http://www.bt.cdc.gov/disasters/handhygienefacts.asp
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Centers for Disease Control and Prevention, U.S. Department of Health and Human Services
After an emergency, finding running water can be difficult. However, keeping your hands clean helps you avoid getting sick. It is best to wash your hands with soap and water for 20 seconds. However, when water is not available, you can use alcohol-based hand products made for washing hands (sanitizers).