Types of Mold

Mold is a fungus that reproduces from seed-like spores and can easily grow in many places of your property. Often, the mold will form in places that are humid and dark such as behind walls or in the attic. Once the mold has formed, mold remediation professionals can properly restore the affected areas.

There are around 1000 species of mold and some species can really be dangerous to one’s health. There are countries where a system to categorize molds according to their health hazards has been adapted. The following are the hazard classifications for different types of mold:

  • Hazard Class A

    Molds belonging to this group are directly affecting one’s health through risk of infection or toxicity. These molds can be present in homes and offices. Controlling and exterminating molds in these areas is imperative.

  • Hazard Class B

    These are molds that result to allergic reactions over longer period of time.

  • Hazard Class C

    Molds in this category are not health risk but they can damage structures. Even this type of mold needs to be rid of.

Common Types of Mold

Generally, however, the black color carries an impression of being toxic. In fact, three types of mold that are really toxic — stachybotrys, memnoniella, and acremonium — are really black molds. They contain mycotoxins or substances produced by molds that cause diseases or allergies.

Acremonium (also known as Cephalosporium)

This type of fungus grows outdoor and indoor and can be classified as Hazard Class B or C.


This common indoor mold can cause asthma problems, hay fever and allergic reactions. It forms in almost any color and is often found in food, plants and soil.


With more than 160 species, this mold produces mycotoxins. Aspergillus can cause infections and allergic reactions. It is found in soil and food.


This type of mold is most commonly found indoors on plants, soil and textiles. It can be harmful to human health, causing asthma problems, allergic reactions and weakening of the immune system. Cladosporium is dark green and black in color and has over 30 different species.


This type of mold can be found indoors in food and dust. It is harmful to those susceptible to it, such as people with weakened immune systems and allergies.

Stachybotrys (or Stachy)

This type of mold is a toxic mold belonging to Class A that thrives on highly moist environment or water damaged objects. They appear as black, shiny and slippery. Stachybotrys breeds in very damp or humid environment and can survive and grow after 24 hours of continuous wet condition like slow plumbing leaks, shower or bathing spill or water leaking on walls.

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