Statistics show that between home, work, and school,
most people spend an average of 90 percent of their
time indoors. We like to think our homes are healthy
places to live and raise our families and that our
offices safe to work in. But just how safe are they?
people are sensitive to molds. For these people,
exposure to molds can cause symptoms such as nasal
stuffiness, eye irritation, wheezing, or skin
irritation. Some people, such as those with serious
allergies to molds, may have more severe reactions.
Severe reactions may occur among workers exposed to
large amounts of molds in occupational settings.
Severe reactions may include fever and shortness of
breath. Some people with chronic lung illnesses,
such as obstructive lung disease, may develop mold
infections in their lungs.1
Some molds release volatile compounds into the air,
produce unpleasant odors and have been associated
with a variety of specific health problems.
Scientists label these compounds “microbial volatile
organic compounds” or “mVOCs”. Exposure to mVOCs has
been associated with headaches, dizziness, and
fatigue. According to the California Department of
Health Services, molds produce health effects
through inflammation, allergy, or infection.
Allergic reactions are most common following mold
exposure. Typical symptoms that mold-exposed people
- Respiratory problems such as wheezing,
difficulty breathing, shortness of breath
- Nasal sinus congestion
- Eye irritation (burning, watering or
- Dry hacking cough
- Nose and throat irritation
- Skin rashes or irritations
Headaches, memory problems, mood swings,
nosebleeds, body aches and pains, and fevers are
occasionally reported in mold cases, but their cause
is not understood.2
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How Much Mold Can Make Me Sick?
How much mold might make you sick depends on the
situation as well as the person. This question is
difficult to answer in the same way it's hard to say
how much sun causes a sunburn: the amount varies
from person to person. What one person can tolerate
with little or no effect may cause symptoms in
another individual.3 For some people, a relatively
small number of mold spores can trigger an asthma
attack or lead to other health problems. For other
people, symptoms may occur only when exposure levels
are much higher.2
The long-term presence of indoor mold may eventually
become unhealthy for anyone. Those with special
health concerns should consult a medical doctor if
they feel their health is affected by indoor mold.
The following types of people may be affected sooner
and more severely than others:
- Babies and children
- Elderly persons
- Individuals with chronic respiratory conditions or
allergies or asthma
- Persons having weakened immune systems (for
example, people with HIV or AIDS, chemotherapy
patients, or organ transplant recipients
Nonetheless, indoor mold growth is unsanitary and
undesirable. If you can smell mold or see mold
indoors, take steps to indentify and eliminate it
and the moisture source that caused it.2 If you
believe you are ill because of exposure to mold in
the building where you work, you should first
consult your health care provider to determine the
appropriate action to take to protect your health.
Notify your employer and, if applicable, your union
representative about your concern so that your
employer can take action to clean up and prevent
mold growth. 4
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Are Some Molds More Hazardous Than Others?
Mold spores are organized into three groups
according to human responses;
(most likely to affect those who are already
allergic or asthmatic
(serious health effects in persons with suppressed
(capable of causing serious health effects in almost
Allergic persons vary in their sensitivities to
mold, both as to the amount and the types to which
they react. In addition to their allergic
properties, certain types of molds, such as
Stachybotrys chartarum, may produce compounds that
have toxic properties, which are called mycotoxins.
Mycotoxins are not always produced, and whether a
mold produces mycotoxins while growing in a building
depends on a number of factors such as, what the
mold is growing on, conditions such as temperature,
pH, humidity, and other unknown factors. When
mycotoxins are present, they occur in both living
and dead mold spores and may be present in materials
that have become contaminated with molds.
While Stachybotrys is alive and growing, a wet slime
layer covers its spores, preventing them from
becoming airborne. However, when Stachybotrys dies
and dries up, air currents or physical handling can
disturb the mold and cause spores to become
airborne.2 At present there is no environmental test
to determine whether or not Stachybotrys growth
found in buildings is producing toxins.
Nevertheless, since the health effects of mold on
people and animals are the same whether the mold is
viable (alive) or non-viable (dead), whenever test
result confirm the presence of Stachybotrys indoors,
appropriate steps to remediate should be taken
immediately whether the mold is growing or not.
The Amounts of Mold Present Is More Concerning Than
Experts will argue about which molds are potentially
more hazardous than others. But more concerning are
the levels of airborne spores than the types of
molds present indoors. Stachybotrys and other
toxigenic molds such as Chaetomium, Aspergillus, and
others are absolutely undesirable to have growing
indoors and should always be taken seriously. But a
few rogue spores of toxigenic mold in an air sample
is far less worrisome than a few million spores the
common molds such as Penicillium or Cladosporium.
