Cleaning safety

Cleaning Products You Should Never Mix

Some everyday cleaners are perfectly safe on their own — but combined, they release toxic gas. Here are the mixes to never make, and what to do if it happens.

The golden rule

Use one cleaning product at a time, in a well-ventilated room, and never combine products — especially anything containing bleach. Most dangerous reactions involve bleach meeting an acid or ammonia.

The dangerous combinations

Bleach + ammonia → chloramine gas

This is the most common serious mix-up. Ammonia hides in many glass and window cleaners, dishwasher detergents and drain cleaners. The chloramine gas that forms irritates the eyes and airways, and in higher concentrations can cause nausea, vomiting and lasting lung damage.

Bleach + vinegar → chlorine gas

People reach for both as disinfectants, but the acid in vinegar reacts with bleach to release chlorine gas. Even low levels irritate the eyes, nose and throat; higher levels can cause severe breathing trouble. Many glass cleaners and toilet-bowl cleaners are acidic too, so the same warning applies.

Bleach + rubbing alcohol → chloroform

Combining bleach with isopropyl alcohol produces chloroform and other harmful compounds. Store the bottles well apart and never use them together.

Hydrogen peroxide + vinegar → peracetic acid

Mixed together (not layered on a surface), these form peracetic acid, which is corrosive and irritates skin, eyes and airways.

If you accidentally mix products and smell a sharp odour: leave the room immediately, open windows and doors, and don’t go back until the air clears. Seek medical advice if you feel any breathing symptoms.

How to stay safe

• Read the label before using any product — look for “bleach”, “ammonia” or acid ingredients.
• Use one product at a time and rinse surfaces between different cleaners.
• Always ventilate — open a window or run a fan.
• Never decant cleaners into unlabelled bottles.
• Wear gloves, and eye protection when using bleach.

General safety information only, based on guidance from public-health sources (WA Dept. of Health, NJ Dept. of Health, TURI). In an emergency, call 000. For poisoning advice in Australia, call the Poisons Information Centre on 13 11 26.