Each header corresponds to a certain level of hazard severity and serves a definitive purpose. Use a ‘Danger’ header asbestos hazard sign to communicate immediate danger and the corresponding necessary precautions. Install ‘Warning’ header signs to identify a hazard level that lies between danger and caution, where ‘Caution’ header warns against potential hazards and/or unsafe practices. You also have the option to use signs with the notice header, which is used to communicate information that is important but not related to hazards. These signs can be used to complement the other hazard-related signs. OSHA standard 1910.145 provides detailed information about safety signs and headers.