Occupational cardiovascular disease is disease of the heart or blood vessels that are caused by working conditions, making them a form of occupational illness. Cardiovascular disease is the leading cause of death in the US. Little is known about occupational risks for heart disease, but links have been established between cardiovascular disease and certain toxins (including carbon disulfide, nitroglycerin, and carbon monoxide), extreme heat and cold, exposure to tobacco smoke, ultrafine particles, depression, and occupational stress. Other occupational hazards potentially related to cardiovascular disease include noise exposure at work, shift work, and physical activity at work.