Can You Say Phthalates?

William C Montgomery
by William C Montgomery

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.

William C Montgomery
William C Montgomery

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  • Chiboy Chiboy on Sep 28, 2006

    I'm not sure of the truth of this story but it is entertaining. Some years ago a GM plant manager was contacted by plant security that a number of assembly workers were in on a day off and playing cards in a breakroom. The security folks asked them to leave but they insisted on staying. They stated that they enjoyed being at the plant even when they were not working. Since this is not behaviour becoming of the typical UAW worker, GM investigated the matter further. It was found that a new paint that was being tested in the paint department emited a fume that was mildly addictive and these workers were unknowingly going for a "fix". They paint was not used in production for this reason. Maybe this would be the answer to the Big 2.5's problems - simply "addict" potential buyers to their cars paint fumes.

  • Matt Matt on Sep 28, 2006

    I had a class with a nun from Africa, and it was brought up that glaciers on top of Kilimanjaro were melting. Having lived around the mountain, and being familiar with the local culture, she said that she thought the reason why the glaciers were melting was because every year, the locals burn a bunch of trees as a sacrifice to have a good harvest, and in recent years they had been burning more and more trees. Granted, she was no scientist, but I think alot of us are forgetting that just a little bit of knowledge is a dangerous thing.

  • Wjtinfwb Funny. When EV's were bursting onto the scene; Tesla's, Volt's, Leaf's pure EV was all the rage and Hybrids were derided because they still used a gas engine to make them, ahem; usable. Even Volt's were later derided when it was revealed that the Volt's gas engine was actually connected to the wheels, not just a generator. Now, Hybrids are warmly welcomed into the Electric fraternity by virtue of being "electrified". If a change in definition is what it takes, I'm all for it. Hybrid's make so much sense in most American's usage patterns and if needed you can drive one cross-country essentially non-stop. Glad to see Hybrid's getting the love.
  • 3-On-The-Tree We also had a 1973 IH Scout that we rebuilt the engine in and it had dual glass packs, real loud. I miss those days.
  • 3-On-The-Tree Jeff thanks. Back in 1990 we had a 1964 Dodge D100 with a slant six with a 3 on the tree. I taught myself how to drive a standard in that truck. It was my one of many journeys into Mopar land. Had a 1973 Plymouth duster with a slant six and a 1974 Dodge Dart Custom with 318 V8. Great cars and easy to work on.
  • Akear What is GM good at?You led Mary............................................What a disgrace!
  • Randy in rocklin I have a 87 bot new with 200k miles and 3 head gasket jobs and bot another 87 turbo 5 speed with 70k miles and new head gaskets. They cost around 4k to do these days.