Dr. Arlene Blum is a biochemist who also happens to be a fearless mountaineer. In the 1970s, as a researcher at the University of California at Berkeley, she coauthored a groundbreaking study on a flame retardant, Tris-BP, which determined that the chemical, then widely used in children's sleepwear, causes cell mutations. Tris-BP was banned from children's pajamas and replaced with a chemical known as chlorinated Tris. Blum and her colleagues tested chlorinated Tris and found that it was just as dangerous. Chlorinated Tris, too, was removed from children's pajamas.
Following this work, Blum left academia to, among other things, climb Annapurna and wrote two books about her adventures. Then, about five years ago, she decided she'd like to get back into science and attended a "green chemistry" meeting in Oakland. There she learned that chlorinated Tris had been quietly making a comeback as a flame retardant in the foam that's used to stuff sofas and chairs. It is now found in nearly 80 percent of upholstered home furniture in the U.S. and in the bloodstream of just about everyone. Blum had stumbled, as she later put it, across her "next mountain." She established a nonprofit group to try to fight the use of Tris. Chemical manufacturers fought back, pouring more than $23 million into a campaign—so far successful—to thwart her efforts.
Blum's campaign against chlorinated Tris was recently recounted in the New York Times Magazine. As it happens, the article ran just around the time of the 50th anniversary of the publication of Silent Spring, a coincidence that struck me as both unfortunate and fitting. Half a century after Rachel Carson warned about the threat of "substances that accumulate in the tissues of plants and animals and even penetrate the germ cells to shatter or alter the very material of heredity," that warning remains all too relevant today.
Pesticides like DDT, dieldrin, and heptachlor persist in the environment for decades, and have a nasty habit of accumulating as you move up the food chain. Silent Spring so persuasively laid out the dangers of these chemicals—and led to such an aggressive and expensive attack on Carson by pesticide manufacturers—that millions of Americans began to wonder what they were being exposed to. The fight for more effective pesticide regulation led to a ban on the domestic sale of DDT in 1972 and of dieldrin two years later. Rarely, if ever, has a book had more impact on public policy.
But as Carson knew better than anyone, DDT and dieldrin were just pieces in a much larger puzzle. "New chemicals come from our laboratories in an endless stream," she observed. "Almost 500 annually find their way into actual use in the United States alone." Most of these chemicals were untested, and by the time anyone figured out how harmful they were, the chemicals would be virtually ubiquitous.
Most of the chemicals finding their way into "actual use" in the United States remain untested; as the Times Magazine's piece on Blum noted, "of the 84,000 industrial chemicals registered for use in the United States, only about 200 have been evaluated for human safety by the Environmental Protection Agency." Meanwhile, more are being created each year.
In the broadest sense, Carson's message was that people are clever, but not necessarily wise. We are very good at coming up with compounds to kill mosquitoes and ants, but not so good at foreseeing what the effects of this will be on other creatures. Will we ever take this broader message to heart? Half a century after Silent Spring, the record is not encouraging. We may have banned DDT, but if you are sitting on a couch or an upholstered chair, chances are that you are breathing in chlorinated Tris right now.