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151 Biological Health Hazards in Construction
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Mold Hazards

Mold is a type of fungus that consists of small organisms found almost everywhere.

Black mold on the floor or wall is a common occurrence in older structures.

It can be black, white, orange, green, or purple and lives both indoors and outdoors. Molds thrive on moisture and reproduce by means of tiny, lightweight spores that travel through the air. You're exposed to mold every day.

Mold thrives in environments that are typically:

  • Moist: Mold requires moisture to grow. This can come from high humidity, leaks, or condensation.
  • Warm: Most molds prefer temperatures between 60 and 80 degrees Fahrenheit (15 to 26 degrees Celsius).
  • Dark: Mold typically does not need sunlight and often grows better in darker environments.
  • Oxygen-Rich: Mold needs oxygen to grow, but not much light.
  • Nutrient Source: Molds grow on organic materials such as wood, paper, carpet, foods, and insulation.

These conditions often occur in places like basements, bathrooms, kitchens, and areas with high humidity, poor ventilation, or water damage. Regular cleaning, adequate ventilation, and moisture control are key to preventing mold growth.

Molds are organized into three categories according to human responses:

  • allergenic
  • pathogenic
  • toxigenic

We will look at each of these mold categories in the next section.

Knowledge Check Choose the best answer for the question.

1-3. In which environments are molds likely to grow and become a problem?