Respirable Silica Dust Suppression During Artificial Stone Countertop Cutting

Details

• Personal Author:
  Cooper, Jared H. ; Johnson, Douglas L. ; Phillips, Margaret L.
• Description:
  Purpose: To assess the relative efficacy of three types of controls in reducing respirable silica exposure during artificial stone countertop cutting with a handheld circular saw. Approach: A handheld worm drive circular saw equipped with a diamond segmented blade was fitted with water supply to wet the blade as is typical. The normal wetted-blade condition was compared to (i) wetted-blade plus 'water curtain' spray and (ii) wetted-blade plus local exhaust ventilation (LEV). Four replicate 30-min trials of 6-mm deep, 3-mm wide cuts in artificial quartz countertop stone were conducted at each condition in a 24-m3 unventilated tent. One dry cutting trial was also conducted for comparison. Respirable cyclone breathing zone samples were collected on the saw operator and analyzed gravimetrically for respirable mass and by X-ray diffraction for respirable quartz mass. Results: Mean quartz content of the respirable dust was 58.5%. The ranges of 30-min mass and quartz task concentrations in mg m-3 were as follows - wet blade alone: 3.54-7.51 and 1.87-4.85; wet blade + curtain: 1.81-5.97 and 0.92-3.41; and wet blade + LEV: 0.20-0.69 and <0.12-0.20. Dry cutting task concentrations were 69.6mg m-3 mass and 44.6mg m-3 quartz. There was a statistically significant difference (a = 0.05) between the wet blade + LEV and wet blade only conditions, but not between the wet blade + curtain and wet blade only conditions, for both respirable dust and respirable silica. Conclusions: Sawing with a wetted blade plus LEV reduced mean respirable dust and quartz task exposures by a factor of 10 compared to the wet blade only condition. We were unable to show a statistically significant benefit of a water curtain in the ejection path, but the data suggested some respirable dust suppression. Correction https://doi.org/10.1093/annweh/wxae036: In the originally published version of this article, there is an error in Table 2, in the lines for "Mean" and "SEM", which were reproduced from Table 1 and correspond to a different set of data. The correct version of Table 2 is provided at this DOI. [Description provided by NIOSH]
• Subjects:
  Dust Engineering Occupational Health Quartz Safety Silicon Dioxide
• Keywords:
  Author Keywords: Countertop Cutting; Engineering Controls; Respirable Silica Silica Dusts; Respirable Dust; Stone Processing; Quartz Dust; Dust Control; Dust Exposure; Control Methods; Engineering Controls; Control Technology;
• ISSN:
  0003-4878
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Oklahoma ; OSHA Region 6
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  5 pdf pages
• NIOSHTIC Number:
  nn:20045221
• Citation:
  Ann Occup Hyg 2015 Jan; 59(1):122-126
• Contact Point Address:
  David L. Johnson, Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, 801 NE 13th Street, Oklahoma City, OK 73104, USA
• Email:
  David-Johnson@ouhsc.edu
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2015
• Performing Organization:
  University of Oklahoma Health Sciences Center
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Annals of Occupational Hygiene
• End Date:
  20290630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ba2c82fdb2f84122618e729bb4fb1ea0b0dfd335390e3e1cf55be406cfbc1e270e3acce88a4679902e22754eb59abe93344ea29e32e61d12bc999149efe6bb28
• Download URL:
  https://stacks.cdc.gov/view/cdc/231616/cdc_231616_DS1.pdf
• File Type:
  [PDF - 756.69 KB ]