SUPREME
COURT OF CANADA
Citation: British Columbia (Workers’ Compensation Appeal Tribunal) v.
Fraser Health Authority, 2016 SCC 25, [2016] 1 S.C.R. 587
|
Appeal
heard: January 14, 2016
Judgment
rendered: June 24, 2016
Docket: 36300
|
Between:
Workers’
Compensation Appeal Tribunal
Appellant
and
Fraser
Health Authority, Katrina Hammer, Patricia Schmidt and Anne MacFarlane
Respondents
And between:
Katrina
Hammer, Patricia Schmidt and Anne MacFarlane
Appellants
and
Workers’
Compensation Appeal Tribunal and Fraser Health Authority
Respondents
- and -
Attorney
General of Canada, Attorney General of Ontario, Ontario Network of Injured
Workers’ Groups, Industrial Accident Victims’ Group of Ontario, Community Legal
Assistance Society and British Columbia Federation of Labour
Interveners
Coram: McLachlin C.J. and Abella, Moldaver, Karakatsanis, Wagner,
Côté and Brown JJ.
Reasons
for judgment:
(paras. 1 to 40)
|
Brown J. (McLachlin C.J. and Abella,
Moldaver, Karakatsanis and Wagner JJ. concurring)
|
Reasons
dissenting in part:
(paras. 41 to 82)
|
Côté J.
|
British Columbia (Workers’ Compensation Appeal Tribunal) v. Fraser
Health Authority, 2016 SCC 25,
[2016] 1 S.C.R. 587
Workers’ Compensation Appeal
Tribunal Appellant
v.
Fraser Health Authority,
Katrina Hammer,
Patricia Schmidt and
Anne MacFarlane Respondents
- and -
Katrina Hammer,
Patricia Schmidt and
Anne MacFarlane Appellants
v.
Workers’ Compensation Appeal Tribunal
and
Fraser Health Authority Respondents
and
Attorney General of Canada,
Attorney General of Ontario,
Ontario Network of Injured Workers’
Groups,
Industrial Accident Victims’ Group of
Ontario,
Community Legal Assistance Society and
British
Columbia Federation of Labour Interveners
Indexed as: British Columbia (Workers’ Compensation Appeal Tribunal)
v. Fraser Health Authority
2016 SCC 25
File No.: 36300.
2016: January 14; 2016: June 24.
Present: McLachlin C.J. and Abella, Moldaver, Karakatsanis,
Wagner, Côté and Brown JJ.
on appeal from the court of appeal for british columbia
Workers’
compensation — Occupational disease — Causation — Evidence — Standard of proof
— Hospital laboratory technicians diagnosed with breast cancer applying for
compensation on basis that their cancers are occupational diseases —
Compensation payable if employment is of causative significance in development
of disease — Medical experts unable to find sufficient scientific basis to
establish causal link between workers’ cancers and employment — Whether Tribunal
erred in its approach to causation in deciding that workers’ cancer was
occupational disease arising due to nature of employment — Workers Compensation
Act, R.S.B.C. 1996, c. 492, ss. 6, 250(4).
H, S and M (the “workers”) were among seven technicians at a single
hospital laboratory who were diagnosed with breast cancer. Each of them applied
for compensation under the Workers Compensation Act on the basis that
the cancer was an occupational disease. The Act provides that where a
worker is disabled from an occupational disease that is due to the nature of
his or her employment, compensation is payable as if the disease were a
personal injury arising out of and in the course of that employment. In
accordance with the applicable policy, the payment of benefits is conditional
upon the employment having been of “causative significance” in the development
of the worker’s illness.
The
medical experts who provided evidence concluded that there was a lack of a
sufficient scientific basis to causally link the incidence of breast cancer to
the workers’ employment in the laboratory. A review officer of the Workers’
Compensation Board denied each of the workers’ claims. The workers each
appealed the Board’s decision to the Workers’ Compensation Appeal Tribunal. A
majority of the Tribunal found that the workers’ breast cancers were indeed
occupational diseases. Upon application by the employer to the Tribunal for
reconsideration, a reconsideration panel upheld the original decision. The
employer’s application for judicial review of the Tribunal’s original and
reconsideration decisions was allowed: both decisions were set aside and the
matter was remitted back to the Tribunal. On appeal by the workers, the
majority of the Court of Appeal dismissed the appeal, holding that the
Tribunal’s reconsideration decision was a nullity and that the Tribunal’s
original decision was patently unreasonable. The workers now appeal to
this Court, raising the issue of whether the Tribunal erred in its approach to
causation. The Tribunal also appeals to this Court, raising the issue of
whether it can, by way of a reconsideration decision, reopen an earlier
decision to consider whether it was patently unreasonable.
Held
(Côté J. dissenting in part): The appeal by the workers should be
allowed. The appeal by the Tribunal should be dismissed.
Per
McLachlin C.J. and Abella, Moldaver, Karakatsanis, Wagner and Brown JJ.:
The standard of review applicable to the Tribunal’s original decision requires
curial deference, absent a finding of fact or law that is patently
unreasonable. Because a court must defer where there is evidence capable of
supporting a finding of fact, patent unreasonableness is not established where
the reviewing court considers the evidence merely to be insufficient.
The
presence or absence of opinion evidence from an expert positing or refuting a
causal link is not determinative of causation. Causation can be inferred — even
in the face of inconclusive or contrary expert evidence — from other evidence,
including merely circumstantial evidence. Subject to the applicable standard of
review, the task of weighing evidence rests with the trier of fact. In the
instant case, the Tribunal’s original decision cannot be said to have been
patently unreasonable. While the record on which that decision was based did
not include confirmatory expert evidence, the Tribunal nonetheless relied upon
other evidence which, viewed reasonably, was capable of supporting its finding
of a causal link between the workers’ breast cancers and workplace conditions.
In
addition, according to the standard of proof set out in s. 250(4) of the Act,
where the evidence is evenly weighed on causation, that issue must be resolved
in the workers’ favour. This standard of proof contrasts sharply with the
scientific standards employed by the medical experts in the case at bar. The
majority of the Tribunal was right to consider that the experts thus imposed a
too stringent standard of proof. In relying upon the inconclusive quality of
the experts’ findings as determinative of whether a causal link was established
between the workers’ breast cancers and their employment, the chambers judge
and the majority of the Court of Appeal erred in law.
With
respect to the appeal by the Tribunal, the employer agrees with the Court of
Appeal’s assessment that the Tribunal’s reconsideration decision was a nullity.
Accordingly, there is no reason to interfere with that aspect of the Court of
Appeal’s decision.
Per
Côté J. (dissenting in part): There is agreement with the majority
with respect to the Tribunal’s appeal only. As for the workers’ appeal, it
should be dismissed since the original decision of the Tribunal is patently
unreasonable and ought to be set aside. There is no evidence — and certainly no
positive evidence — capable of supporting a causal link between the workers’
employment and the development of their respective diseases.
Experts are
responsible for providing decision-makers with precisely those inferences that decision-makers — due to the technical nature of the issues
— are unable to formulate themselves. The Tribunal is not presumed to possess
medical expertise. As a result, while the Tribunal is not bound by the medical
experts’ findings, it cannot simply disregard their uncontradicted conclusions.
In this case, the expert reports before the Tribunal were unequivocal: the
available evidence could not establish any causal relationship between the
workers’ employment as laboratory technicians and the development of their
breast cancer.
In the instant case,
the medical experts did not seek to establish causation on a level of
scientific certainty. Having undertaken a more limited investigation, the
medical experts simply found no workplace exposure that could plausibly have
increased the risk of developing breast cancer. As a result, even on the
relaxed standard of proof applicable under s. 250(4) of the Act,
there is still no positive evidence capable of establishing causative
significance.
