Fire-Retardant Chemicals Linked To Thyroid Disease In Pet Cats


Researchers are reporting that a strange epidemic of thyroid disease in cats living in the U.S. may be related to dust from flame-retardant chemicals used in furniture, carpets, mattresses, electronics, and even pet food.

There is no evidence to suggest that the chemicals, polybrominated diphenyl ethers (PBDEs), pose a risk to humans, but the possibility cannot be ruled out. Researchers said that cats are highly exposed to chemicals, and the levels are higher in cats compared to people. This could be used as an indicator to gauge the indoor exposure to people.

Cats with hyperthyroidism may show the following symptoms: weight loss, increased appetite, hair loss and irritability. This disease is one of the most common and deadly illnesses in older felines. Due to their grooming habits, indoor cats are at a higher risk because they can ingest large amounts of dust containing PBDEs.

In this recent study, which is published in Environmental Science and Technology, the research team took blood samples from 23 cats. Eleven of them were diagnosed with hyperthyroidism. The cats with the illness measured levels of PBDEs three times higher than younger cats and cats without hyperthyroidism.

PBDEs can also be found in canned cat food, particularly in fish/seafood flavors, such as salmon and whitefish. An analysis showed that diets based on canned food could have PBDE levels 12 times higher than dry-food diets. Researchers stated that cats could be getting as much as 100 times greater PBDE exposure in their diets that humans.

Cats may have a higher risk of getting feline hyperthyroidism in the United States because people in the US have the highest reported PBDE levels among other countries. Also, by the late 1990s, North America accounted for almost 50% of the worldwide demand for PBDEs for commercial materials.

Feline hyperthyroidism is also being seen in Canada, Australia, Japan and many parts of Europe.

Concerns about the effects from PBDEs began in the late 1990s. Researchers have shown that these chemicals can cause liver and nerve toxicity in animals. There has also been a recent study that showed an association with house dust and the levels of PBDEs in women’s breast milk.

Various PBDEs, which have been used in polyurethane foam for cushions and pillows, have been phased out either by manufacturers or by bans from states and the U.S. government and other governments.

Amidst the bans, PBDEs will still take a long time to disappear from the environment because they are environmentally persistent compounds.

Source: U.S. News and World Report

(Thanks Mike)

17 Responses to “Fire-Retardant Chemicals Linked To Thyroid Disease In Pet Cats”

  1. thomas says:


  2. thomas says:

    I misspelled in above comment. should read ” Why in the hell would you put flame retardent in pet food ? Welcome to the world of pet food chemicals.”

  3. Roberto P. says:

    I’m going to guess the flame retardant chemicals were in the sawdust they added to the food for fiber. And I remember reading several years ago that farm animals were destroyed and farm families became sick because fire extinguisher materials were “accidentally” added to animal feed.

  4. pat says:

    according to several studies, this compound is actually in the fish… a quick google search for “polybrominated diphenyl ethers, fish” brings up a wealth of information on the topic, and from the looks of things it’s been recognized as problem for awhile, but the link to thyroid disease in cats is disturbing. my cats love fish.

  5. thomas says:

    Lest we forget melamine is also a flame retardant. Their post is dated Aug.1.07

  6. Roberto P. says:

    From the EPA :
    “What are concerns associated with PBDEs?

    Although use of flame retardants saves lives and property, there have been unintended consequences. There is growing evidence that PBDEs persist in the environment and accumulate in living organisms, as well as toxicological testing that indicates these chemicals may cause liver toxicity, thyroid toxicity, and neurodevelopmental toxicity. Environmental monitoring programs in Europe, Asia, North America, and the Arctic have found traces of several PBDEs in human breast milk, fish, aquatic birds, and elsewhere in the environment. Particular congeners, tetra- to hexabrominated diphenyl ethers, are the forms most frequently detected in wildlife and humans. The mechanisms or pathways through which PBDEs get into the environment and humans are not known yet, but could include releases from manufacturing or processing of the chemicals into products like plastics or textiles, aging and wear of the end consumer products, and direct exposure during use (e.g., from furniture).”

    So it sounds like it’s a good possibility they get into the environment from the factories. Why am I not surprised?

  7. Kaffe says:

    oh man… one of cats simply adore fish - especially tuna. He doesn’t get much now, since he is on a raw diet. Thnak goodness I made the switch! I have gone real easy on the tuna becuase of the mercury levels. Now I need to go easy on ALL the fish flavors. Will the flame retardant be in fish oil pharmacuetical grade do you think? I give my cats fish oil in their diet. Oh man… when will the worry end?

