Take an introductory law class, and you'll no doubt be introduced to the concept of "joint and several liability". It's a legal principle that states multiple parties can be held liable for the same event, regardless of their individual share of the liability.
In the occupational health and safety context, the principle of joint and several liability ensures that the maxims “safety is everyone’s responsibility” and “everyone is responsible for everyone else”, are more than just catchy sayings. On the contrary, it operates such that if one party drops the ball in relation to health and safety and another isn't there to catch it, both parties face the risk of prosecution - regardless of the relationship (i.e. employer, worker, prime contractor, etc.).
That being said, however, that doesn't mean that it will always be appropriate or in the public interest to prosecute everyone involved in an incident. Sometimes the facts and rationale necessary to make that determination emerge prior to charges being laid. Other times it's only after, and through the work and efforts of experienced defence counsel.
That's exactly what happened in one of our recent cases, where charges were initially brought against both our corporate client, and a supervisor at the work site, for the roles they allegedly played in a workplace incident.
While there were a variety of considerations that factored into the decision (including the nature of the incident, which party had control of the worksite, the respective degrees of responsibility, etc.), the Crown ultimately accepted a guilty plea on behalf of the supervisor, and stayed the proceedings against our corporate client!