While drawing
inferences is important in fact finding, the evidence in the record must still
be capable of supporting the inferences drawn. Otherwise, the fact-finder is at
risk of straying outside the realm of inference and reasonable deductions and
into the wilderness of mere speculation or conjecture. Common sense or inferential
reasoning cannot bridge insuperable gaps in the evidence, in either a standard
civil action or in an administrative claim under the Act. In the case at
bar, the only support for the Tribunal’s original decision is the existence of
a cluster of diagnosed cases of breast cancer. The Tribunal’s findings of fact
simply do not rise above the level of mere speculation. The Tribunal
disregarded the consensus view of the medical experts, in spite of its own lack
of expertise in medical matters. The Tribunal also ignored the applicable
policy, which states that there must be sufficient positive evidence capable of
supporting a finding of causative significance, failing which the only possible
option is to deny the claim.
Cases Cited
By Brown J.
Referred
to: Mustapha v. Culligan of Canada Ltd., 2008 SCC 27, [2008] 2
S.C.R. 114; Snell v. Farrell, [1990] 2 S.C.R. 311; Toronto (City)
Board of Education v. O.S.S.T.F., District 15, [1997] 1 S.C.R. 487; Sam
v. Wilson, 2007 BCCA 622, 78 B.C.L.R. (4th) 199; Moore v. Castlegar
& District Hospital (1998), 49 B.C.L.R. (3d) 100; Dunsmuir v. New
Brunswick, 2008 SCC 9, [2008] 1 S.C.R. 190; Chandler v. Alberta
Association of Architects, [1989] 2 S.C.R. 848; Ediger v. Johnston,
2013 SCC 18, [2013] 2 S.C.R. 98; Speckling v. Workers’ Compensation Board
(B.C.), 2005 BCCA 80, 209 B.C.A.C. 86; F.H. v. McDougall, 2008 SCC
53, [2008] 3 S.C.R. 41; Kovach, Re (1998), 52 B.C.L.R. (3d) 98, rev’d
2000 SCC 3, [2000] 1 S.C.R. 55; Pasiechnyk v. Saskatchewan (Workers’
Compensation Board), [1997] 2 S.C.R. 890; Medwid v. Ontario (1988), 63
O.R. (2d) 578; Clements v. Clements, 2012 SCC 32, [2012] 2 S.C.R. 181.
By Côté J. (dissenting in part)
Canada
(Director of Investigation and Research) v. Southam Inc., [1997] 1 S.C.R.
748; Dunsmuir v. New Brunswick, 2008 SCC 9, [2008] 1 S.C.R. 190; Toronto
(City) Board of Education v. O.S.S.T.F., District 15, [1997] 1 S.C.R. 487; Lester
(W.W.) (1978) Ltd. v. United Association of Journeymen and Apprentices of the
Plumbing and Pipefitting Industry, Local 740, [1990] 3 S.C.R. 644; R. v.
Abbey, [1982] 2 S.C.R. 24; R. v. Abbey, 2009 ONCA 624, 97 O.R. (3d)
330, leave to appeal refused, [2010] 2 S.C.R. v; Page v. British Columbia
(Workers’ Compensation Appeal Tribunal), 2009 BCSC 493; Snell v. Farrell,
[1990] 2 S.C.R. 311; Fairchild v. Glenhaven Funeral Services Ltd.,
[2002] UKHL 22, [2003] 1 A.C. 32; Caswell v. Powell Duffryn Associated
Collieries, Ltd., [1940] A.C. 152; Kozak v. Funk (1997), 158 Sask.
R. 283, aff’g in part (1995), 135 Sask. R. 81; Meringolo v. Oshawa General
Hospital (1991), 46 O.A.C. 260, leave to appeal refused, [1991] 3 S.C.R.
vii; Canadian Union of Public Employees, Local 963 v. New Brunswick Liquor
Corp., [1979] 2 S.C.R. 227.
Statutes and Regulations Cited
Administrative Tribunals Act, S.B.C.
2004, c. 45, s. 58.
Workers Compensation Act, R.S.B.C. 1996,
c. 492, ss. 6, 96, 96.2 to 96.4, 245.1(w), 250(2), (4), 253.1, 254,
255(1), 256(2), Sch. B.
Authors Cited
Anderson, Glenn R. Expert Evidence, 3rd ed. Markham, Ont.:
LexisNexis, 2014.
British Columbia. Workers’ Compensation Board. Rehabilitation
Services & Claims Manual, vol. II (online: http://www.worksafebc.com).
Cheifetz, David. “The Snell Inference and Material Contribution:
Defining the Indefinable and Hunting the Causative Snark” (2005), 30 Advocates’
Q. 1.
Haack, Susan. Evidence Matters: Science, Proof, and Truth in the
Law. New York: Cambridge University Press, 2014.
Hill, Austin Bradford. “The Environment and Disease: Association or
Causation?” (1965), 58 Proc. R. Soc. Med. 295.
Occupational Health and Safety Agency for Healthcare in British
Columbia. Cancer Cluster Investigation within the Mission Memorial Hospital
Laboratory, Final Report by George Astrakianakis et al. March 31, 2006
(online: http://www.phsa.ca).
Wright, Richard W. “Proving Causation: Probability versus Belief”,
in Richard Goldberg, ed., Perspectives On Causation. Oxford: Hart, 2011,
195.
APPEALS
from a judgment of the British Columbia Court of Appeal (Newbury, Chiasson,
Frankel, Bennett and Goepel JJ.A.), 2014 BCCA 499, 364 B.C.A.C. 241, 82
Admin. L.R. (5th) 246, 67 B.C.L.R. (5th) 213, 380 D.L.R. (4th) 204, 625 W.A.C.
241, [2015] 4 W.W.R. 1, [2014] B.C.J. No. 3111 (QL), 2014 CarswellBC 3824
(WL Can.), affirming a decision of Savage J., 2013 BCSC 524, [2013] B.C.J.
No. 605 (QL), 2013 CarswellBC 795 (WL Can.). Appeal by the Workers’
Compensation Appeal Tribunal dismissed. Appeal by Katrina Hammer, Patricia
Schmidt and Anne MacFarlane allowed, Côté J. dissenting.
Timothy J.
Martiniuk and Jeremy Thomas Lovell, for the
appellant/respondent the Workers’ Compensation Appeal Tribunal.
Tonie
Beharrell, Randall J. Noonan and Kaity
Cooper, for the appellants/respondents Katrina Hammer, Patricia Schmidt and
Anne MacFarlane.
Nazeer T.
Mitha, Dianne D. Rideout and Erin
Cutler, for the respondent Fraser Health Authority.
Christine
Mohr and Alexander Pless, for the intervener
the Attorney General of Canada.
Sara
Blake and Sandra Nishikawa, for the
intervener the Attorney General of Ontario.
Ivana
Petricone, for the interveners the Ontario Network
of Injured Workers’ Groups and the Industrial Accident Victims’ Group of
Ontario.
Monique
Pongracic-Speier, for the interveners the Community
Legal Assistance Society and the British Columbia Federation of Labour.
The
judgment of McLachlin C.J. and Abella, Moldaver, Karakatsanis, Wagner and Brown
JJ. was delivered by
Brown J. —
I.
Introduction
[1]
These appeals call upon the Court to consider
(1) whether the British Columbia Workers’ Compensation Appeal Tribunal can, by
way of a “reconsideration” decision, reopen an earlier decision to consider
whether it was patently unreasonable (the “WCAT Appeal”); and (2) whether, in
the circumstances of this case, the Tribunal erred in its approach to causation in deciding that each
of three workers’ cases of breast cancer was an “occupational disease” arising
“due to the nature of [their] employment” (the “Workers’ Appeal”). A majority
of the British Columbia Court of Appeal held that the Tribunal’s
reconsideration decision (which simply affirmed its original decision) was a
nullity, and that the Tribunal erred in its original decision in finding a
causal link between the workers’ breast cancers and their employment.
[2]
I would allow the Workers’ Appeal and dismiss
the WCAT Appeal. As to the WCAT Appeal, as I will explain, the respondent
Fraser Health Authority agrees with the Court of Appeal’s assessment that the
Tribunal’s reconsideration decision was a nullity. I therefore see no reason to
interfere with that aspect of the Court of Appeal’s decision. On the issue of
causation raised by the Workers’ Appeal, however, for the reasons that follow I
am of the view that, in light of the applicable standard of review, the
Tribunal’s finding of a causal link between the workers’ breast cancers and
their employment should not have been upset.
