Disability and Causation in Workers' Compensation (7:IX)

This information applies to British Columbia, Canada. Last reviewed for legal accuracy by the Law Students' Legal Advice Program on June 30, 2021.

A. Types of Claims

Before a compensation claim can be accepted, the Board must find that the worker’s injury, death, or disease was disabling and that the disability occurred as a result of employment. The WCA addresses these matters differently for different types of injuries and conditions.

Sections 134 and 146 [Former Act, s. 5]: personal injury (physical or physical/psychological)
Section 135 [Former Act, s. 5.1]: psychological injury only (“mental stress”)
Section 136(1)[Former Act, s. 6(1)]): occupational disease (Occupational Disease) – no presumption of work causation
Section 137 [Former Act, s. 6(3)]: Occupational Disease – presumption of work causation
Section 145[Former Act, s. 7]: hearing loss

Detailed policies regarding each of these conditions are set out in the RSCM II. Chapter 3 sets out policies for personal and psychological injuries and compensable consequences. Chapter 4 sets out policies for all Occupational Disease, including repetitive strain injuries and hearing loss. Students handling appeals should note that most causation disputes come down to matters of evidence, and the policies provide important guidance on what evidence is required in each case.

B. Injury Disease or Both?

Because the statutory and policy requirements for an injury and Occupational Disease are different, it is important to consider the worker’s disability under the correct relevant category. Sometimes this is not clear.

Policy #C3-12.00 of the RSCM II has a helpful section on the distinction between an “injury” and a “disease”. Some conditions, like tendonitis or hearing loss, can be either an injury or a disease, depending on the circumstances of the injury. For example, hearing loss from a single occurrence like an explosion is treated as an injury while gradual loss of hearing due to occupational noise is treated as a disease.

Sometimes, a worker is disabled by a combination of a slow-developing disease followed by a single event. The combination results in a significant disability, although neither event by itself would have been disabling. This is a difficult causation case. While the single event may not be sufficient to injure a healthy person, the worker is “working hurt” so a minor event is sufficient to disable him. This is the compensation version of the “thin skull” victim in tort law. The Board may not accept work causation in the initial decision and deny the claim as not meeting the causal standard under WCA ss. 134 and 146 [Former Act, s. 5]. On review or appeal, the best way to address this matter is to have good evidence, preferably medical evidence, of the worker’s medical condition prior to the single event. The key for a finding of work causation under s. 134 is “causative significance”. Further, it is noted in court decisions that compensability will be denied only if personal or non-employment related factors are so dominant or exclusive that the compensable injury is not a significant causal factor (WCAT-2009-02226, affirmed by WCAT-2011-92511).

In some cases, the worker’s pre-existing condition is actually a developing Occupational Disease, such as gradual onset repetitive strain or gradual hearing loss. In these cases, you may wish to ask the Board to accept the pre-existing condition as a compensable Occupational Disease under section 136 and 137 [Former Act, s. 6]. If the Board denies this aspect as well, you may appeal this denial and join the two appeals together at the Review Division or WCAT so an appeal panel may consider the “whole worker”.

C. Compensable Aggravation

For both injuries and Occupational Diseases, it is also recognized that the worker can have a pre-existing condition which is aggravated or activated by the compensable injury or disease. For injuries, the relevant policy is set out in RSCM II #16.00; for Occupational Diseases, the policy is set out in RSCM II #25.20. It is necessary to distinguish between injuries or death resulting from employment (which are compensable), and injuries resulting from pre-existing conditions or diseases (which are not compensable). There must have been something in the employment activity or situation that had causative significance in producing the injury or death. In adjudicating these types of claims, the Board considers:

The nature and extent of pre-existing injury;
The nature and extent of the employment activity; and
The degree to which the employment activity may have affected the pre-existing injury.

