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

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.

An updated evaluation of potential health hazards associated with exposures to asbestos-containing drywall accessory products

“…The authors noted that their estimate was "an order of magnitude lower" than the value of 12-26 f/cc-year presented earlier in Phelka and Finley (2012). They attributed this difference to Verma and Middleton's assumption that a drywaller would spend 25-30% of their week performing sanding tasks, which was far greater than the value of 1-11% determined by Boelter et al (2015). It is unclear why their observations differed.…”

“…The authors concluded that the fiber concentrations estimated with the new model were not significantly different from fiber concentrations measured during the historical use of asbestos-containing joint compound, for both enclosed and non-enclosed environments (Brorby et al 2012). Boelter et al (2015) calculated cumulative asbestos exposures for the sanding tasks performed by drywallers based on previously published survey data, direct field observations from contemporary construction worksites, and a semi-empirical mathematical model (Boelter et al 2015). At each worksite, the investigator recorded the dimensions of the floor and wall area, and task-specific durations (drywall installation, tape and joint compound application, sanding, and other activities), and calculated the sanding speed for the drywaller.…”

“…It is important to note that, in addition to addressing asbestos exposure during sanding work, the Phelka and Finley (2012) cumulative exposure estimate also accounted for potential exposures during mixing, application, and clean-up tasks. Further, the Phelka and Finley (2012) estimate relied on PCM data, while Boelter et al (2015) reported chrysotile-specific data.…”

“…We utilized exposure and task duration values reported in Verma and Middleton (1980) and Boelter et al (2015), and job tenure data from Carey (1988) and Maguire (1993) to estimate upper and lower bound cumulative asbestos exposures for career drywallers (Verma and Middleton 1980;Carey 1988;Maguire 1993;Boelter et al 2015). The lower bound estimate is intended to apply to drywallers who performed wallboard cutting and hanging tasks and joint compound work, while the upper bound estimate applies to workers who only performed joint compound finishing work.…”

A Bayesian Model and Stochastic Exposure (Dose) Estimation for Relative Exposure Risk Comparison Involving Asbestos‐Containing Dropped Ceiling Panel Installation and Maintenance Tasks

“…The predicted eight‐hour TWA airborne asbestos fibers concentrations are not above current or historical occupational exposure limits (OELs). Estimated exposures (dose) to airborne asbestos fibers are not in the range associated with elevated rates of lung cancer or mesothelioma . Although relative exposure risks are very low regarding the handling of ceiling panels, continued diligence in the use of built environment bulk material survey techniques as well as management and abatement methods are appropriate precautions as conditions above the ceiling may be unknown.…”