What the DEET? : Safely Repelling Mosquitos (Part I)

DEET or West Nile: Is There a Safe Option?

My husband and I met a couple of friends at the Shakespeare Festival St. Louis in Forest Park. It was a lovely summer evening, perfect temperatures, slight breeze, colorful characters, fresh lemonade, and Taming of the Shrew. I especially enjoyed the part when our friends’ dog, otherwise quiet and docile, suddenly rushed after two ducks waddling nearby, sending the ducks low-flying across the audience mid-play. It was almost perfect—if only the mosquitoes would leave us alone!

As I readied for the evening pre-play I knew the mosquitoes in the lake-laden Forest Park would be a challenge to the point of disrupting our enjoyment of Taming of the Shrew, but I had already promised myself I wouldn’t use DEET. This was the first time this season I would need to consider using bug repellant. What was in my closet?


DEET bug repellantsThe first bottle I pulled was an orange aerosol can of unscented OFF! brand Insect Repellant, 14.25% N, N-Diethyl-meta-toluamide, aka DEET. I quickly recognized the can as several years old and unused since; I long ago realized the obvious dangers of haphazardly spraying pesticides, which are usually poisons, into the air.

The second bottle I pulled was a blue pump bottle of Deep Woods Sportsmen OFF! I had purchased for our honeymoon to the rainforests of Costa Rica. I remember I didn’t want to buy more DEET but I felt I didn’t have enough time to research alternative options before venturing in the rainforest, so I purchased a pump which I felt would have a more direct application than an aerosol and put less of the poison into the air. But, since I was planning to venture deep into the rainforest, I purchased Deep Woods Sportsman, 25% DEET.

The third bottle I pulled was a friendly looking clear bottle with an orange lid and a family on the front: OFF! Brand Skintastic Family Unscented insect repellant. This one targeted families so it must be safer, right? DEET content: 7%.

The last thing I pulled from our closet was a small stick of Badger Anti-Bug Balm which I had purchased last fall from the nearby Green Earth Grocery. The Badger Balm contained no DEET; instead it used castor oil, citronella, cedar, lemongrass, rosemary, and geranium oils in a carrier of extra virgin olive oil and beeswax to repel bugs. It was also USDA Certified Organic. I had used this balm a couple of times last fall with inconclusive results. Was I willing to test the effectiveness of this natural repellant while sitting in the nesting zone of mosquitoes for two and a half hours? Is DEET such a big deal, anyway?

DEET: The Skinny

DEET, chemical name N,N-diethyl-meta-toluamide, is used in many insect repellents to help consumers avoid biting bugs such as mosquitoes (carriers of malaria and West Nile virus) and ticks (carriers of Lyme Disease-causing bacteria). According to the Environmental Protection Agency, the U.S. Army developed DEET in 1946, and the chemical is currently approved (after a re-assessment in 1998) for skin application by consumers in formulations containing 4-100% DEET. The EPA says that, as human exposure is expected to be brief and long-term exposure is not expected and as long as consumers follow label directions and take proper precautions, they believe DEET does not present a health concern to the general population.

Of course, it’s up to the consumer to figure out who is and isn’t part of the “general population” and what actions and timeframes include “proper precautions” and “brief exposure.”

Interesting, because the EPA also tells us, “There is no safe level of pesticides,” merely acceptable risk.

According to Lynda Fassa, author of Green Babies, Sage Moms, lab tests on animals at Duke University revealed “frequent and prolonged exposure to DEET causes serious brain-cell death and behavioral changes,” and, according to the study researchers, consumers should “use DEET with caution, especially [on] children who are more vulnerable to brain defects that prolonged exposure to DEET causes.”

Furthermore, The Pesticide Information Project  (of Cooperative Extension Offices of Cornell University, Michigan State University, Oregon State University, and University of California at Davis) says, “(DEET is) beneficial as insect repellents, but have also been associated with dermal and neurological reactions in humans.” Furthermore, in addition to serious skin irritations, “Everglades National Park employees having extensive DEET exposure were more likely to have insomnia, mood disturbances and impaired cognitive function than were lesser exposed co-workers.”

The Pesticide Information Project also cites several cases of toxic encephalopathy associated with DEET use on children, the first involving a 3 and a half year-old girl “whose body, bedclothes and bedding were sprayed each night for two weeks with an insect repellent containing 15% DEET.” This and other cited cases of toxic encephalopathy “was characterized by agitation, weakness, disorientation, ataxia, seizures, coma and in three cases resulted in death.” Two of the deaths included autopsies showing edema of the brain, with one case presenting necrotic lesions in the cerebellum and spinal cord and an enlarged liver with “microscopic changes.”

What does this tell me?

I may choose, on rare occasions, to use very low levels of DEET (5% or less, as suggested by the Pesticide Information Project) if I have to—and if there is absolutely no chance I am pregnant—but I would never use DEET on my children or while expecting or trying to conceive. The risk to the brain development of the fetus or my child is not worth the convenience of readily available DEET, especially when other options are available, as I’ll discuss in my next post.

Next article: What the DEET? Safely Repelling Mosquitos (Part II) – Part II will focus on safe and effective DEET alternatives 

Works Cited

Environmental Protection Agency. (2007, March 23). The Insect Repellant DEET. Retrieved May 31, 2011, from Pesticides: Topical and Chemical Fact Sheets: http://www.epa.gov/pesticides/factsheets/chemicals/deet.htm

Fassa, L. (2008). Green Babies, Sage Moms: The Ultimate Guide to Raising Your Organic Baby. New York: New American Library.

Pesticide Information Project of Cooperative Extension Offices of Cornell University, Michigan State University, Oregon State University, and University of California at Davis. (1997, October). Pesticide Information Profile: DEET. Retrieved May 31, 2011, from E X T O X N E T: http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/deet-ext.html



3 responses to this post.

  1. Hmm is anyone else encountering problems with the pictures on this blog loading?
    I’m trying to determine if its a problem on my end or if it’s the
    blog. Any feed-back would be greatly appreciated.


  2. […] my article about DEET use on adults and children for more […]


  3. […] Natural Pest Control « What the DEET? : Safely Repelling Mosquitos (Part I) […]


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