Potential health hazards associated with exposures to asbestos-containing drywall accessory products: A state-of-the-science assessment

Our plain-English summary of Potential health hazards associated with exposures to asbestos-containing drywall accessory products: A state-of-the-science assessment, by A.D. Phelka, B.L. Finley (Critical Reviews in Toxicology, 2012).

The study

• Authors: A.D. Phelka, B.L. Finley
• Journal: Critical Reviews in Toxicology
• Published: 2012;42(1):1-27
• Type of article: Review
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Until the late 1970s, chrysotile asbestos was an ingredient in most industrial and consumer drywall accessory products manufactured in the US. In 1977, the Consumer Product Safety Commission (CPSC) issued a ban of consumer patching compounds containing "respirable, free-form asbestos" based on their prediction of exceptionally high rates of asbestos-related diseases among individuals using patching compounds for as little as a few days. Although hundreds of thousands of workers and homeowners handling these products may have experienced exposure to asbestos prior to the ban, there has been no systematic effort to summarize and interpret the information relevant to the potential health effects of such exposures. In this analysis, we provide a comprehensive review and analysis of the scientific studies assessing fiber type and dimension, toxicological and epidemiological endpoints, and airborne fiber concentrations associated with joint compound use. We conclude that: 1) asbestos in drywall accessory products was primarily short fiber (< 5 µm) chrysotile, 2) asbestos in inhaled joint compound particulate is probably not biopersistent in the lung, 3) estimated cumulative chrysotile exposures experienced by workers and homeowners are below levels known to be associated with respiratory disease, and 4) mortality studies of drywall installers have not demonstrated a significantly increased incidence of death attributable to any asbestos-related disease. Consequently, contrary to the predictions of the CPSC, the current weight of evidence does not indicate any clear health risks associated with the use of asbestos-containing drywall accessory products. We also describe information gaps and suggest possible areas of future research.

In plain English

This was a review of published and unpublished information on chrysotile asbestos in US drywall accessory products (joint, patching and spackling compounds) made before the late 1970s. It covered formulations, bulk analyses, airborne fiber measurements during mixing, application, sanding and cleanup, animal studies, and death-certificate studies of drywall installers. Measured chrysotile in the analyzed products was 3–15%, but only three of 15 consumer-grade products in one analysis contained measurable chrysotile. Some older analyses also reported tremolite, which the authors judged likely came from talc and was likely non-asbestiform. The authors estimated cumulative chrysotile exposures of 12–26 f/cc-years for professional drywallers and 0.01 f/cc-year for lifetime home renovations. They stated these did not exceed exposures at which no asbestos-related effects were seen in other chrysotile cohorts. The reviewed mortality studies did not show increased deaths from cancer of the pleura or peritoneum, or from asbestosis, among drywall installers. However, two NIOSH analyses reported a statistically significant excess of lung cancer deaths among male drywall installers, without control for smoking. The authors concluded the evidence did not indicate any clear health risks, and called for a mesothelioma study of career drywallers.

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: Review and interpretation of published and unpublished data, with the authors' own estimates of cumulative chrysotile exposure for drywalling scenarios
• Who was studied: Historic US drywall accessory products (joint compounds, wall textures, patching and spackling materials) and the drywall workers and homeowners who used them. Airborne data came from studies run 1972–2003, all in the US except one in Alberta, Canada. Mortality data covered US drywall installers.
• Exposure: Processed (mostly Grade 7, short-fiber) chrysotile added to drywall accessory products, inhaled during mixing, application, sanding and cleanup. Some older analyses also reported tremolite or anthophyllite.
• Main results:
  • In the reviewed bulk analyses, measured chrysotile concentrations were 3–15%.
  • In the Mt. Sinai analysis reported in Rohl (1975), only three of 15 consumer-grade products contained measurable chrysotile. The authors attributed this to many of them being small cans of spackling putty.
  • Fischbein et al. (1979) reported tremolite in four of 15 industrial taping and spackling compounds, at 1–2% to 8–12%. The review authors argued that talc was the likely source and that the tremolite was likely non-asbestiform.
  • In the reviewed short-term personal air samples, mixing of dry powder products usually gave the highest fiber levels (means 1.6–89.2 f/cc).
  • In the reviewed short-term air samples, application gave the lowest fiber levels (means 0.09 to 0.9 f/cc).
  • The authors estimated cumulative exposure of 12–26 f/cc-years for professional drywallers doing all joint compound tasks. The estimate used 40-hour work-week averages of 2.1–4.5 f/cc and a median job tenure of 5.7 years.
  • The authors estimated cumulative exposure of 0.01 f/cc-year for a lifetime of do-it-yourself home renovations.
  • Pierce et al. (2008) reported no-effect levels of about 25–1000 f/cc-year for lung cancer and 15–500 f/cc-year for mesothelioma. The authors stated that none of their estimates exceeded the range at which no asbestos-related effects have been observed.
  • Robinson et al. (1995): among white male drywall installers there were no deaths attributed to cancer of the pleura or peritoneum or to asbestosis.
  • Robinson et al. (1995): no increased lung cancer mortality among 355 white male drywall installers compared with all workers (PMR 121, 95% confidence limits 82 to 171).
  • NIOSH (1997) reported a statistically significant number of deaths from cancer of the trachea, bronchus and lung among white male drywall installers over age 20 (PMR 145, 95% confidence limits 115 to 180). There were no deaths from malignant neoplasm of the pleura in this group.
  • NIOSH NOMS database: no evidence of increased mortality from malignant neoplasms of the pleura or peritoneum or from asbestosis among 3,537 male (white and black) drywall installer deaths.
  • NIOSH NOMS database: cancer of the trachea, bronchus and lung was reported as a statistically significant cause of death among drywall installers (PMR 140, 95% confidence limits 125.3 to 155.8), without control for smoking.
  • Fischbein et al. (1979) studied 114 New York drywall workers. More than 50% of those with 20 or more years in the trade, and more than 20% of those with 10–20 years, had chest X-ray abnormalities. The review authors disputed the asbestosis interpretation, citing the lack of lung function tests and the high proportion of smokers.
  • Bernstein et al. (2010), an animal inhalation study: no pathological responses in the group given chrysotile plus sanded joint compound, up to a year after exposure. Amosite exposure caused interstitial fibrosis by 28 days.
• The authors' conclusion: The authors concluded that, contrary to the CPSC's 1977 predictions, the current weight of evidence does not indicate any clear health risks from using asbestos-containing drywall accessory products.
• Limitations the authors state:
  • The standard air-sampling method (PCM) cannot tell asbestos from non-asbestos fibers and does not adequately count fibers shorter than 5 µm.
  • Bulk analysis results from modern techniques are sparse. More data on original historic products are needed, especially products containing talc.
  • There are few airborne fiber data for non-occupational (homeowner) use.
  • The mortality studies reviewed did not control for smoking.
  • No robust epidemiology study of mesothelioma in career drywallers exists; the authors listed this as an information gap.

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, Joint Compound.

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