Consider this: If you open a bottle of Clorox bleach
outdoors and hold it to your chest, how long will it
take you to get sick? You probably won't get sick
outdoors in the open air. But if you open that same
bottle of bleach indoors in a small enclosed space
such as a bathroom, how long will it take you to get
sick? In just a few moments your eyes will be
irritated to tears, your nose and throat will be
burning, and you will most likely become violently
ill, vomiting and unable to get the smell and taste
of bleach out of your nose and mouth for days. Why?
Its the exact same bottle of bleach regardless of
where you open it. Right? So what's the difference?
The difference is the space in which you are exposed
to the bleach. And so it is with mold. You can take
the exact same molds that are outdoors right now,
not bothering anyone in the open air, bring them
indoors in an enclosed environment and multiply them
by 100, or 1,000, or a million, and you will have a
very toxic environment, regardless of what types of
mold it is. That is why testing is so important.
For more information on the differences between
allergenic, pathogenic, and toxigenic molds see
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How Can I Be Exposed to Mold?
Illness from mold exposure can only occur one of
three ways; 1. through absorption into the skin, 2.
ingestion, or 3. inhalation. While it is never good
to have mold growing indoors, if it is, you are not
necessarily exposed to a health risk just because
its there. Nobody gets sick looking at mold on a
wall. But when mold is disturbed, spores are
released into the air and you can then be exposed to
those spores through the air you breathe. Also, if
you directly handle moldy materials, you can be
exposed to mold and mold spores through contact with
your skin. Eating moldy foods or hand-to-mouth
contact after handling moldy materials is yet
another way you may be exposed. Other than small
child who doesn't know any better, most people would
not intentionally touch mold or knowingly ingest it.
But disturbing mold can easily send billions of
spores the air and create an immediate health risk
in an enclosed indoor environment.
How is Mold Disturbed?
An action as simple as cleaning mold that is growing
on a surface will send spores airborne. The process
of mold remediation send billions of spores into the
air. Other ways include:
- Scraping or scrubbing mold off of moldy surfaces
- Demolition or tear out of mold contaminated
- Vacuuming moldy carpet (conventional vacuum
cleaner bags do not trap mold spores - they blow
them through the bag and into the air)
- Running a furnace or air conditioner with mold in
the duct work
- Running fans in rooms where mold with contaminated
- Opening doors an windows - Realtors do this often
when a house smells like mold. They try to get the
property ahead of a buyer or a mold inspector and
open all the doors and windows to remove the smell.
But if a strong breeze is blowing through it can
stir up a lot of settled mold spores into the air.
Eventually mold spores fall down and, like dust,
when spores fall they end up on and in everything,
including furniture, bedding, drapes, carpets,
inside appliances and electronics such as TVs,
computers, stereos, etc. Coming in close contact
with mold spores by lying on the carpet, putting on
clothes, or working near electronics with fans
inside can increase exposure via skin contact and
inhalation. Children who crawl around on
mold-contaminated carpet are most at risk by
scraping their hands and knees, then rubbing their
eyes or handling food.
Lose the Dust
Dust is a magnet for mold spores. Homes and
buildings with a lot of dust are much more likely to
have higher concentrations of airborne mold spores
than cleaner structures. Exposure to unhealthy
levels of dust and mold can be reduced by regular
dusting, periodic cleaning under major appliances,
blowing out electronics with high pressured air, and
eliminating cobwebs. Once every two to three months
Keep It Clean
Greasy, grimey garbage and dirt is an ideal
environment for mold growth. Removing garbage from
indoors and away from the structure outdoors will
reduce the potential for mold growth as will regular
cleaning of cabinet interiors and corners where dirt
and grime tend to build up.
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Who Is Most At Risk of Health Concerns From Mold
Excessive exposure to mold is not healthy for anyone
inside buildings, especially where ventilation is
limited. There are, however, certain individuals who
are more likely to experience severe reactions to
mold exposure. People with allergies tend to be more
sensitive to molds. People with immune suppression
or underlying lung disease are more susceptible to
fungal infections. Other high risk candidates
- Infants, children, and the elderly
- Immune compromised patients
(people with HIV infection, cancer chemotherapy,
liver disease, etc.
- Pregnant women
- Individuals with existing respiratory conditions,
such as allergies, multiple chemical sensitivity,
People with these special concerns who live or work
in mold contaminated structures should consult a
physician if they are having health problems. People
who experience unexplained health problems while
inside a structure that tend to go away when they
leave the structure should consider having an
inspection and testing done to determine the
likelihood that indoor mold growth is the cause of
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There a three common misconceptions about mold.