II.
Overview of Facts and Proceedings
A.
Background and Statutory Provisions
[3]
Katrina Hammer, Patricia Schmidt and Anne
MacFarlane were among seven technicians at a single hospital laboratory who
were diagnosed with breast cancer. Each of them applied for compensation under
the Workers Compensation Act, R.S.B.C. 1996, c. 492, on the basis that
the cancer was an “occupational disease”.
[4]
The Act establishes a comprehensive
no-fault insurance scheme for workers who sustain workplace injuries or suffer
from occupational diseases. More specifically, s. 6 of the Act provides
that where a worker is disabled from an occupational disease that is due to the
nature of his or her employment, compensation is payable “as if the disease
were a personal injury arising out of and in the course of that employment”.
[5]
Upon receiving a claim, the Workers’
Compensation Board inquires into, hears and determines all matters and
questions of fact and law (s. 96). Certain decisions of the Board can be
reviewed by a review officer (ss. 96.2 to 96.4) and, further, can be appealed
to the Tribunal. Section 254 confers upon the Tribunal “exclusive jurisdiction
to inquire into, hear and determine all those matters and questions of fact,
law and discretion arising or required to be determined [on appeals under the Act]”.
Further, the Tribunal may amend its own decisions to cure a clerical or
typographical error, an “accidental or inadvertent error, omission or other
similar mistake” or an arithmetical error (s. 253.1), or it may reconsider a
decision to cure a jurisdictional defect or if new evidence has become available
or has been discovered (ss. 253.1(5) and 256(2)).
[6]
As to whether a worker suffers from an
occupational disease due to the nature of his or her employment, the Board’s Rehabilitation
Services & Claims Manual, vol. II (“RSCM II”) (online),
the relevant policy which must be applied by the Tribunal to decide these
appeals (s. 250(2) of the Act), conditions payment of benefits upon the
employment having been of “causative significance” in the development of the
worker’s illness. This means “more than a trivial or insignificant aspect of
the injury or death” (RSCM II, Chapter 3, policy item #14.00), and
entails consideration of whether:
•
there is a physiological association between the
injury or death and the employment activity, including whether the activity was
of sufficient degree and/or duration to be of causative significance in the
injury or death;
•
there is a temporal relationship between the
work activity and the injury or death; and
•
any non-work related medical conditions were a
factor in the resulting injury or death.
[7]
Section 250(4) of the Act provides that,
where the Tribunal is hearing an appeal respecting the compensation of a worker
and the evidence is “evenly weighted” on an issue, the Tribunal must resolve
that issue “in a manner that favours the worker”. In other words, the
applicable burden of proof is not the civil burden of “balance of
probabilities”. Where the evidence leads to a draw, the finding must favour the
worker. This extends to deciding whether the occupational disease is “due to”
the nature of employment — that is, to the issue of causation:
“. . . if the weight of the evidence suggesting the disease was
caused by the employment is roughly equally balanced with evidence suggesting
non-employment causes, the issue of causation will be resolved in favour of the
worker” (RSCM II, Chapter 4, policy item #26.22).
[8]
By joint operation of s. 245.1(w) of the Workers
Compensation Act and s. 58(2)(a) of the Administrative Tribunals
Act, S.B.C. 2004, c. 45, a reviewing court may not interfere with a finding
of fact or law made by the Tribunal in respect of a matter over which it has
exclusive jurisdiction unless it is patently unreasonable.
B.
Evidence on Causation
[9]
The causal issue before the Board, the Tribunal
and the courts below was the etiology of the workers’ breast cancers. The evidence on that
question comprised three expert reports:
(a) the final report of the Occupational Health and Safety
Agency for Healthcare in British Columbia (“OHSAH”) regarding the incidence of
cancer in the laboratory where the workers were employed (Cancer Cluster
Investigation within the Mission Memorial Hospital Laboratory, Final
Report, March 31, 2006, at p. 35 (online)) and two earlier draft reports, each
produced by various OHSAH staff, consultants and trainees (collectively the
“OHSAH reports”);
(b) the report of Dr. Jeremy R. Beach, a specialist in
occupational medicine; and
(c) the report of Dr. M. W. Yamanaka, a medical
advisor to the Board specializing in occupational medicine.
[10]
The OHSAH reports contained a review of the
scientific literature on factors associated with the risk of breast cancer, an
epidemiological analysis of the cancer cluster among workers in the laboratory,
and a field investigation into possible exposure among laboratory technicians
to potentially carcinogenic substances. They confirmed that the number of
diagnoses of breast cancer (7 of the 63 workers studied were so diagnosed)
represented a statistically significant cluster, with a “standardized incidence
ratio” for breast cancer approximately eight times the rate that would have
been expected in the general population. As to potential causes, the authors of
these reports observed no current occupational chemical exposures, but noted
that past exposures were “likely much higher”, and included one known human
carcinogen (Final Report, at p. 35).
[11]
Ultimately, the authors of the OHSAH reports did
not reach “scientific conclusions to support the association between
work-related exposures and breast cancer in this cluster” (Final Report, at p.
iii). More particularly, they explained that “[o]ur review of the literature
was unable to establish the basis for [an etiological hypothesis based on
scientific evidence of causal mechanisms for breast cancer], as we did not find
any scientific evidence for the plausibility of a laboratory work-related
etiological hypothesis regarding breast cancer” (p. iv). The authors
speculated that the increased incidence of breast cancer among laboratory
employees may have been due to “(1) a cluster of reproductive and other known,
non-occupational, risk factors, (2) past exposures to chemical carcinogens
and less likely to ionizing radiation, and (3) a statistical anomaly” (p. 39
(emphasis added)).
[12]
Dr. Beach’s report and Dr. Yamanaka’s report
were each in substantial agreement with the OHSAH reports. In particular, Dr.
Beach and Dr. Yamanaka shared the OHSAH reports’ conclusion regarding the lack
of a sufficient scientific basis to causally link the incidence of breast
cancer to the workers’ employment in the laboratory. Dr. Yamanaka went somewhat
further than Dr. Beach, saying (without elaboration) that he “would prefer to
refute than support” that posited link, and that he “would favor the opinion
that non-occupational factors were the cause of [the] breast cancer” (J.R.,
vol. 4, at p. 230).
C.
The Decisions Below
(1)
The Workers’ Compensation Board
[13]
A review officer of the Board denied each of the
claims, finding that “there is insufficient
evidence . . . to conclude that [each worker’s] years of
employment as a medical lab technician has played a significant role in causing
breast cancer”, and pointing to various non-occupational risk factors for
breast cancer (J.R., vol. 3, at p. 21).
(2)
The Tribunal’s Original Decisions
[14]
The workers each appealed the Board’s decision
to the Tribunal. At the Tribunal, a majority of two members found that the
workers’ breast cancers were indeed occupational diseases. In doing so, the
majority acknowledged the need for “positive evidence linking the disease to
employment” (J.R., vol. 1, at p. 16) and cited the decision of this Court in Snell
v. Farrell, [1990] 2 S.C.R. 311, as authority for a fact-finder’s ability
to draw a “common sense” inference of causation in the absence of scientific
proof of causation — scientific standards being more rigorous than the “lesser
standard . . . demanded by the law” (J.R., vol. 1, at p.
17). The authors of the OHSAH reports, in seeking “to reach scientific
conclusions to support the association between work-related exposures and
breast cancer in this cluster” (Final Report, at p. iii), therefore applied a
too stringent standard of proof. The applicable standard was not that which is
necessary to support a scientific conclusion, but rather the standard set out
in s. 250(4) of the Act.
