Which action must be taken before entering a confined space with hazardous moving parts?

Locking out the equipment is a critical safety procedure that must take precedence before entering a confined space with hazardous moving parts. This action involves completely disabling the machinery or equipment by physically locking it in a safe position to prevent it from unexpectedly starting or releasing energy while personnel are working within the confined space. This is vital because hazardous moving parts can cause serious injuries, including amputations or crush injuries, if the equipment were to accidentally energize or become operational while someone is in close proximity.

The necessity to lock out equipment follows the established lockout/tagout (LOTO) procedures which are designed to protect workers from the risks of hazardous energy. By ensuring that all energy sources are effectively isolated and controlled, workers can safely conduct their tasks without the fear of an unexpected incident.

In this context, while tagging the parts, wearing protective gear, or assessing the atmosphere are important safety practices, they do not specifically address the immediate risks posed by moving parts, making this action the most critical step prior to safe entry.