1. United States Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Western States Division , Denver, CO , USA
2. Synergy America, Inc. , Duluth, GA , USA
3. United States Department of the Interior, Office of Wildland Fire , Denver, CO , USA
4. United States Department of the Interior, Office of Occupational Safety and Health , Denver, CO , USA