Mould Contamination

Additional Mould Information

Moulds are a naturally occurring and essential part of our environment. They can be found almost everywhere outdoors and indoors, but typically do not become a problem in indoor environments until conditions exist that allow moulds to proliferate. Catastrophic or chronic water damage events combined with the presence of cellulose building materials (wood, drywall, ceiling tiles, etc.) allows mould to grow and proliferate within buildings. Under these conditions mould growth within buildings can present a risk to the building structure itself (through decomposition of building materials) as well as to occupants in the building (through potentially adverse health effects).

Health effects posed by airborne exposure to moulds (as well as other types of fungi and bacteria) are not well understood. Current evidence suggests that health effects caused by inhalation of fungal spores (and other fungal fragments) most commonly results in allergic-type reactions such as runny nose, cough, congestion, eye irritation and aggravation of asthma. Exposure to very high concentrations of bacteria or fungi (such as those that may be observed during remediation of contaminated building materials) can result in more serious health effects such as Organic Dust Toxic Syndrome (ODTS) or Hypersensitivity Pneumonitis (HP), where flu-like symptoms are exhibited. Serious infections to immune-compromised individuals have also been documented while controversy exists regarding health effects associated with so-called “toxic moulds”.

Regardless of the type or severity of health effects that may be caused by microbial exposure, mould growth inside a building should be considered unacceptable from a building operations and maintenance standpoint as well as from a health risk standpoint. In Ontario the Ministry of Labour (MOL) recognized this and in September of 2000 issued an alert regarding mould titled “Mould in Workplace Buildings”. This alert outlined potential health effects caused by mould exposure, causes of mould growth in buildings and the need to properly remediate mould-contaminated building materials. Further to the MOL alert, several government agencies and special interest groups have developed guidelines for the proper assessment and remediation of fungal-contaminated buildings. Common to all is the need to remediate contaminated building materials under controlled conditions, with the extent of safety measures employed based partially on the extent of contamination.