When a workplace incident occurs in Canada, whether a serious injury, a fatality, or a dangerous condition that could have caused harm, employers face a critical moment of accountability. Regulatory inspectors arrive, investigations commence, and the question that will ultimately determine the organization's fate is not simply whether something went wrong, but whether the employer did everything reasonably practicable to prevent it. This is the essence of the due diligence defence, a legal concept that sits at the heart of Canadian occupational health and safety law and shapes how employers must think about their obligations long before any incident ever occurs.
The due diligence defence exists because Canadian occupational health and safety legislation operates on a strict liability framework. Unlike criminal law, where the prosecution must prove that an accused intended to commit an offence, regulatory offences under OHS statutes do not require proof of intent. If a violation of the legislation occurs, the employer is presumed to have committed the offence simply by virtue of the violation existing. This might seem harsh, but the rationale is straightforward and deeply embedded in Canadian public policy. Workplaces present inherent risks to human life and safety, and the law places the primary burden of managing those risks on the party with the greatest control over the work environment, which is the employer. The due diligence defence provides a meaningful counterbalance to this strict liability approach. It allows employers who have genuinely committed to safety, who have taken proactive and systematic measures to identify hazards, implement controls, and ensure compliance, to avoid conviction even when something goes wrong.