PROTOCOL OUTLINE: This is randomized study. Patients are randomized to receive succimer in addition to standard treatment (arm I) or standard treatment only (arm II).

Succimer is administered orally 3 times a day for 7 days, then twice daily for 19 days. Patients may receive up to 3 courses.

Standard treatment consists of a medical history and physical examination, environmental assessment with modification to reduce lead exposure, dietary modifications to decrease lead absorption, the use of a daily multivitamin and mineral supplement with iron, developmental screening and intervention, and frequent follow up of lead levels.

If blood lead level rises above 45 mcg/dL, patient receives succimer regardless of treatment arm originally assigned.

Patients are followed every 3-4 weeks for 2 months, then every 3 months for 6 months, and then every 6 months thereafter.

PROTOCOL ENTRY CRITERIA:

--Disease Characteristics-- Asymptomatic children with confirmed venous blood lead of at least 20 mcg/dL and less than 45 mcg/dL Children with blood lead of 45 mcg/dL or greater are not randomized in this study since they probably will receive succimer regardless of being enrolled in this study --Patient Characteristics-- Other: No contraindications to the use of succimer (i.e., allergy or a lack of lead safe environment in which to live during chelation)