Getting the Lead Out
If only it were as easy as recalling the Mattel toys.
Mattel's recent recall of more than 1 million toys coated with lead paint has left parents feeling that their children's health was risked by poor safety procedures. So far, it's unknown whether the toys have harmed anyone. But as parents rush to doctors' offices to test their toddlers, many are bound to discover their children possess small amounts of lead, since epidemiological data before the Mattel scare suggest that millions of American children already have the heavy metal in their blood. These folks will be reassured by their pediatricians that the Centers for Disease Control and Prevention consider blood lead amounts under 10 mcg/dl —the amount present in many toddlers—safely below the "level of concern."
Unfortunately, recent medical evidence shows even trace amount of lead—at amounts now considered acceptable by the CDC—can damage a child's IQ. Why regulators refuse to believe the data continues a decades-old exercise in willful ignorance. And it's children who are still paying the price.
Doctors have known for more than a century that children could develop seizures and comas from severe lead toxicity, and that surviving victims were frequently brain-damaged. The question has become—and remains—how much lead is too much? Though federal authorities refuse to admit it, it's increasingly clear that no safe threshold for lead exists, and even the tiniest amount can hurt children's developing brains.
While tainted toys are in the news now, kids historically have gotten lead from two sources: the atmosphere and house paint. Roughly a quarter-million tons of lead compounds entered the atmosphere annually beginning in 1922, after a General Motors scientist developed a lead-based gasoline additive that prevented auto knocking. Lead's chemical durability, recognized centuries ago, also made it an attractive paint additive. Toddlers are particularly susceptible to eating lead paint because it has a sugary taste; ancient Romans used lead powder to sweeten wine. By 1980, more than half a million American children—4 percent of all toddlers—had quite toxic blood lead levels from these sources.
Initially, the Centers for Disease Control thought kids' brains could tolerate up to 60 mcg/dl of lead because no seizures occurred at that level. But in 1979, Dr. Herbert Needleman reported in the New England Journal of Medicine that lead levels considered safe by the CDC—though far lower than needed to produce seizures and coma—correlated with lower IQs in children. Later, his group reported that lead-poisoned children were more likely to drop out of school and have reading disabilities.
But lead controls were slow in coming, due to powerful industry resistance. As exhaustively recounted by journalist Jamie Kitman, the lead lobby openly retaliated against those promoting regulation. In the 1970s, Du Pont and Ethyl, the largest manufacturers of lead additive, sued the Environmental Protection Agency to repeal tighter emissions standards. Though lead paint in homes was banned in 1978, pro-lead lobbyists persuaded then-Vice President George Bush in 1982 to recommend removing limitations on leaded gasoline (the effort ultimately failed). In the 1980s, the Reagan administration barred the CDC from collecting data on national pediatric lead levels. To intimidate lead researchers, a bitter harassment campaign was launched against Needleman.
Though faced with more and more data from independent researchers about lead's dangers, the federal government chose an excruciatingly slow approach to children's health. The CDC, in a leisurely fashion, dropped lead limits (subscription required) from 60 mcg/dl in the 1960s to 40 mcg/dl in the 1970s, ambled down to 25 mcg/dl in the mid-'80s, and finally got to 10 mcg/dl in 1991. That's where it remains stuck now.
Darshak Sanghavi is Slate's health care columnist. He is chief of pediatric cardiology and associate professor of pediatrics at the University of Massachusetts Medical School as well as the author of A Map of the Child: A Pediatrician's Tour of the Body. Follow him on Twitter.
Photograph of toy car by Pat Roque/AP. Photograph of frowning child on Slate's home page by Photodisc.