Is DEET a safe way to keep insects off?

                                      
-- M. Frey, Milwaukee
     DEET (short for “diethyltoluamide”) is a synthetic compound, invented by the U.S. Army in 1946, that can be applied topically to repel mosquitoes, ticks, fleas, chiggers, leeches and other biting insects. Unlike other repellents that deter bugs with smells they don’t like—or even kill them on contact—DEET just makes it harder for pests to smell us so they are more likely to leave us alone.
     DEET has been available to the general public since the Army released it in 1957, and today it is the repellent of choice for most people, with 90 percent market penetration in the U.S. An estimated one-third of Americans use DEET for protection from not only mosquito bites but also from mosquito-borne illnesses like Eastern Equine Encephalitis, West Nile Virus, the Zika virus and malaria, not to mention tick-borne illnesses like Lyme disease and Rocky Mountain spotted fever.
     DEET is not only effective, but also convenient. The repellant is sold in a variety of formulations (liquid, lotion, spray, towelette) ranging in strength from 5 percent to 99 percent. The U.S. Environmental Protection Agency considers DEET safe to use topically, and has approved 30 companies to sell some 120 different DEET-based repellents online and in stores across the the country. And with its 90 percent market penetration, DEET seems to be here to stay.
      That said, many of us are still concerned about the effect of DEET on our health and the environment. According to the nonprofit Environmental Working Group, exposure to high concentrations of DEET can irritate the eyes and in very rare cases impair the nervous system, with symptoms including seizures, tremors and slurred speech. But despite these risks, the group acknowledges that DEET is still probably the safest option for preventing insect-borne diseases. 
      If you want to use DEET, keep in mind that pediatricians generally recommend not using it on babies up to 2 months old and sticking to concentrations of 10 to 30 percent for infants and children. The stronger the concentration of the DEET you apply, the longer lasting protection you’ll get from mosquitoes. Consumer Reports found that 99 percent of DEET formulations gave up to 12 hours of protection while lower concentrations (20 to 34 percent) lasted three to six hours.
     If you want to avoid DEET altogether, several effective alternatives are available, including Picaridin and PMD (Oil of Lemon Eucalyptus). Several botanical oils -- castor oil, cedar oil, citronella oil, clove oil, geraniol oil, lemongrass oil, peppermint oil, rosemary oil and soybean oil -- are known for repelling insects, but the Environmental Working Group warns most of them are not very effective and could trigger allergic reactions in the user.
     To decide what’s best for you and your family given where you live and the risks for insect-borne diseases there, check out the EPA’s “Find the Repellent that is Right for You” search tool, which bases its recommendations on your inputs regarding what you are trying to battle, how long you will be outside and potentially exposed, active ingredient preference, and even preferred brand name.   

     Related:
     Are pesticides worth the environmental risk?

    This column was reprinted with permission. EarthTalk is produced by Roddy Scheer and Doug Moss and is a registered trademark of the nonprofit Earth Action Network. To donate, visit www.earthtalk.org. Send questions to: question@earthtalk.org.      

    Like us on Facebook and tell us what you think..