Demonizing Plastics is Not Good Science

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When it comes to regulating chemicals, there’s a host of reasons to be critical of Europe’s embrace of the precautionary principle, a notion that often puts fear ahead of evidence as the guiding principle. But there’s hope. As scientists confront the challenge of how to regulate plasticizers—chemicals that make plastics soft, transparent and durable—the European Union is moving towards a model that US regulators should emulate.

Finally, Europe Endorses Science Over Hysteria

This endorsement of scientific rigor did not begin quite so optimistically. Earlier this month, the French National Assembly voted to ban products containing phthalates (the legislation also proposed doing away with parabens and alkylphenols). The legislation, which is now before the Senate, is controversial because the science is in flux. The legislators acted not on hard evidence that these substances caused harm but suspicions based on controversial tests on animals. The action appeared to be a show vote by lawmakers to demonstrate they could “get tough” on industry—warranted or not.

The initial vote certainly reflected the world view of anti-chemical campaigners, who contend that all plastics are toxic threats and phthalates—used in everything from drug pills to textiles to toys—are the most harmful of all, as they purportedly ruin fertility, distort development and cause birth defects. Except that’s not what the science says. The story is more complex, which is not reflected in media hit pieces that dominate this controversy.

The belief by a faction of the science community that phthalates represent a serious danger is based on small-scale “explorative” studies of rodents exposed to high doses, continuously, over many years—unlike how humans come in contact with different plasticizers. But many studies show little or no effects. The EPA has determined that routine exposure to phthalates can cause gastrointestinal problems, but that’s about it. Scientists are divided about to what degree regulators should rely on contradictory animal studies to engineer changes in industrial processes that would lead to the introduction of new classes of chemicals with unknown interactive effects.

Not All Phthalates Are Created Equal

Acknowledging these challenges, regulators in Europe have begun parsing the issue in a more refined way.  They begin with the fact that not all phthalates are created equal. So-called low-density phthalates widely used in children’s toys and medical tubing—DEHP, BBP, DBP and DIBP—are considered more problematic because they are chemically less stable and more readily release outgasses into the environment. More tightly bound high-density plasticizers such as DINP, DIDP and DPHP are more stable and resilient.

This more sophisticated evaluation model is having an impact. Last week, the sponsor of the French bill, Yvan Lachaud, announced he’s reviewed the science more carefully and no longer supports a sweeping ban on phthalates. We shouldn’t lump all phthalates together in terms of their potential impact, he says. His enlightenment all but dooms, in its current form, the reckless legislation. Using risk/benefit analysis, high-density phthalates offer significant benefits for literally millions of uses, and in many cases there are no safe and effective alternatives. “It’s necessary that the bill be changed so it includes only the most dangerous mix of substances, not whole groups,” says Lachaud.

Lachaud’s reversal is heartening for those committed to evidence-based science, and it comes on the heals of a number of science-focused decisions across the EU. Last February European health and consumer protection commissioners “classified” low-density plasticizers as reproductive toxicants. They put them on the Substance of Very High Concern list under the new Registration, Evaluation, Authorisation & Restriction of Chemicals (REACH) legislation. The additives will have to undergo authorization over the next four years.

Earlier this month, the Danish Environmental Protection Agency, one of the most aggressive regulatory bodies in the world, proposed bans on the low-density plasticizers, DEHP, BBP, DBP and DIBP, which they believe may accumulate in the body and chemically interact. But Frank Jensen, chief advisor to the Danish EPA’s chemical unit and co-author of the advisory report, also said that DINP and other high-density phthalates make cost effective, quality substitutes for the low molecular weight ones. He wrote that there remain some concerns from animal studies that high molecular weight phthalates may subtly impact reproduction, but he also noted that data shows that they have significantly lower potency than the four listed phthalates.

Toxic Exaggerations

The nuanced EU and Danish assessments and the French turnaround contrast with the blunt rhetoric of advocacy groups, Internet bloggers and many journalists, who caricature plastics, phthalates in particular, as uniformly dangerous. The latest in a long line of feckless attacks is the new book Plastics: A Toxic Love Story, which is getting great play on the National Public Radio circuit. Its author, Susan Freinkel, never differentiates or even acknowledges that she’s aware that there are different types of phthalates, instead discussing them in what she must believe is even-handed scientific jargon. Phthalates, she writes, are a new kind of “environmental villain” that “plays havoc with the body’s endocrine system”—which is a gross distortion of rodent studies and not confirmed in human evaluations. Freinkel discusses DEHP and phthalates almost interchangeably—an indication she is not even aware of the basic science.

Freinkel’s reporting appears to be inspired by a widely publicized 2005 study conducted at the University of Missouri-Columbia that has become the Holy Grail of anti-phthalate campaigners. Researchers examined infant boys of mothers with a high concentration of phthalates in their urine. The children were born normal although some had smaller genitals (but within the normal range in size) and a shortening of the distance between the anus and genitalia. The media jumped on this sketchy data, and after mixing into the pot a handful of small-scale rodent studies, served up a story that all phthalates disrupt the endocrine system. So much for subtlety.

Responsible scientists and regulators have not followed such reflexive critics over the exaggeration cliff. The National Toxicology Program challenged the “validity and biological plausibility” of the study because of its tiny sample size and homogenous test population. No other reports since have shown comparable results. The most recent—a 2010 study by the Children’s National Medical Center and George Washington University confirmed its 2004 research that indicated no adverse effects in organ or sexual functioning in adolescent children exposed to phthalates as neonates. The Missouri study also failed to address the crucial distinction between low and high molecular weight phthalates. In cases where effects have been shown, the outgassing problem might be limited to the low-density phthalates.

Spurred by this evolving paradigm, regulators may now be poised to ask the kind of refined questions that will separate hysteria from genuine risk. The cynical side of me wonders whether the surprising restraint demonstrated in precautionary-obsessed Europe suggests little more than a broken clock that’s right twice a day. Let’s be optimistic. When scientists look to isolate genuine risk factors, and limit their regulatory recommendations to what the evidence actually shows, the public interest can be served. Phthalates certainly deserve scrutiny, especially when it comes to their cumulative impact on development. But wholesale demonization is not science.

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