The highly toxic PBB poisoning of Michigan remains the most widespread chemical contamination known in U.S. history. The Poisoning of Michigan is an investigative journalist's account of the contamination of Michigan's dairy cattle with the highly toxic chemical PBB (polybrominated biphenyl) in 1973. A near relation of PCB, this now-banned substance, designed as a fire retardant, was mistaken for a nutritional supplement at a chemical plant. It ended up in cattle feed that was distributed to farms throughout the state. By the time the error was discovered, virtually all nine million residents of Michigan had been ingesting contaminated milk and meat for almost a year.      A new introduction by the author and an afterword by three distinguished environmental scientists explain how the legacy of Michigan's poisoning lives on—and how equally toxic substitutes for PBB still invade our homes and lives. This new edition of Egginton's environmental classic—first published in 1980 and long out of print—tells how the tragedy affected both the farm community and the wider populace, and how federal and state authorities failed to respond. "We were mired in a swamp of ignorance," one state official admitted.