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Indoor Air Quality Program
Mold in the Home
General Mold Cleanup Procedures
- Identify and correct the moisture source
- Clean, disinfect, and dry the moldy area
- Bag and dispose any material that has moldy residues, such as rags, paper, leaves, or debris
What can I save? What should I toss?
Substances that are porous and can trap molds, such as paper, rags, carpet, wallboard, and rotten wood should be decontaminated and thrown out. Harder materials such as glass, plastic, or metal can be kept after they are cleaned and disinfected.
Ultimately, it is critical to remove the source of moisture first, before beginning remedial action, since mold growth will return shortly if an affected area becomes re-wetted.
Removal of moldy materials
After fixing the moisture source and removing excess moisture, the cleanup can begin:
- Wear gloves when handling moldy materials
- Remove porous materials (examples: ceiling tiles, sheetrock, carpeting, wood products)
- Carpeting can be a difficult problem - drying does not remove the dead spores. If there is heavy mold, disposal of the carpet should be considered
- Bag and discard the moldy substances
- Allow the area to dry 2 or 3 days
- If flooded, remove all sheetrock to at least 12 inches above the high water mark. Visually inspect the wall interior and remove any other intrusive molds. (This step may have to be carried out by a licensed contractor)
CAUTION: Spores are easily released when moldy material is dried out.
Before disinfecting contaminated areas, clean the areas to remove as much of the mold (and food it is growing on) as possible.
- Wear gloves when doing this cleanup
- Use a non-ammonia soap or detergent, or a commercial cleaner, in hot water, and scrub the entire area affected by the mold
- Use a stiff brush or cleaning pad on block walls or uneven surfaces
- Rinse clean with water. A wet/dry vacuum is handy for this
If you chose to disinfect with bleach:
- Wear gloves when using disinfectants
- After thorough cleaning and rinsing, disinfect the area with a solution of household bleach and water.
- The Centers for Disease Control and Prevention (CDC) recommends using no more than 1 cup of bleach per gallon of water. Using bleach straight from the bottle will not be more effective
- Never mix bleach with ammonia or other cleaners -the fumes are toxic
- For spraying exterior large areas, a garden hose and nozzle can be used
- If the area to be cleaned is more than 10 square feet, consult the Environmental Protection Agency (EPA) guide titled Mold Remediation in Schools and Commercial Buildings. (Although focused on schools and commercial buildings, this document also applies to other building types.)
- Let disinfecting areas dry naturally overnight - this extended time is important to kill all the mold.
- EPA and Occupational Safety & Health Administration (OSHA) do not recommend the use of bleach when cleaning up mold, except as needed for immuno-compromised individuals. They recommend using a detergent and water solution only in most circumstances
CAUTION: Bleach fumes can irritate the eyes, nose, and throat, and damage clothing and shoes. Make sure the working area is ventilated well.
Can cleaning up mold be hazardous to my health?
Yes. Exposure to mold can occur during the cleaning stage. Mold counts are typically 10 to 1000 times higher than background levels during the cleaning of mold damaged materials. Take steps to protect your health during cleanup:
- Seal off the moldy material from the other areas
- When handling or cleaning moldy materials, consider using a mask or respirator to protect you from breathing airborne spores
Respirators can be purchased from hardware stores; select one for particle removal (sometimes referred to as a N95 or TC-21C particulate respirator). Respirators are not as effective removing bleach fumes, so minimize your exposure when using bleach or other disinfectants.
- Wear protective clothing that is easily cleaned or discarded
- Wear eye protection
- Use rubber gloves
- Try cleaning a small test patch of mold first. If you feel that this adversely affected your health, you should consider paying a licensed contractor or professional to carry out the work
- Ask family members or bystanders to leave areas when being cleaned.
- Work over short time spans and rest in a fresh air location.
- Air your house out well during and after the work
CAUTION: Never use a gasoline engine indoors (e.g. pressure washer, generator) - you could expose yourself and your family to carbon monoxide.
Can air duct systems become contaminated with mold?
Yes. Air duct systems can become contaminated with mold. Duct systems can be constructed of bare sheet metal, sheet metal with an exterior fibrous glass insulation, sheet metal with an internal fibrous glass liner, or made entirely of fibrous glass. If your home's air duct system has had water damage, first identify the type of air duct construction that you have. Bare sheet metal systems, or sheet metal with exterior fibrous glass insulation, can be cleaned and disinfected. If your system has sheet metal with an internal fibrous glass liner, or are made entirely of fibrous glass, the ductwork normally will need to be removed and discarded. Ductwork in difficult locations may have to be abandoned. If you have other questions, contact an air duct cleaning professional, or licensed contractor.
After I've cleaned everything as thoroughly as possible, can I still have mold odors?
Yes. It is possible that odors may persist. Continue to dry out the area and search for any hidden areas of mold. If the area continues to smell musty, you may have to re-clean the area again (follow the cleaning steps given in this sheet). Continue to dry and ventilate the area. Don't replace flooring or begin rebuilding until the area has dried completely.
How can further damage to my home be prevented?
Check regularly for the following:
- moisture condensation on windows
- cracking of plasterboard
- drywall tape loosening
- wood warping
- musty odor
If you see any of the above, seek out and take steps to eliminate the source of water penetration, as quickly as possible.
Can ozone air cleaners help remove indoor mold, or reduce odor or pollution levels?
Some air cleaners are designed to produce ozone. Ozone is a strong oxidizing agent used as a disinfectant in water and sometimes to eliminate odors. However, ozone is a known lung irritant. Symptoms associated with exposure include cough, chest pain, and eye, nose, and throat irritation. Ozone generators have been shown to generate indoor levels above the safe limit. Furthermore, it has been demonstrated that ozone is not effective in controlling molds and fungi, even at high concentrations far above safe health levels. Also, ozone may damage materials in the home. For these reasons, the Arizona Department of Health Services strongly recommends that you do not use an ozone air cleaner in any occupied residential space.