It lurks in your favorite easy chair, your hair dryer, even your microwave ... what is it? It's a chemical known as polybrominated diphenyl (PBDE). It's a flame retardant used in many different kinds of products to reduce their flammability, and manufacturers -- who have been using the chemical since the 1960s -- say the chemical could prevent consumer injury or death by fire by 45%.

So why do PBDEs have experts concerned? The chemical is so pervasive in our environment that experts say we come into contact with products containing PBDE over 100 times every day. The chemical is fat soluble, which means it dissolves in body fat, and it's been found to mimic the female hormone estrogen, as well as thyroid hormones. Researchers are unsure what those findings mean, but they believe the chemical may cause insulin resistance -- which can lead to type 2 diabetes -- or even make the body more prone to producing fat cells.

New studies on the effects of PBDEs in mice are just getting underway, but if these theories are proven true, researchers say it will be a mixed blessing. On one hand, PBDEs are nearly impossible to avoid. On the other, findings from these studies could yield even more clues in the development and treatment of obesity.