Chapter 10: Acids and alkalis · Part 2: Acids
Acetic acid
- Poison schedule (Australia)
- Made from a hazardous chemical
- Contaminant risk
The worst fact: at high strength, swallowing as little as 1 mL has perforated the oesophagus. Table vinegar (4 to 10%) in the eye causes immediate pain and, in some cases, injury to the surface of the eye. Above 30% it's a Schedule 5 Poison in Australia, and above 80% a Schedule 6 Poison. Table and most cleaning vinegars are well below 30% and aren't scheduled.
Why brands use it: it dissolves limescale and soap scum, and it's cheap and familiar.
Take care if: you have children, marble or limestone, or a kettle used for baby formula. In a Finnish study of children treated from 1976 to 1990, household vinegar was the acid swallowed most often (12 of 23). Never mix vinegar with bleach.
Comes from: brewed vinegar is made by fermenting alcohol. Imitation vinegar, and many strong vinegars, are acetic acid mixed with water; industrial acetic acid is mostly made from methanol and carbon monoxide, the most cost-efficient method. Australia classes carbon monoxide as "May damage the unborn child." That doesn't mean it's in the product, but it's not a great starting point for something you clean with.
Myth check: "Vinegar disinfects": not reliably at household strength. A Melbourne lab found vinegar "completely ineffective" against the COVID-19 virus after 30 seconds or 5 minutes, while dishwashing detergent and bleach worked. It kills some germs at higher strength or with long contact.
Contaminants: formic acid, acetaldehyde and mercury are sometimes found in industrial acetic acid. They're unlikely in a well-made product, but it's a factor you can't see on the label.
Fair to say: people have eaten vinegar for centuries without harm. Australian vinegar must be at least 4% acetic acid (40 g/kg). It's the strength that matters.
Correct as of November 2026. What the badges mean
Sources
- Australian Government. Poisons Standard October 2026 (SUSMP), F2026L01327: sodium hydroxide, potassium hydroxide, alkaline salts, monoethanolamine, sulfamic acid, hydrochloric acid, acetic acid; Appendix B (sodium bicarbonate).
- Safe Work Australia. Hazardous Chemical Information System (HCIS): classifications for each chemical, and for ethylene oxide, carbon monoxide and acetaldehyde.
- AICIS / NICNAS. IMAP assessments: soluble silicates; ethanolamine (2013); hydrochloric acid (Tier II 2014, Tier III 2018); acetic acid (2013).
- FSANZ. Food Standards Code, Standard 2.10.1: vinegar.
- HSDB (US National Library of Medicine), via PubChem: production and impurity data for each chemical.
- Nuutinen M et al. Consequences of caustic ingestions in children. Acta Paediatr 1994.
- Almeida et al. Household cleaning products and SARS-CoV-2. Viruses 2022.
- Johnston CS, Gaas CA. Vinegar: medicinal uses and antiglycemic effect. MedGenMed 2006;8(2):61.
- Kilah N. Cleaning with vinegar and baking soda. The Conversation, 2024.
The full source list is at the end of Chapter 10.