Another excerpt from previously posted link:

Then there is pesticide contamination to be concerned about.  In John
Robbins first book Diet for a New America he pointed out another problem
with animal protein, that had an important connection to our family.  On
page 324 he writes:


...occurred in Michigan in 1973 and 1974, and involved one of the worst
cases of pesticide poisoning yet to come to light.  Here, the poison
involved was PBB's (polybrominated biphenyls).  When the U.S. Congress
finally investigated the fiasco six years later, they asked expert witnesses
about PBB's.  The answers were not reassuring.  Impartial experts testified:
"PBB's are persistent and can be passed on for generations.  PBB's are
stored in the body fat, where they can remain indefinitely.  During
pregnancy, they can cross the placenta to the developing fetus...PBB
is...capable of producing physical defects in offspring in utero."
Not substances you'd particularly want in your hamburgers.  Yet, in 1976
alone, several years after the PBB contamination occurred, Michigan
residents ate over 5 million pounds of hamburger contaminated with PBB's.
What had happened was that this toxic chemical had somehow gotten mixed into
livestock feed which was dispersed throughout the state.  When the PBB's
were first discovered in virtually all of Michigan's meat and dairy
products, state officials tried in every way to cover up the incident.  Had
the public been notified of the extreme urgency of the situation, a great
deal of tragedy could have been avoided.  But as it is, according to
testimony before Michigan's Senate Commerce Subcommittee on March 29, 1977,
nearly all of Michigan's residents now have unacceptable levels of PBB's in
their bodies.  It is quite likely that every single person who consumed
meats, dairy products or eggs in the state of Michigan during 1976 or 1977
now has significant amounts of these carcinogens in his or her organs.
Tests in 1976 found that 96% of nursing mothers in Michigan had PBB's in
their milk.

Siobhan