What is a 'control failure' and how is it identified in an investigation?

• A. A control failure occurs when existing barriers fail to prevent or mitigate harm; identified by analyzing whether controls existed, were adequate, and functioned properly.
• B. A control failure is when new controls are added after an incident.
• C. A control failure is when a supervisor is absent during an incident.
• D. A control failure means the incident has no contributing factors.

Answer: (A)

A control failure means the safeguards that are meant to stop or limit harm did not perform as intended. In an investigation, you identify it by checking whether protective measures were in place, appropriate for the hazard, and functioning properly at the time of the incident. This involves reviewing design specifications, installation, maintenance, testing records, and how workers interacted with the controls. If the hazard still causes harm despite those safeguards, or if there are gaps, malfunctions, or improper operation that undermined protection, that points to a control failure. For example, a guard that was present but left open, a safety interlock that failed, or ventilation that wasn’t properly maintained would illustrate a control failure. Adding new controls after the incident is a corrective action, not a sign that existing controls failed; likewise, an absent supervisor or the claim that there were no contributing factors doesn’t itself define a control failure.