1. University of California San Francisco, School of Nursing, Department of Community Health, and University of California San Francisco, School of Medicine, San Francisco, California.
2. Occupational and Environmental Health Program, University of California San Francisco, School of Nursing, Department of Community Health Systems, San Francisco, CA.
3. California Department of Health Services, Occupational Health Surveillance Branch, Oakland, CA.
4. California Department of Health Services, Occupational Health Surveillance Branch, Oakland, CA, and University of California San Francisco, Division of Occupational and Environmental Medicine, San Francisco, CA.