Testimony in environmental claims – Participant vs litigation experts

By Tamara Farber

The Ontario Court of Appeal has recently discussed the drafting of expert reports and the nature of expert testimony (respectively in Moore v Getahun, 2015 ONCA 55 (CanLII) and Westerhof v Gee, 2015 ONCA 206 (CanLII)). Neither of these cases related to environmental claims, but both have implications relating to the rules under which experts might testify in environmental cases.

What constitutes an “expert” witness and to whom do the expert witness provisions in the Ontario Rules of Civil Procedure apply? Do they apply to anyone offering an expert opinion?

Often in environmental claims, more than one expert will testify at trial. For example, in a contaminated land case, the expert who carried out the remediation might testify, while an opposing expert might be called to give an opinion as to whether that remediation was carried out appropriately:

• The first witness, a “participant” expert, a term used by the Court of Appeal in the Westerhof case, might provide trial testimony including opinions as to groundwater flow direction, the extent of contamination, hydraulic conductivity or the ability of contamination to move within subsurface conduits or fractures. Specific remedial method analysis might have been done to assess which method should have been used.
• The second witness, a litigation expert, might provide trial testimony offering different opinions from the first expert concerning groundwater flow, hydraulic conductivity, contaminant migration, whether the first expert’s analysis of the remedial options was flawed, or whether implementation of those options was flawed.

Are both experts subject to the same requirements under the Rules?  The Ontario Court of Appeal says “no”. In the Westerhof case, the plaintiff was injured in a car accident. He was treated by a number of experts, including his family doctor, a psychiatrist, a chiropractor, a neurologist and an orthopaedic surgeon.

In a contaminated land case, the expert who carried out the
remediation might testify, while an opposing expert might be called to give an opinion as to whether that remediation was
carried out appropriately.

Many of these witnesses were not considered to be “expert witnesses” by Westerhof’s lawyer for the purposes of trial and their evidence did not comply with Rule 53.03, which sets out specific requirements for the content of an expert report. The trial judge excluded much of this evidence as being expert evidence that was non-compliant with the Rules and dismissed the entire action.

Westerhof appealed to the Divisional Court. In dismissing the appeal, that Court noted that the “important distinction is not in the role or involvement of the witness, but in the type of evidence sought to be admitted. If it is opinion evidence, compliance with Rule 53.03 is required; if it is factual evidence, it is not.”¹

The Divisional Court concluded that “evidence of diagnosis and prognosis were opinions because they involve inferences from observed facts and may turn out to be either right or wrong. Thus, although a treating physician may give evidence of his or her diagnosis to explain the treatment provided, such evidence is not admissible for the truth of its contents. Rather, it is admissible only to understand the basis of the treatment provided.”²

This decision was then appealed to the Ontario Court of Appeal. The appeal raised the question whether Rule 53.03 applied only to experts described in Rule 4.1.01 and Form 53, i.e., those “engaged by or on behalf of a party to provide opinion evidence in relation to a proceeding”, or, whether it applied more broadly to all witnesses with special expertise who give opinion evidence. As the Court of Appeal stated, “this broader group of witnesses would include, for example, treating physicians who form opinions based on their participation in the underlying events (referred to in these reasons as “participant experts”) rather than because they were engaged by a party to the litigation to form an opinion.”³

The Court of Appeal granted the appeal and ordered a new trial. Writing for a unanimous panel, Madam Justice Simmons disagreed with the Divisional Court’s conclusion that the type of evidence (fact or opinion) is the key factor in determining whether Rule 53.03 applies. Instead, she held that a witness with special skill, knowledge, training, or experience, who has not been engaged by or on behalf of a party to the litigation, may give opinion evidence for the truth of its contents without complying with Rule 53.03 if:

• The opinion to be given is based on the witness’s observation of or participation in the events at issue; and,
• The witness formed the opinion to be given as part of the ordinary exercise of his or her skill, knowledge, training and expertise, while observing or participating in such events.