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.