Asbestos exposure of building maintenance personnel

Our plain-English summary of Asbestos exposure of building maintenance personnel, by S. Mlynarek, M. Corn, C. Blake (Regulatory Toxicology and Pharmacology, 1996).

The study

• Authors: S. Mlynarek, M. Corn, C. Blake
• Journal: Regulatory Toxicology and Pharmacology
• Published: 1996;23(3):213-24
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The exposures of building maintenance personnel and occupants to airborne asbestos fibers, and the effects of operations and maintenance programs on those exposures, continue to be an important public health issue. The subject of this investigation was a large metropolitan county with numerous public buildings which routinely conducted air sampling for asbestos. A total of 302 personal air samples in nine task categories collected during maintenance worker activities in proximity to asbestos-containing materials were analyzed; 102 environmental air samples in four task categories were also analyzed. The arithmetic means of the 8-hr time weighted average exposures for personal sampling for each task category were all below the Occupational Safety and Health Administration permissible exposure level of 0.1 fibers (f)/cc > 5 microm. The highest mean 8-hr time weighted average exposure was 0.030 f/cc > 5 microm for ceiling tile replacement. The maximum asbestos concentration during sample collection for environmental samples was 0.027 f/cc > 5 microm. All asbestos-related maintenance work was done within the framework of an Operations and Maintenance Program (OMP) which utilized both personal protective equipment and controls against fiber release/dispersion. Results are presented in association with specific OMP procedures or controls. These results support the effectiveness of using Operations and Maintenance Programs to manage asbestos in buildings without incurring unacceptable risk to maintenance workers performing maintenance tasks.

In plain English

This study analyzed air samples a large U.S. metropolitan county took on its maintenance workers near asbestos-containing materials in 41 buildings from 1988 to 1993, under its asbestos Operations and Maintenance plan. Defendants in litigation obtained the records; two authors were consultants and expert witnesses for the defendant. The authors analyzed 302 personal samples from nine tasks and 102 environmental samples. Fibers were counted by phase contrast microscopy, which also counts non-asbestos fibers. Every task's average 8-hour time-weighted exposure was below the OSHA limit of 0.1 fibers per cc. The highest average, 0.030, was for ceiling tile replacement, where individual 8-hour values reached 0.21. The 30-minute excursion limit of 1.0 fibers per cc was exceeded three times, all in ceiling tile replacement. For cable pulling and ceiling tile replacement, the only tasks with enough samples, mean 8-hour exposures with and without a Kontrol Kube or negative air did not differ significantly; the authors said this deserves careful future study. The authors concluded such plans are an effective way to keep exposures acceptable. They noted total asbestos-related work time was not recorded.

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: Analysis of existing industrial hygiene air-sampling records from a county government database. The defendants in building litigation obtained the records, and two of the authors were consultants and expert witnesses for the defendant.
• Who was studied: Maintenance staff employed by a large U.S. metropolitan county, sampled in 41 county buildings during 1988 to 1993. The analysis covered 302 personal air samples in nine task categories and 102 environmental (area) samples in four categories, drawn from a database of 1008 samples.
• Exposure: Airborne fibers longer than 5 micrometers, counted by phase contrast microscopy. The method does not identify asbestos fiber types. Sampling took place during nine maintenance tasks near asbestos-containing materials such as fireproofing, ceiling tile, acoustic spray, TSI, transite pipe, surfacing material and light fixtures with ACM debris. The tasks were ACM debris cleanup, bulk sample collection, cable pulling, ceiling tile replacement, electrical installation, electrical repair, fluorescent lamp replacement, HEPA vacuuming or wet wiping of dust and debris, and wet wipe cleaning. Workers used respirators and coveralls along with controls such as HEPA vacuums, sprayers, plastic sheeting, negative air and a Kontrol Kube.
• Main results:
  • For maintenance workers, the mean 8-hr time-weighted average exposure in every one of the nine task categories was below the OSHA permissible exposure limit of 0.1 fibers per cc.
  • The highest task mean 8-hr time-weighted average was 0.030 fibers per cc, for ceiling tile replacement.
  • For ceiling tile replacement, the highest individual values printed were a sample concentration of 3.5 fibers per cc, an 8-hr time-weighted average of 0.21 fibers per cc, and a 30-minute excursion concentration of 1.5 fibers per cc.
  • The OSHA 30-minute excursion limit of 1.0 fibers per cc was exceeded three times in the 5-year period, all during ceiling tile replacement. The authors describe this limit as a control device, not a health-based standard.
  • In the environmental (area) samples, the highest category mean sample concentration was 0.027 fibers per cc and the highest single value was 0.062 fibers per cc. Both were recorded during HEPA vacuuming or wet wiping of dust and debris (19 samples).
  • 57 environmental samples also had transmission electron microscopy analysis. It found a total of 6 asbestos structures shorter than 5 micrometers and no asbestos structures longer than 5 micrometers.
  • The authors compared personal 8-hr time-weighted averages with and without a Kontrol Kube or negative air only for cable pulling (Table 3) and ceiling tile replacement (Table 4), the only tasks with enough samples in each group. Equal means could not be rejected: P equal to 0.18 for Table 3 and 0.16 for Table 4. The authors said the suggestion that these controls may have little, if any, impact deserves careful future study.
• The authors' conclusion: The authors concluded that a building Operations and Maintenance plan for asbestos-containing materials is an effective way to keep maintenance worker and occupant exposure to airborne asbestos acceptable. They also concluded that adding a Kontrol Kube and negative air to HEPA vacuuming and water did not have a major impact on worker exposure.
• Limitations the authors state:
  • The total time maintenance workers spent on asbestos-related tasks was not recorded, so the results describe exposure per task, not total exposure over time.
  • Phase contrast microscopy is not specific to asbestos and also counts other fibers. The authors say the reported concentrations should therefore be viewed as maximum estimates.
  • The data set made it difficult to separate out the effect of specific controls on measured exposures.

Topics

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

Related studies

• Airborne fiber control in buildings during asbestos material removal by amended water methodology — R.N. Sawyer, A.N. Rohl, et al. (1985)
• Airborne asbestos concentrations in buildings — G.J. Burdett, S.A. Jaffrey (1986)
• Development of an exposure assessment method for epidemiological studies of New York State personnel who responded to the World Trade Center disaster — M.L. Herdt-Losavio, M.P. Mauer, et al. (2008)
• Airborne asbestos in public buildings — J. Chesson, J. Hatfield, et al. (1990)
• Asbestos-related abnormalities in school maintenance personnel — L.C. Oliver, N.L. Sprince, et al. (1991)
• Asbestos exposure during brake lining maintenance and repair — A.N. Rohl, A.M. Langer, et al. (1976)

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