How Household Mold Gets a Grip

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http://www.washingtonpost.com/wp-dyn/articles/A3071-2002Sep11.html

How Household Mold Gets a Grip

By Mike McClintock

Special to The Washington Post

Thursday, September 12, 2002; Page H01

There are thousands of types of mold; most are beneficial and even

essential. Outside, for instance, mold thrives in soil and helps to break

down fallen leaves and other plant debris, basically by digesting them. But

when mold grows inside buildings, it can cause trouble ranging from minor

cleaning difficulties to major health problems.

Particularly in today's houses, which are built tightly to conserve energy,

exposure to mold can cause a wide range of coldlike symptoms.

In some people, according to the Atlanta-based Centers for Disease Control

and Prevention (CDC), mold can trigger more severe reactions, such as fever

and shortness of breath, and even internal mold infections. There is no way

to completely eliminate the health risk, because mold is found year-round in

virtually every environment. But there are ways to control the growth and

spread of the organism.

This week, we'll look at how and where mold forms and the problems it can

present. Next week, we'll cover how to clean mold deposits and reduce

formations in the future.

Molds migrate by making tiny spores (the way plants make seeds) to

reproduce. But while seeds drop to the ground, microscopic mold spores

become airborne, waft through open windows and doors, and start to grow when

they land on a damp surface. Spores also migrate by water, insects and pets.

The spores flourish on building materials such as wood and drywall, on

furnishings and finishes such as carpeting and paint, on clothes, food and

almost any surface where there is moisture, even a slight haze of summer

humidity.

Mold is common in the environment, inside and outside, and goes unnoticed

for the most part. But aside from the musty odors and cleaning problems, in

some people mold can trigger coldlike symptoms, such as a sore throat,

watery eyes, wheezing and dizziness.

According to the American Lung Association, mold in large quantities can

cause serious health problems, including allergic reactions, toxic

reactions, asthma episodes, infections and respiratory damage.

The Environmental Protection Agency (EPA) estimates that there are up to 100

common indoor mold types with the potential for creating health problems.

The EPA says these molds play a major role in cases of sick building

syndrome and related illnesses -- in public buildings as well as in houses.

Although some molds, such as the somewhat notorious Stachybotrys chartarum

(known as black mold), might contain toxins, the EPA says there are very few

cases in homes of toxic molds that can cause unique or rare health

conditions such as pulmonary hemorrhage or memory loss. The EPA advises that

it is not necessary to determine what type of mold you may have, and that

all molds should be treated the same way with respect to potential health

risks and removal.

Particular concern about Stachybotrys chartarum stems from a 1994 CDC report

on the deaths of several infants in Cleveland. According to the CDC, the

deaths were caused by idiopathic (no known cause) pulmonary hemorrhage

initially associated with the particular mold, although a summary of peer

reviews concluded that the association was not proven.

Like the EPA, the CDC reports that it is not necessary to identify the

species of mold growing in a residence and does not recommend routine

sampling for molds. Furthermore, reliable sampling can be expensive, and

there are no EPA or other agency standards for determining what is an

acceptable or unacceptable level of mold. If you are susceptible to mold and

see it or smell it, says the CDC, there is a potential health risk and you

should remove it.

A mycologist -- a scientist who studies fungi -- uses the term mildew only

for whitish fungi that grow on plants. But for all practical purposes, mold

and the generally greenish spots many people call mildew are the same.

You can't see mold in the form of spores. You can see it and smell it after

the spores germinate and start growing, which in some cases can be within 24

hours.

Molds can become embedded in porous materials or form a furry coating on

solid surfaces. Generally, molds give off a musty, unpleasantly medicinal

and even slightly rotten odor. (Moldy bread might ring a sensory bell.) They

also cause discoloration, although mold can be white, green, brown, black or

even orange. The discoloration can remain long after mold is dead. The odor

is a sign that mold is actively growing.

Where mold thrives

You're most likely to find mold in normally damp areas, such as kitchens,

bathrooms (particularly around showers) and basements. It thrives in warm,

damp conditions, wherever there is an active leak, and in areas with chronic

condensation problems. Flooding can cause explosive mold growth,

particularly when water remains trapped in walls or carpeting.

Deposits are more common on exterior than on interior walls, particularly in

remote areas of a building and near ceilings where insulation may have

settled. Without an insulating buffer in cold weather, for example, moisture

in warm interior air more easily condenses on cool wall surfaces near the

ceiling.

In warm, humid weather, mold deposits are likely to form on and around cool

surfaces that foster condensation, such as toilet tanks replenished with

cold water. Constant dripping can cultivate mold that embeds in tile grout

and is difficult to clean.

The problem is compounded on cool, damp surfaces in areas with minimal air

circulation, such as a metal sink drain enclosed in a cabinet -- even if you

have central air conditioning that cools and dries most exposed surfaces.

According to the EPA, however, there is no practical way to eliminate all

mold and mold spores indoors. To control mold growth, you need to control

moisture. Look for more information on moisture, cleaning and mold control

in next week's column.

© 2002 The Washington Post Company