What personal protective equipment should you wear when near an operating APU?

When working near an operating Auxiliary Power Unit (APU), ear protection is essential due to the high noise levels generated by the unit. APUs can produce sound levels that may exceed safe limits, potentially leading to hearing damage if proper protective gear is not used. It's important to safeguard your hearing, particularly in environments where machinery operates continuously or at high volume.

While eye protection, protective clothing, and a hard hat are also important in various contexts related to equipment operation, they are not as critical specifically for noise exposure from the APU. Therefore, wearing ear protection is the most necessary measure to ensure safety in this scenario.