Cats: The new canary in the coal mine

Own cats -- or owned by them? Then monitor their health carefully, because they indicate the health of your environment.

Cats rarely suffered from thyroid problems until the introduction of flame-retardant chemicals known as PBDEs, or polybrominated diphenyl ethers.

Researchers have reported in the journal Environmental Science and Technology that PBDE levels in cats are 20 to 100 times greater than in humans. The researchers suggest using cats as "sentinel species" to determine high exposure in humans.

• Cats eat PBDEs, particularly from cat food with a seafood flavor.
• Cats spend much of their time on or near our carpets and furnishings, which are full of PBDEs.
• Cats carefully groom themselves, and can ingest PBDEs shed by carpets and furniture.

If your cats have thyroid problems, chances are your environment is full of PBDEs -- and you probably are full of them, too.