Impact of asbestos concentrations in floor tiles on exposure during removal

Our plain-English summary of Impact of asbestos concentrations in floor tiles on exposure during removal, by J.H. Lange (International Journal of Environmental Health Research, 2002).

The study

• Author: J.H. Lange
• Journal: International Journal of Environmental Health Research
• Published: 2002;12(4):293-300
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This study investigated personal airborne exposure to asbestos during its abatement in two projects that had floor tile with different concentrations of asbestos. Abatement of floor tile with the higher percent asbestos exhibited the highest personal exposure level. Airborne exposure concentrations of asbestos between these abatement projects were found to be statistically significant. However, since neither had levels above occupational exposure standards this difference was not considered important, a type two error (false positive). It is suggested that when establishing negative exposure assessments, priority be given to process/work practices, with percent of contaminant in the building component being of less importance. Time period of applicability of data from negative exposure assessments to future projects should be considered indefinite. Neither within- or between-worker variation was predominant, in this study. Likelihood of exceeding occupational exposure standards during abatement of asbestos-containing floor tile, even for materials containing up to 15% asbestos, is low. Regulation of floor tile as a special category or group of asbestos-containing material appears to be warranted. Current schemes in the United States that regulate floor tile in the same group as other asbestos-containing materials would appear to be a legislating of science.

In plain English

The author measured airborne fiber levels in workers' breathing zones while asbestos floor tile was removed at two schools in western Pennsylvania in summer 2001. The tile at school 1 contained 10–15% chrysotile asbestos and the tile at school 2 contained 3–5% chrysotile. At both schools, workers scraped the tile up by hand with ice scrapers, using little water. The 11 personal samples at school 1 averaged 0.032 fibers per cubic centimeter (f/cc) and the 14 at school 2 averaged 0.015 f/cc, a statistically significant difference. No sample exceeded the OSHA limits (0.1 f/cc as a time-weighted average, 1.0 f/cc over 30 minutes). The author judged the difference unimportant because both schools stayed below these limits. The author also noted that some tile at school 2 did not contain asbestos, which may have contributed to the difference. The author concluded that the percent of asbestos in floor tile is not an important factor in OSHA 'negative exposure assessments' and called for further studies.

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: Field exposure-monitoring study comparing personal air samples from two floor tile abatement projects with different asbestos content in the tile
• Who was studied: Workers removing floor tile at two schools in western Pennsylvania, USA, during summer 2001. Removal in each area took 3–5 days with three to eight workers per day. There were 11 personal samples at school 1 and 14 at school 2, plus 2 and 3 excursion (30-minute) samples respectively.
• Exposure: Removal of floor tile containing chrysotile asbestos: 10–15% at school 1 and 3–5% at school 2. Tile was taken up manually by scraping and lifting with ice scrapers, with little if any water, and some well-adhered tile was pounded with hammers.
• Main results:
  • School 1 (10–15% chrysotile tile): 11 personal samples, arithmetic mean 0.032 f/cc, geometric mean 0.027 f/cc, range 0.009–0.076 f/cc
  • School 2 (3–5% chrysotile tile): 14 personal samples, arithmetic mean 0.015 f/cc, geometric mean 0.014 f/cc, range 0.006–0.055 f/cc
  • Personal exposures at the two schools were statistically different (p less than 0.05)
  • No sample at either school exceeded the OSHA permissible exposure limit or excursion limit
  • The OSHA limits used for comparison were 0.1 f/cc as a time-weighted average (PEL) and 1.0 f/cc for 30 minutes per day (excursion limit)
  • Excursion (30-minute) samples, school 1: 2 samples, arithmetic mean 0.136 f/cc
  • Excursion (30-minute) samples, school 2: 3 samples, arithmetic mean 0.133 f/cc, range 0.045–0.221 f/cc
  • Confidence intervals of personal exposure, as printed: school 1, 0.012 (range 0.024–0.044); school 2, 0.007 (range 0.008–0.022)
  • Using summary task-length average values, the estimated probability that at least 5% of employees would be exposed over the PEL was 45% for school 1 and 30% for school 2
  • Between-worker and within-worker variability were similar at both schools, so it could not be determined whether individual practices or the process was the source of exposure
• The authors' conclusion: The author concluded that, given the low exposure levels, percent asbestos content in floor tile is not an important factor when formulating a negative exposure assessment for this material
• Limitations the authors state:
  • Some floor tile at school 2 did not contain asbestos, which may have contributed at least in part to the statistical difference
  • Additional studies are needed to confirm the findings
  • Excursion limit samples were too few to compare statistically
  • Most fibers counted were likely not asbestos, so the calculated probability of overexposure was described as an overestimate
  • Not all workers were included in the between-worker calculations

Topics

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

Related studies

• 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 meta-analysis of airborne asbestos fiber concentrations from work with or around asbestos-containing floor tile — A.L. Perez, M.L. Nelson, et al. (2018)
• 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)
• Exposure to airborne asbestos during removal and installation of gaskets and packings: a review of published and unpublished studies — A.K. Madl, K. Clark, et al. (2007)
• Air sampling during asbestos abatement of floor tile and mastic — J.H. Lange, K.W. Thomulka (2000)
• Asbestos abatement of pipe and floor tile/mastic and comparison of critical plastic barrier controls — J.H. Lange (2004)

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