[15]
The majority then analysed the evidence with
reference to the indicia described by A. Bradford Hill (“The Environment and
Disease: Association or Causation?” (1965), 58 Proc. R. Soc. Med. 295)
for weighing epidemiological evidence of causation. In this case, the criteria
of “strength of association” (the ratio of the incidence of disease among
exposed workers when compared to the incidence within the general population)
and “temporal relationship” (the proximity in time between exposure and the
onset of the disease) were clearly satisfied, although other criteria were not.
The majority concluded, however, that it was not necessary to identify a
specific causal agent, it being sufficient for the evidence merely to point to
a causal link between a disease and an occupation. Here, the evidence of past
carcinogenic exposure, coupled with the statistically significant cluster of
breast cancer cases among laboratory workers, comprised “positive evidence”
supporting a conclusion that it was as likely as not that the workers’ breast
cancers were caused by workplace exposure.
[16]
The dissenting member explained that, while she
agreed that scientific certainty was not required, the expert reports provided
no “positive evidence” of a causal link. Without more, they were therefore
insufficient to support a conclusion that workplace exposures were of causal
significance.
(3)
The Tribunal’s Reconsideration Decisions
[17]
Fraser Health applied under s. 253.1(5) of the Workers
Compensation Act for reconsideration
of the Tribunal’s original decisions. While s. 253.1 permits the Tribunal to
amend its decisions to correct clerical, typographical or mathematical errors,
or to clarify its decisions, subs. (5) provides that “[t]his section must not
be construed as limiting the appeal tribunal’s ability, on request of a party,
to reopen an appeal in order to cure a jurisdictional defect.” Fraser Health’s
argument was that a “jurisdictional defect” arose here, since the Tribunal’s
finding in the original decisions of a causal link between the workers’ breast
cancers and their employment lacked supporting evidence and was, as such,
patently unreasonable.
[18]
The reconsideration panel (comprising a single
member) reviewed the original decisions for patent unreasonableness and
determined that, given the elevated standard incidence ratio and the past
exposure to carcinogens, the original panel had sufficient evidence to support
its conclusions regarding causation.
(4)
British Columbia Supreme Court, 2013 BCSC 524
[19]
Fraser Health sought judicial review of the
Tribunal decisions — the original decisions and the reconsideration decisions.
Savage J. (as he then was) explained that he would review the original decision
for patent unreasonableness and the reconsideration decision for correctness.
He observed that the Tribunal’s decisions are entitled to the highest level of
curial deference and, in particular, that “the [Tribunal] has a right to be
wrong provided that there is some evidence capable of supporting its
conclusion” (para. 11 (CanLII), citing Toronto (City) Board of Education v.
O.S.S.T.F., District 15, [1997] 1 S.C.R. 487, at para. 44).
[20]
That said, the chambers judge observed, the
Tribunal “was not entitled to ignore the expert evidence in favour of its own
expertise or common sense, and it was patently unreasonable [for it] to do so”
(para. 34). Here, he relied on British Columbia Court of Appeal authority —
specifically, Sam v. Wilson, 2007 BCCA 622, 78 B.C.L.R. (4th) 199, at
para. 41, citing Moore v. Castlegar & District Hospital (1998), 49
B.C.L.R. (3d) 100 (C.A.), at para. 11 — which holds that, “where there is
affirmative medical evidence leading to a medical conclusion it is not open to
the court to apply ‘the common sense reasoning urged in Snell v. Farrell’”.
This precluded “the purported application of common sense on matters of
causation where there is contrary expert opinion” (chambers judge’s reasons, at
para. 40). Here, the experts clearly and unambiguously concluded that there was
no evidence that workplace factors caused the workers’ breast cancers. Given
“the absence of any evidence and in the face of expert opinion to the contrary”
(para. 49), the Tribunal’s original decision was patently unreasonable and the
reconsideration decision was incorrect. He set aside both decisions and
remitted the matter back to the Tribunal.
(5)
British Columbia Court of Appeal, 2014 BCCA 499,
67 B.C.L.R. (5th) 213
[21]
The workers appealed Savage J.’s decision, and
the Court of Appeal invited the parties to make submissions as to, inter
alia, the jurisdiction of the Tribunal to reconsider its original decision
in this matter. Chiasson J.A., joined by Frankel and Goepel JJ.A., held that s.
253.1(5) of the Workers Compensation Act merely preserves the Tribunal’s
common law power to reopen a proceeding to complete its statutory task, and
therefore does not permit it to correct errors made within its jurisdiction.
The Tribunal’s interpretation of s. 253.1(5) as permitting it to review its own
decisions to identify and correct patently unreasonable errors is supported
neither by that common law power to reopen nor by the Act’s legislative
history. Since no true jurisdictional defect had been alleged, the Tribunal’s
reconsideration decision was a nullity. Chiasson J.A. therefore dismissed the
appeal of the chambers judge’s order setting aside the reconsideration
decision.
[22]
Newbury J.A., joined by Bennett J.A.,
disagreed. The meaning of “jurisdictional defect” in s. 253.1, having been
drafted prior to the decision of this Court in Dunsmuir v. New Brunswick,
2008 SCC 9, [2008] 1 S.C.R. 190, should not be confined to permitting the
Tribunal to review for errors of “true” jurisdiction as that term was described
in Dunsmuir. Rather, it should be understood in light of the common law
power to reopen which, in her view, included the power of a tribunal to
determine whether an original decision was patently unreasonable. As a
practical matter, limiting the Tribunal’s scope to reconsider its own decisions
for patent unreasonableness would mean more court proceedings, contrary to the
purpose of the Act and to the principles of administrative law
generally.
[23]
On the issue of causation, Chiasson J.A., joined
by Frankel J.A., held that, while there was “some evidence” to support the
Tribunal’s finding of causation (specifically, the “statistical anomaly” of
elevated breast cancer rates among laboratory workers), “something more” was
required (paras. 198-99). The Tribunal’s finding of causation was, therefore,
patently unreasonable.
[24]
Goepel J.A., writing separately, agreed that the
chambers judge did not err in setting aside the original decision as patently
unreasonable. Resolving issues of causation in this case required expert
“medical” and “scientific” evidence (para. 209). Lacking such expertise, the
Tribunal cannot disregard uncontradicted expert evidence in order to substitute
its own opinion. In the absence of “positive evidence linking the disease to
employment” (para. 211), and in the face of expert evidence to the contrary,
the Tribunal’s decision was patently unreasonable.
[25]
Newbury J.A., again joined by Bennett J.A.,
observed that the standard of review of “patent unreasonableness” denotes the
highest level of deference, permitting curial interference only where there is
“no evidence” to support the Tribunal’s findings or where its decision
was “openly, clearly, or evidently unreasonable” (para. 70 (emphasis in
original)). Here, the experts did not rule out a causal connection between
laboratory conditions and the workers’ cancers. While the experts acknowledged
that present chemical exposures were minimal, past exposures had likely been
much higher and included at least one known human carcinogen. The Tribunal’s
conclusion that the likelihood of a statistical anomaly did not exceed the
likelihood that breast cancers in these cases were occupational diseases was
reached appropriately, after a careful review of all the evidence. Viewed through
the scheme and underlying objectives of the workers’ compensation system, which
requires the Tribunal to resolve issues in favour of a worker where the
evidence supporting different findings on an issue is evenly weighted, the
Tribunal’s original decision was not patently unreasonable and should not have
been upset by the chambers judge.
III.
Analysis
A.
The Tribunal’s Jurisdiction to Reconsider Its
Own Decision
[26]
Fraser Health, having sought reconsideration by
the Tribunal, now takes the position that the majority at the Court of Appeal
correctly characterized the reconsideration decision as a nullity. The
Tribunal’s power to reconsider a decision under s. 253.1(5) of the Workers
Compensation Act “to cure a jurisdictional defect” is, it says, limited to
the common law power to reopen as stated by the Court in Chandler v. Alberta
Association of Architects, [1989] 2 S.C.R. 848, at p. 861:
“. . . [a final] decision cannot be revisited because the
tribunal has changed its mind, made an error within jurisdiction or because
there has been a change of circumstances”.
