Truth About Mold

Health Effects

Health Effects

Toxic mold can cause a wide variety of health effects.  The health problems experienced by each person are different due to several factors, including age, genetics, health prior to exposure, amount of exposure, extent of contamination, types of molds and mycotoxins involved, other contaminants such as bacteria, etc.

Contamination in water-damaged buildings is a very complex situation that can result in multi-system health problems.

There are thousands of articles, studies, books and papers written on this topic.  We will provide a brief overview of some of the key statements and conclusions that are presented in the literature.

The following is one example of a list of health problems that can be caused by molds and mycotoxins:

From Dr. Harriet Ammann (Senior Toxicologist)

Is Indoor Mold Contamination a Threat to Health?

Health effects from exposures to molds in indoor environments can result from allergy, infection, mucous membrane and sensory irritation and toxicity alone, or in combination.

Mycotoxins are nearly all cytotoxic, disrupting various cellular structures such as membranes, and interfering with vital cellular processes such as protein, RNA and DNA synthesis.
  •         Vascular system (increased vascular fragility, hemorrhage into body tissues, or from lung, e.g., aflatoxin, satratoxin, roridins).
  •         Digestive system (diarrhea, vomiting, intestinal hemorrhage, liver effects, i.e., necrosis, fibrosis: aflatoxin; caustic effects on mucous membranes:   T-2 toxin; anorexia: vomitoxin.
  •         Respiratory system: respiratory distress, bleeding from lungs e.g., trichothecenes.
  •         Nervous system, tremors, incoordination, depression, headache, e.g., tremorgens, trichothecenes.
  •         Cutaneous system: rash, burning sensation sloughing of skin, photosensitization, e.g., trichothecenes.
  •         Urinary system, nephrotoxicity, e.g. ochratoxin, citrinin.
  •         Reproductive system; infertility, changes in reproductive cycles, e.g. T-2 toxin, zearalenone
  •         Immune system: changes or suppression: many mycotoxins.
From the 2009 World Health Organization Report--Guidelines for Indoor Air Quality: Dampness and Mould

WHO 2009 Report

Indoor air pollution--such as from dampness and mould, chemicals and other biological agents--is a major cause of morbidity and mortality worldwide.

From the Executive Summary:

Exposure to microbial contaminants is clinically associated with respiratory symptoms, allergies, asthma and immunological reactions. 

Toxicological evidence obtained in vivo and in vitro supports
these findings, showing the occurrence of diverse inflammatory and toxic responses after exposure to microorganisms isolated from damp buildings, including their spores, metabolites and components.

From Chapter 2:

Mycotoxins, or fungal toxins, are low-relative-molecular-mass biomolecules produced by fungi, some of which are toxic to animals and human beings. Mycotoxins are known
to interfere with RNA synthesis and may cause DNA damage.

From a report on Neurotoxic Effects

The Validity of the Environmental Neurotoxic Effects of Toxigenic Molds and Mycotoxins

"Exposure to mycotoxin may occur via enteric, inhalation, or direct contact to skin and mucosa. Acute and chronic disorders, irritation, systemic reactions, and even cancer may develop after the exposure to these toxins."

"Symptoms include respiratory complaints that involve the nose and lungs; eye symptoms, and mucous membrane irritation.  The major presentations are headache, general debilitating pains, nose bleeding, fevers with body temperatures up to 40 degrees C (104 degrees F), cough, memory loss, depression, mood swings, sleep disturbances, anxiety, chronic fatigue, vertigo/dizziness, and in some cases, seizures."

"Mycotic demyelinating optic neuritis is a neurological disorder of the visual system caused by mycotoxins released by indoor toxic molds."

"Other neurobehavioral manifestations in the mold-exposed individuals are abnormal decrease in steady balance, reaction time, blink-reflex latency, color discrimination, visual fields, and grip, compared to control. Hence, most exposed patients have reduced cognitive functioning in multiple domains, with memory and executive functions the most commonly affected areas."

From a Wire Service Canada article (January 27, 2010)

B.C. Company Fights Back Against Sick Building Syndrome

"William Fisk from Lawrence Berkeley National Laboratory in California established a baseline for quantifying benefits from improved IAQ and demonstrated the economic impacts of increased productivity. Findings are showing that improvement in IAQ can: Reduce SBS symptoms by 20 to 50 percent, with estimated savings of $10 to $100 billion; Reduce asthma by 8 to 25 percent, with estimated savings of $1 to $4 billion; Reduce other respiratory illnesses by 23 to 76 percent, with estimated savings of $6 to $14 billion; Improve office worker productivity by 0.5 to 5 percent, with estimated savings of $20 to $200 billion."

From the ACGIH book titled "Bioaerosols: Assessment and Control"

Be sure to check out the list of symptoms on page 24-3 of this book.

To purchase the book from ACGIH, go to:


From a November 2012 Alert by NIOSH (National Institute of Occupational Safety and Health)

Preventing Occupational Respiratory Disease from Exposures Caused by Dampness in Office Buildings, Schools, and Other Nonindustrial Buildings

Occupants within damp office buildings, schools, and other nonindustrial buildings may develop respiratory symptoms and disease.

NIOSH has estimated that 29% to 33% of new-onset adult asthma is attributable to work-related exposures and 23% of existing adult asthma is exacerbated by work. If occupants develop asthma or asthma exacerbation while working in damp buildings, medical treatment may not be effective if the occupant continues to be exposed. An occupant in damp buildings with allergic asthma may experience symptoms after exposure to very low levels of a
sensitizing agent that may still be present after remediation; in such cases, an occupant may require relocation to another area.

