9.9 years (173 workers), 4.5% for 10 to 19.9 years (200), 12.3% for 20 to 29.9 years (57), and 37.0% for 30 or more years (27).
  • Among the 64 school-only workers with less than 20 years of school employment, none had abnormalities. Among school-only workers with more than 30 years, 46.2% did. Differences between school-only workers and those with earlier jobs did not reach statistical significance.
  • Mean school employment was 12 (plus or minus 8) years for workers without abnormalities and 23 (plus or minus 11) years for those with abnormalities (P less than 0.001).
  • Among workers with 20 or more years, laborers (N = 5) had 40% abnormal and the maintenance trades group (N = 25: carpenters, electricians, painters, plumbers and plasterers) had 28%. The article's abstract gives 14% for building engineers.
  • Of 41 workers with earlier construction or silica-exposed jobs, 7.3% had abnormal X-rays. This was not statistically significantly different from 5.5% among the 326 with other prior jobs or 8.9% among school-only workers. None of the 457 reported shipyard or asbestos product factory work.
  • In the 130 workers with complete smoking histories, cigarette smoking was not a significant predictor of X-ray abnormalities.
• The authors' conclusion: The authors concluded that school building maintenance and custodial workers are at risk of developing asbestos-caused disease. In their view, the abnormalities could only be explained by exposure to fibers released from in-place asbestos-containing materials during usual work. They called control of exposure from these materials a public health priority.
• Limitations the authors state:
  • No information was available on workers who did not participate.
  • No personal or area asbestos fiber measurements covering the relevant employment years were available.
  • Workers could not be grouped by school building or by type of asbestos-containing material, because most had worked in all the buildings.
  • Detailed lifetime smoking histories were available for only 130 workers. For the rest, never smokers could not be separated from former smokers.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Asbestos-Containing Material (ACM), Abatement, Operations and Maintenance Program.

Related studies

• Asbestos-related disease in custodial and building maintenance workers from a large municipal school district — J.R. Balmes, A. Daponte, et al. (1991)
• Asbestos-related disease in public school custodians — L.C. Oliver, N.L. Sprince, et al. (1991)
• Mesothelioma among employees with likely contact with in-place asbestos-containing building materials — H.A. Anderson, L.P. Hanrahan, et al. (1991)
• Asbestos-related abnormalities in school maintenance personnel — L.C. Oliver, N.L. Sprince, et al. (1991)
• Asbestos in school buildings: results of a nation-wide survey — K.Z. Silver (1979)
• Asbestos in New York City public school buildings--public policy: is there a scientific basis? — R. Wilson, A.M. Langer, et al. (1994)

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