Which are the three categories of engineering controls for chemical hazards?

• A. PPE; administrative controls; and housekeeping
• B. Substitution/elimination; engineering controls (ventilation, enclosure); and isolation
• C. Fire suppression; spill containment; and emergency lighting
• D. Personal hygiene; labeling; and training

Answer: (B)

Controlling chemical hazards uses a progression of protections that reduce exposure at the source and keep workers safe. The three categories here cover the main ways to achieve that: remove the hazard or replace it with something safer (elimination or substitution); apply engineering controls that physically limit exposure (like ventilation to dilute or capture vapors, or enclosing a process to prevent release); and isolate the hazard from people (using barriers or separate work areas). Substitution/elimination stops the hazard before it can affect anyone, which is the strongest win. Engineering controls directly reduce or remove the exposure pathway, and isolation physically separates workers from the hazard.

PPE, administrative controls (like procedures and training), and housekeeping are important safety tools, but they aren’t engineering controls. They’re different layers of protection, whereas the option described combines the major engineering-oriented strategies plus hazard removal, which fits the concept best.