Dr. Needleman played a key role in securing some of the most significant environmental health protections achieved during the 20th century, which resulted in a fivefold reduction in the prevalence of lead poisoning among children in the United States by the early 1990s.

Despite engendering strong resistance from lead-related industries, which made him the target of frequent attacks, Needleman persisted in campaigning to educate stakeholders, including parents and government panels, about the dangers of lead poisoning.

Needleman has been credited with having played a key role in triggering environmental safety measures that have reduced average blood lead levels by an estimated 78 percent between 1976 and 1991.

His most recent research has shown that boys with high levels of lead concentrated in their bones are more likely to develop aggressive or delinquent behavior, such as bullying, vandalism and shoplifting.

[4] COR, which sought to help civilians injured in the Vietnam War, was composed of medical personnel, scientists, clergymen, and citizens concerned about American involvement.

[6] In 1990, a Superfund (industrial pollution cleanup) case was brought against the owners of a defunct lead mill in Utah, where houses had been built on the land where the tailings had been deposited.

Based on what she saw of the printouts, Scarr concluded that Needleman had discarded potentially significant explanatory variables after his first analysis failed to show a lead-IQ relationship until "he got the results he wanted".

[8] Needleman says that the case against him was made by a law firm from Philadelphia who refused to name the company who was paying them,[7] although he wrote that Ernhart received $375,000 over seven years from the International Lead Zinc Research Organization (ILZRO).

[12] The lawsuit and subsequent inquiry remain controversial; according to philosopher of science Clark N. Glymour, "Scarr and Ernhart are sometimes dismissed as tools of the lead industry, but I know of no evidence that they were other than sincere."

[13] EPA scientist Joel Schwartz told Newsweek in 1991 that a reanalysis of Needleman's data incorporating the factor of age, which had been excluded, "found essentially the identical results".