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.
Chemicals and Radiation Linked to Breast Cancer. In our daily lives we are exposed to toxic chemicals and radiation from a wide range of sources, and large and growing body of scientific evidence tells us that some of these exposures can increase breast cancer risk.Exposures to breast carcinogensâchemicals that directly cause breast cancerâare an obvious concern.hemicals and Radiation Linked to Breast Cancer. In our daily lives we are exposed to toxic chemicals and radiation from a wide range of sources, and large and growing body of scientific evidence tells us that some of these exposures can increase breast cancer risk.