Formic acid on your skin: a safety profile
Moderate riskSkin contact with concentrated formic acid (>10%) causes corrosive chemical burns — formic acid penetrates skin rapidly and causes both local corrosive injury and systemic absorption contributing to formate toxicity. Chemical burns from formic acid: concentrated formic acid (85%, as used industrially) causes immediate, painful chemical burns on contact — characteristically forming white, rigid eschars with a pronounced 'waxy' appearance from protein coagulation; the burns penetrate deeply due to formic acid's ability to disrupt skin protein structure and penetrate through the stratum corneum. Systemic absorption through burns: formate absorbed from formic acid skin burns inhibits cytochrome c oxidase — large-area burns with concentrated formic acid have caused severe systemic formate toxicity (metabolic acidosis, optic neuropathy) analogous to methanol poisoning, with documented fatalities from whole-body dermal burns. Agricultural worker exposure: formic acid is used as a silage preservative and beekeeping treatment (varroa mite control) — agricultural workers handling 85% formic acid without adequate PPE face significant burn risk; beekeepers using formic acid pads for mite treatment should use appropriate gloves and avoid inhalation of vapors in warm conditions. Dilute formic acid (food-grade, <10%): causes irritation rather than burns; household cleaning products containing formic acid (descalers) are typically formulated at 5–15% — requires skin precaution during use but is less hazardous than industrial concentrations. Treatment: copious water irrigation for ≥20 minutes; monitor for systemic formate toxicity (metabolic acidosis, visual changes) following large-area burns; folinic acid (leucovorin) treatment for systemic formate poisoning accelerates formate elimination via folate-mediated oxidation.
What is formic acid?
Also known as: Methanoic acid, Formylic acid, Aminic acid, Bilorin.
- IUPAC name
- formic acid
- CAS number
- 64-18-6
- Molecular formula
- CH2O2
- Molecular weight
- 46.025 g/mol
- SMILES
- C(=O)O
- PubChem CID
- 284
Risk for people
Moderate riskSkin contact with concentrated formic acid (>10%) causes corrosive chemical burns — formic acid penetrates skin rapidly and causes both local corrosive injury and systemic absorption contributing to formate toxicity. Chemical burns from formic acid: concentrated formic acid (85%, as used industrially) causes immediate, painful chemical burns on contact — characteristically forming white, rigid eschars with a pronounced 'waxy' appearance from protein coagulation; the burns penetrate deeply due to formic acid's ability to disrupt skin protein structure and penetrate through the stratum corneum. Systemic absorption through burns: formate absorbed from formic acid skin burns inhibits cytochrome c oxidase — large-area burns with concentrated formic acid have caused severe systemic formate toxicity (metabolic acidosis, optic neuropathy) analogous to methanol poisoning, with documented fatalities from whole-body dermal burns. Agricultural worker exposure: formic acid is used as a silage preservative and beekeeping treatment (varroa mite control) — agricultural workers handling 85% formic acid without adequate PPE face significant burn risk; beekeepers using formic acid pads for mite treatment should use appropriate gloves and avoid inhalation of vapors in warm conditions. Dilute formic acid (food-grade, <10%): causes irritation rather than burns; household cleaning products containing formic acid (descalers) are typically formulated at 5–15% — requires skin precaution during use but is less hazardous than industrial concentrations. Treatment: copious water irrigation for ≥20 minutes; monitor for systemic formate toxicity (metabolic acidosis, visual changes) following large-area burns; folinic acid (leucovorin) treatment for systemic formate poisoning accelerates formate elimination via folate-mediated oxidation.
Regulatory consensus
3 regulatory and scientific bodies have classified Formic acid. The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| OSHA | — | Occupational exposure limit | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 7 positive / 7 negative reports) | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 7 positive / 7 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 formic 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 Formic 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 formic acid safe for you?
Skin contact with concentrated formic acid (>10%) causes corrosive chemical burns — formic acid penetrates skin rapidly and causes both local corrosive injury and systemic absorption contributing to formate toxicity. Chemical burns from formic acid: concentrated formic acid (85%, as used industrially) causes immediate, painful chemical burns on contact — characteristically forming white, rigid eschars with a pronounced 'waxy' appearance from protein coagulation; the burns penetrate deeply due to formic acid's ability to disrupt skin protein structure and penetrate through the stratum corneum. Systemic absorption through burns: formate absorbed from formic acid skin burns inhibits cytochrome c oxidase — large-area burns with concentrated formic acid have caused severe systemic formate toxicity (metabolic acidosis, optic neuropathy) analogous to methanol poisoning, with documented fatalities from whole-body dermal burns. Agricultural worker exposure: formic acid is used as a silage preservative and beekeeping treatment (varroa mite control) — agricultural workers handling 85% formic acid without adequate PPE face significant burn risk; beekeepers using formic acid pads for mite treatment should use appropriate gloves and avoid inhalation of vapors in warm conditions. Dilute formic acid (food-grade, <10%): causes irritation rather than burns; household cleaning products containing formic acid (descalers) are typically formulated at 5–15% — requires skin precaution during use but is less hazardous than industrial concentrations. Treatment: copious water irrigation for ≥20 minutes; monitor for systemic formate toxicity (metabolic acidosis, visual changes) following large-area burns; folinic acid (leucovorin) treatment for systemic formate poisoning accelerates formate elimination via folate-mediated oxidation.
What products contain formic acid?
Formic 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 formic acid?
Formic 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 Formic acid in the body app
Look up products containing formic acid, compare to alternatives, and explore the full data record.
Open in body View raw API dataSources (2)
- NIOSH Pocket Guide: Formic Acid — IDLH 30 ppm; PEL 5 ppm; cytochrome c oxidase inhibition; metabolic acidosis; optic neuropathy; chemical burns; agricultural/beekeeping exposure; folinic acid treatment (2019) (2019) — regulatory
- CDC/ATSDR: Formic Acid — ant/bee venom component; methanol metabolite connection; corrosive burns; systemic formate toxicity; hemodialysis; optic nerve injury; silage preservative; beekeeping varroa treatment (2020) (2020) — 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 →