Never mix Hydrogen peroxide with Acetic acid (vinegar)
Respiratory irritation
Peracetic acid is formed, which irritates the eyes, skin and lungs. This is a materially less severe outcome than the chlorine and chloramine hazards, but the combination is widely recommended online as a produce wash and a surface treatment, usually with the reassurance that neither ingredient is anything to worry about.
Precautions
- Never mix with other cleaning products
- Ventilate the area
- Wear eye protection
- Rinse thoroughly afterwards
How this happens
Hydrogen peroxide and acetic acid together form peracetic acid, an oxidising agent used industrially as a disinfectant precisely because it is more aggressive than either starting material. The everyday route to it is the popular advice to spray a surface with one and then the other, which is presented as a two-step natural cleaning method rather than as mixing two chemicals — and which is mixing two chemicals.
If it has already happened
Get everyone into fresh air straight away, and do not go back inside to open windows. Anyone with breathing difficulty, chest pain, persistent coughing, or a chemical splash to the eyes needs medical attention — treat it as an emergency and call your local emergency number. In the United Kingdom, use NHS 111 or 999 as appropriate; clinicians can consult the National Poisons Information Service.
The substances involved
- Hydrogen peroxide — An oxidising bleach that breaks down into water and oxygen. Genuinely milder than chlorine bleach, and not therefore safe to combine with anything.
- Acetic acid (vinegar) — The acid in vinegar. Genuinely effective on limescale and mineral films, and routinely recommended for surfaces it should never touch.
Evidence
Supported
Sources
Hazard Alert — Worker Health and Safety: Mixing Bleach with Other Cleaning Products Can Be Deadly
New Jersey Department of Health, Environmental and Occupational Health Surveillance Program · Government or regulator
Relied on for: That hydrogen peroxide combined with vinegar forms peracetic acid, which can irritate the eyes, skin and lungs. (states this directly)