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DEET Dissolves Breathable Fabrics

Heavily Patched Hard Shell Pants
Heavily Patched Hard Shell Pants

I’m a skeptic by nature and have always questioned authority, standard operating procedures, gut feel, the status quo, and institutional knowledge. In work and at play, I often put these truths to the test by doing experiments or establishing quantifiable metrics that invariably show that long-held beliefs are grossly incorrect.

Does DEET Melt Synthetics?

I’d always heard that DEET dissolves breathable fabrics, such as Gore-Tex, and that you should keep the two from coming into contact with one other. I’ve never had this problem outdoors when I’ve used DEET, but I couldn’t pass up the opportunity to test whether it is true or a myth in a more controlled setting on a pair of breathable rain pants.

One winter, I managed to shred a pair of Mountain Hardware Cohesion Pants, slashing dozens of rips in the legs with sharp front points, while learning to use crampons. Mountain Hardware Cohesion Pants are made with Conduit DT, a proprietary Gore-Tex knockoff that has three layers: an outer shell layer made from Epic nylon, a middle breathable layer made from Conduit DT, and an inner Epic stretch liner. I tried to extend the life of these pants with duct tape (see above), but finally donated their remains to science.

DEET Concentrations

I applied three squirts of Ben’s 100% DEET and Ben’s 30% DEET to the Epic nylon fabric on the outside of the Cohesion pants. After 3 days, the 100% DEET solution (right in photo) was still quite wet, while the 30% DEET Solution (left in photo) had mostly dried. There was little evidence of any external damage to the pants leg.

 

Turning the pant leg inside out however, showed another result entirely. The 30% DEET solution had soaked through the outer shell layer and melted the middle Conduit DT layer and the inner liner. However, the damage was highly localized. [Does the photo below remind you of the Andromeda Strain?]

The damage under the 100% DEET application was much more significant, and large patches of the Conduit DT layer and the inner liner were melted away. As it turns out, this process is ongoing and the fabric continues to dissolve, unabated.

Mitigating DEET Clothing Damage

The evidence is quite clear and shows that DEET does dissolve breathable laminates. However, the strength of the DEET solution that the laminate comes in contact with is a determining factor in the amount of damage that will occur. Hikers who are concerned about the impact of DEET to clothing made using breathable laminates are advised to flush the point of contact with water to minimize potential damage.

Picaridin Instead of DEET

I originally conducted this experiment in 2009. Since then (two years ago) I switch to Sawyer Picaridin Insect Repellent instead of DEET, primarily because it doesn’t melt plastic, fog plastic lenses, or destroy any of the outdoor gear I own. The stuff works great. I’ll never go back to using DEET.

Disclosure: The author purchased all fo the products in this article.

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28 comments

  1. Nice test bro!! I had heard this rumor a few years back but never had the stones to test it on my own gear. Thanks for the sacrifice and for sharing your results.

  2. I recently discolored my plastic Highgear watch with bug-spray (just partial overspray from my arm). I'd guess it's a polypropylene material, but it could also be HDPE (high-density polyethylene). Care to expand your experimentation?

    I'm just keeping bug-spray away from my gear or using a liquid that can be rubbed directly into the skin without overspray.

    Great topic.

  3. We salute those brave pants, which made the ultimate sacrifice in the name of scientific research! Good to know the rumor has some veracity.

  4. I've gotten a lot better at pointing my crampons since then. No rips for a while, now, with my newest pair of pants. :-)

  5. Chad – sorry for the delay in approving your comment. You got trapped in my spam filter. Let me see if I have an old watch somewhere to expand the DEET test. Good idea for a series of posts – maybe I should call for donations.

  6. Thanks for using your gear. I’d heard this rumor and can say it’s true of tent fabric. The only thing good about deet is it keeps my allergy to the out doors from showing up in red spots and welts as it does when ever I try to use one of the new safe products on the market. Sure wish they could come up with something as effective as deet and as benign as skin so soft Oh, and without the grammy smell.

  7. This comports with my own experience. Nylon is just fine (thank goodness for us climbers!) but other plastics are a crapshoot. It will melt plastic bags (making secondary containment a challenge) and is merciless toward swiss army knife handles.

  8. Today I had the misfortune of having a spray bottle of Ben’s Deep Woods with DEET get wedged sideways in the small outer pocket of my daypack. Somehow the plastic cover over the nozzle came off and the spray button was activated, releasing enough Ben’s to leak all over what I had in the bottom of the pocket. The main casualty was my Swiss army knife–I soaked the knife in warm soapy water in the sink to wash off the repellent, and when I rinsed it off I noticed fatal cracks and milky discoloration in the plastic, and in fact some of the plastic turned soft–soft enough to shave off with my fingernail! Very creepy. I’m slightly comforted in finding a few other entries online from other folks who’ve had this same thing happen to them–but still grieving for my knife which will never be the same. My husband says it’s “patina,” and the knife (multitool) still works… I wish there were a way to replace the damaged casing. But the bigger question is, do I want to buy another bottle of this stuff and use it anywhere near my body? I don’t think so!

    • I have found that using a piece of electrical tape around the seam between the top and the can will hold a top on securely. If you fold over the last little bit of tape it will be simple to find the starting point to remove the tape. After using some of the contents of the can you and reuse the tape.

      Hope that helps
      Matthew

  9. A fellow hiker in the Adirondacks once gave me a spare bottle with the comment “Its so good, it will melt plastic” (and gave me a big thumbs up while saying this).

