Chlorine is the 19th most abundant chemical element in the Earth. While elemental chlorine (Cl2 gas) is almost never found in nature, over 2,000 naturally occurring chlorine-containing compounds have been identified in living organisms. Chlorine is also found at some level in virtually every rock on Earth.
Chlorine is produced from one of nature’s most plentiful and inexhaustible minerals—common salt, sodium chloride— as well as potassium chloride. Chlorine is produced using the “chlor-alkali process.” In this process, electricity is applied to a solution of salt water (brine). The electricity separates sodium from chloride and produces chlorine gas, hydrogen gas and caustic soda (sodium hydroxide) solution.
Chlorine effectively destroys a wide range of disease-causing bacteria, viruses and parasitic protozoa.
While chlorine is a chemical element, chlorine bleach is essentially "chlorine to go" providing a convenient vehicle for delivering the germ-busting power of chlorine chemistry. Chemically speaking, chlorine bleach is a solution of the compound sodium hypochlorite. Common household laundry bleach, used to whiten and disinfect laundry, is typically either 5.25 percent (“regular strength”) or 6 percent sodium hypochlorite (“ultra strength”).
Disinfection byproducts, or DBPs, are unwanted chemical compounds formed when chlorine or other disinfectants react with natural organic matter in water. Water treatment operators throughout the country work to minimize the levels of these substances in US drinking water below maximum levels set by EPA.
Used properly, consumers can safely use bleach without significant environmental effects. As chlorine bleach breaks down germs and stains, between 95 and 98 percent of it breaks down and transforms into mostly salty water. Importantly, waste water treatment facilities use chlorine disinfectants to destroy oxygen-robbing contaminants in wastewater, helping to preserve the quality of our nation’s rivers and streams into which the treated wastewater is discharged.