Molds may affect human health by three mechanisms: infection (by exposure of a susceptible

individual to mold spores; generally but not always a person who is immunocompromised),

hypersensitivity (allergy to mold spores, components, or toxins, including asthma and

hypersensitivity pneumonitis), or direct irritation (by mycotoxins, the toxins produced by mold).

air; fungal concentrations are highest in the fall and summer and lowest in the winter and

spring; geographically in the continental U.S., fungal concentrations are highest in the

southwest, far west, and southeast; and the most common culturable airborne fungi, both indoors and outdoors and in all

seasons and regions, were Cladosporium, Penicillium, nonsporulating fungi, and Aspergillus.

Considerable interest and controversy have been generated recently about searching for and

identifying specific molds in buildings. The Centers for Disease Control and Prevention (CDC)

currently state that determining what type of mold exists is unnecessary, and that all molds

Mold may proliferate almost anywhere that has too much moisture. Even if renovation is done

properly, recurrence of moist conditions may cause mold regrowth. In one study, uninstalled

wallboard available from local distributors was found to contain a baseline bioburden, including

Stachybotrys chartarum. The authors noted that sanitation and preservation treatment of the

Mold has been considered as a causative agent of building related illness (BRI). Building related

illnesses are caused by known pathogens, have specific symptoms, and may be serious. Specific

diseases include those caused by Legionella species (Pontiac Fever, Legionnaire’s Disease) and

humidifier fever. Other airborne infectious diseases may have increased transmission when there

from indoor air contamination of offices where workers shared ventilation contaminated with

Revised 7/18/03

Prudent health practice dictates limiting exposure of immunocompromised persons to excessive

levels of mold spores and limiting exposure of sensitized (allergic) individuals to airborne or

surface contamination of the specific mold to which the individual is sensitized.

The medical member of the indoor environmental quality (IEQ) investigative team can

contribute valuable expertise in advising what organisms the industrial hygienist (IH) should

sample for. If there is reason to suspect a particular species of mold - because of worker

concern, fungal infection, or identification by a worker’s health care provider (HCP) of allergy to

a specific mold - IH can be asked to direct sampling to recover and appropriately identify that

organism. Requesting IH to "sample for molds" because of non-specific symptoms in workers

will generally not be helpful, since simply the presence of molds may be insignificant with

respect to human health.

Communication between medical and other team members is important when trying to determine

if there is an exposure pathway. For example, discovery of mold on surfaces may be incidental

in a situation where airborne contamination is the problem (e.g., Legionella).

In general, it is preferable not to keep workers out of the work area, nor to advise workers to

avoid returning to a building unless: (1) a diagnosis of a building-related illness has been

established, or (2) a building-related diagnosis is suspected based on symptoms, disease patterns,

and findings consistent with a building-related illness.

If a worker is confirmed to have building-related mold or other allergy, the worker should not be

allowed back into the building until remediation has been completed and post-remediation

sampling documents confirm reduced levels of mold. After remediation, re-exposure should be

done with caution. It may be appropriate to have medical care immediately available in the case

of serious allergic reactions. If remediation has been adequate, there is reason to expect the

The etiology of a worker’s condition may be unknown, but the worker’s condition is serious

enough that further exposure to any potential offending agent represents an unacceptable health

risk. In such cases, the prudent HCP may recommend against further exposure to a building until

the medical workup is complete. However, the HCP should complete the workup thoroughly

and accurately, being careful to avoid labeling the building a "health hazard" or stating that mold

in the building is the etiology until after the facts have established such a link. Incorrectly

identifying building mold as a source of health hazards can cause undue anxiety and loss of

income among workers, decreased productivity, increased operating costs, and decreased

readiness. Once a causal relationship has been established, however, relocation of affected

workers to a different building may be appropriate.

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A case report of office-related Alternaria allergy supports the following as "considerations" for

concluding an association exists between IEQ-related mold exposure and illness in an

occupational setting: symptoms and signs consistent with a medical diagnosis; either in vitro or

in vivo evidence of exposure; environmental evidence of plausible biological exposure; and

Successful remediation can result in a building that can be reoccupied without recurrent related

If sampling reveals pathogens suspected because of the symptoms or signs exhibited by building

occupants, remediation effectiveness should be confirmed by clearance sampling before building

reoccupation. Building processes (for example, heating, ventilation, and air-conditioning

(HVAC) and humidification systems or decorative fountains) that may be similar in other

buildings may warrant preventive attention as a public health measure. Building engineers,

inspectors, or public health officials may be appropriate points of contact in such situations.

Molds are usually opportunistic pathogens, causing clinically significant infections only in cases

of overwhelming exposure or in individuals who are immune compromised (i.e., debilitated by

extremes of age, underlying infection, poor sanitation, inadequate nutrition, wounds); immune

suppressed (chemotherapy, severe stress, pregnancy); or immune deficient (human

immunodeficiency virus). Mold infection diagnoses will be made by appropriate microbial

identification studies or clinical courses (which are beyond the scope of this document).

