Safety Office, Commissary Building
University of Waterloo
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
Phone 519 888 4567 Ext. 33587
Fax 519 886 8082
Email: safety@uwaterloo.ca
Workers and the public may be exposed to mould on water-damaged building materials inside buildings and during building maintenance and repair operations.
The most common types of mould are generally not hazardous to healthy individuals, but some moulds may be hazardous to certain individuals. The sustained and/or extensive growth of any visible mould on the interior surfaces of a building is unacceptable and remediation is required.
People who have asthma, bronchitis, hay fever, other allergies, or have weakened immune systems are more likely to react to mould. The most common symptoms are runny nose, eye irritation, skin rash, cough, congestion, and aggravated asthma. Symptoms usually disappear after mould exposure stops. Most often there are no known long-term consequences to workplace exposures.
Employers are required by section 25(2)(h) of the Occupational Health and Safety Act (OHSA) to take every precaution reasonable in the circumstances for the protection of workers. The OHSA places a responsibility on constructors (section 23), employers (section 25), and supervisors (section 27) to ensure the health and safety of workers. This includes protecting workers from mould in workplace buildings. Occupants of buildings contaminated with mould should be advised of the presence of the mould.
Moulds (fungi) are present everywhere, indoors and outdoors. Buildings with a history of water leaks, floods, fires, and problems with indoor air quality (e.g. poor humidity control, lack of fresh air) should be considered at greater risk for mould growth. Water-damaged drywall, wood materials, jute, wallpaper, and cardboard are all prone to fungal growth.
All moulds need water to grow. Mould can grow anywhere there is water damage, high humidity, or dampness. Most often moulds are confined to areas near the source of water. When mouldy material becomes damaged or disturbed, mould spores can be released into the air. Exposure occurs if people inhale the spores.
In modern buildings, moisture problems may exist as the result of:
The best method of mould prevention is to reduce the amount of moisture by keeping the relative humidity between 30% and 50%. Prevention measures include:
Note: It is important to keep air conditioners and dehumidifiers in good condition. Empty any water collectors regularly so water does not contribute to moisture problems. If using humidifiers, ensure they are cleaned regularly.
A visual inspection is the most reliable method of identifying mould problems. Common signs of water damage will be discolouration and staining. Moulds will most often appear as dark spots, stains, or patches. Look for puddles of water around or under sinks, tubs, drip pans for dehumidifiers, air conditioners, and refrigerators that may be contributing to the moisture in the building. Monitoring devices can be used to measure the moisture level of drywall, wood, etc. These devices will help indicate whether or not moisture levels exist that would promote the growth of mould.
When looking for mould, inspect:
Level 1 cleanup refers to small isolated areas (less than 10 square feet of mould growth or HVAC equipment with less than 10 square feet of growth in unoccupied areas).
Procedure:
Precautions:
Level 2 cleanup refers to larger isolated areas (10 – 100 square feet, or less than 10 square feet in HVAC equipment in occupied spaces).
Inform the Safety Office upon discovery as it is necessary to have trained professionals assess the cleaning procedures, inspect, and perform environmental sampling. The OHSA requires that notification be made to the Joint Health and Safety Committee (worker member in attendance for environmental sampling).
Level 3 cleanup procedures are required when there is more than 100 square feet of mould-affected material, or more than 10 square feet in HVAC equipment in occupied areas.
Inform the Safety Office upon discovery. If mould is discovered in larger areas, remediation work, inspection and environmental sampling must be performed by trained professionals.
OHSA requires notification be made to the Joint Health and Safety Committee (worker member in attendance for environmental sampling).
It is recommended that porous materials such as dry wall, ceiling tiles, fabric or carpet be thrown out and replaced rather than cleaned whenever possible. Non-porous materials such as metal, glass, hard plastic, and semi-porous materials such as wood and concrete can be cleaned and reused (if structurally sound). In all situations, the underlying moisture problem must be corrected to prevent recurring mould growth.
Safety Office, Commissary Building
University of Waterloo
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
Phone 519 888 4567 Ext. 33587
Fax 519 886 8082
Email: safety@uwaterloo.ca
The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is co-ordinated within the Office of Indigenous Relations.