The Environmental Protection Agency's decision to toughen limits on water tainted with perchlorate is based on sound science. The chemical is valuable when used to treat thyroid disorders but can have health impacts. It offers benefits and risks. Weighing them is what sensible regulation is all about.
Given the measured way in which the EPA has reversed many anti-science biases of the Bush administration, it's disturbing to read the broadside against chemicals in "Legally Poisoned," by UC Riverside professor Carl Cranor.
If the philosophy professor is to be believed, the dangers from chemicals are increasing and cancer stalks us. That's not accurate--cancer rates have pointed steadily downward for decades--but it's a familiar trope to those inclined to believe advocacy group polemics.
Cranor's narrative is that "molecules are harmful." But everything is made of molecules and chemicals. Labeling something "toxic" or a "contaminant" is meaningless. Toxicity is a question of degree. Exposure is different from effect.
Regulators must weigh unknown hazards against financial costs and health risks. Consider California almonds. A natural chemical, aflatoxin, is found in 15 percent of the crop and on other nuts as well. If not eradicated, people die. There are no effective alternatives to removing this killer other than by using pesticides, including atrazine, which has been found safe with buffers 1,000 times what humans are exposed to.
Should we ban atrazine? The World Health Organization last year concluded "no." Recognizing its invaluable role in the Green Revolution, and based on new health studies, it softened its atrazine limits to 100 parts per billion.
The chemophobia movement is rife with contradictions. Bisphenol A (BPA), a ubiquitous chemical used in plastics, is a favorite target. Cranor claims it's dangerous because it's found in the urine of 90 percent of Americans. That sounds scary, but it's not. Advanced bioanalysis--we can identify chemicals in a thimble full of liquid poured into Lake Erie--ensures we can find nanogram traces, even in pure water used for liquid chromatography.
The Centers for Disease Control has been horrified by the misuse of this statistic. It found dietary estrogens--"hormone disruptors" that occur naturally in many foods, including soy, tofu, berries and beer--in the urine at levels 100 times higher than biologically inactive BPA.
"Finding a measurable amount of bisphenol A in the urine does not mean that it causes an adverse health effect," the CDC reported recently, noting that BPA is "excreted in the urine within 24 hours with no evidence of accumulation."
Why shouldn't we act with precaution, and ban it? Because of health trade-offs. BPA is used in can liners to increase the shelf life of food and prevent botulism. There are no effective substitutes. Recklessly ban BPA and people will die.
Cranor derisively cites its use in dental sealants. According to a 2010 Harvard study, one-time exposure to BPA in sealant is two-to-five times lower than what a child is exposed to daily from environmental sources. BPA's critics do not weigh its huge public health benefits against its infinitesimal health hazard (if indeed there is any hazard from a three-hour exposure). The American Dental Association notes cavities are five times more prevalent than asthma.
"Based on current research, the ADA agrees with the authoritative government agencies that the low-level of BPA exposure that may result from dental sealants and composites poses no known health threat."
The FDA, under President Obama, has consistently rejected calls to restrict the use of BPA, stating its benefits outweigh speculative risks. When asked whether it was harmful to pregnant women or children, deputy commissioner Dr. Joshua Sharfstein didn't mince words: "If we thought it was unsafe, we would be taking strong regulatory action."
Only a minority of scientists believes inconclusive and contradictory results from rodent studies at doses far higher than humans are exposed to justify pulling a useful, and in some cases irreplaceable, chemical from the market. Not one science-based agency in the world has called for its ban.
It's become increasingly difficult for the public to distinguish between useful chemicals in products that are demonized in a chemophobic rush and those that pose genuine dangers when misused.
If we abandon risk analysis and let public perception drive regulation, how soon will it be before the majority of Americans who do not embrace the scientific method and question evolution have their way when it comes to science education? Science should not subject to popular will. Evidence matters. With the stakes so high, scientific literacy is no longer a luxury.
Jon Entine is a visiting fellow at AEI.