To the Editor.
—As described in the July 27, 1994, issue of JAMA,1,2 the marked decrease in blood lead levels of the US population between 1976 and 1991, documented by NHANES III, is a tribute to effective preventive health measures, mainly the removal of lead from gasoline, cans, and paint. From 1976 to 1991, the mean blood lead level in the United States decreased more than fourfold, with a 10-fold decrease in prevalence of blood lead levels ≥0.48 μmol/L (≥10 μg/dL) among children aged 1 to 5 years, those most at risk. These results confirm clinical observations during the past 20 years—that symptomatic lead poisoning is disappearing among US children.This good news has been counterbalanced by claims that blood lead levels previously considered safe (<1.21 μmol/L [<25 μg/dL]) may lead to neurobehavioral changes, including lowered IQ and behavioral and learning difficulties. These claims have been promulgated by investigators,