Which of the following is NOT an engineering control?

The choice of personal protective equipment as the option that is NOT an engineering control is correct because engineering controls focus on modifying the environment to reduce exposure to hazards, rather than relying on individual behaviors or equipment worn on the body.

Safety barriers, ventilated workstations, and automatic shut-off valves are all designed to eliminate or minimize hazards at their source. For instance, safety barriers physically prevent access to hazardous areas, ventilated workstations help to remove airborne contaminants, and automatic shut-off valves reduce the risk of spillage or leaks in fluid systems. All these examples illustrate structural or procedural changes implemented in the workplace to enhance safety effectively.

In contrast, personal protective equipment (PPE) serves as a last line of defense that individuals must actively wear or use. While vital in protecting workers from hazardous conditions, it does not alter the hazard itself or the environment in which work is performed. Thus, it falls under a different category of safety measures rather than the engineering controls which seek to change the workplace conditions directly.