The 'accident as prima facie breach' principle has been before the courts in several cases, often with some discrepancy in its application. In R v Midwest Pipelines Inc (2017 ABPC 222) the principle was again before an Alberta court in the context of an application for particulars.


The principle provides that, in some cases, proof that an employee was injured in an accident while performing his or her employment duties proves the actus reus (ie, guilty act) for an occupational health and safety (OHSA) general duty charge, provided that the necessary elements are proven beyond a reasonable doubt. The burden then shifts to the defendant to establish a due diligence defence.


In this case, a worker was seriously injured in a workplace incident and the employer was charged with eight counts. The first count was a general duty breach allegation stating that the employer had failed to ensure, as far as reasonably practicable, the health and safety of the worker, contrary to Section 2(1)(a)(i) of the Occupational Health and Safety Act (Alberta). After receiving the crown's disclosure, the employer applied for particulars of the first count on the basis that the disclosure contained information which left the employer uncertain about which act or omission the crown intended to rely on to sustain the count.


At the application hearing, the first issue before the court was whether the accident as prima facie breach principle for an OHSA general duty charge would preclude an order for particulars. The court reviewed the principle, noting that the case law had established that the principle requires that – in order for the crown to prove the essential elements of an OHSA general duty charge beyond a reasonable doubt – it must prove that:

  • there was an employee;
  • the employee was injured in an accident; and
  • the employee was performing his or her duties in the course of his or her employment when injured.

The court noted that the principle does not relieve the crown of establishing beyond a reasonable doubt that the employer committed a wrongful act, but rather reflects that sometimes proof of the consequence (ie, the accident) is sufficient to establish that a wrongful act was committed. However, the principle would not apply in all cases as there may be instances where the wrongful act by the employer cannot be inferred from the circumstances of the accident.

Requiring the crown to provide particulars of the specific acts, omissions or breaches by the employer would transform those particulars into essential elements of the actus reus of the offence, which the crown would then need to prove beyond a reasonable doubt. The court found that this would be inconsistent with the principle applicable to an OHSA general duty charge and would place a higher onus on the crown.

In this case, it was known why the incident happened. A boom stick being held above the ground by a hook and sling held by a caterpillar tractor fell from the hook and sling, severely injuring the worker. The court determined that it was appropriate to apply the accident as prima facie breach principle and thus it was precluded from making an order for particulars of the acts, omissions or breaches by the employer for the Count 1 OHSA general duty charge.

The court proceeded in obiter to find, in a somewhat confusing decision, that if it was wrong to conclude that the accident as prima facie breach principle precluded it from ordering particulars, then it would have made an order for particulars as requested by the employer.(1)

For further information on this topic please contact Cristina Wendel at Dentons Canada LLP by telephone (+1 780 423 7100) or email ([email protected]). The Dentons Canada LLP website can be accessed at


(1) For more information please see