In the Laboratory
Hand Washing Warning Ben Ruekberg Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
[email protected] It is universally acknowledged and generally included in safety rules that students should wash their hands after laboratory. Changing times have brought the ubiquity of “hand sanitizers”, dispensers of which may be mounted in hallways or carried by the students. Since the advent of the H1N1 virus, the use of hand sanitizers has become habitual, perhaps reflexive. Unfortunately, students cannot always be relied upon to make fine distinctions (1), in this case, between a product designed to kill germs and a process intended to remove contamination. Hand sanitizers are intended to remain on the hands, removing no chemical contamination. Further, the high alcohol content of some of these products may increase the permeability of the skin to harmful chemicals and any hazard the chemicals might pose. The material safety data sheets (MSDS) for the reagent alcohol (ethanol) indicates that the potential health effect of skin contact is “skin irritation, cracking or flaking due to dehydration and defatting action” (2). The use of alcohol-based hand sanitizer strips off skin oils (3), which contribute to the skin's barrier to the absorption of chemicals (4). Hand washing after chemistry laboratories is done to remove chemicals before they can get into the body, a purpose not served by, nor intended for, hand sanitizers. The recommended use of alcohol-based hand sanitizers is to “Rub the product over ... hands ... until hands are dry” (5): no material is removed. Washing with soap and water to remove chemicals is documented in the MSDS of many chemicals and is standard first aid practice (6) in the event of skin exposure to chemicals. Alcohol, ethanol (7), provides a vehicle for transporting chemicals through the skin (8). Both ethanol and isopropanol, common in alcohol-based hand sanitizers, facilitate transdermal transportation of drugs (9). The intent of this note is to prevent misunderstanding. Thus, it must be emphasized that hand washing is no substitute for proper personal protective equipment, in this case, appropriate gloves. After laboratory, students should wash their hands, preferably using a milder antibacterial soap. The ready availability of hand sanitizers might represent the path of least resistance to someone who erroneously believes that using hand sanitizer is equivalent to washing. Thus, it is suggested, to be pro-active, that safety rules explicitly state that the use of hand sanitizer is not a substitute for washing hands with soap and water.
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r 2010 American Chemical Society and Division of Chemical Education, Inc. pubs.acs.org/jchemeduc Vol. 88 No. 2 February 2011 10.1021/ed100447n Published on Web 11/03/2010
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