Polybrominated biphenyl

Studies in animals exposed to large amounts of PBBs for a short period or to smaller amounts over a longer period show that PBBs can cause weight loss, skin disorders, nervous and immune systems effects, as well as effects on the liver, kidneys, and thyroid gland.

FireMaster BP-6 (a yellow-brown powder) is a mixture of many different PBB congeners with 2,2',4,4',5,5'-hexabromobiphenyl and 2,2',3,4,4',5,5'-heptabromobiphenyl being significant constituents by mass (60-80% and 12-25%, respectively).

[11] Some 1.5 million chickens, 30,000 cattle, 5,900 pigs, and 1,470 sheep then consumed this feed, became contaminated with PBBs and the carcasses were disposed of in landfill sites throughout the state.

[12] In 1976, the Michigan Department of Community Health established a PBB registry to gather and analyze data on exposed residents.

It now resides at the Rollins School of Public Health at Emory University,[13][14] and is maintained by epidemiologist Michele Marcus.

[15] Michigan Farmer magazine staff members Richard Lehnert and Bonnie Pollard broke the news of the contamination.

The magazine continued coverage of the issue until the eventual bankruptcy proceedings of the farm cooperative responsible for the accidental contamination and subsequent distribution of the feed.

[16] These events were also portrayed in the 1981 documentary Cattlegate by Jeff Jackson, the true-fiction film Bitter Harvest starring Ron Howard, and in the book The Poisoning of Michigan by Joyce Egginton.

[18] However, as of 2015 these studies are still ongoing, and 40 years later adverse reproductive-system effects (as measured by the Apgar score of the newborns) continue to be found in the grandchildren of those who consumed tainted farm products.

Other countries followed suit, resulting most recently in restriction dates instituted in China on March 1, 2007, and South Korea on July 1, 2007.