Respiratory or skin (allergic contact dermatitis) allergy symptoms are the most likely symptoms

encountered from building-related mold allergy. Sensitivity to mold allergens is an important

such as gastrointestinal hypersensitivity-related complaints, may be a clue that the offending

exposure may not be indoor environment related, but rather related to an ingested allergen.

Allergens are common in most environments. Certain classes of allergens are especially

pertinent to an indoor environmental quality investigation. Again, the history given by those

affected can be the most helpful information in determining the source of the problem. In

addition to potential for infectious disease, molds can cause allergic problems. Buildings that

have been water damaged for several days or more - whether from flood, leaking roofs or walls,

broken plumbing, improperly installed or adjusted humidifiers, or condensation on cold surfaces

- may become culture media for any of a number of molds and fungi.

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Specific IEQ-associated illnesses with an allergic (sensitization) basis include asthma,

hypersensitivity pneumonitis, rhinitis or sinusitis, bronchitis or tracheitis (usually associated with

sinusitis), and humidifier fever (HF). HF is thought to be allergic, as patients have shown

possible that not all etiologies of IEQ-related allergic complaints are biologicals, as one report

Spirometry may help document involvement of the lower respiratory tract. A peak flow meter

may be the simplest way to document expiratory impairment or exacerbation of asthma with

showing serum IgE specific to one or more indoor molds, and building-related symptoms in

sensitive than blood testing (radioallergosorbent test, commonly called RAST) in detecting

Special conditions may be necessary for mycotoxins produced by surface Stachybotrys in a

building to reach sufficient concentrations to cause such effects, according to the results of one

sufficient that direct irritation from mycotoxins, rather than a hypersensitivity-related response to

molds or mycotoxins, has occurred in humans exposed to mold in indoor air.

The primary indicator that symptoms among workers may be caused by building-related mold is

that there is a temporal relationship of the symptoms to building exposure. Mold allergy may

on entering a building, after several hours of exposure, or even 2 to 8 hours after leaving the

building. A clear worker history of a temporal association of allergy symptoms with building

exposure should alert the health care provider to the possibility of building-related allergy.

It is unknown how much exposure time is required before sensitivity to mold develops. As many

molds are commonly found outside of the workplace, it is expected that some individuals have

been sensitized prior to any occupational exposure. Further, since development of allergy to

sensitization develops only after many years.

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fragments may result in airway colonization, which may subsequently cause infections in

nosocomial aspergillosis and the degree of fungal contamination of air and surfaces in patient

hypersensitivity to A. fumigatus may cause Aspergillus asthma and allergic bronchopulmonary

characterized by fleeting pulmonary infiltrates that are often confused with pulmonary

tuberculosis on chest x-ray, and by central bronchiectasis on chest CT (computerized

tomography). Early diagnosis and therapy may alter the course of the disease and prevent the

Aspergillus candidus, common in grain dust, has been suggested to be an etiologic factor in

Aspergillus versicolor has been found in an investigation of building-related complaints, but no

was identified in the indoor air in 6% of the buildings studied and in the outdoor air of 1% of the

S. chartarum produces trichothecene mycotoxins, which are biologically active and can produce

a variety of physiological and pathologic changes in humans and animals, including modulation

Stachybotrys has been found to involve both immunoglobulin IgE and IgG against antigenic

immunologic properties. Inhalation of S. chartarum extract aerosols was observed to provoke

S. chartarum has been associated with nasal bleeding in adults. Stachylysin, a mycotoxin, may

possible association between S. chartarum and pulmonary hemorrhage/hemosiderosis in infants

has been reported, but further review of evidence by the CDC and other experts concluded that

Page 5 of 11

Articles are not consistent as to the significance of Stachybotrys in relation to human health.

Two reviews have found inadequate evidence to clearly establish the place of Stachybotrys in

Thermophilic Actinomyces and Aspergillus fumigatus have been suggested as possibly having a

causative antigenic role in stipatosis, a hypersensitivity pneumonitis found in Mediterranean-area

although the name Actinomyces suggests a fungus, actinomycosis is a bacterial infection.

Cladosporium cladosporioides was found to be the etiologic agent of hypersensitivity

Fusarium species infections in a hospital led to an investigation that identified the water

distribution system of the hospital as the reservoir of Fusarium. Aerosolization of Fusarium

IgG to Sporobolomyces salmonicolor was the most commonly detected anti-mold

immunoglobulin associated with exposure in a Finnish military hospital building with severe,

repeated, and enduring water and mold damage. Rhinitis, asthma, and alveolitis were noted

Streptomyces albus was found to be responsible for a biopsy-proven case of hypersensitivity

An increased risk of developing asthma in adulthood has been found to be significantly related to

For more information on IEQ medical guidance, contact Occupational Medicine at (757) 953-

Page 6 of 11

Information, U.S. National Library of Medicine, PubMed query at

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi

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from nontoxic Stachybotrys chartarum on murine airways. Inhal Toxicol. 2002 May;14(5):521-

effects in mice exposed to airborne emissions from Stachybotrys chartarum and implications for

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