a wave of epidemiological studies launched in the late 1990s to explore the possible effects of environmental chemicals and toxins on fetuses and children. Eskenazi and her fellow scientists across the field have amassed an increasingly consistent, grim picture of possible neurological harms from a variety of environmental poisons, including chemicals found in agricultural pesticides (that also turn up in food), microscopic particles of carbon and other pollutants in the air, barely detectable levels of lead in the water — all are toxins that travel across state lines and abide by no barriers, socioeconomic or otherwise. In 2012, David Bellinger of Harvard’s school of public health published an eye-popping analysis of the impact of just three toxins — lead, methylmercury, and organophosphate pesticides — on neurological development, concludingreduction of environmental lead is widely considered one of the public-health triumphs of the past half-century. But Needleman paid dearly for it.

Gasoline and chemical companies like E.I. DuPont, Dutch Shell, and the Ethyl Corporation of America attacked the lead studies as inconclusive and poorly conducted; one scientist allied with the gasoline industry argued that the loss of IQ in children was due not to lead but to their parents’ low IQs. Needleman, who had moved to the University of Pittsburgh, later faced allegations of scientific misconduct from industry-associated researchers, prompting a two-year investigation by the National Institutes of Health, in which he was ultimately exonerated. In a bid for “transparency,” recalled Philip Landrigan, who headed children’s environmental health research at Mount Sinai School of Medicine for three decades,