By Janet Raloff
In February 1999, panic broke out in Europe with the finding that Belgian producers of livestock feed had inadvertently contaminated 1,500 tons (1.5 million kilograms) of their products with rendered fat containing 50 kg of polychlorinated biphenyls (PCBs) and 1 gram of dioxin.
Analyses later confirmed that traces of these organochlorines wound up in the meat of animals that had eaten the feed and become ill. A new study finds that the contamination of feed wasn’t an isolated episode.