Experimental Evaluation of Respirable Dust and Crystalline Silica Controls During Simulated Performance of Stone Countertop Fabrication Tasks with Powered Hand Tools

Details

• Personal Author:
  Hawley DA ; Johnson, Douglas L. ; Phillips ML ; Qi C ; Van AT
• Description:
  Objectives: Workers who fabricate stone countertops using hand tools are at risk of silicosis from overexposure to respirable crystalline silica. This study explored the efficacy of simple engineering controls that can be used for dust suppression during use of hand tools by stone countertop fabricators. Methods: Controlled experiments were conducted to measure whether wet methods and on-tool local exhaust ventilation (LEV) reduced respirable dust (RD) exposures during use of various powered hand tools on quartz-rich engineered stone. RD samples collected during edge grinding with a diamond cup wheel and a silicon carbide abrasive wheel were analyzed gravimetrically as well as by X-ray diffraction to determine silica content. A personal optical aerosol monitor was used simultaneously with the RD samples and also for rapid assessment of controls for polishing, blade cutting, and core drilling. Results: On-tool LEV and sheet-flow-wetting were effective in reducing exposures, especially when used in combination. Sheet-flow-wetting with LEV reduced geometric mean exposures by as much as 95%. However, typical water-spray-wetting on a grinding cup was less effective when combined with LEV than without LEV. Mean silica content of RD samples from grinding operations was 53%, and respirable mass and silica mass were very highly correlated (r = 0.980). Optical concentration measures were moderately well correlated with gravimetric measures (r = 0.817), but on average the optical measures during a single trial using the factory calibration were only one-fifth the simultaneous gravimetric measures. Conclusions: Sheet-flow-wetting combined with on-tool LEV is an effective engineering control for reducing RD exposures during engineered stone edge grinding and blade cutting. On the other hand, addition of LEV to some water-spray-wetted tools may reduce the effectiveness of the wet method. [Description provided by NIOSH]
• Subjects:
  Aerosols Dust Engineering Environmental Exposure Occupational Health Quartz Risk Assessment Risk Factors Safety Silicon Dioxide Ventilation

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• Keywords:
  Author Keywords: Crystalline Silica Crystalline Silica Dust Suppression Engineering Controls Exhaust Ventilation Exposure Levels Gravimetry Grinding Equipment Hand Tools Local Exhaust Ventilation Monitors Power Tools Quartz Dust Respirable Dust Risk Factors Silicon Carbide Silicosis Stone Dust Stone Products

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• ISSN:
  2398-7308
• Document Type:
  Text
• Funding:
  Contract ; Grant
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DART - Division of Applied Research and Technology
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  61
• Issue:
  6
• NIOSHTIC Number:
  nn:20050015
• Citation:
  Ann Work Expo Health 2017 Jul; 61(6):711-723
• Contact Point Address:
  David L. Johnson, Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, PO Box 26901, Oklahoma City, OK 72126-0901
• Email:
  David-Johnson@ouhsc.edu
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2017
• NORA Priority Area:
  Construction ; Manufacturing
• Performing Organization:
  University of Oklahoma Health Sciences Center
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Annals of Work Exposures and Health
• End Date:
  20290630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:8baffad9b8d7ade6ada15e81ec6318fda7910aaca8314a9abc5307e72d722dcdd8435e531f8a4f6773fe77eb01faa7cdee492ef0ae5e6867c5f07cf561f004ce
• Download URL:
  https://stacks.cdc.gov/view/cdc/210569/cdc_210569_DS1.pdf
• File Type:
  [PDF - 825.80 KB ]