The chronic ingestion or inhalation of lead, damaging the central and peripheral nervous systems, kidneys, the blood-forming organs, and the gastrointestinal tract. Early symptoms include loss of appetite, weight loss, anemia, vomiting, fatigue, weakness, headache, lead line on gums, apathy or irritability, and a metallic taste in the mouth. Later, symptoms of paralysis, sensory loss, lack of coordination, and vague pains develop. Laboratory diagnosis is made through evidence of anemia, blood lead level above 5 μg/dl, elevated free erythrocyte protoporphyrin (FEP), increased excretion of lead in urine, and characteristic x-ray changes in the ends of growing bones.