Meat from lambs raised on 300 farms in Wales could have been contaminated due to an illegal chemical sheep dip that is thought to have been used by some farmers. Some farmers in Wales are believed to have been illegally dipping sheep in a form of Cypermethrin, a pesticide that is normally used on crops. The chemical is up to six times cheaper than approved sheep-dip pesticides, but has never been tested for use on animals and is believed to be harmful to human health if an excessive amount is consumed, reports BBC News Online.