National Marker Company signage with legend ?CAUTION - NO SMOKING? is often used to caution and alert people about places that don?t allow or prohibit smoking. Often used at commercial and residential locations, and in public spaces, apart from warehouses, workplaces and jobsites, this sign is often used as a part of safety measures too where smoking can lead to fire-related safety hazards. Jobsites that handle possibly inflammable solvents, chemicals or materials are usually very specific about putting-up such cautionary signage across the premises. This OSHA signage is easy to spot and read, ensuring working personnel and visitors are immediately cautioned about smoking-related prohibitions/restrictions.