Exposure to chemical substances can cause adverse effects on the cardiovascular (heart and blood vessels) or hematopoietic (blood) systems (Cardiovascular or Blood Toxicity). Exposure to cardiovascular toxicants can contribute to a variety of diseases, including elevated blood pressure (hypertension), hardening of the arteries (arteriosclerosis), abnormal heartbeat (cardiac arrhythmia), and decreased blood flow to the heart (coronary ischemia). Lead, carbon disulfide, arsenic, cadmium, ozone, and vinyl chloride have all been implicated in the etiology of cardiovascular disease. Exposure to hematopoietic toxicants can reduce the oxygen carrying capacity of red blood cells, disrupt important immunological processes carried out by white blood cells, and induce cancer. Chronic exposure to benzene (a component of gasoline fuel) leads to the decreased production of all types of blood cells, and ultimately to leukemia, a cancerous proliferation of white blood cells.