Why We’re DEET-Free: What DEET Does to the Environment
Key takeaways
- DEET is a synthetic repellent that works well for people, but research keeps finding it in rivers, streams and wastewater because it washes off skin and rinses down drains in huge volumes.
- Standard sewage treatment does not fully remove DEET, so it is one of the most frequently detected man-made chemicals in surface water worldwide.
- DEET is a solvent — the same property that lets it damage plastics, watch straps and synthetic fabrics also makes it a concern for aquatic life at higher concentrations.
- incognito® uses PMD (para-menthane-3,8-diol), a plant-derived active that is vegan and biodegradable, and belongs to the same class of repellents health authorities recommend alongside DEET.
- You do not have to trade protection for the planet: plant-based PMD is clinically proven and recommended against both mosquitoes and ticks.
DEET (chemical name N,N-diethyl-meta-toluamide) has protected people from mosquito bites since the 1950s and remains effective. But every product has a footprint beyond the person using it. This article looks at what DEET does once it leaves your skin — and why we build incognito® around a plant-derived alternative instead.
Is DEET bad for the environment?
For most people, DEET is considered safe to use as directed — that is not in dispute. The environmental question is different: what happens to the millions of litres of repellent applied worldwide each summer once it washes off in the shower, the sea or the rain? DEET is used in enormous quantities, and a large share of it ends up in the water cycle. Regulators classify it as a chemical that is not strongly bioaccumulative, but its sheer volume of use keeps it continuously present in the environment.
How DEET ends up in our waterways
DEET reaches the environment through very ordinary routes:
- Washing and swimming — repellent rinses off skin in showers, lakes, rivers and the sea.
- Down the drain — that shower water flows to wastewater treatment plants, which are not designed to remove DEET completely.
- Rainfall runoff — residues on skin and clothing are carried into storm drains and soil.
Because it is so widely used and only partly removed by treatment, DEET is repeatedly detected in surface waters. Scientists describe compounds like this as pseudo-persistent: individual molecules break down reasonably quickly, but a constant stream of new input means the chemical is almost always present somewhere in the water.
What DEET does once it is in the water
DEET is a solvent. Anyone who has watched it cloud a pair of sunglasses, soften a plastic watch strap or mark a synthetic jacket has seen this first-hand. That same solvent action is why researchers study its effect on aquatic organisms. At the low levels typically found in the environment, DEET is not considered a major acute hazard, but laboratory studies have shown it can be moderately toxic to some fish and freshwater invertebrates at higher concentrations. Its habit of turning up almost everywhere in freshwater is precisely why it is used as a marker of human contamination in water-quality monitoring.
DEET and everyday materials
The solvent effect is not just an environmental footnote — it is visible on your holiday. DEET can dissolve or dull:
- Plastics and painted surfaces
- Spectacle frames and lenses
- Watch straps and phone cases
- Synthetic fabrics and some waterproof coatings
DEET vs plant-based PMD: an environmental comparison
| Factor | DEET | Plant-based PMD (incognito®) |
|---|---|---|
| Origin | Synthetic chemical | Plant-derived from Javanese citronella (Cymbopogon winterianus) |
| Biodegradable | Breaks down but continuously replenished in water | Yes — biodegradable |
| Commonly detected in waterways | Yes — frequently | Not a widespread water pollutant |
| Damages plastics and fabrics | Yes (solvent action) | No |
| Vegan | Varies by product | Yes |
| Recommended by health authorities | Yes | Yes (PMD is an EPA-registered, CDC/ECDC-recommended active) |
Both DEET and PMD appear on the shortlist of actives that bodies such as the CDC and EPA recommend for reliable protection. The difference is what they are made from and what they leave behind.
Why plant-based PMD is our answer
PMD, or para-menthane-3,8-diol, is the active ingredient that gives plant-based repellents their staying power. Unlike raw citronella oil — which smells pleasant but fades within an hour or two — PMD provides long-lasting protection and is the only plant-derived repellent that leading health authorities place in the same recommendation tier as DEET. In our formula it is derived from Cymbopogon winterianus (Javanese citronella) under the trade name Citrepel®, and it is both vegan and biodegradable.
How incognito® helps
We built incognito® so you never have to choose between protecting yourself and protecting nature. Our DEET-free insect repellent spray is clinically proven, vegan and biodegradable, and is recommended against both mosquitoes and ticks. If you want to see how the same plant-based approach runs through everything we make — from sprays to sun care and bite relief — browse the full incognito® range. The active does its job on your skin, then breaks down instead of building up in the rivers and seas you travel to enjoy.
FAQs
Is DEET bad for the environment?
DEET is considered safe for people when used as directed, but it is used in very large volumes and frequently ends up in rivers, streams and wastewater. Standard treatment does not fully remove it, so it is one of the most commonly detected synthetic chemicals in surface water.
Does DEET pollute water?
Research repeatedly finds DEET in surface waters because it washes off skin and rinses down drains faster than treatment plants can remove it. It is often used as a marker of human wastewater contamination in water-quality studies.
Is a DEET-free repellent as effective as DEET?
Plant-based PMD is the one botanically derived active that health authorities recommend alongside DEET. It offers comparable, long-lasting protection at lower concentrations and is clinically proven against mosquitoes and ticks.
What is PMD and where does it come from?
PMD (para-menthane-3,8-diol) is the active in plant-based repellents. In incognito® it is derived from Javanese citronella (Cymbopogon winterianus), and it is vegan and biodegradable.
Why does DEET damage plastic and clothing?
DEET is a solvent, so it can dissolve or dull plastics, lenses, watch straps and synthetic fabrics. Plant-based PMD does not have this effect.
Sources
- US EPA — DEET
- US EPA — Skin-Applied Repellent Ingredients (DEET, OLE/PMD, picaridin, IR3535)
- CDC — Prevent Mosquito Bites
- ECDC — Protective measures against mosquitoes
- Maia & Moore (2011), Malaria Journal — Plant-based insect repellents: a review
This article is for general information only and is not medical advice. Always read and follow the product label, and consult a healthcare professional for guidance specific to you.