What is required to protect employees from falling into or through openings?

To safeguard employees from falling into or through openings, multiple protective measures can be implemented, making the most comprehensive answer "any of these."

Proper signage serves as a visual cue to inform individuals of potential hazards, warning them about openings in walkways or floors, thus promoting caution. While signage is an important aspect of safety, it primarily raises awareness rather than provides physical protection.

Guardrails and barriers are crucial for physically preventing falls. They create a barrier around openings, effectively blocking access to dangerous areas. This is one of the most common and effective ways to mitigate fall risks in construction and maintenance environments.

Safety nets serve as a secondary protective measure. When placed below susceptible areas, they catch individuals who might fall, further reducing the risk of injury.

Implementing any or all of these measures contributes to a comprehensive safety strategy. This highlights the importance of combining awareness tools like signage with physical barriers and secondary measures like safety nets to create a safer working environment. Thus, recognizing that multiple protections can be in place justifies the selection of all the options as valid solutions.