Due Diligence in Managing Water Damage or Mould Growth in Buildings

Indoor Air Quality & Mould
PEN #14

Mould growth in buildings and the possible adverse health impact on occupants has emerged as one of most pressing and common health and safety issues of the day.

Employers, property managers and contractors understand they are responsible to protect the health and property of employees, clients and occupants. This article and the accompanying flowchart will assist these responsible parties in meeting current standards for managing water damage or mould growth in buildings.

Mould microorganisms are rapidly growing fungi, present throughout the natural world. Mould spores will always be present in buildings, whether blown in through windows or other openings, brought in by ventilation equipment, or tracked in with dust and dirt.
The growth of mould can occur whenever susceptible building materials are wet for long enough to allow the spores to germinate and multiply. Common sites for mould growth include drywall, carpets, ceiling tiles, wood and wood products, and paper products.

Once the mould spores are formed, they are readily airborne and will remain a health hazard until the growth is removed. This is the case even when the mould growth is within wall cavities or other concealed locations.

The most common symptoms reported from mould exposure in buildings are running nose, eye irritation, cough, nasal congestion, aggravation of asthma, headache and fatigue. There is also a risk of fungal respiratory infections in occupants who have a compromised immune system. There is no safe level of airborne mould exposure in buildings, that is, an airborne level without a risk of adverse health effects among at least some of the occupants.

Several professional bodies have issued standards in the past few years on the assessment and remediation of mould growth in buildings. The most significant of these are given below.

  1. Guidelines on Assessment and Remediation of Fungi in Indoor Environments, New York City Department of Health, 2008.
    The New York City guidelines are widely quoted by public health departments and other regulatory agencies. The Ontario Ministry of Labour refers employers to these guidelines in a Hazard Alert on Mould in Workplace Buildings issued in 2000.
  2. Construction – Related Nosocomial Infections in Patients in Health Care Facilities: Decreasing the Risk of Aspergillus, Legionella and Other Infections, Health Canada, 2001; Infection Control during Construction, Renovation and Maintenance of Health Care Facilities, CSA Standard Z317.13-07, Canadian Standards Association, 2007.
    These two Canadian standards give precautions for construction or restoration work in hospitals and health care facilities, to reduce the risk of patients acquiring mould infections or infections with Legionella bacteria.
  3. Standard and Reference Guide for Professional Water Damage Restoration, 3rd Edition, US Institute of Inspection, Cleaning and Restoration, 2006. The IICRC provides training and certification for restoration contractors. The S500 Standard emphasizes steps to be taken to protect building occupants from the risks of contaminated flood water or harmful microbial growth.
  4. Mold Remediation in Schools and Commercial Buildings, US Environmental Protection Agency, 2001.
    The EPA standard details procedures to be followed in remediating mould growth. It also gives useful advice on the effectiveness of drying efforts and the time that finishes can remain wet before mould growth might occur.
  5. Mold Remediation Procedures, Environmental Abatement Council of Ontario, 2nd Edition, 2010.
    EACO, in consultation with the Ontario Ministry of Labour, developed a code of practice for mould abatement, incorporating on the recommendations of various standards and industry practices in Ontario. The Ministry of Labour accepts the EACO guidelines as meeting the due diligence requirements of the Occupational Health and Safety Act.
  6. Mould Guidelines for the Canadian Construction Industry, Canadian Construction Association, 2004.
    The CCA guidelines give advice on prevention of mould growth on construction projects, demolition precautions and legal and insurance considerations, among other issues. The guidelines also give precautions for mould remediation (Levels I, II and III plus HVAC abatement).
  7. Fungal Contamination in Buildings: Health Effects and Investigation Methods, Health Canada, 2004.
    This Health Canada update of a 1995 guideline presents a literature review on health effects of indoor mould and concludes that living or working in mouldy buildings is harmful to health. It gives detailed recommendations for mould investigations and provides general advice for abatement and supervision of abatement.

The attached flowchart summarizes the major requirements of the standards listed above, as well as some general responsibilities under the Ontario Occupational Health and Safety Act pertinent to this work.

Are occupants experiencing adverse health effects?

At the outset, the responsible party should be attentive to the health complaints and the health status of the occupants. The New York City protocol recommends that occupants who are experiencing significant adverse health effects that might be related to mould exposure be advised to see a doctor. It may be necessary to re-locate susceptible persons. In a workplace building, the Ministry of Labour Sensitive Worker policy might be applied in such a case.
Evacuation of a building would only be warranted in cases of widespread mould related symptoms (preferably physician confirmed) and widespread mould contamination. In most cases, occupants can safely remain in the building during remediation. However, both the New York City Protocol and the IICRC S500 standard state it may be necessary to re-locate susceptible individuals until the remediation is complete.

Does the affected area contain possible asbestos-containing building materials (ACM)?

