The National Marker Company sign with the legend âDANGER - FACE SHIELD MUST BE WORN WHEN OPERATING THIS MACHINEâ is commonly used in industrial facilities and construction sites to ensure that the proper safety procedures are being followed by the workers. The danger sign shows the message in clear, bold white text on a red base with black text on a white base to ensure easy visibility and readability even from a distance. The OSHA compliant danger signage is non-corrosive and weatherproof. The material is UV resistant, chemical resistant, graffiti proof and has an NMC Sign Muscle coating that protects the text against fading, scratches, scuffing, mold, and moisture.