Mold Hazards

Does Bleach Kill Mold? The Bleach Mold Myth Exposed.

Chlorine Bleach(sodium hypochlorite 6%) does not kill mold. Why?
Mold’s hyphae (root structures) actually grow into wood and drywall like roots. The hyphae are not killed by bleach because bleach’s ion structure prevents chlorine from penetrating into porous materials such as dry wall and wood. It stays on the outside surface, whereas mold has protected enzyme roots growing inside the porous construction materials. When you spray porous surface molds with bleach, the water part of the solution soaks into the wood while the bleach chemical sits atop the surface, gasses off, and thus only partially kills the surface layer of mold while the water penetration of the building materials fosters further mold growth.

Chlorine bleach causes long term breakdown of wood products like studs, sheathing, plywood, OSB, and other building materials over time.
Here is an example of why bleach does not kill mold: Have you ever used bleach or products like Tilex® to clean mold or mildew out of grout in a tiled shower? If so, you would notice that it does a great job getting the “mold stains” off the grout, however 1-2 weeks later, the mold is back again….Why? The ionic structure of bleach does not allow it to get to the roots and kill the mold and mildew. The mold is just being “bleached out” and the roots remain intact. Thereby allowing the mold to return 1-2 weeks later, stronger than ever.

How do I kill the mold then?
Use a Green technology/EPA registered water borne coating to kill the mold at the roots. Chlorine Bleach is NOT a registered EPA mold killing product.
You can verify it yourself when you are unable to find an EPA registration number for killing mold on the label of any brand of chlorine bleach. Why not? Because it is not effective at killing mold as other EPA approved chemicals.

University Study Discovers Bleach is Ineffective at Killing Mold on Wood and Other Porous Surfaces
While bleach is often recommended for remediation of surface mold on wood and other porous surfaces, our [university research study] study results illustrate that the treatment does not eliminate the surface microflora,” is the conclusion of the Oregon State University study of the effects of chlorine bleach on mold growth on Douglas fir wood [an important timber crop in the state of Oregon]. The research study was conducted by Professor Jeffrey Morrell, Dept. of Wood Science, Oregon State University, as assisted by Adam Taylor [graduate research assistant] and Camille Freitag [Senior Research Associate], as published in Forest Products Journal, 54:4, 2004.

To read the Forest Products Journal Research Study on the effectiveness of chlorine bleach What does the EPA have to say about using bleach to kill mold? “The use of chlorine bleach is not recommended as a routine practice during mold cleanup,” please visit the EPA website

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