Some everyday cleaners release toxic gas when combined. This guide lists the pairings to avoid, what they produce and what to do if it happens.
The CDC's guidance on cleaning with bleach says plainly not to mix household bleach with any other cleaner or disinfectant, because it can release vapors that are very dangerous to breathe. The same CDC home-cleaning guidance extends the idea to products generally: do not mix products or chemicals with each other.
Following that single rule avoids every combination below. You do not need to memorize a chart. Use one product at a time, rinse the surface and let the room air out before you try a different one.
The risk is highest in small, closed spaces such as bathrooms, laundry rooms and utility closets, where gas has nowhere to go. A product that is safe to use alone in a ventilated room can still cause trouble if you add another product to the same surface before the first has been rinsed away.
A workplace health alert on mixing cleaners, from the New Jersey Department of Health, lists the following reactions. Some of these products are sold under many brand names, so check the ingredient list for the active chemical, not the logo.
Two entries in the table deserve a note. Drain cleaners and oven cleaners are strong and caustic on their own, and adding bleach makes them worse. If a drain is slow to clear, resist the urge to try product after product; a plumber can solve the problem without a chemical accident.
| Do not combine | What can result | Main effects |
|---|---|---|
| Bleach and ammonia | Chloramine gas | Coughing, shortness of breath, chest pain, wheezing, watery eyes; severe cases can cause fluid in the lungs |
| Bleach and acids (vinegar, lemon juice, rust or lime removers, some toilet bowl cleaners) | Chlorine gas; vinegar can also produce chloramine | Irritation of eyes, nose and throat, coughing, breathing problems; high exposure can be fatal |
| Bleach and rubbing alcohol | Chloroform | Dizziness, nausea, headaches, loss of consciousness |
| Bleach and drain cleaners or oven cleaners | Chlorine gas | Irritation of the respiratory system; drain cleaner mixtures can cause long-term harm |
| Hydrogen peroxide and vinegar | Peracetic acid | Irritation of eyes, skin and lungs |
| Different brands of drain cleaner | Dangerous reaction | Never combine them |
Few people pour bleach into ammonia on purpose. Accidents usually come from sequence. Someone cleans a toilet with one product, then adds another to 'finish the job'. A sponge holding one chemical is rinsed into a bucket holding another. A bleach cleaner is sprayed on a surface where a vinegar solution was just used.
Ammonia turns up in some glass cleaners, and bleach in many mildew, toilet and general-purpose cleaners, so you can combine them without realizing it. Reading the label of each product before use is the only reliable defense. Our green cleaning guide covers the 'natural' pair people often combine, vinegar and baking soda, and why the vinegar-and-bleach combination in particular is a mistake.
Bathrooms are a frequent setting because they contain so many products at once: toilet bowl cleaner, tile cleaner, mildew remover and drain cleaner, often within arm's reach. Using one product, rinsing, and leaving the room to air before the next product is a habit worth building.
A handful of habits remove most of the risk, whether you are cleaning a home or running a workplace.
Label reading includes checking the 'do not mix' statement, which many products print on the back. If a product does not name its main ingredients, look up its safety data sheet, which manufacturers publish and which lists the hazards and incompatible substances.
Leave the area immediately and get to fresh air. Do not stay to clean up the spill. If someone has trouble breathing, collapses or has severe symptoms, call 911. For advice on milder exposure, call Poison Control at 1-800-222-1222, the national number in the United States.
Do not return until the room has been ventilated and the source dealt with by the label directions. Anyone with asthma or lung conditions should be especially cautious, since reports of serious harm in the New Jersey alert involved people with such conditions.
After any exposure, tell a clinician or Poison Control what products were involved and roughly how long you were exposed. Bring the containers or photograph the labels, since the ingredient list can guide treatment.
Employers whose staff use cleaning chemicals have training and labeling duties under the federal hazard communication standard, 29 CFR 1910.1200, which includes keeping safety data sheets available. If you manage a workplace, our commercial cleaning page and office cleaning checklist discuss how to scope chemical use. When you are unsure whether a product is safe with another, treat it as unsafe and ask the manufacturer.
If you hire a service, ask which products they use and whether they bring their own. A clear policy on not mixing products, and on labeling every bottle, is a sign of careful practice and costs nothing to ask about.
No. Bleach combined with acids such as vinegar can release chlorine gas, and vinegar can also produce chloramine. Use one product at a time.
The health alert lists this pair as producing peracetic acid, which irritates eyes, skin and lungs. Do not store or apply them as a mixed solution.
Leave the area, get fresh air and ventilate the room if you can do so safely. Call 911 for severe symptoms and Poison Control at 1-800-222-1222 for advice.
Describe the space and the kind of clean you want, and we will reply with next steps.