Can You Say Phthalates?

It’s been many years since the media entertained spurious claims about the toxicity of automotive plastics. Guess what? They’re at it again; ready to alert the world to the “dangers” of the plasticizers that make dashboards supple and vinyl pliable. Both ABC’s The View and National Geographic Magazine (October 2006) took major shots at these chemicals, known collectively as phthalate esters. Without these plastics, every car interior would have all the allure and comfort of an up-armored military spec Humvee.

Even before David Ewan Duncan’s “The Pollution Within” gets into high gear, the National Geographic’s subhead links automotive plastics and toxicity: “Thanks to modern chemistry… SUVs hit 60 in six seconds. But such convenience has a price: Chemicals that suffuse modern life– from well known toxins to newer compounds with unknown effects– are building up in our bodies and sometimes staying there for years.” In the main piece, Duncan carefully avoids calling phthalates toxins. They’re “chemicals of concern.” But the implication is clear: phthalates are poisonous.

Phthalates are found in a wide range of everyday products: shampoo bottles, medical equipment, toys, food wrap, cosmetics, water bottles and [woo hoo!] sex toys. When plastics get hot, the phthalates leech out. The haze that films the inside of our windshields consists of phthalates that have “evaporated” out of interior plastics and collected on the glass. Long-term phthalate loss accounts for dashboards becoming increasingly brittle and splitting. Phthalates also account for new car smell as well as the funny taste of water from plastic bottles left in the sun.

The human body absorbs phthalates through the skin, orally or through the lungs. The chemicals don't stay inside us for long; our bodies break them down and pass them out within a few hours or a couple of days. Nor do the chemicals build up in our body tissues. Long term exposure is considered safe; the plastics industry has used them since the ‘20’s without any indication (i.e. lawsuit) that they cause acute or chronic illness.

In the late ‘90’s, these plasticizers came under fire for a myriad of alleged health concerns. Phthalates were accused of being estrogenic and suspected of causing cancer. The European Union reacted to the anti-phthalate hysteria by banning some phthalate-infused plastics from children’s toys. Once again, the chemicals are under the preventative health industry’s microscope.

Meanwhile, allegations that phthalates mimic estrogen, the female hormone, offer some curious possibilities. Do cars with more plastics yield more sensitive drivers? Indeed, if phthalate-laden interiors were used more, would there be less road rage? Would women of child bearing age become more fertile? Would menopausal women riding in cars experience less severe hot flashes? And, if the use of phthalates were banned for use in autos, would the highway safety devolve under an assault of testosterone-crazed drivers?

I jest. In fact, the research conclusions prompting the estrogen claim are deeply flawed. Absurdly large doses of phthalates were administered through the skin to rats, resulting in some birth defects (e.g. male offspring with more than two nipples.) While this result has been duplicated in other rodent studies, it’s never been replicated in animals that more closely resemble humans. (Human skin is known to be more resistant to chemical absorption than rats’.) Furthermore, humans are exposed to much higher levels of estrogen-mimicking chemicals from other sources, including wheat, soybeans, potatoes, carrots, apples and coffee. Obviously, no one is proposing banning any of these foodstuffs.

Dr. Scott D. Phillips of the University of Colorado’s Division of Clinical Pharmacology and Toxicology wrote in the Journal of the American Medical Association, “This mischaracterization of the scientific evidence [regarding phthalate exposure] reflects a lack of understanding of basic toxicological principles… We put chemical substances into our bodies daily that can cause harmful effects in animals. It is the dose that differentiates medicines from poisons.” Aspirin in low doses is a miracle drug – a near-panacea. Yet, many a desperate person has ended their own life by ingesting sufficient quantities aspirin. A British study of infants exposed to phthalates through milk fed through plastic containers found no risk, even when applying the European Union’s 100-fold safety margin.

The belief that phthalates cause cancer is wrong. The suspect phthalate, known as DEHP, has been cleared by scores of peer-reviews and research studies. The study used as the basis for this claim is now viewed as “junk science” and the use of these plastics in toys, medical equipment or cars is deemed to pose no human health risk.

While there are many chemicals, natural and synthetic, that merit careful concern, forty years of extensive research indicates that phthalates are not among them. Nonetheless, a lie repeated often enough takes on the ring of truth. And public policy based on such distortions could profoundly affect our cars’ comfort. So enjoy sitting in your car. Breathe deeply. Caress the soft plastics. And put your mind at ease.