In first and second grades, he had difficulties with reading, writing, and arithmetic and he suffered various language delays.32 In his teenage years, a battery of neuropsychological exams indicated that Sam “had a number of deficiencies in various areas of brain function . . . : problem solving, planning, executive function, fine motor function, expressive language, aspects of visual-spatial construction, visual working memory, visual-spatial memory and verbal concept formation”33—an array of deficits consistent with what is known about damage from lead ingestion. “[Sam]’s injuries are permanent and irreversible,” the examining physician concluded.34 By his midteens Sam, who had been described as a normal, happy infant, had become a failure in school, a troubled young man who lacked the skills to escape the dangerous neighborhood in which he was raised.35
The lessons of America’s continuing lead-poisoning epidemic are not confined to the tragedies of a few specific children like Sam T. Nor are its lessons limited to lead alone. Discovery by lead researchers of the impacts of early low-level lead exposure has been instrumental in revolutionizing our understanding of environmental danger and how we define what is a risk. As a result, our concerns regarding environmental dangers can no longer be confined to worries over cancer, heart disease, and the like. Researchers have identified that low-level exposures can result in biological changes with measurable and important consequences for individuals. Behavioral changes such as hyperactivity, attention deficit disorders, and even antisocial behaviors have been linked to low-level exposures to lead, mercury, and other heavy metals in infancy and even in utero. Morphological changes such as premature puberty and an increased proportion of female births have been linked to the rise in the use of plastics and bisphenol A and other “endocrine disruptors.”36
Researchers into low-level exposures to a variety of substances have also challenged, even transformed, our understanding of what is toxic and what is toxicology. We can no longer take solace in believing that any substance can be used if a “safe” level of exposure is officially identified. Researchers have shown that for many synthetic materials introduced yearly into our environment, the developmental moment at which a fetus or child is exposed to a toxin is every bit as important as the amount to which he or she is exposed.37 Many of these issues that challenge us today were first identified while studying lead and lead exposures. The modern history of this unfolding understanding and corresponding attempts to regulate lead may thus give us insight applicable to current debates over other toxic substances.
Sam T.’s story is similar to that of countless others, often who have ingested far less lead. In fact, from the 1970s to the 1990s a growing body of research indicated that as each lower “safe level” was agreed upon by the federal government, deleterious effects were found at a still lower level. Investigators such as Philip Landrigan at Mount Sinai Medical Center in New York, Herbert Needleman at the University of Pittsburgh, and Kim Dietrich and Bruce Lanphear, both then at the University of Cincinnati, showed that even quite small amounts of lead, between 1 and 10 micrograms per deciliter of blood, were associated with deficits similar to Sam’s: lowered IQ, behavioral disorders, perceptual problems, and other effects that seriously undermined the ability of children to succeed in school or work environments. This shift in focus—from the impact of relatively high blood lead levels as the cause of severe, sometimes fatal neurological damage to the subtler behavioral and intellectual deficits associated with low-dose lead exposure—raised new concerns about lead’s wide-ranging toxic effects and forced rethinking of what clinicians should attend to beyond textbook symptoms of severe lead poisoning. The growing scientific literature on lead’s effects, as we will see, has been bitterly contested by the lead industry at every step and has resulted in some classic instances of attempted intimidation of university researchers and attacks on their scientific integrity.38
The extensive documentation of low-level effects over recent decades has led the Centers for Disease Control to progressively lower the blood lead levels considered to put children at risk. Until the late 1960s, most public health officials and physicians believed that 60 micrograms per deciliter of blood was not dangerous for children. But by 1978 the CDC had halved this figure, reducing it still further in 1985, to 25 μg/dl, and then in 1991 to 10 μg/dl.39 Jane Lin-Fu, a leading lead researcher, has observed that today “we know that normal [blood-lead level] should be near 0, that unlike essential elements such as calcium . . . lead has no essential role in human physiology and is toxic at a very low level.”40 Most prominent researchers agree with Lin-Fu’s assessment.41 Indeed, the CDC’s lead advisory committee, the scientific body that consults on the federal definition of lead poisoning, recommended in January 2012 that the level of concern for lead be cut in half, to 5 μg/dl. This was adopted by the CDC later that year.42 The political implications of this recommendation are profound and contentious, however. As a result, the number of children considered at risk of lead poisoning rose dramatically, from an estimated 250,000 children with levels above 10 μg/dl to as many as 450,000 with levels exceeding 5 μg/dl, placing renewed pressure on government, industry, and public health officials to take action.
Lowering the overall exposure of children to lead entails eliminating the wide variety of ways that children come in contact with lead in their everyday lives. Newspapers are filled with stories of children who have been poisoned by the lead paint on imported toys, lead solder on children’s jewelry, lead from pipes that deliver water to homes, lead in soil tainted by leaded gasoline that once powered cars, lead spewed from smelters in the United States and throughout the world, and, still most importantly, lead from paint that remains on the walls of nearly all houses built before 1960 or that was applied in many other homes until lead paint was banned in 1978.
Just as there have been disagreements over what constitutes a “safe” blood lead level, so too have there been debates about how best to protect children from lead in their homes. In 1991 the CDC, under the auspices of the U.S. Department of Health and Human Services, published its Strategic Plan for the Elimination of Childhood Lead Poisoning,43 which some prominent researchers called “a truly revolutionary policy statement.”44 This document, building on an extensive period of reevaluation among researchers of childhood lead poisoning, proposed “a society-wide effort [to] virtually eliminate this disease as a public health problem in 20 years.”45 The document’s publication led to a host of studies seeking ways to eliminate or at least broadly curtail lead poisoning in America. While some researchers developed protocols aimed at eliminating lead as a widespread urban pollutant through its complete removal, others sought more pragmatic solutions—pragmatic, that is, from the viewpoint of the politics of the times, not from that of families whose children were at risk of permanent brain damage—seeking to remove some if not all lead from the windowsills, walls, ceilings, and woodwork of older homes.
The debate in the early 1990s over what should be done developed in a dramatically altered political environment, as memories of the Great Society were replaced by a more conservative political culture. The rise of Reaganism after 1980, the growing power of corporations, the decline of the civil rights and labor movements, the end of the construction of low-income public housing, and the antigovernment rhetoric and attacks on what were considered liberal social reforms all undermined support for more far-reaching solutions to the lead-poisoning problem. As Herbert Needleman, a pioneer in the early studies of low-level lead neurotoxicity, put it: “Instead of asking, ‘how can we develop a plan to spend U.S. $32 billion over the next 15 years and eliminate all of the lead in dangerous houses?’ the question became, ‘how little can we spend and still reduce the blood-lead levels in the short term?’” Opposition from industry, landlords, and others was so strong, and the countervailing voices so few, said Needleman, that “it was not long before the vision of the early 1990s, true primary prevention, eradication of the disease in 15 years, was replaced by an enfeebled pseudopragmatism,” which came down to only partial abatement of polluted homes.46
One researcher’s pseudopragmatism, however, is another advocate’s realistic attempt to help children at risk. And one person’s policy failure is another’s public health success story. Those who have watched a century of children sacrificed on the