1. Misconception: "BLACK MOLD"
The mold that most people are referring to when they
use the term "BLACK MOLD" is a mold called
Stachybotrys, pronounced STACK-EE-BOT-TRIS, which is
either black or dark gray. But the truth is, there
are thousands and thousands of different molds and
many of them are black. Some molds will change
colors and texture at different stages of their
growth. Some molds can be gray one day, black the
next day, and green the day after that.
2. Misconception: "TOXIC MOLD"
Contrary to the widely-used term, "toxic mold", the
premise that mold is toxic is not accurate. While
certain molds are toxigenic, meaning they can
produce toxins (specifically mycotoxins), the molds
themselves are not toxic, or poisonous. Mycotoxins
are fungal metabolites produced by a mold or fungus
- including mushrooms - which contaminate food and
are poisonous to animals and humans. Molds that
produce mycotoxins only do so under under certain
conditions and at certain times. Mycotoxins can be
found in both living (viable) and dead (non-viable)
There is always some mold present everywhere - in
the air and on many surfaces. Hazards presented by
molds that produce mycotoxins should be considered
the same as other common molds which can grow in
your house. There are reports that toxigenic molds
found inside homes can cause unique or rare health
conditions such as pulmonary hemorrhage or memory
loss. In 2004 the Institute of Medicine (IOM) found
there was sufficient evidence to link indoor
exposure to mold with asthma symptoms in people with
asthma; hypersensitivity pneumonitis in individuals
susceptible to that immune-mediated condition; as
well as upper respiratory tract symptoms, cough, and
wheeze in otherwise healthy people. Mycotoxins,
although unseen by the naked eye, are most often
inhaled but can enter the body through the skin,
mucous and eyes. Once inside the human body, mold
has all the requirements it needs to colonize and
3. Misconception: "ALLERGY SHOTS PROTECT AGAINST
A common misconception among allergists who are
untrained in mold-related toxicity levels in humans,
(which is technically not their area of expertise
unless they have trained specifically in
environmental medicine with their background in
immunology), is to do general allergen testing. Most
tests usually result in a 2+ or less.
Because not all allergists and doctors are trained
in this field, they may try to "guess" at a
diagnosis. Some physicians response is to order
allergy shots. However, allergy shots are virtually
worthless (and could possibly be harmful) to a
person who has been heavily exposed to mycotoxins
since they are already in a state of toxicity. If
anything, this could exacerbate the problem.
Fungi, or microorganisms related to them, may cause
other health problems similar to allergic diseases.
Some kinds of Aspergillus may cause several
different illnesses, including both infections and
allergy. These fungi may lodge in the airways or a
distant part of the lung and grow until they form a
compact sphere known as a "fungal mass." In people
with lung damage or serious underlying illnesses,
Aspergillus may grasp the opportunity to invade the
lungs or the whole body.
In some individuals, exposure to these fungi can
also lead to asthma or to a lung disease resembling
severe inflammatory asthma called allergic
bronchopulmonary aspergillosis. This latter
condition, which occurs only in a minority of people
with asthma, is characterized by wheezing, low-grade
fever, and coughing up of brown-flecked masses or
mucus plugs. Skin testing, blood tests, X-rays, and
examination of the sputum for fungi can help
establish the diagnosis. Corticosteroid drugs are
usually effective in treating this reaction;
however, immunotherapy (allergy shots) is not a
reliable "one-shot-fix-all" treatment.
Why Take Chances?
Life is too short to not live it well. If you
suspect you have a mold problem in your home or
workplace, address it early. Call an AMI
representative to discuss services available to you
to help accurately asses mold problems and resolve
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Adverse Human Health Effects Associated with Indoor
Printable Documents by The American College of
Occupational and Environmental Medicine - Choose:
[Word File] [HTML] [PDF]
[return to top of page]
1. EPA - Environmental Protection Agency website:
Mold Resources/Health and Mold/How do molds affect
2. CDHS - California Department of Health Services:
Indoor Air Quality Info Sheet/Mold in My Home: What
Do I Do?
3. FDOH - Florida Department of Health website:
Indoor Mold and Health - How much mold does it take
to make me sick?
4. CDC - Centers for Disease Control and Prevention
website: Basic Facts/Molds in the Environment/I'm
sure that mold in my workplace is making me sick.
This website was developed primarily to provide
general information about mold and services offered
by AMI with respect to mold inspections, mold
testing, and other indoor environmental testing.
This site is not intended to be a resource for
medical advice or information concerning health
matters. The information being disseminated in this
site is believed by AMI to be the most recent and
most reliable information available at the time.
Neither AMI nor its principles or employees warrants
all of the information contained herein to be 100%
factual. For proper medical advice you should always
consult a physician or other qualified expert.