Airborne fiber control in buildings during asbestos material removal by amended water methodology

Our plain-English summary of Airborne fiber control in buildings during asbestos material removal by amended water methodology, by R.N. Sawyer, A.N. Rohl, A.M. Langer (Environmental Research, 1985).

The study

• Authors: R.N. Sawyer, A.N. Rohl, A.M. Langer
• Journal: Environmental Research
• Published: 1985;36(1):46-55
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004120).

Abstract

Removal of friable asbestos-containing material can cause high levels of airborne contamination. The potential efficacy of control methods recommended by the Environmental Protection Agency (EPA) was evaluated by examination of 503 air samples obtained in 40 removal projects in a number of locations. The EPA methodology with amended water for fiber emission control was utilized on all of the observed removal projects. The projects were also considered to be well controlled and the study cannot be considered representative of common work practices. The EPA amended water methodology, when effectively utilized and administered, can provide a high degree of contamination control. Mean fiber levels in the work area in this study (1.1 f/cm3) were well below those of dry removal (38.9 f/cm3) and control by application by untreated water (28.6 f/cm3). Airborne contamination was higher during bagging debris (3.8 f/cm3) than during material removal from structural surfaces. The range of fiber levels during removal was 0.0 to 37.0 f/cm3 and fibers were detected from initial barrier construction through final cleaning. Contamination was also occasionally detected outside work area containment barriers. Air sampling produced 0.0 counts in areas of obvious contamination by settled dust and debris. Control methodologies, respiratory protection, and decontamination are discussed.

In plain English

This study measured airborne fibers during removal of friable asbestos fireproofing and insulation from buildings using the U.S. Environmental Protection Agency's recommended wet method, which uses "amended water" (water with a surfactant). The authors analyzed 503 air samples from 40 removal projects by 11 contractors in 21 cities in 10 states. Chrysotile was the only asbestos type in 32 of the 40 projects. In the work area during wet removal, counts averaged 1.1 fibers per cubic centimeter (226 samples, range 0.0 to 37.1). During clean-up and bagging of debris they averaged 3.9. Fibers were detected during barrier construction (average 0.6) and outside the barriers during removal and bagging (average 0.1). Other studies had recorded 38.9 for dry removal and 28.6 with untreated water. Readings of 0.0 were obtained repeatedly where settled debris was present. No statistically significant link was shown between fiber counts and asbestos content or type. The authors concluded that the method, effectively used and administered, can give a high degree of contamination control. They noted that their projects were well controlled and not representative of common work practices.

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 air-monitoring study of asbestos removal projects, with comparison to fiber counts from other studies of dry removal and untreated-water removal
• Who was studied: 40 asbestos removal projects carried out by 11 contractors in schools and private, commercial and public buildings in 21 cities in 10 US states; 503 air samples. Dates of the projects are not given.
• Exposure: Removal of friable asbestos fireproofing or insulation using EPA amended-water methods. Mean asbestos content was 28% (SD 18%), with a range of 8 to 85%. Chrysotile alone was found in 32 of 40 projects (80%). Amphibole asbestos, alone or with chrysotile, was found in 8 projects (20%); amosite was the predominant amphibole, anthophyllite and tremolite were also seen, and crocidolite was found in one application.
• Main results:
  • Work area during wet (amended water) removal: mean 1.1 f/cm3. For comparison, uncontrolled dry removal gave 38.9 f/cm3 and untreated water gave 28.6 f/cm3; these comparison figures come from other studies.
  • Work area fiber counts ranged from 0.0 to 37.1 f/cm3 during amended-water removal (226 samples). Scraping dry, highly friable material in other studies ranged from 8.1 to 117.8 f/cm3.
  • Clean-up and bagging of debris in the work area: mean 3.9 f/cm3 (8 samples). The authors attributed this to delays in containment that allowed debris to dry.
  • Fibers were detected in the work area during barrier erection and sealing (mean 0.6 f/cm3).
  • Outside the containment barriers, counts averaged 0.1 f/cm3 during removal and bagging.
  • In the work area during wet removal, 85% of samples were below 2.0 f/cm3 and 99% were below 20.0 f/cm3.
  • Personal samples averaged 1.6 f/cm3 (13 samples, range 0.7 to 2.9). Area samples averaged 1.1 f/cm3 (213 samples, range 0.0 to 37.1).
  • Samples taken by removal contractors averaged 0.5 f/cm3 (161 samples). Samples taken by consultants averaged 2.0 f/cm3 (18 samples). Consultants tended to sample closer to active work and only during work.
  • No statistically significant relationship was shown between fiber counts and asbestos content or asbestos type. Material thickness appeared to correlate with higher fiber levels.
  • Air samples reading 0.0 f/cm3 were obtained repeatedly where settled debris was present.
• The authors' conclusion: The authors concluded that the EPA amended-water method, when effectively used and administered, can provide a high degree of contamination control. They also concluded that respiratory protection and decontamination are necessary throughout a removal project.
• Limitations the authors state:
  • The projects studied were considered well controlled, and the authors state the study cannot be considered representative of common work practices.
  • Where and when samples were taken affected results. Contractors who placed pumps at the edge of the work zone and sampled through all activity levels appear to have diluted and reduced fiber counts.
  • A 0.0 reading by standard optical microscopy did not show that contamination was controlled or that the environment was clean.

Topics

Medical terms in this study, explained in our Lexicon: Friable, Air Sampling, Settled Dust, Respirator.

Related studies

• Worker exposure to asbestos during removal of sprayed material and renovation activity in buildings containing sprayed material — N.W. Paik, R.J. Walcott, et al. (1983)
• Airborne asbestos in public buildings — J. Chesson, J. Hatfield, et al. (1990)
• Composition of heavy metals and airborne fibers in the indoor environment of a building during renovation — M.T. Latif, N.H. Baharudin, et al. (2011)
• Airborne asbestos concentrations in buildings — G.J. Burdett, S.A. Jaffrey (1986)
• Asbestos exposure of building maintenance personnel — S. Mlynarek, M. Corn, et al. (1996)
• 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)

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