The cartilage rings are C-shaped because the back of the trachea presses against the esophagus. The cartilage opens at the esophagus and is replaced by connective tissue and muscle. This gives the esophagus space to allow food to be swallowed easily. The rings of the trachea are stacked one on top of the other, with a small space between them.
In 2014, a survey of the Australian working population revealed that the most common carcinogenic exposures in the workplace were solar ultraviolet radiation, diesel engine exhaust, environmental tobacco (second-hand) smoke, benzene, lead and silica.
Asbestos â a group of minerals that includes chrysotile, crocidolite, amosite, anthophyllite, tremolite and actinolite â is one of the most important occupational carcinogens. At least 107 000 people die each year from asbestos-related diseases, including lung cancer. / CHRYSOTILE ASBESTOS Elimination of asbestos-related diseases Updated March 2014 Asbestos is one of the most important occupational carcinogens, causing about half of the deaths from occupational cancer (1, 2) .