Ever since a Scottish chemist mixed chlorine gas with limestone back in 1799 to create chlorine bleach (sodium hypochiorite), the world has been a cleaner, less dangerous place. This compound quickly caught on as a whitener for clothing and writing paper and later as a mildew remover for washable surfaces.

Chlorine is added to everything from household cleansers, vinyl, plastics, and wood pulp and recycled paper to swimming pools and washing machines. The same chlorine found in bleach is an excellent disinfectant for drinking water. Very small amounts are used to help purify the water supply of many cities in the U.S. and Canada. In the case of chlorinated drinking water, the problem is that chlorine undergoes many changes when added to water, forming small amounts of potentially cancer causing by products such as trihalomethanes.

Are these compounds indeed harmful?

The question has been under study for two decades and the research at this point indicates that chlorinated drinking water probably doesn't increase cancer risk.

Household hazards

Chlorine bleach leaches out the dyes in fabric that is not colorfast, and if not properly diluted, it eats holes through the fabric. It will not remove rust and can discolor clothing washed in water that has a high iron content.

Even more serious are the health hazards associated with chlorine bleach. Never mix chlorine bleach with products that contain ammonia; the fumes caused by these combinations can be lethal. Also avoid combining chlorine bleach with acids, such as vinegar, or other household products containing acids, such as drain openers, toilet bowl cleaners, or rust removers; these blends may also emit hazardous gases. To avoid any problems, check the labels on household detergents for ammonia and acids before adding chlorine bleach to them.

Sensitive to chlorine?

Chlorine is not an allergen, but some people may find that fabrics washed in it can be irritating to their skin. Good substitutes for chlorine bleach in your laundry are the non chlorine bleaches. To help your wash look cleaner, pre treat stains with detergent and presoak clothes that is very dirty. Use the hottest water that your fabrics can stand, and add a little extra detergent to each load.

Chlorine and the environment

Laundry bleach biodegrades harmlessly into oxygen, salt, and water. Unlike some chlorines employed in industry, laundry bleach poses no environmental threat.

Chlorine bleach not only brightens laundry, it also removes mildew from your house's exterior. Always dilute it, using one part bleach to three parts water.

If bleach splashes into your eyes, flush them with water for 15 minutes, then call your doctor. If bleach is swallowed, do not induce vomiting. Immediately drink 180 milliliters (6 ounces) of water, milk, or milk of magnesia. Then call your Poison Control Center.