SAN FRANCISCO (KCBS)— A recent Michigan study shows bald eagles are being exposed to more toxins, including banned flame-retardant chemicals that were once commonly used in the manufacturing of furniture.

The study, published by Journal of Great Lakes Research, shows how the chemicals have negatively impacted one of the country’s most iconic birds.

“The use of flame retardants was spurred on by TB117 (technical bulletin), a bill that California passed that required a certain amount of flame retardants in furniture. What we’ve seen in the years is that this has built up in the environment,” said Dr. Jennifer Scarlett with the San Francisco SPCA.

The study suggests the bald eagles there are among the most contaminated birds on Earth and that the chemical used, known as PBDEs, directly affects their livers.

Scarlett says the chemicals are likely getting to the birds either by leaching out from dumps, getting into the water system as well as through dust or preening off of their feathers.

The chemical causes impaired reproduction and development as well as hormone disruption.

But why are bald eagles owed the distinction of being the most polluted in this regard? Scarlett explains that as predators, the bird is at the top of the food chain.

“We’re going to see them accumulate toxins as we go up through the food chain. The highest in the food chain is also going to be the highest exposed in toxins, which is also a lesson for humans being that we’re also very high on the food chain.”