Respirators are commonly used to protect workers who could be exposed to workplace hazards that can cause breathing difficulties, disease or death — hazards such as environments that have insufficient oxygen, harmful dusts, smokes, mists, gases or vapors. These people can include construction workers, emergency and hazmat responders, chemical plant employees, those employed in certain medical fields and many other industries. In fact, OSHA reports that there are five million workers in the United States who are required to wear respirators while on the job.