1. Department of Medicine and Department of Environmental and Occupational Health Sciences, The University of Washington , Seattle, WA 98195 , USA
2. Washington State Department of Labor and Industries, Safety and Health Assessment and Research for Prevention (SHARP) Program , Olympia, WA 98501 , USA
3. Virginia Mason Franciscan Occupational Medicine Associates , Tacoma, WA 98003 , USA
4. Department of Environmental and Occupational Health Sciences, University of Washington , Seattle, WA 98195 , USA