Responders should wear which PPE level commonly for an unknown gas hazard before identification?

• A. Level B
• B. Level C
• C. Level D
• D. Level A

Answer: (D)

When the hazard is unknown, you can’t assume anything about the atmosphere or the substance. The responder needs maximum protection to prevent both inhalation and skin exposure while identifying the material. Level A PPE provides that. It includes a fully encapsulated chemical-resistant suit with an independent breathing source (SCBA), which protects the skin, eyes, and respiratory system from vapors, splashes, and potential contact with unknown toxins. This level also shields you if the atmosphere is hazardous or oxygen-deficient, since your breathing air isn’t tied to the surrounding air. Other levels either protect less of the body, rely on air-purifying respirators, or offer no respiratory protection at all, which isn’t sufficient when the substance hasn’t been identified. So the appropriate choice for an unknown gas hazard before identification is the highest protection: Level A.