  10. The chemical DEET is a plasticizer and will harm a wide range of outdoor gear containing plastics or film if not carefully stored and applied. Many repellent brands use DEET including OFF, Repel, Cutter and Ben’s to name a few. If you do use a DEET based repellent, as many do, use precautions when storing and applying to your skin. If you are concerned with the plasticizing effects of DEET use a repellent with the active ingredient, Picaridin. This active ingredient will not harm your outdoor gear or clothing and will provide up to 8 hours of mosquito and tick protection. I recommend a Picaridin 20% active such as Natrapel. The company I work for, Tender Corporation, manufactures both Ben’s and Natrapel.

    Frank Meyer, Chief Marketing Officer, Tender Corporation

  11. Good info. Wonder if DEET affects DWR finishes as well.

  12. How do you use sunglasses when you use a DEET based repellent in your face?

  13. ARGH! This is why my rain jacket disintegrated in Costa Rica! It looked just like your pictures and the light colored “lining” that comes off gets stuck to you and anything you wear. It is a total mess. I threw away the jacket. Same thing happened to the inside of my pack. I never sprayed the inside of my pack but I must have put clothes inside that had deet on them. Now I use picaridin and I have not had any problems with gear or ticks/mosquitos.

  14. Thanks for the advice. While on a 4 day backpacking trrp I sprayed a squirt of 100% deet Repel on the outside vestibule of my tent fly. It’s made of ripstop nylon. I noticed a dark blackish stain immediately. I washed it off with my water bottle within a few minutes, but the stain remained. After googling the subject at home 2 days later, I rubbed the spot with white vinegar (great general cleaner) and the dark spot went away. No sign that the deet melted the nylon, but I had washed it off quickly. I assume the white vinegar removes any waterproofing on the outside, so I may spray a little waterproofing back on that spot. Luckily, no permanent damage to my new Big Agnes ultralite tent fly.

  15. I thought I was under attack this weekend when I camped at Mt. Mitchell in NC. Every time I looked at my tent I saw 2-3 little black tick-like bugs. It freaked me out, so I sprayed Picaridin on the rainfly of my nylon tent. Did I kill my rainfly? The can said ,”Does not harm gear or equipment.” I didn’t have Permethrin with me, but wouldn’t have sprayed it anyway since it was really windy. BTW, it turns out that the bugs weren’t ticks. A ranger told me that ticks weren’t at that altitude (6,000 ft.), but were harmless weevils. At least it was my old tent, not my new one.

    Thanks for experimenting with DEET on your gear!

  16. I’ve been using products from Greenerways Organic for a couple years now. They are DEET free and non-toxic and work pretty well. My fave item they sell is a little pouch you hang in your campsite. you add water to it and it creates a “Mosquito Free Zone” in your campsite or yard. it works in about a 100 ft. radius and lasts a WEEK. i was so skeptical, especially since they don’t use toxic chemicals. but it freaking works. crazy.

  17. My 11 year old went backpacking with Scouts this weekend. Her rainfly came home super sticky. Turns out she sprayed it with DEET. Brand new tent, of course. I’ve got it soaking it hot soapy water but I bet it’s toast. Right?

  18. Had my ‘fun’ with deet products in the army and in my more recent times in south american jungles – now, I’ve turned more eco conscious and take care of not just myself and my lightweight synthetic tropical gear (which deet played havoc with – as you’ve demonstrated perfectly above!) but also for the environment – so I use a natural product that has no chemicals, is totally biodegradable,is non-toxic and isn’t contained in plastic like most other products – and yes it does work exceptionally well. It’s made in the UK, by The Solid Bar Company but I get mine from their outlet near me in Tennessee called That Cool Place – don’t knock it until you try it, it’s got oil of lemon eucalyptus aka PMD (not lemon eucalyptus essential oil – big difference!) in it – works like a trooper and is safe. Maybe you could test it for yourself.

    Going slightly sideways off this topic – just have to say 2 things about your other reviews. Got myself a NEMO Galaxi 2P Tent and I love it, so lots of praise there.

    But, moving on to the footwear – I used to swear by my Merrell Moabs and have got through 4 pairs but the quality seems to have gone downhill in the last few years so much so that I’ve had to swap for some Altra Lone Peaks which now suit me fine. My question is, was I just unlucky with my last 2 pairs of Merrells or have they switched their manufacturing base or something? Any light you can shed appreciated – hate to see Altra’s go down the same road.

    Otherwise keep up the great work!

    • Have always sprayed yard work clothes with Repel 40% Deet- NOT skin. (Use essential oils in skin to repel mosquitoes.) This time in heat, lots of sweating, I have blisters on face & painful blisters on chest. I think Deet ‘soaked through clothes’ which I probably touched clothing with gloves & wiped sweat from face. Will only use non-Deet spray in future. Does anyone have recommendations for STRONG mosquito deterrent? I’ve used Berts Bees but comes out as oil; Badger has worked well

      • I second the picaridin. Consumer Reports says 20% picaridin works as well as DEET. I can’t stand the feel of DEET on my skin and I’ve damaged plastic goods with the overspray. Picaridin doesn’t give me the clammy feel on my skin and will leave plastics alone.

      • Deet is a plasticizer. It basically dissolves and separates the long chain polymers that hold a plastic together. It only does this with certain plastics as nylon is not affected. As your skin is not composed of long chain polymers, it has no possibility of affecting your skin in the same manner. Though you could have some sort of allergic reaction to the DEET, it is just as likely that the essential oils you have been using could have caused the skin irritations

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