A New Year’s Day story eclipsed by the budgetary brinksmanship in Washington DC highlights a different sort of precipice. 1300 miles from the Capitol, in Gun Barrel City Texas, Linda and John Rigo decided to operate their new Teflon-coated self-cleaning oven. Not long after, their two pet macaws stopped breathing. One simply fell dead off his perch.
The news out of Gun Barrel City (town motto: "We Shoot Straight with You") was reported by Jobin Panicker of WFAA Dallas/Fort Worth (http://www.wfaa.com/news/local/Gun-Barrel-parrots-185500962.html). It included advice from the North Texas Poison Control Center that “people with asthma and respiratory conditions should leave the house during the cleaning.”
Health problems arising from over-heated Teflon and similar manmade materials are not new. Technically known as polytetrafluorethylene or PTFE, the biggest consumer product use of Teflon is in nonstick pots and pans. But, as the Rigos learned, it has many other applications as well.
This class of synthetic polymer has been on the market for more than half a century and for much of that time its major booster has been the entity with the most at stake: Du Pont. Du Pont trumpets its Teflon success on its own website. “To date, cooks in more than forty countries around the world have purchased over two billion pots and pans with Teflon® brand nonstick coatings for home and commercial use. In all of this experience, there has been no record of any significant human health problems.” (http://www2.dupont.com/Teflon/en_US/products/safety/cookware_safe...).
There are just a couple of tiny caveats to that statement. First: safe, presuming “proper” use. Proper use in this context means not overheating. That is, never, never leave to pot or pan on the stove too long. Lord knows, that would have to be a really freak accident scenario, wouldn’t it?
The second caveat is: safe for humans. Du Pont’s explicit warning is for the birds. “Bird owners should be aware that there are potential dangers in the kitchen. Cooking fumes, smoke and odors that have little or no effect on people can seriously sicken and even kill some pet birds, often quite quickly. Also cooking fumes from any type of unattended or overheated cookware, not just nonstick, can damage a bird's lungs with alarming speed.”
Inarguably, birds are exquisitely sensitive to Teflon/PTFE fumes. An overheated pan is the classic exposure scenario. A detailed report out of England from 1975 documented the deaths of five cockatiels from just such a mishap. Two years before that, Du Pont itself showed that 6 out of 6 Japanese quail exposed to fumes from a Teflon coated pan heated to 330 degrees centigrade died while others were unaffected when the temperate was just 15 degrees lower; parakeets, however, were killed by fumes produced at 280 degrees. Other Du Pont research showed that rats are a hardier species, only succumbing to fumes produced at a whopping 450 degrees. Moreover, lower concentrations of oxygen led to less lethal fume production. This should be reassuring to cooks in Cuzco Peru or other high-altitude venues.
The self-cleaning Teflon-coated oven is simply a variation on a theme. Unfortunately, the Rigo’s experience is not novel. As long ago as 1992, the scientific journal Veterinary and Human Toxicology reported the deaths from the operation of a self-cleaning oven of 10 psittacine birds (the family of parrots and macaws). Another major killer has been the use of PTFE-coated heat lamp bulbs in chicken facilities: more than 1000 killed-off in a report from a Missouri site a decade ago and, just this past year, a similar report from Michigan. The heat-lamp fiascos both occurred at university research facilities, which may account for the systematic investigations that ensured.
Which brings us back “significant human health problems.” The inhalation of fumes generated by overheated Teflon is not benign for people, either. Early in the commercialization of PTFE, an odd new syndrome became recognized and came to be called polymer fume fever. This flu-like illness is caused by PTFE breakdown fumes generated within a particular temperature range. One of the best documented outbreaks of polymer fume fever was linked to smoking cigarettes contaminated in workplace. The symptoms of achiness, chills, and just being sick may not be significant to Du Pont. Or I guess at least compared to falling over dead if you are a macaw or cockatiel. In fact, the owner of the 5 dead cockatiels in that 1975 English report himself came down with fume-fever.
But there are no guarantees if the temperature goes up. In industrial applications where Teflon was heated too high, severe illness and even death has occurred. Just as with birds, the lungs are the site of injury. Nor has the general public been safe. An extremely well-documented case published in 1993 described a 26 year-old woman whose two pet parakeets died and who herself became severely ill from overheated PTFE (http://www.ncbi.nlm.nih.gov/pubmed/8497834). Her exposure scenario involved a small overheated Teflon block that served as the axle for a rotating microwave oven platform. Follow-up testing four months later showed that her lung function was still impaired. A more recent case from Japan of man who was hospitalized and treated for pulmonary edema (fluid on the lungs) caused by an overheated Teflon frying pan (the patient fell asleep while cooking soba noodles) also underscores the fact that the symptoms of exposure can go way beyond those of a simple case of the flu.
The great British scientist J.S. Haldane may have been the first to promote the use of canaries to warn of the dangers of coal mine gases (he thought canaries might serve a similar role in bomb shelters as well). There was no Teflon in his day.