1. Indian Health Service, Office of Environmental Health and Engineering, Phoenix, AZ, USA
2. Department of Preventive Medicine and Biostatistics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
3. Industrial Hygiene Department, Naval Medical Center–San Diego, San Diego, CA, USA
4. Indian Health Service, Office of Environmental Health and Engineering, Rockville, MD, USA