Truth About Mold - Health Effects
From Dr. Ruth Etzel (2006)

What the Primary Care Pediatrician Should Know About Syndromes Associated with Exposures to Mycotoxins

"Mycotoxins can have protean manifestations; the symptoms depend on the specific toxin or mixture of toxins, the age, sex, and diet of the child, the dose, and whether exposure is by ingestion, inhalation, skin and mucosal exposure, or a combination of two or more of these routes.  The most well-characterized presentations among infants and children are summarized in Table 2 under four headings: vomiting illness, bone marrow failure, acute pulmonary hemorrhage, and recurrent episodes of apnea and/or pneumonia."

From the 1999 Bulletin of the World Health Organization

Toxic Effects of Mycotoxins in Humans

"Exposure to mycotoxins is mostly by ingestion, but also occurs by the dermal and inhalation routes."

"Mycotoxicoses often remain unrecognized by medical professionals, except when large numbers of people are involved."

"Aflatoxins are acutely toxic, immunosuppressive, mutagenic, teratogenic and carcinogenic compounds."

From a 1989 U.S. EPA Report for Congress on Indoor Air Pollution

U.S. EPA Report for Congress on Indoor Air Quality. Volume II: Assessment and Control of Indoor Air Pollution. August 1989.

Health effects from indoor air pollution cover the range of acute and chronic effects, and include eye, nose, and throat irritation, respiratory effects, neurotoxicity, kidney and liver effects, heart functions, allergic and infectious diseases, developmental effects, mutagenicity, and carcinogenicity.

From the 1989 Massachusetts Special Legislative Commission on Indoor Air Pollution

The Commonwealth of Massachusetts, Special Legislative Commission on Indoor Air Pollution: Indoor Air Pollution in Massachusetts

The Commission's efforts confirm the seriousness of the indoor air pollution health threat, which worsened with the energy conservation efforts of the 1970s.  More insulation and tighter construction led to lower ventilation rates and build-up of contaminants.  Many 'sick' buildings have been identified where occupants suffer severe or recurring discomforts such as headaches, dizziness, fatigue, eye irritation, and respiratory problems.  Other conditions attributable to indoor air contaminants include: cancer; bronchitis; pneumonia; heart, circulatory and respiratory problems; impaired vision; skin rash; chemical sensitivity; birth defects; and mental, nervous and immunological disorders.

From Jack Thrasher, Ph.D. Toxicologist (2009)

Biocontaminants and Complexity of Damp Indoor Spaces: More Than What Meets the Eyes

Exposure of occupants mainly results from inhalation and, to a lesser extent, skin absorption and ingestion.  Molds produce mycotoxins during rapid growth.  At low concentrations, they cause mycotoxicosis in humans and animals. The mycotoxins causing disease include aflatoxins, ochratoxin A, trichothecenes, citreviridins, fumonisins and gliotoxins.  Mycotoxins can regulate the immune system up or down as well as inhibit synthesis of protein, RNA and DNA.  Moreover, they can form DNA adducts, protein adducts and cause oxidative stress as well as mitochondrial directed apoptosis.

Toxic encephalopathy involves multiple symptoms, including loss of balance, recent memory decline, headaches, lightheadedness, spaciness/disorientation, insomnia, loss of coordination.

From the 2008 Report of the U.S. Government Accountability Office (GAO)

Indoor Mold: Better Coordination of Research on Health Effects and More Consistent Guidance Would Improve Federal Efforts

"Mold may affect human health through a number of routes and mechanisms.  While inhalation is generally the most common route of exposure for mold in indoor environments, exposure can also occur through ingestion (for example, hand-to-mouth contact) and contact with the skin.  The roles of these routes of exposure in causing illness are unclear. Once exposure occurs, health effects may arise through several potential mechanisms, including allergic (or immune-mediated), infectious, and toxic.  It is not always possible to determine which of these mechanisms is associated with a specific health outcome."

From a 2004 U.S. Army Textbook

Medical Management of Biological Casualties Handbook

"Exposure causes skin pain, pruritis, redness, vesiculation, necrosis, and sloughing of the epidermis.  Effects on the airway include nose and throat pain, nasal discharge, itching and sneezing, cough, dyspnea, wheezing, chest pain, and hemoptysis.  Toxin also produces similar effects after ingestion or eye contact. Severe intoxication results in prostration, weakness, ataxia, collapse, shock, and death."

From a 1999 study by the Mayo Clinic

Mayo Clinic Study Implicates Fungus as Cause of Chronic Sinusitis

"Mayo Clinic researchers say they have found the cause of most chronic sinus infections--an immune system response to fungus."

"An estimated 37 million people in the United States suffer from chronic sinusitis, an inflammation of the membranes of the nose and sinus cavity.  Its incidence has been increasing steadily over the last decade."

From a 2007 study by Berkeley Labs and the EPA

Berkeley Lab, EPA studies Confirm Large Public Health and Economic Impact of Dampness and Mold

"Of the 21.8 million people reported to have asthma in the U.S., approximately 4.6 million cases are estimated to be attributable to dampness and mold exposure in the home,” says the study. In addition, this paper estimates that “the national annual cost of asthma that is attributable to dampness and mold exposure in the home is $3.5 billion."

From a 2007 study by Brown University

Brown Study Finds Link Between Depression and Household Mold

"A groundbreaking public health study, led by Brown University epidemiologist Edmond Shenassa, has found a connection between damp, moldy homes and depression."

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