What is PTFE? How can it harm my chickens?
Polytetrafluoroethylene or PTFE, often known by the brand name Teflon, is a synthetic polymer often used as a non-stick coating for cooking pans. It is also used to coat shatter-resistant heat lamps, particularly within the food service industry. When heated beyond a certain point, PTFE begins to break down and release toxic gases. These gases may cause flu-like symptoms in humans that resolve when the source is removed. However, birds have a respiratory system 10 times more efficient than a mammal's respiratory system [1] and will die after minimal levels of exposure.
At what temperature does PTFE begin to break down?
Most technical data sheets as well as the official guidance for Teflon products provide a maximum continuous use limit of 500*F or 260*C. [2] At 535*F or 280*C, PTFE begins to deteriorate and release gases and particulates that can be harmful to birds. [3]
Official safety packets for Teflon detail that the maximum temperature for continuous use is 260*C [2], but it has been documented that deterioration begins and avian deaths can and will occur at temperatures as low as 200*C [3] [4]. Damage to the surface of the coating—not an uncommon occurrence in a barnyard setting—lowers the point at which it will begin to emit gasses. Carbonyl fluoride is typically indicated as the chief toxin in these situations, but as the temperature rises, more and more toxic gasses are released: tetrafluorethylene, monofluoroacetic acid, hydrofluoric acid, and perfluoroisobutane, which is classified as a potential chemical warfare agent, are only a few of the litany of products [5] [6] [7].
What are the symptoms of PTFE toxicosis?
The progression of the damage is so rapid that in many instances there will not be any symptoms, only dead birds on the coop or brooder floor. When there are symptoms present, they take the form of acute respiratory distress, such as gasping for air, wheezing, incoordination, weakness, depression, tail bobbing, agitation, and dropping off the roosts. Low levels of the toxins can cause intermittent deaths over a period of weeks. The cause of death is usually diagnosed through necropsy and a history of exposure to suspect items. Evidences visible in a necropsy include dark red lungs showing hemorrhaging and congestion, heart damage, and PTFE particulates in the lungs. The last item is discernible only with a microscope. Hemorrhaging and congestion can also be present in the trachea and bronchi. Several of these signs can also be caused by other toxins, so a necropsy should not be used as a sole form of diagnosis. The cause of death in these birds is suffocation from fluid in the lungs. Carbon monoxide toxicity may show similar symptoms to the naked eye, but the necropsy shows differences from typical PTFE damage, such as exhibiting a lack of dark red lung color.
What treatment options are available?
There is no treatment for the damage caused by PTFE. Supportive measures may improve the survival rates of an affected population. If you discover a possible toxicity event, move all survivors to fresh air immediately. Keep the bird's environment warm and calm. In a veterinary setting, the bird may be placed in an oxygen cage and administered antibiotics and diuretics. Whether the bird survives depends on its size, how much toxic gas it inhales, and the available ventilation in the affected area. If the bird lives it may have chronic respiratory issues. If there is too much damage to the lungs, the birds will usually die within twelve hours despite the best efforts of the owner or veterinarian.
How can I keep this from happening to my birds?
Check the label on every heat lamp that you purchase. The box should have a warning on it if there is a coating present that contains PTFE, but unlabelled shatter-resistant bulbs and those with an opaque or hazy look to the top should also be held suspect.
PTFE free red bulbs:
PTFE free white bulbs:
Click HERE and HERE or Google search "Shatterproof 250w bulb" to see some images of PTFE coated bulbs. Unfortunately, copyright concerns make it so that the actual images cannot be inserted into this article.
While heat lamps are the main source of PTFE toxicity, heating pads, hair dryers, and space heaters can all contain PTFE. Many of us use a few of these these items regularly near our birds with no issues, so I would surmise that items like heating pads do not get hot enough or have a sufficient quantity of PTFE to cause issues. Still, due to safety concerns, it would be ideal to dispose of old or worn out products before any issues have the chance to arise.
What are some
- Many birds (52%) in a 2400 count broiler flock at a Missouri poultry research facility died over several days. Necropsy indicated exposure to noxious gas. The only changes that had been made were the addition of 48 PTFE coated heat bulbs. The poultry housing had been tested for many other gases that would produce similar signs on necropsy, and none were found. The link to the paper is here and the complete text has been included as a set of screenshots below.
- A member here on BYC had all but one of her flock members die after accidentally using a PTFE coated heat lamp. See her thread here.
- The website ewg.org has kept an extensive log of indoor bird deaths stemming from PTFE coated objects and the circumstances surrounding the incidents.
- A group of White Leghorn chicks in a research facility had extremely high mortality rates in a short period of time. The cause was determined to be the new, shatter-proof heat lamps installed. The study is available for free here.
Resources for further research
Polytetrafluoroethylene:
Formula: (C2F4)n
https://www.suiter.com/patent-week-tetrafluoroethylene-polymers-teflon/
https://en.wikipedia.org/wiki/Polytetrafluoroethylene
https://www.ncbi.nlm.nih.gov/pubmed/1664259
https://www.ewg.org/research/canaries-kitchen
https://www.sciencedirect.com/science/article/pii/014139109390111U
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/polytetrafluoroethylene
https://academic.oup.com/annweh/article-abstract/20/3/247/136981?redirectedFrom=fulltext
https://www.thefreelibrary.com/Polytetrafluoroethylene+decomposition+in+Air+and+Nitrogen.-a082094099
https://www.tandfonline.com/doi/pdf/10.1080/0002889738506828?needAccess=true
http://pslc.ws/macrog/ptfe.htm
http://catalog.wshampshire.com/Asset/psg_teflon_ptfe.pdf
Chart sourced from above link.
Thermal conductivity: 0.25 W/(m·K)
The Avian Respiratory System:
http://www2.ca.uky.edu/agcomm/pubs/ASC/ASC200/ASC200.pdf
https://articles.extension.org/pages/65375/avian-respiratory-system
Citations
[1]
https://www.frontiersin.org/articles/10.3389/fanim.2022.851574/full
removed
M. R. Fedde. "Relationship of structure and function of the avian respiratory system to disease susceptibility." Poultry Science, Volume 77, Issue 8, August 1998, Pages 1130–1138. https://doi.org/10.1093/ps/77.8.1130
[2]
Teflon.com, accessed 11/15/19.
https://www.teflon.com/en/products/coatings
[3]
M. Boucher, T. J. Ehmler, and A. J. Bermudez. "Polytetrafluoroethylene Gas Intoxication in Broiler Chickens." Avian Diseases, Volume 44, Issue 2, 2000, pages 449-53. doi:10.2307/1592561.
[4]
fluoridealert.com, accessed 11/15/19. Reference #2.
https://www.fluoridealert.org/wp-content/pesticides/teflon.decomposition.prod.htm
[5]
ewg.org, accessed 11/15/19.
https://www.ewg.org/research/canaries-kitchen/teflon-offgas-studies
[6]
fluoridealert.com, accessed 11/15/19. See chart at beginning of article.
https://www.fluoridealert.org/wp-content/pesticides/teflon.decomposition.prod.htm
[7]
H. Arito, R. Soda. "Pyrolysis Products of Polytetrafluoroethylene and Polyfluoroethylenepropylene with Reference to Inhalation Toxicity." Annals of Occupational Hygiene, Vol 20, 1977, pages 247--255. https://www.thevespiary.org/rhodium...ITH-REFERENCE-TO-INHALATION-TOXICITY-ae22.pdf
