For a very long time, the only real laundry bleach on the market was chlorine bleach, popularized by industry leaders, such as Clorox. Bleach is not only used for stain removal in laundry, but to clean and sterilize objects and surfaces. Chlorine bleach is not good for every fabric and has a very harsh smell, so oxygen bleaches were developed that clean as well as chlorine bleaches in most applications, but are safer on fabrics and are less harsh. Both are effective, but one may be preferable over the other depending on the application.
Chlorine beach is sodium hypochlorite, diluted with water to around a five percent concentration. Manufacturers make it by heating lye (sodium hydroxide) or quicklime (calcium hydroxide) and allowing chlorine gas to bubble up through it. They then add water to the right concentration. Chlorine bleach is highly caustic. It will eat away fabric and skin if left on for an extended period, especially at full strength and take away color. Chlorine bleach is typically diluted even further when used for stain removal or cleaning. It is an unstable product that begins to lose its effectiveness after manufacturing and becomes ineffective over time, and must be stored in a cool, dark place in a plastic container.
Oxygen bleach is hydrogen peroxide with some sodium and sometimes carbon added to it to form a compound that releases the hydrogen peroxide when added to water. Oxygen leach is a more highly concentrated product than chlorine bleach. Many times, it is found in powdered form, which is then added to water to activate it. Oxygen bleach is known as “color-safe” or “all fabric” bleach, since it does not degrade most fabric or strip most color if used correctly, though you must still test colorfastness before using. It is very stable and can be kept for over a year with no loss of effectiveness. However, it should never be stored in metal or organic containers.
Both bleaches work by oxidizing stains and microbes, allowing them to be broken up and lifted away from fabrics and surfaces. Both have excellent anti-microbial qualities that make them good for disinfecting laundry and surfaces, though chlorine bleach has an edge in effectiveness. Neither is effective in cold water, and both require garments be rinsed well after use.
Chlorine bleach does not differentiate between color molecules and stains or microbes; it lifts colors away using oxidation as well. Even in low concentrations, it eats away at fabric, so over time, the regular use of bleach will deteriorate garments and fade their color. Chlorine bleach is toxic to aquatic life if released straight into surface water, as in stormdrain runoff from outdoor cleaning projects. It is also harmful to the essential bacteria in septic tanks if used in anything but very small quantities. It works best in hot water, but is also effective in warm water. It cannot be used with other cleaners such as ammonia, as contact can released deadly chlorine gas. It is less expensive to use than oxygen bleach.
Oxygen bleach is safe to use on nearly any fabric and to add to laundry loads for extended periods with no damage to clothing. Oxygen bleach turns to water and oxygen when broken down, so it has no negative impact to the environment and is safe for septic systems. It is best if used in the same step as laundry detergent, which makes it even more effective, but combining steps also saves time. It only works well in hot water, but additives can make it effective in warm water.