The Environmental Protection Agency (EPA) and Occupational Safety and Health Administrations (OSHA) no longer recommend the use of bleach because chlorine bleach to kill mold is one of the worst things you can do. The Biotoxin Foundation supports this recommendation.

Why? Bleach contains 90% of water. Mold loves water. The chlorine quickly evaporates after use, leaving behind a great deal of water. Water then soaks into the porous surfaces, allowing the mold to flourish and continue to grow in moist environments. Bleach feeds the internal mold spores. Even though the surface may look clean and bleached, the remaining spores will grow in deeper, stronger, and worse than before.

1. Bleach doesn’t kill all mold. Despite what big bleach companies have promised, bleach will not do the job. Oh, bleach is great for disinfecting, and removing mold from hard surfaces, like the bathtub, shower surrounds, or tiles. However, in porous and semi-porous surfaces like drywall, it will not work and may even contribute negatively to particular mold problems.
2. Bleach can weaken the wood. Chlorine bleach is harmful to wood and other surfaces. If bleach is applied on wood, it can break down the fibers. This adds to further problems of the structure of the home.
3. Bleach will make your mold problem worse in the long run. While mold may look like it’s gone after using bleach, but it will come back. Chlorine cannot penetrate to destroy the growth as it grows at the roots. Mold spores spread its roots, into deep porous surfaces.
4. Bleach is dangerous to humans and pets. Chlorine produces fumes that pollute the air and can become dangerous to both humans and animals. It also creates a byproduct called dioxin which is linked to cancer. The last thing you want to do is create more toxic chemicals in your home