The University of Iowa

Lab News - This 20-Second Activity Can Prevent the Spread of Contaminaiton

Hand washing is an essential component of laboratory safety. In fact, this 20-second activity is considered one of the most important procedures used to prevent microbiological agents, radioactive materials, and chemicals from contaminating you and the surrounding environment. Unfortunately, despite its importance, a recent study revealed laboratory workers often fail to follow hand washing policies 1. So, in recognition of Global Hand Washing Day (celebrated annually on October 15), EHS Biosafety staff wanted to remind everyone about the importance of hand washing.

Although appropriate gloves should be worn when handling hazardous materials, gloves do not eliminate the need for regular and proper hand washing. Failure to wash your hands after removing your gloves may result in transmission of pathogens from your hands to your mucous membranes, causing infection, or contamination of nearby surfaces, posing a risk to others in the lab.

Hands must be washed with soap and running water after handling chemicals, biohazardous materials or animals, before leaving the laboratory; and before eating. In most situations, thorough washing of hands with ordinary soap and water is sufficient to decontaminate them, but the use of germicidal soaps is recommended in high-risk situations. Alcohol-based hand-rubs should be used to decontaminate lightly soiled hands when proper hand washing is not available.

To prevent the spread of contamination, follow these hand washing steps:

  • Wet your hands and wrists with running water.
  • Apply soap to your hands (Note: Liquid soap is preferred over bar soap).
  • Work soap into a lather.
  • Scrub your hands and wrists vigorously for at least 20-30 seconds. (Tip: sing or hum the “Happy Birthday” song from beginning to end twice).
  • Rinse your hands well under running water.
  • Dry your hands with a clean, dry paper towel.
  • If applicable, use the paper towel to turn off the faucet.



1. Johnston, J. D., Merrill, R. M., Zimmerman, G. C., Collingwood, S. C. & Reading, J. C. Factors associated with biosafety level-2 research workers’ laboratory exit handwashing behaviors and glove removal compliance. J. Occup. Environ. Hyg. 13, 254–264 (2016).