Biggs & Narciso

Mould Information Sheet

Types of Mould

While there are dozens of varieties of mould that find their way into buildings, the most dangerous strains are: Chaetomium (Kay-toe-MEE-yum) and Stachybotrys chartarum which produce airborne mycotoxins which are linked to autoimmune disease. Under certain environmental conditions, both of these fungi release mycotoxins that can cause irreversible neurological and immunological damage in humans. Spores, when inhaled, can begin to colonize in the sinuses and other parts of the body, including the brain, lungs and digestive tract. Stachybotrys has gained special attention recently because it has been discovered in portable classrooms with ongoing moisture problems. It appears as small black patches and thrives on water-soaked cellulose material such as wallpaper, ceiling tiles and drywall. Airborne moulds can spread very easily through any HVAC system.

Health Hazards

Exposure to toxic moulds may irritate skin, eyes, nose, and throat, resulting in allergy-like symptoms such as difficulty in breathing, runny nose, and watery eyes. Other symptoms could include fatigue and headache. People with allergies to moulds may experience asthma attacks. Exposure to the more dangerous moulds such as Stachybotrys or Chaetomium could result in more serious symptoms including burning in the nose, nose bleeds, severe coughing, and impairment of the immune system. Excessive exposure can worsen conditions like asthma, bronchitis, hay fever or other allergies.

In the most severe cases, exposure to toxic moulds can result in brain damage, weakened immune systems, eyesight deterioration, memory loss, coordination/balance impairment and hearing degradation. These symptoms can be permanent.

Identification of Mould Contamination

If mould is suspected, a building owner should arrange for a thorough assessment to determine whether mould is indeed present. The assessment should combine a visual building inspection with a lab analysis of bulk samples.

Visible mould is just one indicator. Since moulds thrive in dark, moist environments, the major contamination may be hidden from view. Inspections of water-damaged areas must include examining wall cavities, looking behind drywall, under carpets, and above ceiling tiles.

Since not all moulds are toxic the lab analysis is critical. It will identify the mould species which will determine the type of remediation required.

Removal and Remediation

It is imperative that mould be removed completely and the problem that created the mould in the first place be rectified. However, this work requires special control measures to prevent worker exposure as well as eliminate the possibility that the mould will spread to adjacent areas. In the case of Stachybotrys contamination this is particularly important because of its potentially severe health effects.

Removing mould can be disruptive to workplace operation. Because mould is constantly spreading it must be dealt with immediately.

Mould always needs a water source to develop. Certain areas or building features create ideal growing conditions for mould. Property managers must be diligent in their search for mould. The quicker mould is detected the more successful (and less costly) the remediation effort will be. Routine investigation for mould including a check for relative humidity and water accumulation should be part of the regular building inspection process.

The first step is to correct the cause of the moisture problems before any mould remediation takes place. Without the initial problem corrected, any mould removal will be a wasted effort. Once the source of moisture is identified and repaired, all affected areas need to be demolished and removed. The area must be thoroughly dried and repaired using suitable building materials meeting local building code specifications.

A follow-up inspection should be conducted 3-6 months after remediation to ensure that the mould has not returned

Sources & Further Information on Mould Removal