Employers registered with the Ontario Workplace Safety and Insurance Board (WSIB) may be entitled to cost relief from workers’ compensation costs arising from a workplace accident if the worker’s prior disability caused or contributed to the compensable accident, or if the period resulting from the accident becomes prolonged or enhanced due to the worker’s pre-existing condition.

To determine the amount of cost relief to be applied in a particular situation, the WSIB compares the medical significance of the pre-existing condition with the severity of the accident, in accordance with WSIB Operational Policy Document No. 14-05-03 – Second Injury and Enhancement Fund (SIEF). Cost relief ranges from 0% (where the medical significance of the pre-existing condition is minor and the severity of the accident is major) to 90-100% (where the medical significance of the pre-existing condition is major and the severity of the accident is minor). It is rare for 100% cost relief to be applied to a claim.

However, a recent decision of the Workplace Safety and Insurance Appeals Tribunal (WSIAT) confirms that 100% cost relief is available to employers in appropriate circumstances.

In that case, a worker was driving a truck in the course of his employment. The worker lost control of the truck, striking multiple posts, another vehicle and several trees. After the accident, the worker was diagnosed with severe obstructive sleep apnea (OSA).

According to medical articles submitted to WSIAT,

OSA is associated excessive daytime sleepiness, inattention, and fatigue which may … increase the likelihood of errors and accidents. Motor vehicle crashes are two to three times more common among patients with OSA than without … Importantly all patients should be warned about an increased risk in motor vehicle crashes associated with untreated OSA and the potential consequences of driving or operating other dangerous equipment while sleepy.

In light of that medical evidence, WSIAT concluded, on a balance of probabilities, that the worker’s OSA was the cause of the workplace accident and, therefore, awarded the employer 100% cost relief.

The case and the resulting WSIAT decision illustrates the advantages to Ontario employers of using applications for cost relief as a strategy for managing workers’ compensation costs.