Chlorine Bleach is Ineffective in Killing Mold

REASONS FOR INEFFECTIVENESS OF CHLORINE BLEACH IN KILLING MOLD: (1) Killing mold at its “roots” is the object to killing mold. Mold remediation concerns the demand of disinfecting wood-based building materials and wood, all of which are basically penetrable materials. As the proclamation of OSHA’s Mold Remediation/ Clean Up Methods guidelines, chlorine bleach should not be used in mold remediation in this way. Using bleach as a mold disinfectant is best left to bathroom countertops and kitchen, shower glass, tubs and etc.

(2) Chlorine Bleach kills virus and bacteria, but yet to be proved effective in killing molds on non-penetrable surfaces. Bleach itself is formed with 99% water. The growth of harmful bacteria and mold is completely dependent on water. Present situations using bleach regenerated and re-grew bacteria and mold twice the CFU counts than were originally counted before bleaching, within a little interval of time. Using bleach is an old method for removing some mold and bacteria. It is the only product people from all over the world have used for years. The strains now operated within Indoor Air quality issues are barrier to the old methods our grandmothers taught to clean-up mold.

(3) The potential mold ‘killing’ power chlorine bleach has, is decreased significantly as the bleach sits in storerooms, warehouses, on grocery shop shelves or inside your business or home 50% loss in ‘killing’ power within the first 90 days inside a never opened sealed container or jug. Chlorine tries to escape constantly through the plastic walls of its holders.

(4) Ionic structure of bleach refrains Chlorine from penetrating into porous properties such as wood and drywall—it exists only on the outer surface, whereas mold creates enzyme roots which grows inside the penetrable construction properties—however, the water content of bleach is porous and actually FEEDS the mold—so, after a few days you can see darker and more concentrated mold growing (faster) on the bleached area.

(5) Chlorine Bleach accelerates the worsening of the properties and wears out the fibers of penetrable materials.

(6) Chlorine Bleach is NOT certified by the EPA as a disinfectant for killing mold. The verification of this important fact could be done when you are NOT able to look for an EPA registration number to kill mold on the label of any types of chlorine bleach.

(7) Chlorine bleach off gases for a particular time. Chlorine bleach off gassing can be awful to animals and humans. In low resistance, it has been known to cause pulmonary embolisms and susceptible people.

(8) Chlorine bleach will be evaporated within a few times. You will have to restart the contamination process immediately and to a greater degree, if the area is wet when the bleach starts evaporating, or moisture exists in the contaminated area (humidity, outside air dampness).

(9) A key component of DIOXIN is Chlorine. Dioxin’s toxicity in animals was that it caused birth defects in mice at lower levels. Dioxin is characterized as “one of the most potent teratogenic environmental agents” and it is the finding led to dioxin. From several animal studies completed the first evidence that dioxin could be a reason for cancer came in late 1970’s. In 1978 by a team of scientists led by Richard Kociba, from Dow Chemical Company published the most important fact. They discovered liver cancer in rats using very low levels of dioxin. This study helped establishing dioxin as “most toxic synthetic chemical known to man” and one of the most vulnerable animal carcinogens ever tested and, together with the finding of birth defects in mice, led to the statement that dioxin is very dangerous.


Confusion and Opposing Views: Chlorine bleach which is commonly referred to as laundry bleach is generally perceived to be an “accepted and answer-all” biocide to kill mold in the removing processes. The recommendations of the Environmental Protection Agency (EPA) and other federal, state and local agencies are extending that belief. And the only confusing issue is the Occupational Health and Safety Administration (OSHA), a federal agency has taken an opposing point of view by NOT providing the using limitation of bleach as a routine practice in mold remediation.

Does Bleach Really Kill Mold? A vital question may rise in your mind- Does chlorine bleach kill mold or not—yes or no? With a precaution, the answer is yes. Manufacturer and distributor of Ultra Clorox® Regular Bleach, The Clorox Company, Oakland CA, that answer comes from. Correspondence of the company’s stated to Spore°Tech Mold Investigations, LLC that independent laboratories supported their Tech Center studies and it shows that “…3/4 cup of Clorox liquid bleach per gallon of water will be effective on hard, non-porous surfaces against… Aspergillus niger and Trichophyton mentagrophytes (Athlete’s Foot Fungus)”. The company did not say chlorine bleach kills other molds and fungi. The words “hard, non-porous surfaces” present the precaution. Mold remediation involves the demand of disinfecting wood-based and wood building elements, all of which are penetrable materials. As the confirmation by OSHA’s Clean Up Methods/ Mold Remediation guidelines, chlorine bleach should not be used in mold remediation in this way. Using bleach as a mold disinfectant is best left to kitchen and bathroom countertops, shower glass, tubs and, etc.

Reason of NOT Recommending Chlorine Bleach for Mold Remediation: Chlorine bleach (sodium hypochlorite) is mordant and this is stated on the product label. But the properties of chlorine bleach restrain it from “soaking into” wood and wood-based building materials to reach to the deeply embedded mycilia (roots) of mold. Killing the “roots” is the object of killing mold. Reputable mold remediation contractors should use appropriate products which can effectively disinfect vulnerable mold infected wood products. Aware of any mold remediation company or mold inspector that uses or recommends bleach for disinfecting mold on wood-based materials.

Chlorine Bleach- an Active Ingredient in Mildew Products & New Mold:

The appearance of mildew household products and new mold on store shelves is on the rise. Most of them are dilute solutions of laundry bleach. The labels on these mildew products and mold mean   that they are not for using on (again) wood-based materials but for hard, non-porous surfaces. Instructions on where to apply of the products are not fixed. The branded products should not be applied on some products including wood or painted surfaces, metal (including stainless steel), aluminum products, marble, natural stone, faucets, and, of course, fabrics, paper, and carpeting. Even one commercial mold and mildew stain remover specifically states without immediate rinsing with water, it should not be applied to metal or porcelain and that the product isn’t recommended for using on vinyl or formica. Before purchasing mildew product and mold, read and fully understand the precautions and advertised purpose of the item — and accurately follow the use instructions of the product. The labeling claims on these new products can be confusing — some say their product is a mildew stain remover while another says their product is a mold and mildew remover and yet others can shout similar ‘ambiguous’ claims. Be assured that the product you bought satisfies your intended demand on the surface to which it is to be used. If you want to kill mold, make double sure the product does exactly that and follow the using instructions. Consumers may discover that mixing their own diluted bleach solution will get the same results as other new mold and mildew products. Mind that the use of chlorine bleach is not for use on mold infected wood products including wall board, fabric, wall studs, ceiling tiles, paper products, etc.


For wood-based building materials, laundry bleach is not an effective mold killing agent and also NOT EFFECTIVE in the mold remediation process. OSHA, the first federal agency declared a departure from the use of chlorine bleach in mold remediation. And other federal agencies are expected to follow OSHA’s lead. Awareness should be raised, however, that a chlorine bleach solution kills mold on hard surfaces and is an effective sanitizing product that neutralizes indoor mold allergens that trigger allergies.

Warning: • Don’t mix chlorine with ammonia products, as the result is severely toxic. Using bleach may be the reason of serious health problems. • The fumes are very harmful and enough care should be taken not to breath it in too much. • It is also very damaging to the human body, clothing and carpeting, and the environment.

If you have any questions please contact the experts at GIP DRS (Greater Indianapolis Property Damage Restoration Services) in Indiana at (317) 435-2335