Asbestos may be present in common finishes in older buildings, such as mechanical insulation, fireproofing, smooth and textured plaster, vermiculite insulation, ceiling tiles or drywall joint compound. Ontario Regulation 278/05 sets standards for the day to day management and safe disturbance of ACM. Prior to any disturbance, check the asbestos inventory for the building, required by the regulation. If information is incomplete or not available, samples must be taken for laboratory analysis or the material presumed to be ACM.

Note that O.Reg. 278/05 requires at least 3 and in some cases up to 7 samples of a material to confirm asbestos is not present. Type 1, 2 or 3 work procedures will be required for any disturbance of confirmed or presumed ACM. Waste must be managed and disposed of in accordance with Ontario’s waste management regulation, O.Reg. 347.

Is the building a hospital or health care facility?

Any work in a hospital or other health care facility has the potential to release settled mould spores, or Legionella bacteria in plumbing systems. If these spores or bacteria are not contained, susceptible patients might develop fungal infections or Legionnaires’ disease, a bacterial pneumonia. Note that mould spores are presumed to be present in all settled dust so that a risk of infection from airborne mould is present even if there is no visible mould growth. If mould growth is present, the risk is even greater. All work in a health care facility should be performed under the direction of infection control personnel, following Health Canada and CSA Z137.13 guidelines.

Contamination with sewage or other highly contaminated water?

Where a building has been contaminated with water containing microorganisms harmful to health (sewage, and also flooding from rivers and streams), Category 3 work practices described by the IICRC S500 standard apply.

The contractor should be trained and experienced in such work and have appropriate liability insurance. The contaminated area should be enclosed, and the ventilation systems turned off and sealed. It may be advisable to install portable filtered exhaust fans to put the area under negative pressure.

All finishes and contents affected by the flood should be sealed in plastic bags and disposed of. The structure should be disinfected and dried as quickly as possible, and the contractor should provide a written report documenting the success of the water restoration including both relative humidity and surface moisture readings. The IICRC Standard recommends a 3rd party health and safety consultant to oversee the work, at least where harmful microbial contamination is present, where there are susceptible individuals present, or where there are public health issues.

Newly reported water damage?

Where a water episode is reported early, an immediate response and professional water restoration practices can prevent or limit mould growth and allow most of the finishes and contents to be saved. Both the New York City protocol and the US EPA standard allow a 24-48 hour grace period during which effective drying will prevent mould growth.

Contractors trained in structural drying methods should be employed and should provide written proof of a dry condition at completion. Note that some porous materials may not be able to be successfully dried, even with the best of efforts. The EPA standard advises that ceiling tiles, cellulose and fiberglass insulations cannot be reliably dried with current methods. Once wet, they should be discarded. Building assemblies with multiple adhered layers that will be difficult to dry quickly (e.g., two layers of drywall, wood paneling on drywall) should be discarded as a proactive measure.

Report of old water episode or signs of mould growth present?

Signs of water damage not properly corrected, musty odours, or reports of potentially mould-related health effects should prompt an investigation for possible mould growth. A professional experienced in mould investigations, preferably with liability insurance including mould hazards, should perform the investigation. The investigation will include an inspection of the property, often with intrusive testing to examine hidden areas, and in some cases might involve air sampling. The investigation should report on the presence and extent of mould, if found, where possible comment on the likely cause of the growth, and give recommendations for remediation.

Is the property a workplace?

In Ontario, the Ministry of Labour considers mould growth in general buildings to be a workplace hazard. The Ontario Occupational Health and Safety Act requires the employer to notify the Joint Health and Safety Committee or the Safety Representative of any investigation for health and safety, including investigations for mould growth. The Act also allows a representative of the Committee to observe the beginning of such testing. The JHSC or Representative must be copied with all reports provided to the employer. Similar legislative requirements apply in most other Canadian jurisdictions.

Once mould growth is confirmed?

Remediation should begin as soon as possible. The CCA and EACO guidelines are recommended as the most up-to-date and detailed procedures. Susceptible occupants (infants, elderly, immunocompromised, etc.) should be relocated from the area of work and perimeter of the work area during abatement. The occupants should be informed of the work to be performed and given information on the methods to be used.

In a workplace building, it is advisable to inform the JHSC of the remediation work, and to provide the committee with any inspection reports. The abatement contractor should be trained, experienced and carry mould remediation insurance. Health Canada recommends that quality assurance measures be applied, typically an independent health and safety professional to oversee the work. Environmental testing, usually air sampling, is performed at completion as part of the quality assurance measures.

This article is modified from an article published in the May 2002 edition of "Without Prejudice", published by the journal of the Ontario Insurance Adjusters Association.

Bruce Stewart CIH, ROH, is a Vice President at Pinchin Environmental Ltd. of Mississauga, Ontario.