What is Polytetrafluroethylene and how can it harm my birds?
Polytetrafluoroethylene (PTFE) is a synthetic polymer with excellent lubrication and electrical insulation properties, among many others. The most common brand name for substances containing it is Teflon, a trademark by Chemours*—formerly named DuPont. In relation to the poultry world, it is used to coat shatter resistant heat bulbs. Unfortunately, the fumes from overheated PTFE are highly toxic to birds and have been the cause of many a chicken keeper's heartbreak. The reason birds are so susceptible to PTFE toxicity is their high metabolism and unique airway system. The chicken has 9 air sacs throughout the body that act as bellows to supply air to the lungs, which do not expand**. The term for this respiratory system arrangement is unidirectional, meaning that air moving through the capillaries and parabronchi move at right angles to each other. This results in an extremely efficient gas exchange, which is needed for flight, but unfortunately any toxic substances in the air are also concentrated.
At what temperature does PTFE become dangerous?
Many studies have shown that 280*C (538*F) is the point where PTFE toxicity becomes a surety, but DuPont studies show that Teflon undergoes pyrolysis and releases toxic particulates at temperatures as low as 230*C (446*F). According to them, at 360*C (680*F), Teflon coated pans release at least six additional toxic gases, including two carcinogens, two global pollutants, and MFA, a chemical lethal to humans at low doses. One of those gases, carbonyl fluoride, is what causes the bulk of the lung issues in birds***. At temperatures that DuPont scientists claim are reached on stovetop drip pans (537*C, 1000*F), non-stick coatings break down to a chemical warfare agent known as PFIB, and a chemical similar to the second world war nerve gas, phosgene. If the surface is scratched or otherwise damaged, the danger point is much lower. 250 watt heat lamps can exceed 250*C (480*F), which is over the point the DuPont studies proved dangerous. Poor ventilation in the coop or brooder will only increase its killing power.
Parts of this paragraph quoted from http://buffalobirdnerd.com/clients/8963/documents/Teflon.pdf
What are the symptoms of PTFE toxicity?
Its progression is so rapid that many times there will not be any symptoms, only dead birds on the coop 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. Evidence visible in a necropsy is dark red lungs showing hemorrhaging and congestion, heart damage, and PTFE particles 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 sole proof. The cause of death in these birds is suffocation from fluid in the lungs. According to https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3276392/ , the way the bird is harmed by PTFE is injury of type 1 pneumocytes and capillary endothelial cells, allowing fluid and blood to leak into the airways. In simpler terms, it is caused by the respiratory tissue being exposed to acidic gases. Carbon monoxide may show similar symptoms to the naked eye, but the necropsy shows differences from a typical PTFE case, such as lack of the typical dark red lung colour.
What are the treatment options?
There is no treatment for PTFE toxicity. Supportive measures may improve survival rates. If you discover a possible PTFE 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 be administered antibiotics and diuretics. Whether a bird survives depends on the size of the bird, how much toxic gas it inhaled, and 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 bird will usually die within 12 hours despite the best efforts of the owner or a veterinarian.
How can I keep this from happening to my birds?
Check the label on any heat lamp that you purchase. The box should have a warning on it if there is a coating present containing PTFE, but to be on the safe side don't buy it if the heat lamp says “shatter resistant” or has an opaque or hazy look to the top.
PTFE free red bulb:
PTFE free white bulb:
Google search "Shatterproof 250w bulb" to see images of PTFE coated bulbs. Unfortunately, copyright concerns make it so that the actual images cannot be inserted in this article. If you have any images of PTFE coated heat lamps you'd be willing to allow use of, please send me a private message; I can't track down any myself.
Cases of PTFE toxicity:
—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.
—One hundred and seven chicks were killed when a non-stick cookie pan was used to catch oven drippings.
—More than 55 birds died when water boiled off a pan.
—A toaster with a non-stick coating was used to prepare food. The bird that was nearby survived, but with respiratory issues.
—Fourteen birds died in fifteen minutes when 4 non-stick drip pans were pre-heated.
—A space heater and an electric skillet were used at the same time. One bird died.
—A grill plate was used at normal temperatures on two separate occasions. Both incidents caused the death of a nearby bird.
—A member here had all but one of her flock members die after accidentally using a PTFE coated heat lamp. See thread here.
Other notes: 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 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 percentage of PTFE to cause issues. Still, due to safety concerns, it would be ideal to dispose of old or worn out products.
Some random PTFE trivia and links to good websites:
Melting point: 620.3°F (326.8°C)
Density: 2.2 g/cm³
IUPAC ID: poly(1,1,2,2-tetrafluoroethylene)
Thermal conductivity: 0.25 W/(m·K)
Polytetrafluoroethylene Toxicity in Chickens
Polytetrafluoroethylene (PTFE or Teflon) is a substance used to coat shatterproof heat lamps that gives off toxic particulates at high temperatures.
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