Lead poisoning: An acute or chronic poisoning caused by the absorption of lead or any of its salts into the body. Lead poisoning is an environmental hazard that is capable of causing mental retardation, behavioral disturbance, and brain damage. Lead poisoning is formally defined in the US as at least 10 micrograms of lead per deciliter of blood. Lead poisoning is more common in children than in adults because young children often put their hands and other objects in their mouths, and these objects can have lead dust on them. Furthermore, lead poisoning is more dangerous in children than in adults because children absorb more lead and the developing brain and nervous system are more sensitive to the damaging effects of lead. Lead was used in household paint until 1978, and it was also found in leaded gasoline, some types of batteries, water pipes, and pottery glazes. Lead paint and pipes are still found in many older homes, and lead is sometimes also found in water, food, household dust, and soil. Lead can be a workplace hazard for people in some occupations. A diet that is high in iron and calcium can help protect people against absorbing lead. Treatment involves chelation therapy, whereby blood is removed and metals are filtered out through a machine, then reinfused into the patient. Treatment cannot repair damage to the brain done by lead poisoning, but it may prevent further damage. Also known as plumbism.