Canada: Mould Growth Personal Injury Claims Spreading

Several years ago, mould issues in residential or commercial buildings would only have been a major concern in exceptional circumstances. However, technology and detection techniques have resulted in a proliferation of mould based claims and associated legal issues. Allegations of health impacts caused by mould are common in so-called "sick building syndrome" litigation. Property damage claims relating to mould also increasingly include some personal injury allegations, perhaps based on nothing more than common respiratory symptoms or rashes.

For common indoor moulds, the only real consensus is that prolonged exposure is associated with issues such as nasal stuffiness/rhinitis, chest congestion and skin irritation.1 This is mostly limited to people with some specific sensitivity to mould, akin to an allergic reaction. Adverse effects are theoretically as wide ranging as immunotoxic, neurological, respiratory and dermal responses and exposure can occur through inhalation, ingestion or skin exposure.2 Indoor mould exposure has been linked to respiratory tract symptoms in healthy people, and exacerbating asthma symptoms in people with asthma.3 More severe reactions are possible following large scale exposure in an occupational setting, and people with chronic pre-morbid respiratory issues can develop mould infections in their lungs.4 Damp indoor environments have been found to favour growth and proliferation of house dust mites and microbial growth, and especially fungal growth such as moulds.5 Accordingly, mould based personal injury claims often arise in claims involving water infiltration or damage.

Standards have been developed on allowable amounts of mould in an indoor space. The standards are based on loose criteria of what could be harmful to some people in some situations, and therefore it is difficult to link non-compliance with these standards with an adverse impact in an individual.

The array of symptoms that could result from mould exposure can be difficult to distinguish from typical cold symptoms, chronic respiratory or dermatological conditions that are notoriously difficult to trace to any given source with certainty. The vague and transitory nature of the typical symptoms from exposure to mould are also difficult to distinguish from exposure to other environmental irritants encountered routinely, and even exposure to normal levels of mould. This makes for a strong causation defence for a personal injury claim based on mould exposure. The symptoms typically associated with mould exposure are not considered very severe compared with typical personal injury claims. The causation difficulties and the fact that particulars of the science is very much open to interpretation, means expert evidence will be a large part of any such claim, with associated expense.

The highest profile example of personal injury litigation based on mould exposure is an American case Ballard v. Fire Insurance Exchange,6 where the lower court awarded an incredible $32 million dollars to homeowners in 2001 following a botched repair of a water leak by an insurer. The award was significantly reduced on appeal, then settled for an undisclosed amount pending a further appeal, but the original reward received wide attention and opened a floodgate of mould-based personal injury litigation. At least this was the case in the US, but in Canada there have been several high-profile evacuations based on mould infestation, including court buildings.

In Somerville v. Ashcroft Development Inc.7 the plaintiffs alleged a variety of health issues and claimed mould issues required them to vacate the home. The alleged symptoms included chronic cough, sore throat, nasal congestion, lethargy, aching and asthma. Despite there being visual evidence of mould, the court accepted expert evidence that the amount of mould was within normal limits, and air quality testing was fine. Accordingly, the plaintiff's claim failed.

The decision in Somerville highlights a recurring theme in defendant mould based personal injury claims. Mould is present in all buildings. The presence of visible mould often causes alarm even if health impacts are unlikely. Due to the vague and transitory symptoms, it can be easy for a person to perceive health impacts not actually experienced. Commonly, occupants are improperly advised to vacate when any problem is actually minimal, either due to the advisor being overly cautious and/or uninformed regarding potential for health issues. In reality, only fairly extensive mould infestation will violate the various standards, let alone support a sufficient causal link with any actual health impacts.

In Duguay and Canadian Broadcasting Corp., Re,8 a federal employee made allegations of "sick building syndrome" based on the prevalence of mould in the building he was working in. The Tribunal put "great credibility" on the plaintiff's assertion that the mould exposure was making him sick. The employer was ordered to shut down the workplace until it was remedied. This was despite a doctor finding the employee was not allergic to the types of mould found, and that the mould counts would generally be insufficient to trigger reactions in any case.

The Duguay findings show the risk that a trier of fact may give only partial value to objective evidence in comparison with subjective complaints. The Canada Occupational Health and Safety Tribunal is not a court, and it is somewhat doubtful such a finding could be made by a judge. In this sense, defendants should be cautious about filing a jury notice in these claims, as the less strenuous analysis in tribunals such as in the Duguay decision suggests there is room for juries to be more easily swayed by personal and subjective testimony.

The recent BC Supreme Court decision Strata Plan VIS114 v. John Doe9 discussed the inconclusive evidence about quantifying actual impact of mould infestation on the plaintiff's health, and relied on a statement that the "significantly higher" spore concentration of some common moulds "has a definite risk to the wellbeing and health of the plaintiff". Despite the scientific consensus suggesting only a weak causal connection and relatively minor health issues, this decision shows there is certainly much room for interpretation.

In summary, although Canadian Courts have remained fairly skeptical about the impact of mould issues on health in a personal injury claim, they are far from dismissive of the possibility. This shows there is certainly risk with these sorts of personal injury claims. As symptoms can be wide-ranging but not particularly severe, class action litigation is an obvious way to advance litigation if there has been exposure to a large group, such as in a workplace or apartment building. Having a working knowledge of the science and the caselaw, as well as the knowledge to retain the proper experts, is an essential component for defendants and their counsel in defending this type of claim.


1. Centre for Disease Control and Prevention - Molds in the Environment.

2. Damp Indoor Spaces and Health, 2004, Institute of Medicine (US) Committee on Damp Indoor Spaces and Health.

3. Ibid.

4. Ibid.

5. Ibid.

6. Ballard v. Fire Insurance Exchange, 2001, Texas District Court.

7. >Somerville v. Ashcroft Development Inc., 2005 CarswellOnt 3516.

8. Duguay and Canadian Broadcasting Corp., R , 2008 CarswellNat 6658 (Canada Occupational Health & Safety Tribunal)

9. Strata Plan VIS114 v. John Doe, 2015 BCSC 13, 2014 CarswellBC 3974

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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