Workplace safety in Canada rests on a fundamental principle that shapes every decision employers make about protecting workers: hazards should be controlled at their source whenever possible, and the responsibility for safety should never fall primarily on the individual worker. This principle finds its clearest expression in the hierarchy of controls, a framework that ranks control measures from most effective to least effective and that underpins occupational health and safety legislation across all Canadian jurisdictions. Understanding this hierarchy is not merely an academic exercise for HR professionals and business owners but rather an essential competency that determines whether safety programs actually protect workers or simply create the appearance of protection while leaving employees vulnerable to preventable injuries and illnesses.
The hierarchy of controls emerged from decades of industrial hygiene practice and has been codified in various forms across Canadian occupational health and safety statutes. The Canada Labour Code, which applies to federally regulated industries including banking, telecommunications, interprovincial transportation, and federal Crown corporations, establishes the general duty of employers to ensure the health and safety of every person employed by them and to take prescribed health and safety measures. Provincial legislation mirrors this duty across all jurisdictions, from British Columbia's Workers Compensation Act and its accompanying Occupational Health and Safety Regulation to Ontario's Occupational Health and Safety Act to Quebec's Act Respecting Occupational Health and Safety. While the specific language varies, all jurisdictions share a common expectation, reflected in regulatory provisions and enforcement practices as of the date of authorship, that employers will implement controls in a hierarchical manner, beginning with the most effective measures and descending to less effective measures only when higher-order controls prove infeasible.