Bleach + Hydrogen peroxide
Oxygen gas
Don't mix bleach and hydrogen peroxide. Washington State DOH says bleach reacts with hydrogen peroxide. [1]
If you already mixed
Leave the area right away and get to fresh air. For household cleaners, open windows and doors to let in fresh air, and stay away until the gas has gone away. [2] [3]
Call 911 for any trouble breathing or swallowing. [2]
Eyes: rinse with lots of room-temperature running water for at least 15 to 20 minutes. [4]
Remove contaminated clothing; wash skin with soap and water. [5] [6] [2]
For mild symptoms or questions, call Poison Help 1-800-222-1222. [2]
A fading smell is not an all-clear: the smell may not be noticeable to people exposed many times, and chlorine gas is heavier than air, so it may linger near the ground. [6]
The Missouri Poison Center lists hydrogen peroxide among the things never to mix with bleach. [7]
The NJ fact sheet says sodium hypochlorite is incompatible with hydrogen peroxide: the reaction may release oxygen gas and can cause a closed container to burst (rupture). [5]
Rapid fizzing or foaming can splash bleach onto skin or eyes. CCOHS warns that corrosive cleaning products can burn skin and eyes. [5] [8]
Chemicals
Sources
- Washington State Department of Health — Dangers of Mixing Bleach with Cleaners retrieved 2026-10-27
- Washington Poison Center — Chloramine Gas retrieved 2026-10-27
- Centers for Disease Control and Prevention — Chlorine fact sheet retrieved 2026-10-27
- National Capital Poison Center (Poison Control) — Help for poisons splashed in the eye retrieved 2026-10-27
- NJ Department of Health — Hazardous Substance Fact Sheet: Sodium Hypochlorite retrieved 2026-10-27
- National Capital Poison Center (Poison Control) — Chlorine gas retrieved 2026-10-27
- Missouri Poison Center — Some Things Just Don't Mix: Poison Center Tips for Chemicals retrieved 2026-10-27
- Canadian Centre for Occupational Health and Safety (CCOHS) — Cleaning Products - Working Safely retrieved 2026-10-27