June 13, 2024

NIOSH Report Addresses Silica Exposures during Drywall Sanding

A recent health hazard evaluation (HHE) report by NIOSH includes recommendations for controlling respirable crystalline silica (RCS) exposures among employees engaged in drywall sanding, based on the agency’s assessment of a hospital construction site in early 2023. At the request of a drywall finishing company, NIOSH evaluated a crew of three employees responsible for sanding prepared drywall before painting. Two of these employees used sandpaper and sanding foam blocks for this task. The other employee used a power drywall sander attached to a vacuum with a high-efficiency particulate air (HEPA) filter. Sampling by NIOSH staff showed that one worker was overexposed to RCS and all three had RCS exposures surpassing OSHA’s action level, requiring their employer to take steps to protect their health. None of the workers reported health symptoms when interviewed by NIOSH staff. However, RCS exposure is associated with silicosis, lung cancer, and other lung diseases and with kidney and autoimmune diseases, the report explains.

NIOSH advised the drywall finishing company to adjust work practices to keep employees’ RCS exposures below OSHA exposure limits. The evaluators had observed employees standing on scaffolding to hand sand the higher sections of drywall, while their coworkers stood directly below them to hand sand lower sections of the same surface. The report recommends the employer address this issue by equipping workers with pole sanding equipment. To prevent workers from shaking dust off their clothing at the end of their shift, the employer should provide a vacuum fitted with a HEPA filter to clean their dusty clothing. The company should also provide clearer employee guidance for using the power drywall sander, such as by equipping the vacuum with a disposable bag that would be regularly changed.

Due to previous exposure monitoring results, the workers engaged in drywall sanding at the hospital construction site were not required to wear respirators during sanding activities. One worker voluntarily wore a filtering facepiece respirator, but NIOSH staff observed this worker wearing the device incorrectly. The HHE report notes that, based on the results of NIOSH’s sampling, the employer must implement a respiratory protection program until further sampling shows that RCS exposures are below OSHA’s permissible exposure limit.

Other recommendations in the report cover the implementation of regular RCS exposure monitoring and address other health and safety issues that NIOSH staff observed during the evaluation. These include preventing non-employees from entering areas where drywall sanding was occurring and providing employees with head lamps so that they have direct light when working.

The HHE report may be downloaded as a PDF from NIOSH’s HHE report archive.