A myth exists concerning the use and “effectiveness” of chlorine bleach (sodium hypochlorite) in the remediation of a mold problem. Mold remediation involves the removal and or clean up and restoration of mold contaminated building materials.
Opposing Views and Confusion.
Chlorine bleach, commonly referred to as laundry bleach, is generally perceived to be an “accepted and answer-all” biocide to abate mold in the remediation processes. Well-intentioned recommendations of health departments and other state and local agencies are perpetuating that belief. The Occupational Health and Safety Administration (OSHA) who once recommended using clorine bleach for mold abatement was the first federal agency to stop recommending the use of liquid bleach in mold remediation. Subsequently, The Environmental Protection Agency wrote-out/edited their A Brief Guide to Mold, Moisture and Your Home (EPA 402-k-02-003) to exclude their once recommended use of bleach as a mold clean-up agent.
Does Bleach Really Kill Mold?
Will chlorine bleach kill mold or not—yes or no? The answer is yes, but with a caveat. That answer comes from The Clorox Company, Oakland CA, manufacturer and distributor of Ultra Clorox® Regular Bleach. The company’s correspondence to Spore°Tech Mold Investigations, LLC stated that their Tech Center studies supported by independent laboratories show 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)”. Whether or not chlorine bleach kills other molds and fungi, the company did not say. The “hard, non-porous surfaces” part of the sentence is a caveat. Mold remediation involves the need to disinfect wood and wood-based building materials, all of which are porous materials. Thus, chlorine bleach should not be used in mold remediation as confirmed by OSHA’s and EPA’s updated recommendations and suggested guidelines. The use of bleach as a mold disinfectant is best left to kitchen and bathroom countertops, tubs and shower glass, etc.
Why Chlorine Bleach is NOT Recommended for Mold Remediation.
Clorine bleach is corrosive and that fact is stated on the product label (not to mention the exposure hazards of dioxins). Yet the properties of chlorine bleach prevent it from “soaking into” wood-based building materials to get at the deeply embedded mycelia (roots) of mold. The object to killing mold is to kill its “roots”. Reputable mold remediation contractors use appropriate products that effectively disinfect properly scrubbed and cleaned salvageable mold infected wood products. Beware of any mold inspector, mold remediation contractor or other individual that recommends or uses chlorine bleach for mold clean up on wood-based building materials.
Chlorine Bleach Is Active Ingredient in New Mold & Mildew Products.
The appearance of new mold and mildew household products on store shelves is on the rise. Most are dilute solutions of laundry bleach. The labels on these mold and mildew products state that they are for use on (again) hard, non-porous surfaces and not for wood-based materials. Instructions where not to apply the products are varied. A few examples where the branded products should not be applied include wood or painted surfaces, aluminum products, metal (including stainless steel), faucets, marble, natural stone, and, of course, carpeting, fabrics and paper. One commercial mold and mildew stain remover even specifically states it should not be applied to porcelain or metal without immediate rinsing with water and that the product isn’t recommended for use on formica or vinyl.