[27]
Conversely, the Tribunal submits that s.
253.1(5)’s language of “cur[ing] a jurisdictional defect” is sufficiently broad
to permit reconsideration for patent unreasonableness. In the Tribunal’s view,
when it undertakes to reconsider its own decision, it effectively operates as a
court on judicial review by applying the standard of review of patent
unreasonableness stated in s. 58(2)(a) of the Administrative Tribunals Act.
[28]
In light of the position taken by Fraser Health
— that it should not have been able to obtain reconsideration of the Tribunal’s
original decision and that the reconsideration decision is a nullity — I see no
basis for interfering with the decision of the Court of Appeal on this issue.
B.
Causation
(1)
Standard of Review
[29]
As already noted, and as the parties agree, the
applicable standard of review requires curial deference, absent a finding of
fact or law that is patently unreasonable (Administrative Tribunals Act,
s. 58(2)(a)).
[30]
The Tribunal’s conclusion that the workers’
breast cancers were occupational diseases caused by the nature of their
employment was a finding on a question of fact (Ediger v. Johnston, 2013
SCC 18, [2013] 2 S.C.R. 98, at para. 29). That finding is therefore entitled to
deference unless Fraser Health demonstrates that it is patently unreasonable —
that is, that “the evidence, viewed reasonably, is incapable of supporting a
tribunal’s findings of fact” (Toronto (City) Board of Education, at
para. 45). Because a court must defer where there is evidence capable of
supporting (as opposed to conclusively demonstrating) a finding of
fact, patent unreasonableness is not established where the reviewing court
considers the evidence merely to be insufficient (Speckling v. Workers’
Compensation Board (B.C.), 2005 BCCA 80, 209 B.C.A.C. 86, at para. 37).
Simply put, this standard precludes curial re-weighing of evidence, or
rejecting the inferences drawn by the fact-finder from that evidence, or
substituting the reviewing court’s preferred inferences for those drawn by the
fact-finder.
(2)
The Tribunal’s Finding on Causation
[31]
Understandably, the workers stress s. 250(4) of
the Workers Compensation Act which signifies that, where the evidence is
evenly weighted on causation, that issue must be resolved in their favour. We
agree that this represents an important distinction from civil tort claims,
where causation must always be established on a balance of probabilities (F.H.
v. McDougall, 2008 SCC 53, [2008] 3 S.C.R. 41, at para. 49; Ediger,
at para. 28; Kovach, Re (1998), 52 B.C.L.R. (3d) 98 (C.A.), at para. 30
(per Donald J.A., dissenting), rev’d 2000 SCC 3, [2000] 1 S.C.R. 55). This less
stringent burden of proof, like the RSCM II’s direction that the
workplace need only be of “causative significance” or “more than a trivial or
insignificant aspect” in the development of a worker’s illness, furthers at
least one of the core policy goals of workers’ compensation schemes identified
by the Court in Pasiechnyk v. Saskatchewan (Workers’ Compensation Board),
[1997] 2 S.C.R. 890, at para. 27, citing Medwid v. Ontario (1988), 63
O.R. (2d) 578 (H.C.), at p. 586, being to have “compensation to injured workers
provided quickly without court proceedings”. Section 250(4) therefore reflects
the legislature’s intention that workers should obtain compensation for
occupational diseases without having to satisfy the requirements of a civil
tort claim.
[32]
Section 250(4)’s standard of proof contrasts
sharply with the “scientific” standards employed by the authors of the OHSAH
reports. Their inability “to reach scientific conclusions” (Final Report, at p.
iii) to support the causal association between workplace conditions and the
workers’ breast cancers, or to “find any scientific evidence for the
plausibility of a laboratory work-related etiological hypothesis regarding
breast cancer” (p. iv), spoke not to the burden imposed upon the workers
by s. 250(4), nor even to the burden imposed upon plaintiffs in a civil tort
claim (Ediger, at para. 36; Clements v. Clements, 2012 SCC 32,
[2012] 2 S.C.R. 181, at para. 9; Snell, at pp. 328-30), but to a
standard of scientific certainty. The majority of the Tribunal considered that
the OHSAH reports thus imposed a too stringent standard of proof. I agree. This
standard is wholly inapplicable to determining causation in the workers’ claims
(R. W. Wright, “Proving Causation: Probability versus Belief”, in R. Goldberg,
ed., Perspectives On Causation (2011), 195; S. Haack, Evidence
Matters: Science, Proof, and Truth in the Law (2014), at p. 22). In my
respectful view, therefore, in relying upon the inconclusive quality of the
OHSAH reports’ findings as determinative of whether a causal link was
established between the workers’ breast cancers and their employment, the
chambers judge and the majority of the Court of Appeal erred in law.
[33]
All that said, the central problem in the
handling of causation in the courts below arose not in their failure to have
appropriate regard to the less stringent standard of proof required by s.
250(4), but from their fundamental misapprehension of how causation —
irrespective of the standard of proof — may be inferred from evidence.
[34]
As I have recounted, the evidence before the
Tribunal on causation comprised, principally, the OHSAH reports (supported by
the reports of Dr. Beach and Dr. Yamanaka), which (1) confirmed a
“statistically significant cluster” of breast cancer, with a standard incidence
ratio approximately eight times the rate of breast cancer in the general
population; and (2) noted that past occupational chemical exposures were likely
“much higher” than current exposures, and included one known carcinogen; but
also (3) reported that they were unable “to reach scientific conclusions to
support the association between work-related exposures and breast cancer in
this cluster” (Final Report, at p. iii). Consequently, the OHSAH reports would
only speculate that the increased incidence of breast cancer among the
laboratory workers may have been due to non-occupational risk factors, to
occupational risk factors such as chemical carcinogens or ionizing radiation,
or to a statistical anomaly.
[35]
The Tribunal, in lengthy and comprehensive
reasons explaining why it found “causative significance” in the evidence of
past carcinogenic exposure and in the statistically significant cluster of
breast cancer cases, gave careful consideration to the OHSAH reports. It
correctly noted that the OHSAH reports “did not exclude the possibility of
occupational causation”, and that the Tribunal did not have before it “much
detailed evidence as to historical exposures” (J.R., vol. 1, at p. 47). And, it
acknowledged that “it is possible that the breast cancer cluster is a
statistical anomaly”, and that “this matter is not without some uncertainty”
(p. 48). The Tribunal chose, however, to “attach weight” to the reports’
observations that past exposures were “likely much higher” (p. 47), leading it
to find that the likelihood of a statistical anomaly did not exceed the
likelihood that the workers’ breast cancers were an occupational disease caused
by the nature of their employment. As it explained:
Perhaps the most compelling evidence for us involves the fact that
the workers with breast cancer were exposed to carcinogens and there is a very
elevated statistically significant [standardized incidence ratio] for breast
cancer. Our decision does not simply rest on the occurrence of a very elevated
statistically significant [standardized incidence ratio] for breast cancer.
That [standardized incidence ratio] occurs against the backdrop of
the particular standard of proof employed by us, the workers’ exposure to
carcinogens, and the comments of [the Final Report] to the effect that all
cancer causing agents have the potential to initiate and promote cancer, little
is known about the possible synergistic, additive or antagonistic effects of
multiple chemical exposures, and past exposures were likely much higher. [J.R.,
vol. 1, at p. 48]
[36]
The chambers judge, seeing “no evidence that
workplace factors caused [the workers’] cancers” (para. 44), viewed the
Tribunal as having impermissibly “ignore[d] the expert evidence in favour of
its own expertise or common sense” (para. 34). Similarly, at the Court of
Appeal, having found there to be no “positive evidence linking the disease to
employment” (para. 211), Goepel J.A. (for the majority on this point) agreed
that “[t]he issue for determination is one that required expert scientific
evidence” (para. 209), which expertise the Tribunal could not be presumed to
have.
