What Is Sodium Hypochlorite?

Sodium hypochlorite is the chemical in bleach. ATSDR says it is generally used dissolved in water, forming clear, greenish to yellow solutions with an odor of chlorine, and that sodium and calcium hypochlorite are used mainly as bleaching agents or disinfectants in commercial bleaches, cleaning solutions, and disinfectants for drinking water, wastewater and swimming pools. CDC says most household bleach contains 5 to 9 percent sodium hypochlorite.

Handle it carefully. CDC says never to mix household bleach, or any disinfectant, with other cleaners or disinfectants, because this can release vapors that may be very dangerous to breathe in. ATSDR says hypochlorite's toxic effects come mainly from its corrosive properties, that swallowing a small amount of 3 to 6 percent household bleach may cause gastrointestinal irritation, that more concentrated commercial bleach of 10 percent or higher can cause severe corrosive injuries and death, and that inhaling chlorine gas released from concentrated solutions may cause nasal irritation, sore throat and coughing.

It also disinfects water and food equipment. For emergency drinking water, the EPA says to use only regular, unscented chlorine bleach labeled suitable for disinfection and sanitization, which may list 6 or 8.25 percent sodium hypochlorite, adding for example 8 drops of 6 percent bleach or 6 drops of 8.25 percent bleach per gallon, and doubling that if the water is cloudy, colored or very cold. FDA rules at 21 CFR 178.1010 allow sanitizing solutions containing sodium, potassium or calcium hypochlorite, used and adequately drained before contact with food.