Pet Safety / Compounds / Bronopol (2-bromo-2-nitropropane-1,3-diol)

Is Bronopol (2-bromo-2-nitropropane-1,3-diol) safe for dogs and cats?

Low risk for pets

Low concern at cosmetic levels.

What is bronopol (2-bromo-2-nitropropane-1,3-diol)?

The IUPAC name is 2-bromo-2-nitropropane-1,3-diol.

Also known as: 2-bromo-2-nitropropane-1,3-diol, bronopol, 2-Bromo-2-nitro-1,3-propanediol, Bronosol.

IUPAC name
2-bromo-2-nitropropane-1,3-diol
CAS number
52-51-7
Molecular formula
C3H6BrNO4
Molecular weight
199.99 g/mol
SMILES
C(C(CO)([N+](=O)[O-])Br)O
PubChem CID
2450

Risk for dogs

Low risk

Low concern at cosmetic levels.

Risk for cats

Low risk

Low concern.

Regulatory consensus

14 regulatory and scientific bodies have classified Bronopol (2-bromo-2-nitropropane-1,3-diol). The classifications differ — that's the data.

AgencyYearClassificationNotes
US EPA2000not classifiable as to human carcinogenicity (Group D)
EFSA2010not evaluated for carcinogenicity as standalone; nitrosamine formation in bronopol-containing cosmetic formulations regulated under EU Cosmetics Regulation Article 15 which prohibits placing cosmetics containing nitrosamines on the market; SCCS opinion notes that bronopol's genotoxicity concern derives from nitrosamine formation in the finished product, not intrinsic carcinogenicity of bronopol itself; maximum 0.1% in cosmetics (Annex V No. 34)
EPA CTX / EPA OPP—Group E Evidence of Non-carcinogenicity for Humans
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 0 positive / 3 negative reports)
EPA CTX / Genetox—Genotoxicity: negative (Ames: negative, 0 positive / 3 negative reports)
EPA CTX / Skin-Eye—Eye Irritation: Eye Dam. 1 (score: very high)
EPA CTX / Skin-Eye—Skin Irritation: Skin Irrit. 2 (score: high)
EPA CTX / Skin-Eye—Skin Sensitization: Sh (score: high)
EPA CTX / Skin-Eye—Eye Irritation: Category 1 (score: very high)
EPA CTX / Skin-Eye—Skin Irritation: Category 2 (score: high)
EPA CTX / Skin-Eye—Eye Irritation: Category 8.3A (Category 1) (score: very high)
EPA CTX / Skin-Eye—Skin Irritation: Category 6.3A (Category 2) (score: high)
EU BPR—Approved active substance for multiple biocidal product types
EU Cosmetics—Allowed in cosmetics at ≤0.1%. Must be labeled. Cannot be used with amines (nitrosamine concern)

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 bronopol (2-bromo-2-nitropropane-1,3-diol)

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles
  • Personal Care — shampoo, conditioner, lotion, cosmetics, sunscreen
  • Pharmaceutical — Ophthalmic solutions, Topical medications
  • Industrial — Paper mill slimicide, Oil field biocide, Metalworking fluid preservative, Latex paint preservative

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Bronopol (2-bromo-2-nitropropane-1,3-diol):

  • Physical/mechanical pest control (IPM)
    Trade-offs: More labor-intensive. May not be sufficient for severe infestations.
    Relative cost: 1.2-2×
  • Phenoxyethanol
    Relative cost: 1.2-2×
  • Organic acids
    Relative cost: 2-5× conventional
  • Ethylhexylglycerin
    Trade-offs: Alternative approach; specific tradeoffs depend on application context, scale, and regulatory requirements. Full hazard assessment of alternative recommended before adoption to avoid regrettable substitution.
    Relative cost: 1.2-2×

Frequently asked questions

Is bronopol (2-bromo-2-nitropropane-1,3-diol) safe for pets?

Low concern at cosmetic levels.

What products contain bronopol (2-bromo-2-nitropropane-1,3-diol)?

Bronopol (2-bromo-2-nitropropane-1,3-diol) appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); shampoo (Personal care).

Why do regulators disagree about bronopol (2-bromo-2-nitropropane-1,3-diol)?

Bronopol (2-bromo-2-nitropropane-1,3-diol) has been classified by 14 agencies including US EPA, EFSA, EPA CTX / EPA OPP, EPA CTX / Genetox, EPA CTX / Genetox, 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 Bronopol (2-bromo-2-nitropropane-1,3-diol) in the pets app

Look up products containing bronopol (2-bromo-2-nitropropane-1,3-diol), compare to alternatives, and explore the full data record.

Open in pets View raw API data

Sources (2)
  1. US EPA Bronopol: Group D Not Classifiable; FIFRA Antimicrobial; Nitrosamine Formation with Amines; NDELA IARC 2B; FDA 1992 Guidance Minimize Amine Co-formulation; Contact Sensitizer; Aquaculture Parasite Treatment (2000) — regulatory
  2. EFSA/SCCS Bronopol: EU Cosmetics Regulation Annex V No. 34 Maximum 0.1%; Nitrosamine Prohibition <50 ppb; Article 15 N-Nitroso Restriction; Aquatic LC50 2–10 mg/L; Aquaculture Biocide Environmental Concern; Algal EC50 <1 mg/L (2010) — regulatory

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 →