  8. mittens says:

    half of my 6 cats are/were hyperthyroid. half were not. they had the exact same diet-canned fish catfood primarily. they all are or lived to over 20. my feeling is somethings gonna kill you anyway- that’s the way life works. cats and humans live longer than ever despite all the crap we consume and the chemicals in the environment.while there’s no doubt chemicals can be poisonous there’s also no doubt everyone lives longer than humans ever had.cats used to be good for those breeding years than that was it. now theyre pushing the 20s and beyond. the glass isnt exactly mostly empty.

    considering the rate at which these studies pop up-it’s hard to know what to believe. it does make sense that man made chemicals make their way into the waters.and seeing how the environment isnt going to mystically be cured over night it might be some comfort to know that hyperthyroid is a highly treatable disorder.

    hyperthyroid is so easily controlled( well as easy as it is to pill a cat) through radiation. surgery or medication. uncontrolled it can cause serious heart/renal problems. everyone should get their cats over 7 tested for hyperthyroid.

    i have to pill a tortie psycho 2 times a day. oh the humanity! those gloves people use to feed sharks are helpful….

  9. Traci says:

    “tortie psycho”

    Isn’t that redundant? :O)

    You know, if you get the mouth open and tilted up while the cat is trying to hiss, and you have your split second timing and excellent aim down pat, you can just drop it in (quickly moving to hold kit’s mouth closed for the swallow).

    As far as canned pet food and particularly fish, the article really didn’t qualify that as to quality or brands of food etc. It was annoyingly vague. I figure these days that the best rule of thumb is would you eat it or eat it without worry for your own health.

  10. Anonymous says:

    Mittens: It’s good to know your cats were “treatable” and lived. However, your post promotes a fallacy. There is no cure for this except radiation. Surgery is minimally effective and dangerous due to proximity of the thymus. Medication - tapezole - has many side effects which depending upon your cat, many say are as bad or worse than the disease. On top of that, the test for this is not even routinely included in blood tests. The results from the first level testing is not always conclusive since by the time the cat reaches the high end T4 “normal” values range HT can already be advancing. In addition to the fact that cats hide symptoms so well, hyperT affects every organ system of the body, making it difficult to diagnose.

    Please stop promoting this fallacy that HT is treatable, or even easily treatable. This does not reflect the facts about this disease.

  11. Anonymous says:

    From article: There is growing evidence that PBDEs persist in the environment and accumulate in living organisms

    re link to fish you’re talking about accumulation in the environment - in water, perhaps in feed for farmed fish, which is then concentrated in the
    FISH MEALS in catfood.

  12. Melissa says:

    I’ve been giving my hyperthyroid 11-year-old tabby medication for almost a year now. Pills were nearly impossible; she figured out how to “cheek” them and spit them out in a corner five minutes later. My vet sent me to a compounding pharmacist, and now she gets her methimazole in liquid salmon solution. Now I guess I have to worry about that as well! But it’s a lot easier to squirt liquid down her throat than to get her to swallow a pill.

  13. Anonymous says:

    In addition, Mittens, just to show how glibly you have addressed this horrible disease:
    by the time your cat needs surgery or radiation you have a very sick pet already.

    Surgery or radiation can only be done if your cat is young and in fairly good health. This is not always the case with older cats.

  14. Anonymous says:

    Thanks to Itchmo for getting news out on this disease.

  15. Anonymous says:


  16. Anonymous says:

    “The epidemic of hyperthyroidism in cats began almost 30 years ago, experts say, at the same time that PBDEs were introduced into household materials for fire-prevention. Now the disease has been seen in Canada, Australia, Japan and many parts of Europe.”

    Notice it says “epidemic” ?

  17. Cathy_H says:

    This is for Mittens: I ditto “anonymous” and the other person or two who said (she?) was NOT on the right track.

    I had 3 cats, and 2 of the 3 developed hyperthyroidism. This might have been as long ago as a decade, so there was not the recent awareness (due to research) that this is something to watch out for. By the time we caught it (the 2 afflicted cats developed it about 2 years apart), the tumors were in BOTH thyroid glands, and were so huge each cat needed TWO DOSES of radiation to kill it.

    Aside from the expense (can’t recall but think it was about $850/dose) it is NOT something you want to have to subject your cat to. After the dose, the poor cat has to be IN ISOLATION for “x’ number of days because THEY ARE LITERALLY RADIOACTIVE. Once the radiation goes down to a certain level, you can take them home.

    I talked to my vet about this new finding, and he said (natch) more research needs to be done. For instance, are certain breeds more prone to it than others? (that only applies to purebreds.) Also is there a genetic factor? (That would explain why my 3rd cat never caught it when the other 2 did………in fact she’s 14 now and never sick a day in her life.

    He also said that when he was in vet school, the teacher only touched on hyperthyroidism ONCE, and said “this is a discase you’ll probably only see once in a lifetime.” Well, now, he says the vet hospital sees about THREE CASES PER MONTH….

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