“Certain cleaning chemicals can be very poisonous when mixed together, and in general cleaning products should never be mixed together because of the risk of unwanted toxic inhalation effects," says Kelly Krisna Johnson-Arbor, MD, FACEP, FUHM, FACMT, medical toxicologist, co-medical director and interim executive director of the National Capital Poison Center. Furthermore, while many people may think that mixing products makes cleaning faster or more effective, according to Dr. Johnson-Arbor, that isn’t necessarily true. That saying about having too much of a good thing rings especially true here. So, keep it simple and stay safe by never mixing up the dangerous cleaning product combinations below.
Toilet Bowl Cleaner and Bleach
Toilets can get pretty dirty, and sometimes one go-round with toilet bowl cleaner and a quick brushing isn’t quite enough to remove all the surface gunk. So, while you might be tempted to finish off the job by pouring in some bleach—it’s best to avoid temptation. Dr. Johnson-Arbor tells me this is a dangerous mix. “Combining toilet bowl cleaner and bleach can make chlorine gas," she says. “For healthy people, inhalation of either of these gases can cause coughing, irritation of the nose and throat, and even trouble breathing. For those who have asthma, COPD, or other lung diseases, serious respiratory problems can occur after inhalation of these chemicals and can even result in death.” While this rule might not apply to every toilet bowl cleaner on the market, it’s generally unsafe to mix bleach with anything. If you are exposed to any of these chemicals and have difficulty breathing, Dr. Arbor-Johnson suggests going outside immediately to get fresh air. “If the irritating symptoms persist after 10 to 15 minutes or if you have a history of asthma or other lung diseases, you may need to go to an urgent care center or emergency room for specialized treatment.”
Bleach and Ammonia
Jenna Arkin, chief innovation officer for ECOS, a brand of non-toxic cleaning products, says there is no federal law that requires ingredient disclosure on cleaning product labels. So, oftentimes consumers unintentionally combine things they shouldn’t. One of the most common examples of this is bleach and ammonia. “Chlorine bleach—found in whitening laundry products, toilet cleaners, and some disinfectants—mixed with ammonia, most often found in window cleaners, results in a chemical reaction that creates a toxic fume of chloramine gas,” Arkin says. “In high enough concentration, this gas can be lethal.” While many cleaning products that contain bleach state it prominently on the front of the label as a selling point, it may be less obvious for products with ammonia. Be sure to read the back of the bottle if it isn’t listed on the front. And, when in doubt, look for labels that promote ammonia-free formulas.
Bleach and Vinegar
Mixing pure chlorine bleach, like Clorox bleach, or bleach-based products (like Lysol Mold and Mildew Remover With Bleach) and white vinegar, cleaning vinegar, or even non-toxic vinegar-based solutions (like Aunt Fannie’s Cleaning Vinegar) can be hazardous. “[Mixing] bleach and vinegar—or any acid or acidic product, such as toilet cleaner—[creates] chlorine gas,” says David A. Walla, PhD, lead scientist for Defunkify. “This can lead to coughing, breathing problems, burning, and watery eyes.” If you accidentally create chlorine gas, Dr. Walla says to avoid any impulse to “water it down.” Chlorine gas and water combine to make hydrochloric and hypochlorous acids, which are also irritants. Instead, remove yourself, your family, and any pets from the area, get fresh air, monitor your symptoms, and seek medical attention if needed.
Hydrogen Peroxide and Vinegar
Considering mixing hydrogen peroxide-based products (such as Lysol Multi-Purpose Cleaning Spray) with vinegar? Dr. Walla warns that hydrogen peroxide and vinegar create peracetic acid. This combination isn’t just highly corrosive but also poses danger to the eyes, skin, throat, nose, and even the lungs.
Drain Cleaner and Bleach
Do your pipes have a stinky odor? You might think that pouring in bleach after drain cleaner is the trick to eliminating that smell, but Carol Mehas, founder of eco-friendly cleaning brand Arbour, warns that this can be incredibly dangerous. “It’s a recipe for a lethal reaction to take place in a very small pipe. Drain cleaners are usually made with lye, also known as sodium hydroxide, to chemically break apart buildup and caustic potash to speed the destruction of organic matter—the yucky hair and soap scum lining your drain,” she says. “Since your drain is a small confined space, the noxious gasses that form from the chemical reactions taking place have nowhere to go but straight up the drain, back into your shower.” Mehas cautions that if this combination is inhaled, it can burn your mouth and throat or potentially cause lung damage.
Different Brands of Drain Cleaners
Clogged drains are frustrating, and if Drano doesn’t work the first time, you might be tempted to try another brand, such as Liquid-Plumr. However, cleaning and design expert Stefan Bucur of Rhythm of The Home tells me this is a combination to avoid. “Some drain cleaners are alkaline-based while others are acid-based," Bucur says. “[The combination] can cause the release of chlorine gas, or worse, an explosion.” So, either pour some more of the product you already used down the drain and wait for it to fully work, or call a professional for help.
Bleach and Rubbing Alcohol
Trying to disinfect your bathtub or countertop? Don’t combine bleach and rubbing alcohol, because it creates chloroform. “This highly toxic combination can harm the eyes, skin, liver, kidneys, and nervous system,” Dr. Walla says. Even if you aren’t using pure rubbing alcohol for cleaning, note that many popular cleaning products contain this ingredient, such as Fantastik Multi-Purpose Cleaner, Clorox Wipes, and Lysol Wipes.
Oxalic Acid and Trichloroisocyanuric Acid
Oxalic acid-based cleaners, such as Bar Keepers Friend, are great for removing stuck-on food and grease from pans and stovetops, but be sure to avoid mixing them with products that have trichloroisocyanuric acid, such as Ajax and Comet powders. “Like many other bad cleaning product combos, this can create chlorine gas,” Bucur says.
