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Chlorine Bleach – Does it kill mold or not?

Volunteer Mold Inspector Bob poses in a laundry room in front of Chlorine Bleach container.

Chlorine Bleach is an ineffective and dangerous mold treatment.

Chlorine Bleach (sodium hypochlorite) is commonly found in most homes and businesses. Chlorine is used as a disinfectant in water and many cleaning products. Chlorine gas has also been used as a chemical weapon in war. Many people misuse chlorine, in concentration, and often experience the effects of poison from breathing and skin contact.

In my practice I commonly hear from clients that attempted to treat or remove mold using chlorine solutions either straight from the bleach bottle or specialty products purchased from the local grocery store.  Does it actually kill mold?

Chlorine Does Not Kill Mold on most materials.

The objective in killing mold is to kill mold at it roots (hyphae) so it doesn’t grow back.  In mold remediation (removal) we work largely with organic materials like wood, paper, insulation and gypsum board. Organic material,s commonly make up the, buildings we work and live inside. All organic materials, are highly porous. When bleach is applied to the surface it does not absorb in the the capillaries or pores of the material because of its ionic structure.  In fact only the water contained in the bleach penetrates into the materials and actually “feeds” the growth of the mold. Often times, the growth returns, shortly after cleaning and is larger and darker.

Many people who use chlorine report that the mold “disappeared” and don’t understand why it grew back just a few days or weeks later. The truth is, that although the surface was cleaned, the roots were allowed to remain.

Think of your bathroom tile cleaners.

The bathroom cleaning industry earns billions of dollars selling products to “kill’ mold on grout and kitchen and bath surfaces. Have you ever asked yourself, why you co

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Mold attacking the corner wall in our clients home. Growth determined to be Stachybotrys Highly Toxic Mold. Senior Citizens in the home were suffering from a host of lung and eye problems.

nstantly reapply the cleaners to kill mold every week? Products with chlorine bleach rarely kill the mold on porous surfaces. It just appears that way on the surface.

OSHA and the EPA

OSHA (Occupational Safety Health Adminstration  and the EPA (Enviormental Protection Agency) specifically recommend “Avoiding the the use of chlorine or bleach products to kill mold”.

Chlorine Bleach and Chlorine Products should never be used in mold remediations.

A mold professional would never use chlorine to treat mold on any surface other than glass, vinyl or metal. A reputable remediator would never use any chlorine or chlorine based products in the performance of mold remediation or removal.

Chlorine off gases for a period of time and is harmful to the health of people and pets.  Chlorine and bleach products have been known to cause pulmonary embolisms in low resistant and susceptible people like children and seniors.

Case study in brief

Read Our Case Study by Clicking this NOW.



1. Chlorine Bleach does not kill mold. A possible exception is on exterior vinyl siding or glass when applied to mildew growths. Chlorine does not absorb into building materials and therfore cannot kill the Hypha (mold roots) thus the mold will “comeback”. Chlorine Bleach causes the mold to “go transparent”. Just because you can’t see it does not mean its gone.

2. Chlorine Bleach is a highly TOXIC solution. In high enough concentrations chlorine can damage your lungs.

3. Personel Protective Equiptment is a must! One should never work around areas of mold or go into a crawl space without a proper resperator, gloves and a protective suit. Comtaminating your clothing means you take it into your house and spread the spores and toxicity within in your home.

4. Call a professional and have a proper inspection and testing performed first. Proper treatment can be prescribed and steps can be taken to protect your family.

5. Mold removal or Mold Remediation is not a do it yourself project. Your familys health is at stake.

Bob at Volunteer Inspections visits the mold lab and enjoys a selfie with weird piece of equipment.

Bob Byrne, the author, is a professional mold inspector and remediator and General Manager of Volunteer Mold and IAQ.

Comment or question? Let us hear from you.


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2 thoughts on “Chlorine Bleach – Does it kill mold or not?”
  1. Sally Lobsinger says:

    I read your information and very concerned about the ceiling in our bathroom. We thought the
    appearance was just from the steam when using the shower. Now we worry that is could possibly be MOLD. We are seniors and would appreciate your expert attention to this problem.

    1. admin says:

      The lack of ventilation in any bathroom is a legitimate concern. Bathrooms that lack a powered ventilation fan typically allow for lots of potential condensation on walls and ceiling of the bath room. Alternately,
      the bathroom window should be opened for a period of 30 minutes or so after showering to allow moisture to escape outdoors and allow dryer exterior air to enter.

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