Question

approved safety glasses or goggles must be worn

Explanation:

In laboratory or work environments where safety glasses/goggles are required, the standard safety protocol is to wear approved safety glasses or goggles at all times to protect the eyes from potential hazards (like flying debris, chemicals, etc.) that can occur unexpectedly, not just in designated hazardous areas or optionally. The other options (only in hazardous areas, never, only when you want to) go against safety regulations and best practices for eye protection.

Answer:

at all times