The label is the law. Rates and restrictions below are taken from the product labels listed under Sources. Your product's own label governs; read it before you mix or apply. Mixing calculator · Disclaimer
- Active ingredient
- Allethrin (d-cis/trans allethrin)
- Chemical class
- Pyrethroid; IRAC lists d-cis-trans allethrin in Group 3A sodium channel modulators.[2]
- Mode of action
- IRAC Group 3A: Sodium channel modulators: pyrethrins and pyrethroids[2]
- Signal word
- Thermacell Mosquito Repellent (repeller mats and devices): Caution[1]
Where you can and can't run it
The label allows outdoor use only. Never run it indoors, in a tent or in any enclosed space, and never leave it unattended.[1]
Run it on a flat, stable surface with the grill facing up and the vents uncovered, and don't touch the hot grill. Cover or remove exposed food, and use only Thermacell mats and cartridges.[1]
Handheld units must not be clipped to your body or clothing while running. Fuel cartridges aren't allowed on planes, checked or carry-on.[1]
Where it is used
Set the device in the middle of the area you want protected and start it 15 minutes ahead, because the full zone takes that long to form.[1]
Each mat lasts up to 4 hours and turns from blue to white when spent. Each fuel cartridge runs up to 12 hours. Turn the device off before changing a mat.[1]
Wind weakens the zone, so place the device upwind on breezy days. For bigger areas, the label says to space several devices up to 15 feet apart.[1]
Keep open mats out of the rain. If mosquitoes still bother you after 15 minutes, check for the orange glow, remaining fuel and a fresh mat.[1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Thermacell Mosquito Repellent (repeller mats and devices)[1] | Thermacell Repellents, Inc. | 71910-2 | 21.97% | heat-activated repellent mat (used with a butane-fueled device) | Caution |
Safety and environmental hazards
People
Signal word CAUTION: harmful if swallowed or absorbed through skin, and causes moderate eye irritation. Wash hands after handling mats. The butane cartridges are extremely flammable and under pressure.[1]
Pets
Store unused mats in the original box, somewhere cool and dry that children and pets can't reach.[1]
Bees and pollinators
The label has no bee or pollinator statement. Its only use is as an outdoor mosquito repellent.[1]
Fish and water
Toxic to fish and aquatic invertebrates. Don't use it directly over water, and never put unused mats down an indoor or outdoor drain.[1]
Common questions
- How big is the Thermacell protection zone?
- The label says efficacy data show a 15-foot zone, about 225 square feet, per device.[1]
- Can I use a Thermacell in my tent or screened room?
- No. The label says outdoor use only, and not indoors, in tents or in any enclosed area.[1]
- How do I know when to change the mat?
- The mat turns from blue to white when it needs replacing, after a maximum of 4 hours.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Thermacell Mosquito Repellent label, EPA Reg. No. 71910-2 (EPA-stamped, April 1, 2022).” www3.epa.gov/pesticides/chem_search/ppls/071910-00002-20220401.pdf (accessed 2026-10-06)
- Insecticide Resistance Action Committee, “IRAC Mode of Action Classification Scheme, Version 11.5 (Feb. 2026).” irac-online.org/documents/moa-classification/ (accessed 2026-10-06)