Bifenthrin: Uses, Health Effects, Safety and Regulation

Bifenthrin is a contact, broad-spectrum insecticide in the pyrethroid class. Labels cover farms, turf and commercial buildings. It is toxic to people mainly through skin, airway and stomach effects. The 25.1% EC product is highly toxic to bees exposed to direct treatment. It is also extremely toxic to fish and aquatic invertebrates. The EPA regulates bifenthrin through registration and legally binding label restrictions. To use it more safely, start with storage, because the label sets clear limits.

What Is Bifenthrin?

Bifenthrin is a contact, broad-spectrum insecticide in the pyrethroid class. Bifenthrin is more toxic to insects than to people, because insects have lower body temperatures and smaller body size. Pyrethroid insecticides are synthetic versions of pyrethrins, which are natural insecticides extracted from chrysanthemum flowers. A 2013 study by A Giampreti classed bifenthrin as a Type I pyrethroid. Products with this active ingredient are sold as insecticides and miticides.

How Does Bifenthrin Kill Pests?

Bifenthrin kills pests by disrupting the central nervous system of insects. Bifenthrin acts on contact, so pests that touch or feed on the active ingredient become paralyzed and die. Paralysis ends in death for the exposed insect.

A 2019 study by Mónica Elizabeth Mosquera Ortega tested oral bifenthrin doses from 0.5 to 12 mg/kg in adult rats. The same Toxicological Sciences study found that 3 mg/kg was the minimal oral dose that affected subcutaneous temperature.

What Is Bifenthrin Used For?

The bifenthrin technical product (EPA Reg. 94730-3) is used in insecticide and miticide products. Registered sites include artichokes, cotton, pears and turfgrass, including golf courses and sod farms. The bifenthrin 7.9% SC product (EPA Reg. 42750-369) lists food processing plants, hospitals, hotels, granaries and laboratories as permitted indoor use sites. Labels therefore cover farms, turf and commercial buildings.

A 2025 study in Environmental Toxicology and Pharmacology tested bifenthrin among commonly used agricultural insecticides. That study shows bifenthrin in routine farm use.

Which Pests Does Bifenthrin Control?

Bifenthrin controls these pests: ants, chinch bugs, imported fire ants, Japanese beetle adults, stink bugs and bed bugs. Turf insects on the 7.9% SC label include the first five. Bifenthrin in UC IPM pest notes names ants and bed bugs. Turf and structural lists differ, because each product targets its own settings.

Turf pests on the 7.9% SC label include banks grass mites, billbugs, crickets, earwigs, grasshoppers, millipedes and sowbugs. UC IPM notes add fungus gnats, silverfish, firebrats and invasive shothole borers.

Rate tables on the 7.9% SC label are given in fluid ounces per 1000 square feet. The listed turf rate for ants is 0.5 to 1.0 fluid ounces per 1000 square feet.

Thai H Pham of the Research Center for Tropical Bees and Beekeeping tested bifenthrin on four honey bee species. That work shows the insect activity of bifenthrin reaches bees.

How Toxic Is Bifenthrin to People?

Bifenthrin is toxic to people mainly through skin, airway and stomach effects. The National Pesticide Information Center is an information service that publishes pesticide fact sheets on these effects. Rats show an acute oral LD50 of 53.4 to 210.4 mg/kg, which makes bifenthrin moderately toxic when ingested. The acute reference dose is 0.328 mg/kg/day, and the chronic reference dose is 0.013 mg/kg/day.

Skin contact can cause tingling, itching, burning or numbness, and within 48 hours these sensations usually go away. Inhaling bifenthrin can irritate the nose, throat and lungs. Large oral amounts cause sore throat, nausea, abdominal pain and vomiting almost immediately.

The 25.1% EC label states that the product causes moderate eye irritation. The 7.9% SC label carries the signal word CAUTION.

A 2013 study by A Giampreti from IRCCS Maugeri Foundation Clinical Institute and University of Pavia covers a case. A 19-month-old ingested an insecticide with bifenthrin (5%), esbiothrin (3%) and piperonyl butoxide. Esbiothrin is a Type I pyrethroid insecticide. Piperonyl butoxide is a chemical that was in the same product. The child progressed to tonic-clonic seizures and coma.

A two-year rat feeding study at 0 to 200 ppm showed no tumor potential. The U.S. EPA classifies bifenthrin as a possible human carcinogen, based on studies in mice. No data show that children have increased sensitivity specifically to bifenthrin.

Is Bifenthrin Harmful If Swallowed or Inhaled?

Yes. The bifenthrin 7.9% SC product is harmful if swallowed, inhaled or absorbed through skin. The bifenthrin 25.1% EC product may be fatal if swallowed.

