Hmm, better start checking breast milk here in Michigan. Line forms to the right!
You probably already got your dose:
"Despite having been banned, PBB-153 continues to be found in human blood in Michigan. This may be due to a 1973 accident in Michigan in which PBBs (mostly 153) were accidentally mixed with dairy cow feed. This accident caused PBBs to get into the milk supply and be widely distributed and consumed in the state." - link
There was a memorable TV movie about this incident starring Ron Howard as a young farmer who begins wondering about strange illnesses in his cows. In the climactic scene cows were herded into a large pit while farmers surrounded it with rifles.