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Department of Labor

Mold: Frequently Asked Questions

General Information

  • What is mold?

    • Multi-cellular fungi, similar to mushrooms and yeast
    • Thousands of species, found naturally in both indoors and outdoors
    • Can have different colors, with fuzzy, slimy or powdery appearance
    • In nature, mold helps decompose dead leaves, wood and plant debris
    • Emits musty odor when present in large quantities
    • Needs three basic conditions to grow:
      • water/moisture (typically more than 55% indoor humidity levels)
      • organic food source (paper, fabric, sheetrock, etc.)
      • proper temperature (typically 40OF to 99OF)
    • Mold can begin to develop and grow on damp surfaces within 24 to 48 hours
    • Reproduce through tiny airborne spores
    • Impossible to ‘mold-proof' your house; however, mold growth can be reduced by controlling indoor humidity levels and eliminating water leakage/problems

  • What are the symptoms of mold exposure?

    • Health problems can potentially occur when people inhale large quantities of airborne mold or are allergic to mold. This typically occurs indoors where there is a lack of air circulation in an enclosed space.
    • Exposure by swallowing moldy/spoiled food.
    • Vulnerable populations include infants, children, pregnant women, the elderly, people with allergies and asthma, and people with compromised immune system.
    • Symptoms can be immediate or delayed:
      a)Common Symptoms: Wheezing, difficulty breathing, nasal congestion, eye, nose and throat irritation, skin rashes
      b) Severe Symptoms: Headache, fatigue, nausea, memory problems, mood swings, fever
    • Keep in mind that symptoms associated with mold exposure may also be caused by many other illnesses. Consult a health professional if you suspect you have been exposed to mold and are exhibiting symptoms.

Household Mold

  • What do I do if I find mold in my house?

    • In most cases, air sampling and mold testing is unnecessary. There are currently no EPA or Federal standards for mold, so any interpretation of sampling results would not be based on any established health or environmental standard. If the total mold affected area is less than 10 square feet (approximately 3' by 3' square) and you do not have any sensitivity towards mold, mold removal may be done on your own.
    • Biocide is not recommended as a routine cleanup for mold as it may cause sensitivity in some people. Ventilate the room if a biocide is used. Observe and follow the manufacturer's labeling instructions.
    • If the total mold affected area is more than 10 square feet or if you have sensitivity towards mold, consider hiring a professional for assessment and remediation.


    • Use non-ammonia soap and hot water for cleaning; dry thoroughly
    • Use personal protective equipment (gloves, goggles) if necessary
    • Throw out items that are extensively damaged by mold. Wrap and seal in a plastic bag prior to disposal

    Do Not:

    • Mix ammonia and bleach for cleaning as this could release toxic fumes
    • Paint or caulk over moldy surfaces
    • Leave any areas of dry mold remain after cleaning since this could still cause allergic reactions in some people

  • How do I prevent mold from becoming an issue in my house, and what can I do to keep my house from further mold problems after a mold clean-up has been done?

    The key to mold control is moisture control. Practice the following housekeeping tips to reduce moisture and humidity in your house:

    1. Allow adequate air flow - open windows, use exhaust/vent fans when high humidity is present inside the house
    2. Reduce humidity inside the house - air-conditioning, dehumidifiers, use of heavy plastic to cover earth floors in crawl spaces,
    3. Eliminate water problems - repair water leaks, get rid of standing water, insulate cold surfaces to prevent water condensation, slope the ground away from the house foundation, ensure air-condition drip pans and drain lines are dried, cleaned and drained properly
    4. Dry water-damaged items within 24 to 48 hours. If mold is already present, scrub the mold off the surface completely and dry thoroughly.


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