A 2025 study by Musa S Alfaifi from the Armed Forces Hospital Southern Region reports four cases. Four siblings ate contaminated shawarma sandwiches containing carbofuran and bifenthrin. The patients showed cholinergic symptoms.

Carbofuran, a carbamate insecticide, was found with bifenthrin in this food-poisoning outbreak. One patient showed diminished acetylcholinesterase activity, which suggests severe inhibition. Three patients had normal or low-normal acetylcholinesterase levels. Individual variability, delayed testing or improper sample handling probably explain those results. The cases therefore leave some doubt about the exact cause.

Is Bifenthrin Toxic to Bees?

Yes. The bifenthrin 25.1% EC product is highly toxic to bees exposed to direct treatment. The label extends the warning to residues on blooming crops or weeds.

A 2023 study by Qibao He from Anhui Agricultural University found an oral LD50 of 0.4507 μg per larva. That dose applies to honey bee larvae in an acute oral test. The small value shows how little bifenthrin a larva needs to die.

A 2025 study by Thai H Pham from the Vietnam National University of Agriculture tested four honey bee species. The bee toxicity tests measured oral toxicity. The wild species A. dorsata and A. florea were significantly more sensitive. Apis mellifera is the western honey bee, the species used in LD50 studies of bifenthrin.

The 25.1% EC label sets a control for bee safety. It forbids drift or application to blooming crops or weeds while bees are actively visiting the treatment area.

Is Bifenthrin Toxic to Fish and Aquatic Life?

Yes. The bifenthrin 25.1% EC product is extremely toxic to fish and aquatic invertebrates. A 2022 study by Guixian Hu from the College of Plant Protection reports a 96-hour LC50 of 0.15 mg/L. The test used larval zebrafish. Danio rerio is the zebrafish, a fish species used in 96-hour toxicity tests. Bifenthrin had the highest toxicity of the agrochemicals tested. Chlorpyrifos followed at 0.36 mg/L, and azoxystrobin followed at 0.63 mg/L.

A 2024 study by Gaoyi Du from Zhejiang University modelled cis-bifenthrin, the cis isomer of bifenthrin. In the model, the kidney had the fastest accumulation rate in fish. Carassius auratus is the goldfish, the fish model in these studies. The skin was fastest in frogs, and Xenopus laevis is the African clawed frog. Bifenthrin can last a long time in the environment and may accumulate in fish.

The 25.1% EC label bars direct application to water or to areas where surface water is present. It bars application to intertidal areas below the mean high-water mark. The technical product label bars discharge of effluent into lakes, streams, ponds or public waters without an NPDES permit.

How Does the EPA Regulate Bifenthrin?

The EPA regulates bifenthrin through registration and legally binding label restrictions. The bifenthrin 25.1% EC product is a restricted use pesticide. Using it in a manner inconsistent with its labeling violates federal law. Formulators using the technical product must obtain EPA registration of their formulated products.

The 25.1% EC label prohibits use in areas that may result in exposure of endangered species. The EPA rates bifenthrin as a possible human carcinogen. State or tribal requirements, set by the agency responsible for pesticide regulation, can add further rules.

The 7.9% SC label excludes some uses. It bans use on sod farm turf, golf course turf and grass grown for seed.

A 2022 Scientific Reports study found bifenthrin the most toxic of five agrochemicals to larval zebrafish. Water protection rules on the labels reflect that hazard.

How Can Bifenthrin Be Used More Safely?

To keep bifenthrin more safely used, start with storage, because the label sets clear limits. Keep the bifenthrin 7.9% SC product from freezing, and never store it below 40 °F. Warm crystallized product once it sits above 60 °F. Keep bifenthrin out of reach of children and animals, and store it in original containers only. Never contaminate water, food or feed by storage or disposal. Keep the 25.1% EC product away from open flame, because it is combustible.

A 2025 study in the Journal of Taibah University Medical Sciences links bifenthrin poisoning to contaminated food. That link is a reason to keep storage away from food.

What Personal Protective Equipment Does Bifenthrin Require?

Bifenthrin labels require protective equipment for handlers, and the 25.1% EC label lists four items. The key items include:

• Long-sleeved shirt and long pants: These garments cover the arms and legs of every handler, and they are the base layer for all dilute handling.
• Chemical-resistant gloves: Gloves of barrier laminate or Viton must be at least 14 mils thick, so thin disposable gloves do not meet the label.
• Shoes plus socks: This footwear covers the feet of the handler, and it completes the base layer on the label.
• Protective eyewear: Handlers exposed to the concentrate must wear it, because the product causes moderate eye irritation.

Bifenthrin in UC IPM notes calls for chemical resistant gloves, long sleeves and goggles. Read the product label for the exact requirements.

Mónica Elizabeth Mosquera Ortega reported in 2019 that 3 mg/kg of oral bifenthrin affected subcutaneous temperature in adult rats.