Each year, thousands of Americans call their local poison control centers—and some are even hospitalized—because they are unaware of the dangers of mixing household cleaners. Countless others experience burning eyes, sore throats, headaches, nausea, and difficulty breathing as a result.

A BRIGHTENER'S DARK SIDE 

Chlorine bleach whitens, brightens and generally lightens the load on cleaning day. It’s great for removing stains and is a powerful disinfectant. But as any label will tell you, there are two things you should never mix with chlorine bleach: ammonia and acids.

Favored for its degreasing action, ammonia combines with chlorine bleach to form harmful vapors called chloramines. Acids, found in a variety of products and naturally in vinegar and lemon juice, can turn liquid chlorine into chlorine gas.

When inhaled, chloramines and chlorine gas damage the mucous membranes in the respiratory system, causing acute irritation of the nose, throat and lungs. Prolonged exposure can make it difficult for the lungs to extract oxygen from the air.

The American Association of Poison Control Centers tallied 3,380 cases of chloramine exposure and 1,127 cases of chlorine gas exposure in 1996. Most were treated at home with fresh air and water. However, about 700 people required medical attention, and a handful suffered permanent lung or neurological damage. At least one exposure to chlorine gas was fatal.

Although it’s easy to remember not to pour straight ammonia into a bucket of bleach, you should never mix household chemicals. Formulations change frequently, and you can never be sure exactly what chemicals are in a product.

POW! RIGHT IN THE KITCHEN! 

A less common but real danger lurks in the plumbing under your kitchen sink. Most commercial drain openers are chemically basic, rather than acidic. When the greasiest, most stubborn clogs refuse to break up, some people resort to using sulfuric acid on top of what they tried first.

The result? “It’s like a volcano. There’s a second or two of fizzing, then pow!” says Donald Wink, a chemistry professor at the University of Illinois at Chicago. “When the bases and acids neutralize each other, they create enough heat to boil the water and cause splatter.”

DO THE ALTERNATIVES MATCH UP? 

BAKING SODA

Chemical reactions can be avoided by using food-grade products instead of commercial cleaners. Mold or mildew can be removed with equal parts vinegar, a natural disinfectant, and salt, an abrasive. Home recipes exist for ink spots (cream of tartar, lemon juice and water), toilet bowls (baking soda and castile soap) and windows (vinegar and warm water).

ARE THEY SAFE? 

The greatest danger in using homemade cleaners is storing them in unmarked containers. Even “natural” cleaners, like lemon juice, are made of chemicals such as citric acid that can react negatively with other substances. To prevent problems, always list the exact ingredients on the container so a poison-control center will know how to respond in an emergency.

DO THEY WORK?

Mix-at-home recipes work better than plain water, but studies show they pale in comparison to commercial products. According to a study published in the Journal of Environmental Health, alternative cleaners such as lemon juice, vinegar and baking soda were less effective both as disinfectants and as soil removers than conventional cleaners.

REMEMBER THIS FORMULA: BLEACH + AMMONIA = POISON FUMES!