Does DEET damage nylon, tents and Gore-Tex?

DEET does not damage nylon fabric at the strengths most people buy. Four of the six DEET labels read here say it "will not damage cotton, wool, or nylon". It does damage plastics, vinyl, rubber, spandex, rayon, acetate, leather and paint. The newer labels also rule out every synthetic fabric other than nylon, which takes in polyester tent flies and waterproof membranes. Keep DEET on skin and cotton. On gear, picaridin is the repellent whose label clears plastics and synthetics.

What DEET and picaridin are#

DEET is the common name for N,N-diethyl-meta-toluamide. It is the active ingredient in most insect repellents sold for skin. The label states its strength as a percentage: 25 percent in a typical spray, up to about 98 percent in a "max" bottle.

DEET also behaves like a solvent on some materials. The National Pesticide Information Center (NPIC) says "DEET is a plasticizer and can damage certain rubber, plastic, vinyl, or elastic materials". A plasticizer is a chemical that softens a plastic by working its way in between the polymer chains. That is why the damage looks like softening, tackiness or fogging rather than a hole. NPIC's list includes "contact lenses, eyeglass frames and lenses, watch crystals" and "certain synthetic or treated fabrics". It adds that DEET "does not damage natural fibers including cotton and wool."

Picaridin is a different repellent active ingredient. In Europe it is usually called icaridin. Labels in the US give it as a percentage too, commonly 15 or 20 percent.

The label is the key document here. In the US every repellent is a registered pesticide. The words on its label are submitted by the maker and accepted by the Environmental Protection Agency (EPA). Each label has an EPA registration number, so you can look up the exact text for the bottle in your hand.

Does DEET damage nylon?#

No, on the label evidence and on the one lab test we could find.

Three DEET labels from 2013 and 2019, two different makers, use nearly the same words. The OFF! label reads: "Will not damage cotton, wool, or nylon. Do not apply on or near: acetate, rayon, spandex or other synthetics (other than nylon), furniture, plastics, watch crystals, leather and painted or varnished surfaces including automobiles." The Coleman-branded 25 percent spray and a 17.5 percent spray repeat it, and name "eyeglasses and watch crystals" as the plastics. Repel 29, from 1999, says "Will not damage cotton, wool and nylon."

The lab evidence points the same way. Sterling Rope published a letter from Honeywell Performance Fibers on how rope fibres stand up to DEET. Samples of nylon, polyester and Spectra (a polyethylene fibre also sold as Dyneema) were each soaked for 24 hours at room temperature in two repellents. The letter describes one as 95 percent DEET and the other as 7 percent DEET "and probably some oil based solvents". Neither lost tensile strength.

There was one catch. Nylon in the 7 percent product stretched 25 percent more before breaking and became less stiff. The letter put this down to "the other solvents in the product", not the DEET. A postscript limits the result to the two formulas tested. It says "it is probably safe to say DEET itself has no effect", but other chemicals in other repellents may.

So the fibre is safe, and the rest of the formula is the open question. That matters later.

Why "DEET dissolves nylon" keeps getting repeated#

The claim is everywhere. SectionHiker states that "DEET dissolves nylon and waterproof/breathable fabrics". A Backpacking Light thread opens with DEET "degrading materials like nylon". Neither page cites a label or a lab test for it. Three things keep it going.

One label really did say it. Bug Stuff, a 20 percent DEET lotion registered as 305-44, read in 1999: "Avoid contact with plastics, acetate, spandex and nylon." Its sister product from the same maker, Repel 29 (305-49), said nylon was safe. EPA noticed. Its letter of 24 August 1999 quotes both directives and tells the maker: "Please revise the labels accordingly to make this directive the same on each label." The letter does not say which way to settle it. Every later label we read that names nylon lists it as safe.

The things that do fail sit on nylon gear. A nylon pack has plastic buckles, elastic and a coated inside face. A nylon tent has a polyurethane or silicone coating and plastic clips. A shell jacket is a face fabric bonded to a membrane. When one of those parts goes soft or tacky, the gear "made of nylon" gets the blame.

Forum reports rarely name the material. In a 2009 Mountain Project thread, a climber found a crushed bottle of 98 percent DEET in a haul bag. The inside of the bag "had attained the consistency of gum". A stuff sack and tape rolls were ruined, and the ropes were missed. The post does not say what the bag lining was made of. Another poster wrote "I have melted nylon tents with repellent", then added "don't know if it was the DEET or another ingredient."

Both answers are partly right. Nylon fibre survives DEET. Many things fixed to nylon do not.

Label by label: what each one says, material by material#

Six DEET labels and one picaridin label, all from the EPA's own label files. Strength is the active ingredient as printed. "Safe" means the label says "will not damage". "Keep off" means it says do not apply, avoid contact, keep off or may damage.

