Acetic acid on your skin: a safety profile
Moderate riskSkin contact hazard from acetic acid is concentration-dependent: dilute solutions (household vinegar, 5%) cause minimal irritation with prolonged contact; concentrated industrial acetic acid (>25%, glacial) causes significant corrosive burns similar in mechanism to other carboxylic acids. Dilute exposure (food-grade vinegar): prolonged skin contact with vinegar (5% acetic acid) may cause mild irritation and maceration with extended contact but poses no significant burn risk — used therapeutically for jellyfish sting treatment (deactivates nematocysts) and as a dilute antiseptic. Concentrated acetic acid burns: glacial acetic acid (99.5%) or concentrated solutions (>25%) cause immediate burning pain, erythema, and at high concentrations, blister formation and coagulative necrosis similar to other strong organic acid burns; the burn injury is less severe than equivalent concentration mineral acids (H₂SO₄, HCl) due to slightly higher pKa (4.76 vs. <<0 for mineral acids), but still clinically significant. Vinegar and acetic acid ear drops: acetic acid otic solutions (2%) are used medically for external otitis (swimmer's ear) — safe at this concentration in clinical use, but higher concentrations should not be instilled in ears. Hair care products: acetic acid rinses (dilute, 1–3%) are used after alkaline hair treatments (permanent waves, relaxers) to restore hair pH — safe at these concentrations with standard rinse-off. Industrial worker protection: concentrated acetic acid handling requires acid-resistant gloves (nitrile or neoprene), face shield, and chemical-resistant apron; emergency eyewash and shower required at work stations. Ecological note: acetic acid in large quantities (industrial runoff) can lower aquatic pH and deplete dissolved oxygen — biodegrades readily via BOD.
What is acetic acid?
Also known as: ethanoic acid, Vinegar acid, Acetic acid glacial, Ethylic acid.
- IUPAC name
- acetic acid
- CAS number
- 64-19-7
- Molecular formula
- C2H4O2
- Molecular weight
- 60.05 g/mol
- SMILES
- CC(=O)O
- PubChem CID
- 176
Risk for people
Moderate riskSkin contact hazard from acetic acid is concentration-dependent: dilute solutions (household vinegar, 5%) cause minimal irritation with prolonged contact; concentrated industrial acetic acid (>25%, glacial) causes significant corrosive burns similar in mechanism to other carboxylic acids. Dilute exposure (food-grade vinegar): prolonged skin contact with vinegar (5% acetic acid) may cause mild irritation and maceration with extended contact but poses no significant burn risk — used therapeutically for jellyfish sting treatment (deactivates nematocysts) and as a dilute antiseptic. Concentrated acetic acid burns: glacial acetic acid (99.5%) or concentrated solutions (>25%) cause immediate burning pain, erythema, and at high concentrations, blister formation and coagulative necrosis similar to other strong organic acid burns; the burn injury is less severe than equivalent concentration mineral acids (H₂SO₄, HCl) due to slightly higher pKa (4.76 vs. <<0 for mineral acids), but still clinically significant. Vinegar and acetic acid ear drops: acetic acid otic solutions (2%) are used medically for external otitis (swimmer's ear) — safe at this concentration in clinical use, but higher concentrations should not be instilled in ears. Hair care products: acetic acid rinses (dilute, 1–3%) are used after alkaline hair treatments (permanent waves, relaxers) to restore hair pH — safe at these concentrations with standard rinse-off. Industrial worker protection: concentrated acetic acid handling requires acid-resistant gloves (nitrile or neoprene), face shield, and chemical-resistant apron; emergency eyewash and shower required at work stations. Ecological note: acetic acid in large quantities (industrial runoff) can lower aquatic pH and deplete dissolved oxygen — biodegrades readily via BOD.
Regulatory consensus
3 regulatory and scientific bodies have classified Acetic acid. The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| OSHA | — | Occupational exposure limit | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 5 positive / 6 negative reports) | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 5 positive / 6 negative reports) |
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 you encounter acetic acid
- Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
- Occupational Environments — Factories, Warehouses, Transportation vehicles
- Food — processed food, beverages, candy, baked goods
-
Fragrance
— perfume, cologne, scented personal care products, household fragrance products, candles
Identified in Fragrance Ingredient Safety Priority Research database (2,325 ingredients)
Safer alternatives
Lower-risk approaches that achieve a similar outcome to Acetic acid:
-
Physical/mechanical pest control (IPM)
Trade-offs: More labor-intensive. May not be sufficient for severe infestations.Relative cost: 1.2-2×
Frequently asked questions
Is acetic acid safe for you?
Skin contact hazard from acetic acid is concentration-dependent: dilute solutions (household vinegar, 5%) cause minimal irritation with prolonged contact; concentrated industrial acetic acid (>25%, glacial) causes significant corrosive burns similar in mechanism to other carboxylic acids. Dilute exposure (food-grade vinegar): prolonged skin contact with vinegar (5% acetic acid) may cause mild irritation and maceration with extended contact but poses no significant burn risk — used therapeutically for jellyfish sting treatment (deactivates nematocysts) and as a dilute antiseptic. Concentrated acetic acid burns: glacial acetic acid (99.5%) or concentrated solutions (>25%) cause immediate burning pain, erythema, and at high concentrations, blister formation and coagulative necrosis similar to other strong organic acid burns; the burn injury is less severe than equivalent concentration mineral acids (H₂SO₄, HCl) due to slightly higher pKa (4.76 vs. <<0 for mineral acids), but still clinically significant. Vinegar and acetic acid ear drops: acetic acid otic solutions (2%) are used medically for external otitis (swimmer's ear) — safe at this concentration in clinical use, but higher concentrations should not be instilled in ears. Hair care products: acetic acid rinses (dilute, 1–3%) are used after alkaline hair treatments (permanent waves, relaxers) to restore hair pH — safe at these concentrations with standard rinse-off. Industrial worker protection: concentrated acetic acid handling requires acid-resistant gloves (nitrile or neoprene), face shield, and chemical-resistant apron; emergency eyewash and shower required at work stations. Ecological note: acetic acid in large quantities (industrial runoff) can lower aquatic pH and deplete dissolved oxygen — biodegrades readily via BOD.
What products contain acetic acid?
Acetic acid appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); processed food (Food).
Why do regulators disagree about acetic acid?
Acetic acid has been classified by 3 agencies including OSHA, 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 Acetic acid in the body app
Look up products containing acetic acid, compare to alternatives, and explore the full data record.
Open in body View raw API dataSources (2)
- NIOSH Pocket Guide: Acetic Acid — IDLH 50 ppm; PEL 10 ppm; glacial acetic acid burns; flammable liquid; industrial uses; corrosive concentrations; occupational monitoring (2019) (2019) — regulatory
- FDA GRAS: Acetic Acid and Vinegar — GRAS food additive; pickling; preservation; ACV supplement concerns; esophagitis; otic solution clinical use; biological metabolite (2021) (2021) — 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 →