Pet Safety / Compounds / Deltamethrin

Is Deltamethrin safe for dogs and cats?

Low risk for pets

Deltamethrin is FDA-veterinary-approved for dogs in multiple formulations including the Scalibor protector band (tick collar) for Leishmania prevention in the US and Europe; dogs tolerate deltamethrin well at product label doses due to efficient hepatic esterase metabolism. Overdose scenarios include accidental collar ingestion or prolonged mouthing; mild GI signs and transient tremors at high doses.

What is deltamethrin?

The IUPAC name is trans-[(S)-cyano-(3-phenoxyphenyl)methyl] (1R,3R)-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropane-1-carboxylate.

Also known as: trans-[(S)-cyano-(3-phenoxyphenyl)methyl] (1R,3R)-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropane-1-carboxylate, Decamethrin, Decis, Decamethrine.

IUPAC name
trans-[(S)-cyano-(3-phenoxyphenyl)methyl] (1R,3R)-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropane-1-carboxylate
CAS number
52918-63-5
Molecular formula
C22H19Br2NO3
Molecular weight
505.2 g/mol
SMILES
CC1(C(C1C(=O)OC(C#N)C2=CC(=CC=C2)OC3=CC=CC=C3)C=C(Br)Br)C
PubChem CID
40585

Risk for dogs

Low risk

Deltamethrin is FDA-veterinary-approved for dogs in multiple formulations including the Scalibor protector band (tick collar) for Leishmania prevention in the US and Europe; dogs tolerate deltamethrin well at product label doses due to efficient hepatic esterase metabolism. Overdose scenarios include accidental collar ingestion or prolonged mouthing; mild GI signs and transient tremors at high doses.

Risk for cats

Extreme risk

Deltamethrin is a highly potent type II pyrethroid (highest insecticidal potency per mg of any synthetic pyrethroid) — cats are intensely sensitive; the mechanism is the same as permethrin and other type II pyrethroids (sodium channel persistent activation → CS syndrome: choreoathetosis and salivation). Deltamethrin dog tick collars (Scalibor) placed on or around cats have caused fatal toxicosis; cats grooming dogs wearing deltamethrin collars risk significant oral exposure. Treatment: methocarbamol, cyproheptadine, IV lipid emulsion in severe cases.

Regulatory consensus

6 regulatory and scientific bodies have classified Deltamethrin. The classifications differ — that's the data.

AgencyYearClassificationNotes
EPA CTX / IARC—Group 3 - Not classifiable as to its carcinogenicity to humans
EPA CTX / EPA OPP—Not Likely to Be Carcinogenic in Humans
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 0 positive / 1 negative reports)
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 0 positive / 1 negative reports)
US_EPA2024registeredEPA-registered pyrethroid.
EU_COSMETICS2019under_investigationCommission EDC list for cosmetics.

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where pets encounter deltamethrin

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Deltamethrin:

  • Physical/mechanical pest control (IPM)
    Trade-offs: More labor-intensive. May not be sufficient for severe infestations.
    Relative cost: 1.2-2×
  • Spinosad
    Relative cost: 1.2-2×
  • Pyrethrin (natural)
    Relative cost: 2-5× conventional
  • Diatomaceous earth
    Relative cost: 1.2-2×

Frequently asked questions

Is deltamethrin safe for pets?

Deltamethrin is FDA-veterinary-approved for dogs in multiple formulations including the Scalibor protector band (tick collar) for Leishmania prevention in the US and Europe; dogs tolerate deltamethrin well at product label doses due to efficient hepatic esterase metabolism. Overdose scenarios include accidental collar ingestion or prolonged mouthing; mild GI signs and transient tremors at high doses.

What products contain deltamethrin?

Deltamethrin appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).

Why do regulators disagree about deltamethrin?

Deltamethrin has been classified by 6 agencies including EPA CTX / IARC, EPA CTX / EPA OPP, EPA CTX / Genetox, EPA CTX / Genetox, US_EPA, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Deltamethrin in the pets app

Look up products containing deltamethrin, compare to alternatives, and explore the full data record.

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Sources (2)
  1. US EPA Pyrethroid Reregistration Eligibility Decision — cypermethrin/deltamethrin/lambda-cyhalothrin/bifenthrin/cyfluthrin/fenvalerate/tau-fluvalinate/fenpropathrin; type I/II classification; aquatic toxicity; cat sensitivity; sodium channel mechanism; human paresthesia; buffer zones (2011) (2011) — regulatory
  2. ASPCA Animal Poison Control Center: Pyrethroid Toxicosis in Cats and Dogs — type I vs type II CS/T syndromes; extreme cat sensitivity (sodium channel/UGT deficiency); bathing decontamination; methocarbamol tremor control; cyproheptadine; lipid emulsion severe cases (2023) (2023) — veterinary

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →