What is the meaning of the Blue 'NOTICE' RF signs?

• A. RF hazard is optional
• B. RF is safe here
• C. You are entering an area where RF levels may exceed safe exposure limits—proceed with care
• D. Access is restricted to authorized personnel

Answer: (C)

Blue NOTICE signs warn that radiofrequency exposure in the area may exceed safe limits, so you should proceed with care. It’s an informational alert, not an immediate emergency, signaling you to be mindful of exposure duration and follow any posted precautions or guidance from site safety.

Why this fits best: it directly communicates potential RF exposure risk and the need to take precautions without declaring immediate danger or restricting access.

Why the other ideas don’t fit: calling the RF hazard optional would downplay the warning and isn’t aligned with a notice. Saying RF is safe here contradicts the purpose of the sign. Saying access is restricted implies a controlled entry requirement, which isn’t what a blue notice sign conveys.