[37]
With respect, the issue that the Tribunal
decided was precisely the sort of issue that the legislature intended that it
should decide. Section 254 of the Act provides that, on appeals from
decisions of the Board, the Tribunal has exclusive jurisdiction
to determine all questions of fact. While, in doing so, the Tribunal may
choose to draw from the expert evidence put before it (as it drew here from
expert evidence of historical exposures and of a statistically significant
cluster of breast cancer cases among laboratory workers), the decision remains
the Tribunal’s to make.
[38]
The presence or absence of opinion evidence from
an expert positing (or refuting) a causal link is not, therefore, determinative
of causation (e.g. Snell, at pp. 330 and 335). It is open to a trier of
fact to consider, as this Tribunal considered, other evidence in determining
whether it supported an inference that the workers’ breast cancers were caused
by their employment. This goes to the chambers judge’s reliance upon the Court
of Appeal’s decisions in Sam and Moore and to Goepel J.A.’s
statement that there must be “positive evidence” linking their breast cancers
to workplace conditions. Howsoever “positive evidence” was intended to be
understood in those decisions, it should not obscure the fact that causation
can be inferred — even in the face of inconclusive or contrary expert evidence
— from other evidence, including merely circumstantial evidence. This does not
mean that evidence of relevant historical exposures followed by a statistically
significant cluster of cases will, on its own, always suffice to support a
finding that a worker’s breast cancer was caused by an occupational disease. It
does mean, however, that it may suffice. Whether or not it does so depends on
how the trier of fact, in the exercise of his or her own judgment, chooses to
weigh the evidence. And, I reiterate: Subject to the applicable standard of
review, that task of weighing evidence rests with the trier of fact — in this
case, with the Tribunal.
[39]
In light of the foregoing, the Tribunal’s
original decision cannot be said to have been “patently unreasonable”. While
the record on which that decision was based did not include confirmatory expert
evidence, the Tribunal nonetheless relied upon other evidence which, viewed
reasonably, was capable of supporting its finding of a causal link between the
workers’ breast cancers and workplace conditions.
IV.
Conclusion
[40]
I would allow the Workers’ Appeal, with costs to
Katrina Hammer, Patricia Schmidt and Anne MacFarlane in this Court and in the
courts below as against Fraser Health Authority. The Tribunal’s original
decisions are restored. I would dismiss the WCAT Appeal, without costs.
The following are the reasons
delivered by
[41]
Côté J. (dissenting in part) — I part ways with my colleague Justice Brown
with respect to the appeal by Katrina Hammer, Patricia Schmidt and Anne
MacFarlane (the “Workers’ Appeal”) because, in my view, the original decision
of the Workers’ Compensation Appeal Tribunal is patently unreasonable. On my
reading, there is no evidence — and certainly no positive evidence — capable of
supporting a causal link between the workers’ employment and the development of
their respective diseases. The three expert reports before the Tribunal only
established the existence of a cluster of diagnosed cases of breast cancer, and
nothing more. In my view, the Tribunal relied on what it called “ordinary
common sense” to speculate about a possible causal link, while openly
disregarding the medical experts’ consensus view. As such, the Tribunal’s decision is “openly,
evidently, clearly” wrong and ought to be set aside: Canada (Director of
Investigation and Research) v. Southam Inc., [1997] 1 S.C.R. 748, at para.
57.
[42]
Regarding the appeal by
the Tribunal (the “WCAT Appeal”), raising the issue of the nullity of the
Tribunal’s reconsideration decision, I agree with my colleague Brown J. that it
should be dismissed. The conclusion of the majority of the British Columbia
Court of Appeal should not be disturbed.
A.
Background
[43]
The issue before the Tribunal was whether each
of the three workers’ breast cancer was “due to” her employment as a laboratory
technician at the Mission Memorial Hospital, a causal link required by s.
6(1)(b) of the Workers Compensation Act, R.S.B.C. 1996, c. 492 (“WCA”).
[44]
While Schedule B of the WCA lists a
number of occupational diseases which are deemed to be “due to the nature of
[the] employment” in the context of specific processes or industries, breast
cancer is not listed among them. As a result, a causal link must be established
on the basis of the evidence before the Tribunal.
[45]
A policy of the Workers’ Compensation Board, the
Rehabilitation Services & Claims Manual, vol. II (“RSCM II”)
(online), specifies that in order for the disease to be “due to” the nature of
the employment, the employment “has to be of causative significance,
which means more than a trivial or insignificant aspect of the injury or
death”: c. 3, policy item #14.00 (emphasis added).
[46]
The Board’s policy goes further, however, and
requires that there be sufficient positive evidence to ground a finding
of causative significance. The RSCM II states that “[i]f the Board
has no or insufficient positive evidence before it that tends to
establish that the disease is due to the nature of the worker’s employment, the
Board’s only possible decision is to deny the claim”: c. 4, policy
item #26.22 (emphasis added). As my colleague Brown J. has observed,
policies of the Board must be applied by the Tribunal in making its decisions:
s. 250(2) of the WCA. The Tribunal also recognized this requirement:
WCAT-2010-03503 (the “Original Decision”), at paras. 46-47.
[47]
In this case, the workers’ claims were initially
denied by the Board. A review officer with the Board’s Review Division
confirmed these decisions, finding that there was insufficient evidence to
conclude that each worker’s years of employment as a laboratory technician had
played a significant role in causing breast cancer. On appeal, a two-member
majority of the Tribunal concluded that there was sufficient positive evidence
to establish that the workers’ breast cancer was due to their employment, but a
dissenting member disagreed, finding that the expert reports had provided
insufficient positive evidence of a causal link. That dissenting member’s
conclusion was later vindicated, as the British Columbia Supreme Court set the
Tribunal’s decision aside, an order which was upheld by a majority of the
British Columbia Court of Appeal.
[48]
It is common ground
that a reviewing court can only interfere with the Tribunal’s decision if it is
patently unreasonable: s. 58 of the Administrative Tribunals Act, S.B.C. 2004, c. 45;
s. 255(1) of the WCA. On the authority of jurisprudence pre-dating Dunsmuir
v. New Brunswick, 2008 SCC 9, [2008] 1 S.C.R. 190, a decision is
patently unreasonable if it is “openly, evidently, clearly” wrong: Southam,
at para. 57. More specifically, findings of fact will be “patently
unreasonable” where they are either based on “no evidence” or where “the evidence,
viewed reasonably, is incapable of supporting” the finding of fact in question:
Toronto (City) Board of Education v. O.S.S.T.F.,
District 15, [1997] 1 S.C.R. 487, at paras. 44-45; Lester (W.W.) (1978) Ltd. v. United
Association of Journeymen and Apprentices of the Plumbing and Pipefitting
Industry, Local 740,
[1990] 3 S.C.R. 644, at p. 669.
[49]
Neither the British
Columbia Supreme Court nor the majority of the Court of Appeal sought to
reweigh the evidence before the Tribunal. The lower courts did not, in other
words, depart from this highly deferential standard of review. Rather,
Chiasson, Frankel and Goepel JJ.A. of the Court of Appeal and Savage J. of the
Supreme Court were of the view that there was no evidence before the Tribunal
capable of supporting an inference of causative significance. I agree. Even on
this highly deferential standard of review, the Tribunal’s decision should be
set aside.
B.
The Expert Reports Before the Tribunal
[50]
All three of the expert reports before the
Tribunal were unequivocal. In the experts’ collective view, expressed in clear,
unambiguous language, the available evidence could not establish any causal
relationship between the workers’ employment as laboratory technicians and the
development of their breast cancer.
[51]
Speaking of one of the workers, Ms. Katrina
Hammer, the Board’s medical advisor Dr. Yamanaka concluded that “there
is insufficient medical evidence to support that the work environment caused or
significantly contributed to the development of Ms. Hammer’s breast carcinoma
left side”: J.R., vol. 4, at p. 226. That conclusion was
stated more forcefully in the final version of a report titled Cancer
Cluster Investigation within the Mission Memorial Hospital Laboratory,
prepared by seven authors for the Occupational Health and Safety Agency for
Healthcare in British Columbia (the “OHSAH Final Report”) (online). The authors
noted that they “did not find any scientific evidence for the plausibility
of a laboratory work-related etiological hypothesis regarding breast cancer”:
p. iv (emphasis added). Finally, Dr. Beach, an expert in occupational medicine
who was tasked with reviewing the OHSAH Final Report, largely supported its
findings.
