1. a Environmental and Occupational Health Sciences (M/C 922), University of Illinois at Chicago, 2121 W. Taylor, Chicago, IL 60612
2. b Current address—Air and Radiation Division, Region 5 U.S. Environmental Protection Agency, AR-18J, 77 W. Jackson Blvd., Chicago, IL 60604-3590
3. c Current address—Bureau of Health Compliance, North Carolina Department of Labor, 901 Blairhill Rd., Suite 200, Charlotte, NC 28217