A Terrible Thing to Waste

Science writer and bioethicist Harriet A. Washington argues that environmental racism, not genetics, is the primary driver of the persistent IQ gap between white Americans and Americans of color. Across tens of thousands of untested industrial chemicals, heavy metals, pesticides, pathogens, and air pollutants, Washington traces how communities of color are disproportionately exposed to substances that damage the brain and lower intelligence. She contends that this loss is correctable, and that the nation's failure to address it squanders both human potential and economic competitiveness.

Washington traces the belief in innate, racially determined intelligence from 19th-century pseudoscience to modern hereditarians, people who claim intelligence is inherited and racially fixed, such as Nobel physicist William Shockley and geneticist James Watson. She argues that this view fosters a false perception that the average 15-point IQ gap between U.S. whites and African Americans is genetic and immune to intervention. To counter the claim, she presents a key historical example: In 1924, the United States began adding iodine to salt to prevent goiters, an enlarged thyroid condition. The program produced substantial cognitive gains later confirmed during World War II, when Air Force recruits from formerly iodine-deficient areas scored significantly higher on military intelligence tests. Iodine is essential for thyroid hormone production directing fetal brain development, and its deficiency remains the world's leading cause of preventable intellectual disability. African Americans have the nation's highest levels of iodine deficiency.

Washington dismantles hereditarian claims through several lines of evidence. Studies of mixed-race children raised in different racial households show that environment, not parentage, determines IQ scores. Kenya's average IQ rose 14 points between 1984 and 1998 as health improved, far too rapidly to be genetic. The Flynn effect, a documented pattern of rising IQ scores named for researcher James R. Flynn, shows a three-point-per-decade increase in the West. She also recounts racial bias in IQ testing, from falsified 1840 census data to the Army intelligence tests of the 1920s, in which Black recruits received pantomimed instructions for questions involving culturally unfamiliar images.

The book's central section examines environmental agents that erode intelligence, beginning with lead. General Motors chose toxic tetraethyl lead over safe, cheap ethanol as a gasoline additive in the 1920s because ethanol could not be patented, despite internal memos acknowledging lead's extreme toxicity. The lead paint industry marketed its products for children's rooms while internally acknowledging the danger, and blocked regulation for decades by demanding ever-higher standards of proof. Washington contrasts this with the precautionary principle practiced by the European Union, which requires safety testing before chemicals enter the market. When whites moved to lead-free suburbs after the civil rights era, the industry blamed Black and Puerto Rican parents rather than its own products.

Washington presents case studies of lead's devastation. In Baltimore, the Kennedy Krieger Institute encouraged landlords to rent lead-tainted housing to families with young children during a mid-1990s study, using the children to evaluate cheaper abatement methods without warning parents of rising blood-lead levels. Maryland's top appellate court later compared the study to the Tuskegee syphilis experiment. In Flint, Michigan, Governor Rick Snyder switched the city's water to the tainted Flint River without corrosion protection. A state nurse wrote off a mother's worry about her son's brain damage, calling it "just a few IQ points" (104). Washington explains that even a five-point average IQ drop would add 3.4 million children with intellectual disabilities to the population while halving the gifted pool, and that lead exposure alone costs the nation 23 million IQ points annually.

Beyond lead, Washington maps a broader landscape of environmental neurotoxins. African Americans breathe 38 percent more polluted air than whites and are 79 percent more likely to live near emissions sources like bus depots, refineries, and highways. Environmental sociologist Robert Bullard's foundational 1983 research found that all five of Houston's garbage dumps and six of eight incinerators were in Black neighborhoods, and that middle-class Black households live in more polluted areas than very poor white households. Air pollution lowers IQ through multiple mechanisms, including triggering asthma that deprives the brain of oxygen and delivering magnetite nanoparticles from diesel exhaust directly into the brain. A Harvard study found that prenatal exposure to black carbon, a soot-like particulate produced by combustion, predicted a three-point IQ decrease.

Washington recounts the Anniston, Alabama, catastrophe. From 1935 to 1971, Monsanto Industrial Chemicals dumped tens of thousands of pounds of polychlorinated biphenyls (PCBs), toxic compounds used in electrical equipment, into creeks in the city's Black neighborhoods. Internal documents showed Monsanto knew its pollution killed fish within minutes but suppressed the findings. Attorney Johnnie Cochran won a $300 million class-action settlement, but after legal fees, adults received only about $9,000 each. Washington also documents arsenic poisoning in the historically Black Dunbar community of Fort Myers, Florida, and contamination by DDT, a toxic pesticide, in Triana, Alabama, where one resident had the highest DDT blood levels ever recorded.

The book examines the extreme vulnerability of developing fetal and infant brains. During critical windows of development, brain cells form at two hundred per second and establish one thousand synaptic connections every second. Toxic exposures during these windows can cause irreversible damage, and children absorb far greater doses per pound of body weight than adults. Washington documents between 218 and 276 fetal deaths and miscarriages in Flint after the water switch. She also presents psychiatrist Carl Bell's research documenting a 57 percent rate of fetal alcohol spectrum disorder in a Chicago clinic serving African American patients, calling it "the largest preventable public health problem in poor African-American communities" (192). This epidemic goes largely undetected because most affected mothers are moderate drinkers, screening efforts focus on other populations, and no law requires newborn screening.

Washington examines infectious diseases as another cognitive threat, presenting the parasite-stress theory developed by University of New Mexico researchers Randy Thornhill and Christopher Eppig. Because brain construction consumes 87 percent of an infant's metabolic energy, fighting infection diverts resources from neural development. Their global analysis found that higher infectious disease burden correlates with lower average IQ, even after controlling for wealth, temperature, and education. Washington documents neglected tropical diseases present in the United States, including Chagas disease, cysticercosis (a brain tapeworm infection causing epilepsy), and toxocariasis, a parasitic roundworm carried by 21 percent of African Americans and linked to cognitive deficits.

The book's final section offers practical recommendations and a blueprint for collective action. Washington advises individuals to enroll children in pre-K programs, use water filters and high-efficiency particulate air (HEPA) vacuums, and choose low-mercury fish. For community organizing, she draws on the 1982 Warren County, North Carolina, protest, in which residents of the predominantly African American community of Afton mounted six weeks of civil disobedience against the dumping of PCB-contaminated soil, resulting in 550 arrests and catalyzing the global environmental justice movement. She recommends using EJSCREEN (the EPA's environmental justice screening and mapping tool) to document pollution, aligning with national organizations, and developing media strategies.

In a preface connecting the book's thesis to the COVID-19 pandemic, Washington argues that every established risk factor for severe coronavirus illness, from respiratory disease to diabetes to immunosuppression, can be caused or worsened by environmental racism. She critiques responses that attributed the disproportionate death toll among people of color to personal choices rather than structural inequities, and cites early evidence that COVID-19 itself causes neurological damage. She concludes by invoking research showing that large resource inequalities raise death rates even among the middle class, arguing that polluted racial enclaves pose a hazard to the wider nation.