Read the table by column. Nylon is safe on four DEET labels. It was "avoid" on one 1999 lotion that EPA told the maker to align, and it falls under "synthetics" on the 98 percent bottle. Polyester never appears by name, but it is covered. Repel 29 bans "synthetic fabrics such as acetate, rayon or spandex" and then exempts nylon. The three newer DEET labels say "other synthetics (other than nylon)". The 98 percent bottle says "synthetics". Leather and painted surfaces are on every DEET label except the 1999 lotion. The picaridin label says nothing about leather or paint either way.

One point about the picaridin wording. Its gear claims sit in the label's optional marketing text, in brackets. A maker may print them or leave them out. They are still claims EPA accepted for that product. Sawyer's 20 percent picaridin page makes a similar claim: it "won't damage plastics or synthetic coatings".

Does DEET damage Gore-Tex and other waterproof jackets?#

Keep it off. The one test reported suggests a splash will not destroy a jacket. Spraying it on a shell is still against the label.

A waterproof breathable jacket keeps rain out with a membrane. That is a thin plastic film that blocks liquid water but lets water vapour through. It is bonded to a face fabric. Every part of that is a synthetic, and none of it is plain nylon fabric. Under the newer labels that puts the whole jacket in "other synthetics (other than nylon)". The face fabric may be nylon. The membrane and its bond are not.

What is known about the membrane comes from one magazine report. Outside wrote in 2018 that "Gore has performed tests that show that after 24 hours of exposure to DEET, its specific membrane doesn't break down." The article gives no method, strength or measured result. It adds that hard data on prolonged exposure "is tough to find". A repellent researcher it quotes, Immo Hansen, says the mosquito tests spray DEET on fabric to see whether mosquitoes bite through, "But the impact on the clothing? We don't study that."

The same article quotes Vern Schrum of Tender Corporation, the maker of Ben's. He says DEET can damage a breathable membrane, "sealing it up so it doesn't work as well". He also says "It takes time to set up, so if you get a bit of DEET on your jacket, you can wipe it off no problem". He then warns that "it doesn't take much", and that "even a small amount can cause damage."

So: wipe a splash off fast, then wash the spot. Never spray DEET over a shell to protect it from insects. If you want repellent on outer clothing, use picaridin, or permethrin on the fabrics its label covers.

What gear is really at risk#

The materials the labels and NPIC name, matched to the camping gear made from them:

• Clear plastics. Watch crystals, glasses and sunglasses lenses, and plastic headlamp lenses. Phone, GPS and satellite messenger screens and their cases. The labels name eyeglasses and watch crystals. Garmin's own manual says to avoid "insect repellents that can damage plastic components and finishes". SectionHiker's author gives DEET damage to "watches, compasses, and GPS units" as the reason for switching to picaridin. See headlamps for what else matters on a lamp.
• Rigid plastic hardware. Buckles, cord locks, tent clips, toggles, zip pulls and bottle lids. The labels say "plastics" without listing types, so read them as covering all of these.
• Vinyl, rubber and elastic. NPIC names all three. Vinyl is PVC: waterproof stuff sacks, older dry bags, map cases, coated tarps. Rubber covers grips, seals and the gaskets in bottle lids. Elastic is shock cord, waistbands and cuffs.
• Stretch fabric. Spandex is the stretch fibre, also called elastane and sold as Lycra. Every DEET label read here bans it, by name or as a synthetic. Most stretch hiking trousers, leggings and the stretch panels in tops blend some in, so check the care tag.
• Polyester and other synthetic fabrics. Polyester tent flies, base layers, fleece and pack fabric fall under "other synthetics (other than nylon)".
• Coatings and membranes. NPIC names "certain synthetic or treated fabrics". The polyurethane coating inside a fly or pack is a treated fabric. A tent coating that has already gone tacky has a different cause, covered in why is my tent sticky?
• Leather, paint and varnish. Boots, knife handles, trekking pole grips and painted surfaces on vehicles.

What is not at risk on the labels' own terms: cotton, wool and nylon fabric. That includes your merino base layer. On the rope test, nylon, polyester and Spectra fibre lost no strength in a 24 hour soak.

Worked case: a 25 percent DEET spray against one hiking kit#

Take a common kit and walk it past one label, the 25 percent OFF! Deep Woods V wording quoted above. Suppose the hiker sprays their arms and neck, then puts the can in a hip belt pocket.

One of eight items is fully on the safe list. The risk is mostly in the hands, not the spray. DEET on the palms goes onto a watch face, a buckle or a headlamp lens the next time you touch them. The OFF! label already says to wash hands with soap and water after handling it. Do that before you handle gear, and the list above mostly stops mattering.

Run the same kit past the picaridin label in the table and every item is on its safe list. That label is silent only on leather and paint, and nothing here is either.

A test you can run before you trust a bottle#

Labels differ by product, so check your own repellent on your own gear before a trip.

1. Read the label first. Find the EPA registration number and the fabric line. If it names nylon as safe and lists "other synthetics", follow it as written.
2. Pick a hidden spot. The inside of a seam allowance, the underside of a buckle, or the back edge of a watch strap.
3. Apply one drop. Use the repellent as it comes from the bottle. Do not dilute it.
4. Wait, then wipe. Leave it for an hour, wipe it off, and let it dry.
5. Check three things. Feel for tackiness or softening. Look for clouding or a dull patch on clear plastic. Check that coated fabric does not stick to itself when folded.
6. If anything changed, that bottle stays off that item.

