Comparative Risks of Cancer from Drywall Finishing Based on Stochastic Modeling of Cumulative Exposures to Respirable Dusts and Chrysotile Asbestos Fibers

Our plain-English summary of Comparative Risks of Cancer from Drywall Finishing Based on Stochastic Modeling of Cumulative Exposures to Respirable Dusts and Chrysotile Asbestos Fibers, by F.W. Boelter, Y. Xia, L. Dell (Risk Analysis, 2015).

The study

• Authors: F.W. Boelter, Y. Xia, L. Dell
• Journal: Risk Analysis
• Published: 2015;35(5):859-71
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Sanding joint compounds is a dusty activity and exposures are not well characterized. Until the mid 1970s, asbestos-containing joint compounds were used by some people such that sanding could emit dust and asbestos fibers. We estimated the distribution of 8-h TWA concentrations and cumulative exposures to respirable dusts and chrysotile asbestos fibers for four worker groups: (1) drywall specialists, (2) generalists, (3) tradespersons who are bystanders to drywall finishing, and (4) do-it-yourselfers (DIYers). Data collected through a survey of experienced contractors, direct field observations, and literature were used to develop prototypical exposure scenarios for each worker group. To these exposure scenarios, we applied a previously developed semi-empirical mathematical model that predicts area as well as personal breathing zone respirable dust concentrations. An empirical factor was used to estimate chrysotile fiber concentrations from respirable dust concentrations. On a task basis, we found mean 8-h TWA concentrations of respirable dust and chrysotile fibers are numerically highest for specialists, followed by generalists, DIYers, and bystander tradespersons; these concentrations are estimated to be in excess of the respective current but not historical Threshold Limit Values. Due to differences in frequency of activities, annual cumulative exposures are highest for specialists, followed by generalists, bystander tradespersons, and DIYers. Cumulative exposure estimates for chrysotile fibers from drywall finishing are expected to result in few, if any, mesothelioma or excess lung cancer deaths according to recently published risk assessments. Given the dustiness of drywall finishing, we recommend diligence in the use of readily available source controls.

© 2014 Society for Risk Analysis.

In plain English

This study modeled exposure; it did not study disease. The authors surveyed 11 contractors and observed drywall work at four sites, one a simulated do-it-yourself bathroom. They built scenarios for specialists, generalists, bystander tradespersons and do-it-yourselfers (DIYers). A model estimated respirable sanding dust, converted to chrysotile levels by a factor from a re-created chrysotile-containing joint compound. Estimated mean 8-hour chrysotile levels were 0.28 fibers per cubic centimeter (f/cm3) for specialists, 0.22 for generalists, 0.15 for DIYers and 0.069 for bystanders. The authors called these above today's 0.1 f/cm3 limit (not the bystander mean) but within the limit when asbestos compounds were used. Specialists' estimated yearly exposure was 0.088 f/cm3-years, about 3.5 over a hypothetical 40 years; the authors considered 2.2 to 2.6 a more likely career maximum, since asbestos compounds were used only 25 to 30 years, post-World War II to the mid 1970s. The authors concluded these exposures were not in the range associated with elevated lung cancer or mesothelioma rates. They noted the conversion factor came from one joint compound and that respirator use was not modeled.

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-modeling (stochastic simulation) study using a contractor survey, field observations and literature to build exposure scenarios; no disease outcomes were measured in workers
• Who was studied: 11 drywall contractors surveyed (16 contacted) in March or April 2008. Observations at three drywall job sites (2008 to 2009) plus a simulated do-it-yourself bathroom in a testing facility. Modeled groups were drywall specialists, generalists, bystander tradespersons and do-it-yourselfers
• Exposure: Respirable dust and chrysotile asbestos fibers from sanding drywall joint compound. Fiber levels were not measured directly but estimated from dust levels using a factor (median 0.044 f/cm3 per mg/m3) that relates fibers from a reformulated asbestos-containing joint compound to dust from a modern asbestos-free joint compound
• Main results:
  • Drywall specialists: estimated mean 8-hour respirable dust 6.40 mg/m3 (central 90% range 0.45 to 19.5); mean 8-hour chrysotile 0.28 f/cm3 (central 90% range 0.020 to 0.86)
  • Generalists: estimated mean 8-hour respirable dust 5.02 mg/m3 (central 90% range 0.26 to 18.5); mean 8-hour chrysotile 0.22 f/cm3 (central 90% range 0.011 to 0.81)
  • Bystander tradespersons: estimated mean 8-hour respirable dust 1.56 mg/m3; mean 8-hour chrysotile 0.069 f/cm3 (central 90% range 0.0030 to 0.24)
  • DIYers: estimated mean 8-hour respirable dust 3.32 mg/m3; mean 8-hour chrysotile 0.15 f/cm3 (central 90% range 0.015 to 0.48)
  • The authors stated that the estimated 8-hour chrysotile concentrations exceeded the current TLV of 0.1 f/cm3 but were within the TLV in force when asbestos-containing joint compounds were used
  • Predicted respirable dust levels suggested all worker groups may be exposed above the dust TLV of 3 mg/m3 on sanding days
  • Estimated annual cumulative chrysotile exposure for drywall specialists was 0.088 f/cm3-years
  • Mean cumulative exposures of specialists were four-fold those of generalists
  • Cumulative exposures of bystander tradespersons were about one-tenth of those of specialists
  • A specialist would accrue about 3.5 f/cm3-years over a hypothetical 40 years of work with asbestos-containing joint compound
  • The authors noted that asbestos-containing joint compound could have been used for at most 25 to 30 years, after World War II through the mid 1970s
  • The authors considered a maximum of 2.2 to 2.6 f/cm3-years more likely for a specialist, assuming the 40-year career spanned the period from after World War II through the mid 1970s
  • At the observed job sites, workers spent 4 to 11% of project time sanding joint compound
• The authors' conclusion: The authors concluded that estimated cumulative chrysotile exposures from drywall finishing were not in the range associated with elevated rates of lung cancer or mesothelioma. They recommended continued diligence in using source controls and personal protective equipment because of the dust levels.
• Limitations the authors state:
  • The fiber-to-dust factor and the exposure model were based on one particular asbestos-free joint compound and one reformulated chrysotile-containing joint compound; other formulations may differ
  • Respirator use was not factored into the modeled exposures
  • The estimates are not meant to describe any single individual's exposure history
  • The survey involved relatively small numbers of participants
  • Exposures from preparing dry-mix joint compound were not included
  • Concentrations may be somewhat higher when several workers sand in the same area
  • Risks for drywall workers may differ from those of non-drywall workers at the same cumulative exposure, so comparisons with risk estimates from other workers may be inappropriate

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Cumulative Exposure, Chrysotile, Joint Compound, Threshold Limit Value (TLV), Mesothelioma, Lung Cancer.

Related studies

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• A comparative study of the clearance of respirable para-aramid, chrysotile and glass fibres from rat lungs — A. Searl (1997)
• Evaluation of the deposition, translocation and pathological response of brake dust with and without added chrysotile in comparison to crocidolite asbestos following short-term inhalation: interim results — D.M. Bernstein, R. Rogers, et al. (2014)
• Evaluation of the dose-response and fate in the lung and pleura of chrysotile-containing brake dust compared to chrysotile or crocidolite asbestos in a 28-day quantitative inhalation toxicology study — D.M. Bernstein, B. Toth, et al. (2018)
• Cytotoxicity of respirable dusts from industrial minerals: comparison of two naturally occurring and two man-made silicates — D. Nadeau, L. Fouquette-Couture, et al. (1987)

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