[52]
The importance of these unanimous expert opinions cannot be overstated.
Experts are responsible for providing decision-makers with precisely those
inferences that decision-makers — due to the technical nature of the issues —
are unable to formulate themselves: R. v. Abbey, [1982] 2 S.C.R. 24, at
p. 42; R. v. Abbey, 2009 ONCA 624, 97 O.R. (3d) 330, at para. 71,
leave to appeal refused, [2010] 2 S.C.R. v; see also G. R. Anderson, Expert
Evidence (3rd ed. 2014), at p. 625.
[53]
I would note here that the Tribunal is not presumed to possess medical
expertise: Page v. British Columbia (Workers’ Compensation Appeal Tribunal),
2009 BCSC 493, at paras. 62-66 (CanLII). As a result, while the Tribunal is not
bound by the medical experts’ findings, it cannot simply disregard their
uncontradicted conclusions. In the absence of any other evidence to the
contrary, one may wonder how the Tribunal could find a causal link where the
experts, together, could see none.
[54]
In the case at bar, the Tribunal’s two-member majority was of the
view that the experts had sought to establish a causal link on
a level of scientific certainty, rather than on the ostensibly lower standard
of proof prescribed by s. 250(4) of the WCA: Original Decision, at
paras. 180-82. If this were true, it would certainly justify the Tribunal’s
rejection of the experts’ common findings. Indeed, the Tribunal’s analysis
echoes the principle established in Snell v. Farrell, [1990] 2 S.C.R.
311, to the effect that causation need not be determined by scientific
precision. This principle applies with even greater force in the context of
claims made under the WCA.
[55]
However, the instant case differs from Snell.
The authors of the three expert reports did not seek to establish causation on
a level of scientific certainty. Rather, they question repeatedly whether
certain workplace exposures “could” or “may” have been related to an “increase
in risk”, “contribute measurably”, or have been of “causative significance”.
[56]
Having undertaken this more limited
investigation, the medical experts could not even make out a plausible
basis for establishing a causal link between the workers’ employment and their
respective diseases.
[57]
The OHSAH Final Report, which constituted the
main piece of medical evidence before the Tribunal, is a good illustration.
That report was simply a “preliminary epidemiological study”. Its authors were
tasked with identifying any “exposures that may be associated
with excess cases in a workplace”: p. 32 (emphasis added). In the event such
exposures were identified, the authors would then recommend proceeding to a
“full-scale epidemiological study” which could “determine the association
between the exposure and [the] increased risk” of developing breast cancer: p.
32. Thus, in their executive summary, the authors of the OHSAH Final Report
spoke not of whether certain workplace exposures caused the workers’
breast cancer on a level of scientific certainty, but rather whether
exposure to certain chemicals “could be related to the increase in
risk”: p. iii (emphasis added).
[58]
Ultimately, the authors of the OHSAH Final
Report did not recommend proceeding to a full-scale epidemiological study, on
the basis that they “did not find any scientific evidence for the
plausibility of a laboratory work-related etiological hypothesis
regarding breast cancer”: p. iv (emphasis added). The authors went on to state
in their conclusion that “no current occupational chemical exposures, or
records of past occupational exposures were found that might relate
working in the [Mission Memorial Hospital] laboratory environment to elevated
breast cancer risk, or cancer in general”: p. 38 (emphasis added).
[59]
In short, these are not the words of medical
experts seeking “but for” causation on a standard of scientific certainty.
Rather, the authors simply found no workplace exposure that could plausibly
have increased the risk of developing breast cancer. On my reading of the OHSAH
Final Report, even on the relaxed standard of proof applicable to the workers’
compensation regime under s. 250(4) of the WCA, there is still no
evidence capable of establishing “causative significance”.
C.
The Bases on Which the Tribunal Inferred
Causative Significance
[60]
In spite of overwhelming expert evidence to the
contrary, a two-member majority of the Tribunal nevertheless saw in the expert
reports sufficient evidence of a causal link.
[61]
The key passages of the Tribunal’s majority
decision read as follows:
As
noted above, we have considered the factors in the Protocol. Perhaps the most
compelling evidence for us involves the fact that the workers with breast
cancer were exposed to carcinogens and there is a very elevated statistically
significant [standardized incidence ratio] for breast cancer. Our decision does
not simply rest on the occurrence of a very elevated statistically significant
[standardized incidence ratio] for breast cancer.
That [standardized incidence ratio] occurs against the backdrop of
the particular standard of proof employed by us, the workers’ exposure to
carcinogens, and the comments of [the authors of the OHSAH Final Report] to the
effect that all cancer causing agents have the potential to initiate and
promote cancer, little is known about the possible synergistic, additive or
antagonistic effects of multiple chemical exposures, and past exposures were
likely much higher.
(Original Decision, at
paras. 192-93)
[62]
It does not take much probing to see that there
is little to no support for these statements in the evidence before the
Tribunal.
(1)
The Cluster of Diagnosed Cases of Breast Cancer
[63]
First, the presence of a cluster of diagnosed
cases of breast cancer does not, on its own, constitute evidence of causative
significance.
[64]
As the OHSAH Final Report explains, clusters can
occur naturally as a result of an uneven distribution of non-occupational risk
factors amongst the general population. For breast cancer, these factors can
include age, weight, family history, age of first menstruation, age at
pregnancy and first birth, and certain lifestyle factors. As the authors of the
OHSAH Final Report explained:
Cluster research has shown that
elevated rates occur by chance at some geographic locations and times. In
fact, clusters always occur and it is a statistical phenomenon — even when
there is no causal factor that is responsible for the increased incidence (this
is why so few cluster investigations uncover any new risk factors). So, if
we look around at many geographic areas and times we will find some clusters;
if a specific cluster is related to statistics and not an etiologic agent, it
is most likely that in the next time period at this location the rate will not
be significantly elevated. Thus, it would be very prudent to continue to
evaluate the incidence of breast cancer in [Mission Memorial Hospital]
Laboratory employees to see if the rate comes closer to what is expected.
[Emphasis added; p. 39.]
[65]
A cluster might also represent a statistical
anomaly. Indeed, since only a total of seven diagnosed cases of breast cancer
were identified at the Mission Memorial Hospital laboratory over a period of 34
years, the possibility that this cluster represents such an anomaly is
significant.
[66]
It is clear that, on its own, correlation is no
proof of causation. On that same logic, I am of the view that, without more,
the mere presence of a cluster of diagnosed cases within a workplace is not
sufficient evidence of any causal link between the disease and the nature of
the employment.
(2)
Exposure to Chemical Substances
[67]
Second, on the question
of exposure to chemical substances, Dr. Yamanaka and the authors of the OHSAH
Final Report were unwavering. In their view, the available evidence regarding
the workers’ exposure to chemical substances like formaldehyde,
xylene, o-toluidine or ethylene oxide could not be related to an increase in the workers’
risk of developing breast cancer.
[68]
Among these chemical substances, ethylene oxide
is the only one that has a recognized association with the development of
breast cancer in human beings and, according to the evidence, this association
is weak. Dr. Yamanaka’s report, drawing on research from the U.S. National
Institute for Occupational Safety and Health, stated that only women exposed to
“very high levels” of ethylene oxide would be at an increased risk of
developing breast cancer. There is no evidence in the record capable of
supporting a conclusion that any of the workers were exposed to such “high
levels” at Mission Memorial Hospital.
[69]
Indeed, the OHSAH Final
Report concluded that current exposure to chemical substances was minimal “because liquid volumes are small and handling is often minimized
through the use of ‘lock and load’ systems”: p. 36. Dr. Yamanaka noted in a May
31, 2007 log entry that, even in the past, high levels of exposure to ethylene
oxide were “highly unlikely”.
