by M.J. Holliday

Created on: June 16, 2008   Last Updated: April 17, 2012

Mold, mold, everywhere! It grows throughout the world. Mold helps decompose dead matter, and is used in medicine, food and beer.

Helpful or not, mold is an unwelcome guest. Research links toxic compounds on mold spores to sickness in human and animals. Mold also feeds on organic matter such as wood and drywall, causing widespread rot as it works to bring your home back to the earth.

Mold facts

Mold is a fungus. Black mold, or Stachybotrys chartarum (Stachybotrys atra) is one of several species of toxic mold in the home. Not all mold is toxic.

Black mold is typically greenish-black. It can grow in bathrooms, but the dark brown mold around the tub or shower stall is usually Cladosporium, a separate species.

A species of Aspergillus helps make the Japanese liquor, sake; but Aspergillus is also a common toxic mold in the home. Penicillium is the greenish-blue mold on food such as oranges. As the name suggests, it's used to make penicillin.

Mildew is a different type of fungus. It's often whitish or grey in color.  All fungi grow in dark, moist conditions.

How does mold grow?

Mold needs oxygen, food and humidity. Spores float into the house through doors, windows and air ducts, or on skin and clothes, pets or dust. It's impossible to keep spores out of the house.

If a spore lands in a dark, damp place, it germinates within a day. As mold grows, it starts to consume its environment. Black mold eats organic substrates such as wood, drywall, wallpaper, books and fabric. Dust, composed of dead skin cells, fibers and other organic matter, is also a favorite food.

The tell-tale musty odor comes from gasses excreted by mold, as it digests food. Toxic molds can produce a rank, overpowering smell.

Health risks

Toxic compounds, or mycotoxins, grow on some mold spores. Humans and animals ingest spores in the air or through food. Medical research links mycotoxins to human and animal illness.

Most at risk are babies and children, the elderly, people with chronic respiratory disease such as asthma, and people with compromised immune systems. Anyone with prolonged exposure to mold may develop a reaction.

Toxic mold can affect pets. In 2005, dozens of dogs died in the United States, when mold growth on corn infected a popular brand of dog food.

Mold may also be a factor in "sick building syndrome". SBS has varying causes and symptoms, and may be linked to construction methods and materials used during the energy crisis of the 1970's.

Possible symptoms of toxic mold reaction

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