What is the rationale for including both engineering and administrative controls in exposure mitigation plans?

• A. PPE is the only control
• B. Administrative controls alone are enough
• C. Engineering controls provide persistent, source-based protection; administrative controls optimize work practices and reduce exposure potential
• D. Engineering controls are unnecessary

Answer: (C)

Mitigation relies on layers that address different parts of the exposure pathway. Engineering controls provide persistent, source-based protection by removing or reducing the hazard at its origin or along its path—think enclosure or local exhaust ventilation—so exposure is lowered regardless of worker actions. Administrative controls complement this by shaping how work is performed: procedures, training, and scheduling reduce the likelihood or duration of exposure by guiding safe practices and limiting time exposed. Together, they create a reliable, layered defense: the engineering controls continuously cut hazard at the source, while administrative controls optimize how work is done to minimize exposure potential. For example, enclosing a process and adding ventilation reduces emissions at the source, while rotating shifts and standard operating procedures further lower exposure by limiting time spent in hazardous conditions. Relying solely on protective equipment would place the burden on proper use and wouldn’t eliminate the hazard or exposure duration, so combining engineering and administrative controls provides the strongest protection.