Personal airborne asbestos exposure levels associated with various types of abatement

Our plain-English summary of Personal airborne asbestos exposure levels associated with various types of abatement, by J.H. Lange, K.W. Thomulka, S.L. Sites, et al (Bulletin of Environmental Contamination and Toxicology, 2006).

The study

• Authors: J.H. Lange, K.W. Thomulka, S.L. Sites, G. Priolo, G. Mastrangelo
• Journal: Bulletin of Environmental Contamination and Toxicology
• Published: 2006;76(3):389-91
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This report gave personal air sampling results for workers removing asbestos-containing materials. Fibers were counted by PCM, which the authors noted counts all fibers equally. The supplied text lacks its introduction and methods, is partly garbled, and has a mostly scrambled results table. Materials included floor tile, mastic, insulation, ceiling tile, caulking, roofing and transite pipe. Most samples were below detection limits, and the highest levels were linked to pipe and boiler insulation. Pipe insulation samples averaged 0.014 fibers per cc (arithmetic mean), range below 0.005 to 0.053. The authors estimated a "probability of overexposure": the chance that at least 5% of employees would exceed the PEL exposure limit. It was below 5% for every material except pipe insulation, at about 27%, or about 10% using the geometric mean. They linked this to high day-to-day variation and said a single sample was unlikely to represent true average exposure. Relying on suggested disease-causation thresholds from a cited publication, the authors concluded these workers were unlikely to be at risk even over 40 years, and suggested abatement is in many cases over-regulated.

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: Exposure assessment: summary statistics of personal air samples (in fibers per cc) taken during asbestos abatement. The methods section is missing from the supplied text.
• Who was studied: Asbestos abatement workers. The number of workers, the location and the dates are not available in the supplied text.
• Exposure: Airborne fibers during abatement of asbestos-containing materials, counted by PCM, which the authors note counts all fibers equally. The materials were floor tile/mastic, pipe insulation, ceiling tile, pipe/boiler insulation, floor tile/fittings/caulking, window caulking, roofing, transite pipe and mastic. Fiber types are not specified.
• Main results:
  • Most samples were below detection limits.
  • The highest exposure levels were associated with pipe and boiler insulation.
  • Pipe insulation (Table 1): arithmetic mean 0.014 f/cc, geometric mean 0.010 f/cc, SD 0.012, range below 0.005 to 0.053 f/cc, GSD 2.5. The number of samples for this row cannot be reliably read from the scrambled table.
  • The estimated probability of overexposure was below 5% for all material types except pipe insulation, where it was about 27%.
  • The authors defined the 27% as the probability that at least 5% of employees would be exposed above the PEL. It is not an individual worker's chance of exceeding the PEL.
  • For pipe insulation, using the geometric mean instead lowered this probability to about 10%.
  • The authors attributed the higher probability for pipe insulation to high day-to-day variation.
  • The authors stated that the exposure results were similar to those of previous studies of similar building materials.
• The authors' conclusion: The authors based their conclusion on suggested threshold levels for causation of asbestos-related disease taken from a cited publication. On that basis they concluded that these workers were unlikely to be at risk even with 40 years in the industry, and said this suggests that abatement of asbestos-containing material is in many cases over-regulated.
• Limitations the authors state:
  • Because of the high variation for pipe insulation, a single sample is unlikely to represent the true average exposure.
  • The values are TLA values. The authors state that converting them to TWA values would give lower concentrations.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Abatement.

Related studies

• Personal exposure during abatement of various asbestos-containing materials in the same work area — J.H. Lange, K.W. Thomulka, et al. (2005)
• Exposure to airborne asbestos during abatement of ceiling material, window caulking, floor tile and roofing material — J.H. Lange, S.L. Sites, et al. (2008)
• A study of personal and area airborne asbestos concentrations during asbestos abatement: a statistical evaluation of fibre concentration data — J.H. Lange, P.R. Lange, et al. (1996)
• Airborne exposure concentrations during asbestos abatement of ceiling and wall plaster — J.H. Lange, K.W. Thomulka (2002)
• Exposure to airborne asbestos during abatement of ceiling material, window caulking, floor tile, and roofing material — J.H. Lange, S.L. Sites, et al. (2006)
• Airborne asbestos levels in school buildings in Italy — A. Campopiano, S. Casciardi, et al. (2004)

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