[70]
The OHSAH Final Report did note that past
exposures to certain chemicals were “likely much higher”, but this statement
must be read in context. For one, the mention of “past exposures” does not seem
to refer to ethylene oxide, the only carcinogenic substance with a recognized
association with the development of breast cancer in humans.
[71]
More importantly, a passing reference to “likely
much higher” past exposures says nothing about whether these past exposures are
“as likely as not” to have increased the workers’ risk of developing breast
cancer. Rather, in their executive summary, the authors of the OHSAH Final
Report observed that a “chemical assessment of carcinogens in the workplace
also did not show any obvious and extreme exposures in the past (based on
current scientific literature), which could be related to the increase in risk”:
p. iii (emphasis added). This point was restated in their conclusion, where the
authors explained that “no current occupational chemical exposures, or
records of past occupational exposures were found that might relate
working in the [Mission Memorial Hospital] laboratory environment to elevated
breast cancer risk, or cancer in general”: p. 38 (emphasis added). Ultimately,
as I have said, in spite of this “likely much higher” exposure to certain
chemicals in the past, the authors of the OHSAH Final Report nevertheless
concluded that they “did not find any scientific evidence for the
plausibility of a laboratory work-related etiological hypothesis
regarding breast cancer”: p. iv (emphasis added).
[72]
Finally, rather than suggest that multiple
exposures can have a “synergistic” or “additive” effect, as the Tribunal seems
to imply, the OHSAH Final Report indicated that no synergistic or additive
effect has been identified in the literature.
[73]
Respectfully, there is simply no basis for
inferring “causative significance” from these passages of the Final Report.
[74]
It is true, as my colleague Brown J. notes, that
the OHSAH Final Report did not exclude the possibility that past exposures
to certain chemicals could have contributed to the development of the workers’
breast cancer. At the conclusion of their report, the authors stated that
[i]n summary, this study confirmed that
the perceived cluster was an observed cluster and that [Mission Memorial
Hospital] Laboratory employees were experiencing an elevated rate of breast
cancer. The factors associated with this increased incidence could not be
determined but may have been due to: (1) a cluster of reproductive and other
known, non-occupational, risk factors, (2) past exposures to chemical
carcinogens and less likely to ionizing radiation, and (3) a statistical
anomaly. [p. 39]
[75]
This statement,
however, should not be mistaken for evidence, and certainly not positive evidence.
The authors of the OHSAH Final Report only meant to set out an exhaustive list
of what could possibly explain the higher incidence of breast cancer in
laboratory technicians at Mission Memorial Hospital.
The inability to rule out a possible explanation simply does not transform that
explanation into positive evidence of a causal link. Moreover, a list of three
exhaustive possibilities says nothing about the likelihood of “causative
significance”. Put simply, this passage provides no basis for inferring such a
causal link, especially when the
OHSAH Final Report otherwise goes to great lengths to
refute the proposition that exposure to workplace chemicals could have
increased the workers’ risk of developing breast cancer.
D.
The Tribunal’s Findings of Fact Amount to Mere
Speculation
[76]
I am left with the view that the only support
for the Tribunal’s original decision is the existence of a cluster of diagnosed
cases of breast cancer. The Tribunal’s findings of fact simply do not rise
above the level of mere speculation. The Tribunal is even candid about the
speculative nature of its own conclusion. For instance, the two-member majority
stated as follows:
. . . we acknowledge that the
amount of exposure is not known and the specific carcinogens which contributed
to their development of breast cancer are not known. As part of that exercise
of “ordinary common sense”, we reiterate we are weighing the evidence using a
standard of proof as set out by subsection 250(4) of the [WCA].
(Original
Decision, at para. 179)
[77]
In speculating in this way, the Tribunal
disregarded the consensus view of the medical experts, in spite of the
Tribunal’s own lack of expertise in medical matters. The Tribunal also ignored
the Board’s policy, set out in the RSCM II, which states that there must
be sufficient positive evidence capable of supporting a finding of
causative significance, failing which the only possible option is to deny the
claim. I would add that, in giving effect to so low a standard of proof,
the Tribunal failed to respect the legislature’s wish not to include breast
cancer among the list of occupational diseases which are deemed to have been
caused by the nature of certain types of employment in Schedule B of the WCA.
[78]
Furthermore, while s. 250(4) of the WCA relaxes
the burden of proof to a limited extent, it is of no assistance to the workers
here. Section 250(4) provides that where the “evidence supporting different findings on an issue is
evenly weighted in that case, the appeal tribunal must resolve that issue in a
manner that favours the worker”. On a literal reading of these words, before s.
250(4) can apply, there must be evidence capable of supporting two different
findings, with each being equally plausible. In the present case, there is
simply no evidence capable of supporting a finding of “causative
significance”. Section 250(4) simply cannot serve to bridge such a major gap in
the evidence.
[79]
My colleague Brown J. has emphasized the
importance of drawing inferences in fact finding. While this may be so, I must
insist that the evidence in the record must still be capable of supporting the
inferences drawn. Otherwise, the fct-finder is at risk of straying outside the
realm of inference and reasonable deductions, and into the “wilderness of ‘mere
speculation or conjecture’”: Fairchild v. Glenhaven Funeral Services Ltd., [2002] UKHL 22,
[2003] 1 A.C. 32, per Lord Rodger, at para. 150, citing Caswell v.
Powell Duffryn Associated Collieries, Ltd., [1940] A.C. 152, per Lord
Wright, at pp. 169-70; see also D. Cheifetz, “The Snell Inference and
Material Contribution: Defining the Indefinable and Hunting the Causative
Snark” (2005), 30 Advocates’ Q. 1, at pp. 46-47.
[80]
This kind of “common sense” or inferential
reasoning simply cannot bridge insuperable gaps in the evidence — in either a
standard civil action or in an administrative claim under the WCA: see
e.g. Kozak v. Funk (1997), 158 Sask. R. 283 (C.A.), at para. 22, aff’g in part
(1995), 135 Sask. R. 81 (Q.B.); Meringolo v. Oshawa General Hospital (1991),
46 O.A.C. 260, at para. 89, leave to appeal refused, [1991] 3 S.C.R. vii.
[81]
In this case, as I have said, there is simply no
evidence — and certainly no positive evidence — capable of supporting a finding
of causative significance. Having allowed mere speculation to suffice, the Tribunal’s decision is “openly,
evidently, clearly” wrong and therefore ought to be set aside: Southam,
at para. 57; Toronto (City) Board of Education, at para. 44; Canadian Union of Public
Employees, Local 963 v. New Brunswick Liquor Corp.,
[1979] 2 S.C.R. 227.
E.
Disposition
[82]
For these reasons, I would dismiss the Workers’
Appeal and the WCAT Appeal.
Appeal
by the Workers’ Compensation Appeal Tribunal dismissed. Appeal by Katrina
Hammer, Patricia Schmidt and Anne MacFarlane allowed with costs, Côté J.
dissenting.
Solicitor for the
appellant/respondent the Workers’ Compensation Appeal
Tribunal: Workers’ Compensation Appeal Tribunal, Richmond.
Solicitors for the
appellants/respondents Katrina Hammer, Patricia Schmidt and Anne
MacFarlane: Health Sciences Association of British Columbia, New
Westminster; Hospital Employees’ Union, New Westminster.
Solicitors for the
respondent Fraser Health Authority: Harris & Company, Vancouver;
Health Employers Association of British Columbia, Vancouver.
Solicitor for the
intervener the Attorney General of Canada: Attorney General of
Canada, Toronto.
Solicitor for the
intervener the Attorney General of Ontario: Attorney General of
Ontario, Toronto.
Solicitors for the
interveners the Ontario Network of Injured Workers’ Groups and the Industrial
Accident Victims’ Group of Ontario: IAVGO Community Legal Clinic,
Toronto.
Solicitors for the
interveners the Community Legal Assistance Society and the British Columbia
Federation of Labour: Ethos Law Group, Vancouver.