This shows short-term damage only. It cannot show slow damage from repeated contact over a season, which nobody we found has measured.

What this answer does not cover#

These labels are the makers' statements accepted by EPA. They are not test reports, and none describes a test method. They cover the products named, at the strengths printed. A repellent made to a different formula can contain other solvents. The Sterling Rope letter shows those can change nylon even when the DEET does not.

The labels we read run from 1999 to 2019. A label can change, and the one on your bottle is the one that applies. Products sold outside the US, including icaridin sprays in the UK and Europe, were not checked. Their labels may say something different.

Gore's 24 hour result comes to us second hand, with no method or strength. It covers Gore's own membrane, not other brands' membranes. It says nothing about what happens to seam tape or laminate bonds. No one we found has tested months of repeated contact on any outdoor fabric.

This page is about damage to gear. It does not cover how well each repellent works, how long it lasts on skin, or whether it is safe for you or for children. Follow the label for those. Permethrin is a different product with a different job: it is an insecticide made to be applied to clothing, not skin. How long it lasts is in how many washes permethrin clothing lasts.

Common mistakes#

Spraying DEET on a rain shell "to keep bugs off". The shell is a synthetic and a membrane, and the labels say keep off. Use picaridin, or treat cotton or nylon outer layers instead.

Assuming nylon means the whole item is safe. The fabric may be. The buckles, coatings, elastic and stretch panels on it may not.

Treating a 98 percent bottle like a 25 percent one. Ben's 100 says keep off synthetics with no nylon exception. Read the label of the bottle you carry.

Handling gear with DEET on your hands. Most of the damage people describe is to things they touch: watches, glasses, phones, headlamps. Wash your hands first.

Storing the bottle loose in a pack. A leaking or crushed bottle soaks everything near it. That is how the haul bag in the Mountain Project thread was ruined. Pack it upright in a sealed bag.

Putting DEET on a jacket you then reproof. If DEET has already been on a shell, wash it out before you add a new water repellent finish. Reproofing rain gear starts with a wash for the same reason: residues on the fabric stop a treatment from bonding.

Expecting the damage to be a hole. DEET softens and fogs. Look for tackiness, a dull patch or a stiff spot, not a tear. A jacket that feels damp inside after a DEET splash is more often a breathability problem in warm humid air than a failed membrane.

Frequently asked questions#

Does DEET damage nylon tents?#

Not the nylon fabric itself, on most labels. OFF! Deep Woods V and other 25 percent DEET sprays say they will not damage nylon. A tent is more than fabric, though. Its waterproof coating, plastic clips and elastic are all on the keep-off list, and a polyester fly is an "other synthetic". Keep DEET off the tent and away from its coatings.

Will DEET ruin a Gore-Tex jacket?#

A small splash wiped off quickly is unlikely to ruin it. Outside reported that Gore's own test found its membrane did not break down after 24 hours of exposure to DEET. A repellent maker quoted in the same article said even small amounts can damage a membrane over time. DEET labels list synthetics other than nylon as keep-off, so do not spray it on a shell.

Is picaridin safe on gear and plastics?#

On the label we read, yes. Cutter's 15 percent picaridin label carries claims that it will not damage plastics, watch crystals, plastic lenses, fishing line or other synthetic materials. It also lists cotton, wool, nylon, acetate and spandex. Sawyer says its 20 percent picaridin will not damage plastics or synthetic coatings. The label says nothing about leather.

What fabrics does DEET damage?#

The labels name acetate, rayon and spandex, which is also called elastane or Lycra. The newer labels add every synthetic fabric other than nylon, which includes polyester. The highest strength bottle says keep off synthetics in general. Coated and treated fabrics are also at risk, according to the National Pesticide Information Center. Cotton, wool and, on most labels, nylon are safe.

Does DEET damage polyester?#

Polyester is never named, but it is covered. The 2013 and 2019 DEET labels say do not apply on "spandex or other synthetics (other than nylon)". Polyester is a synthetic that is not nylon, so it is on the keep-off list. A rope fibre test found polyester lost no strength after a 24 hour soak in DEET. That test did not look at softening or coatings.

Why does DEET melt plastic?#

The National Pesticide Information Center describes DEET as a plasticizer. A plasticizer is a chemical that works its way in between the chains of a plastic and softens it. It names rubber, plastic, vinyl and elastic materials, watch crystals and eyeglass lenses among those it can damage. SectionHiker describes DEET fogging plastic lenses for good, and a climber described a soaked bag lining turning to "the consistency of gum".

How do I get DEET off my gear?#

Wipe it off straight away, then wash the spot with soap and water. A repellent maker quoted by Outside said DEET "takes time to set up", so speed matters. Rinse plastic parts such as buckles and lenses as well.