A safety sign is one which gives a specific message to those who may be exposed to hazards in the work environment. They may be to prevent accidents, signify health hazards, indicate the location of safety and fire protection equipment, or for giving guidance and instruction in an emergency. Lockout-tagout (LOTO) or lock and tag is a safety procedure which is used in industry to ensure that dangerous machines are properly shut off and not able to be started up again prior to the completion of maintenance or servicing work.