Common Questions
Does bleach kill mold?
Answer
Killing mold isn't the goal; removing it is. EPA says dead mold is still allergenic and some dead molds are potentially toxic, so a cleanup has to physically remove the growth. EPA does not recommend bleach or other biocides as a routine part of mold cleanup, and the IICRC S520 standard says no liquid product — antimicrobials, stain removers or cleaners — should take the place of physical removal.
The same reasoning applies to vinegar, hydrogen peroxide and household disinfectants: none of the government or industry sources in this library recommend killing mold in place of removing it. CDC's guidance for homeowners is to clean with water and a detergent, remove all visible mold, dry right away, and never mix bleach with ammonia.
Whatever is used, the moisture problem has to be fixed, or the mold returns.
What the sources say
“It is necessary to clean up mold contamination, not just to kill the mold. Dead mold is still allergenic, and some dead molds are potentially toxic.”
“The use of a biocide, such as chlorine bleach, is not recommended as a routine practice during mold remediation”
“Clean with water and a detergent. Remove all mold you can see. Dry right away.”
“DO NOT mix bleach and ammonia because it can create toxic vapors.”
“No liquid product (antimicrobials, stain-removers, and cleaning solutions) should be used as an alternative to the physical removal of mold contamination.”