Bleach Toxicity(Archived)

Excerpt

Bleach refers to a large class of compounds used to whiten or color-lighten materials. They are frequently used for cleaning and disinfection; bleaches kill or control most types of viruses, bacteria, molds, mildews, and algae. Other, less documented, uses include weed killing and preservation of cut flowers. As such, bleaches are ubiquitous.

Bleach is chlorine-based such as calcium hypochlorite (bleaching powder) and non-chlorine (peroxidase-based).

Bleaching action occurs through oxidation or reduction. Chlorine bleaches work through oxidation; they break the chemical bond of the chromophore (a color-producing portion of pigment) rendering it non-reactive with light. Reductions convert double bonds to single bonds, again making them non-reactive to visible light.

An additional interesting and useful property of bleaches relates to their antimicrobial (disinfecting) properties. Winter et al. observed that bleaches disinfect by denaturing (unfolding) bacterial proteins, causing them to clump and become useless. This is the same reaction as cooking an egg; in the same fashion, an egg cannot be uncooked.

Bleach, as subsequently used here, refers to common household bleach. Bleach contains 3% to 8 % sodium hypochlorite (NaOCl); sodium hydroxide (NaOH) is added to slow decomposition. There are industrial and concentrated forms of bleach that are used to clean equipment and treat water supplies, which are not covered here. For concerns and exposures, see the individual exposure MSDS (Material Safety Data Sheet.)

With the appearance of coronavirus, interest in sanitizing has increased.

Bleach is a very good sanitizer; it kills coronavirus within a minute of contact with 0.1% dilution of hypochlorite bleach.