1. Division of Occupational and Environmental Medicine, Department of Medicine; San Francisco General Hospital, University of California; San Francisco, San Francisco, California
2. California Department of Public Health; Occupational Health Branch; Richmond; California
3. University of California and Kaiser Permanente Combined Preventive Medicine/Internal Medicine Residency Program; San Francisco; California
4. Department of Emergency Medicine; University of California; Irvine Medical Center; Orange, California
5. Public Health Institute; Oakland; California