If the pre-existing condition meets the test for compensable aggravation, this requires an “aggravation” decision separate from a simple acceptance “decision”. For example, the Board may deny that a slip and fall was sufficient to cause a meniscus knee tear in a healthy worker; however, if the worker had pre-existing knee problems, the same claim could have a separate decision accepting an “aggravation” type injury.

If the worker has a pre-existing but non-disabling condition, and the claim is accepted, the worker’s injury is dealt with like any other claim and the whole disability is compensable.

However, if the worker has a pre-existing disabling condition and becomes further disabled in the same body part through a work injury, the Board will apply section 146 of the WCA [Former Act, s.5(5)] or “proportionate entitlement” whereby compensation is paid only for the increase in disability, rather than the whole disability.

D. Section 134: Personal Injury

Chapter 3 – Compensation for Personal Injury is the key chapter of the RSCM II that applies to s. 134 of the WCA [Former Act, s. 5]. This chapter covers the definition of a “personal injury” as well as “arising out of and in the course of employment” and goes on to cover specific circumstances that can prevent an injury from being accepted and specific losses and consequences that can be included in a claim.

1. Did the Injury Happen at Work?

Under sections 134 and 146 of the WCA [Former Act, s. 5], personal injury or death must arise out of, and in the course of, employment in order to be compensable. It is important to check policies and WCAT decisions for qualifying factors, as they can change.

“Arising out of employment” relates to causation and means that the work must have causative significance to the injury. According to well-established jurisprudence, this means that the work does not have to be the sole or even the dominant cause of the injury; it must be only of causative significance greater than being trivial or de minimis: Chima v Workers’ Compensation Appeal Tribunal, 2009 BCSC 1574, Schulmeister v British Columbia (Workers’ Compensation Appeal Tribunal), 2007 BCSC 1580, and v British Columbia (Workers’ Compensation Appeal Tribunal), 2006 BCSC 838. Not all injuries at work are caused by work, as some are naturally occurring conditions which would have happened in any event. For example, a worker with heart disease, who is working in a sedentary job, may have a heart attack at the office. There is likely nothing in the work activity which would have causative significance to this injury.

“In the course of employment” relates to the employment relationship at the time of injury. It generally refers to whether the injury or death happened at the time and place and during an activity reasonably related to the duties and expectations of the employment. Time and place are not strictly limited to the normal hours or work or on the employer’s premises.

NOTE: There is a statutory presumption that if an injury is caused by an accident at work, the injury is presumed to have occurred in the course of employment (WCA s.134(3) [Former Act, s. 5(4)]). An accident can include someone else’s intentional act.

The determination of whether an injury arose out of and in the course of employment is set out in RCMS II #C3-14.00 and can be made with reference to factors such as:

whether the injury occurred on the premises of the employer;
whether it occurred in the process of doing something for the benefit of the employer;
whether it occurred in the course of action taken in response to instructions from the employer;
whether it occurred in the course of using equipment or materials supplied by the employer;
whether the risk to which the worker was exposed was the same as the risk to which they are exposed in the normal course of production;
whether the injury occurred during a time period for which the worker was being paid;
whether the injury was caused by some activity of the employer or of a fellow worker;
whether the injury occurred while the worker was performing activities that were part of their regular job duties; and
whether the injury occurred while the worker was being supervised by the employer.

This list is not exhaustive, and alone, none of the above factors are conclusive.

RSCM II, Chapter 3 sets out further and detailed criteria for acceptance of a claim under sections 134 and 146 of the WCA [Former Act, s. 5]. Current policy states that the injury need not occur while the worker is engaged in specific productive acts, so long as it occurs within the broad circumstances of carrying out the employment duties. An injury incurred while commuting is generally not a compensable injury; however, travelling may be considered an activity in the course of employment if travel is part of the worker’s duties or if the accident occurs on the employer’s property or on a “captive road” provided and controlled by the employer, such as logging roads used by forestry workers.

If serious and willful misconduct on the part of the worker is the sole cause of the injury, no compensation is paid unless death or severe disability results.