Understanding the hazard control hierarchy helps explain why PPE is the last line of defense. Protective equipment is used after higher-level measures have been applied or judged infeasible, serving as a personal barrier to exposure rather than removing or reducing the hazard at the source. Its effectiveness relies on correct selection, proper fit, consistent use, and maintenance, and it can fail due to improper use or equipment limitations. Because it protects only the individual wearer and not everyone in the area, it is considered a supplemental safeguard rather than the primary means of control. Engineering controls, such as ventilation or enclosures, and administrative controls, like work practices and training, aim to eliminate or minimize the hazard at the source or in the process. These higher-level measures reduce or remove exposure for all workers, which is why they come before PPE in the hierarchy. Behavioral safeguards fall under human factors and training, reinforcing safe practices but not replacing the need for protective equipment when exposures persist. PPE remains essential, but it is the last line of defense because it does not remove the hazard and depends on proper use.