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Water Infiltration and Mold

Categories of Water:

  1. Clean - not harmful
  2. Gray - potential to cause discomfort
  3. Black - grossly unsanitary

Categories are determined by the source of the water not the color.

Time is a concern: 24 to 48 hours is enough time for clean water or gray water to change into black water.

Remember! Proper cleanup requires that the source of the water intrusion be identified and fixed. Just cleaning up the water and replacing building materials is not enough.


  • Exposure

    Humans can come into contact with mold spores that enter the air or land on environmental surfaces.

  • Allergens

  • Repeated exposure to molds can cause an allergic reaction.

  • Growth requirements

  • Food source - starch, cellulose, etc.

    Water source

  • Mycotoxins

  • Many factors influence production.

    Individual response to toxin exposure is dependent on many factors.

Other Health Hazards:

  • Asbestos

    This is a concern when remediating damage.

  • Bloodborne Pathogens

  • This is only a concern when coming into contact with blood or other potentially infectious materials - when sewage is present.

  • Lead

  • The primary concern is in older buildings that contain lead-based paint.

  • Waterborne Pathogens

  • These can be found in every water category but are primarily a concern with black water.

Exposure to biological materials can occur through:

Personal protective equipment can be worn as a barrier between the person and the hazard. The type of equipment needed depends on the extent of the damage.

Information for this page was based on information from MSU ORCBS.

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