With many construction workers unable to use soap and running water during their entire workday, how effective are alcohol-based hand sanitizers as a substitute?

Not surprisingly, some of the research comes out of the food preparation and medical industries. The information puts the effectiveness of hand sanitizers in a mostly favorable light – but their effectiveness also depends somewhat on the hands that are being washed.

Also called “alcohol washes,” hand sanitizers must contain a minimum of 62 percent ethyl alcohol in order to be effective. To be most effective, a dime-size dollop of alcohol gel should be rubbed into the hands for 30 seconds. If hands are dry after only 10-15 seconds, studies have shown it is likely that not enough sanitizer was used.

“Alcohol washes are so good,” said the Nutrition Action Newsletter, “that in 2002 the Centers for Disease Control and Prevention (CDC) recommended that hospitals use them instead of antibacterial soap.”

Dr. Elaine Larson of the Columbia University School of Nursing, a past president of the Certification Board for Infection Control, said alcohol washes “quickly kills bacteria, it’s convenient because you don’t need water or a towel to use it, and there’s not even a theoretical possibility of bacteria becoming resistant to it.”

Not so fast, says the Food and Administration, which says using alcohol gel in place of hand washing in retail and food service does not adequately reduce important food-borne pathogens on food-workers’ hands. Alcohol kills all germs – good and bad that it comes in contact with – but has “very poor activity” against bacterial spores and certain viruses.

Squaring up the seemingly conflicting research is the Colorado State University Cooperative Extension, SafeFood Rapid Response Network, which said “research has shown that hand sanitizers can be as effective as hand washing only in certain situations. The type of soil which may be present on hands can significantly alter their effectiveness. Because dirt, food or anything else on your hands can make the alcohol less effective, it is important to first wash hands with soap and water.”

Medical personnel routinely wash away any present soil when they wash their hands with soap and water several times a day, so hand santizers offer an effective sanitizing method in between washings.

“Hand washing guidelines for healthcare workers should not be confused with recommendations for food workers or the general public,” the Colorado State researchers said. “For everyone, washing hands with soap and water is still a must. Hand sanitizers should primarily be used only as an optional follow-up to traditional hand washing with soap and water, except in situations where soap and water are not available. In those instances, use of an alcohol gel is certainly better than nothing at all.”

So until hand-washing stations are made widely available at construction sites, keep a bottle of hand sanitizer in your lunch box.