German authorities have stopped more than 4,700 farms from selling their meat and eggs amid a growing scandal over animal feed contaminated with cancer-causing chemicals.

Germany’s Agriculture Ministry said on Friday it had no immediate reports of health problems connected to the contaminated products. It said it was stopping the sale of products from farms where livestock is believed to have consumed some 150,000 tons of feed for poultry and swine containing industrial fat.

The scandal broke on Monday when excessive dioxin levels were discovered in eggs from chickens in western Germany and has continued to spread.

German media reported that the contaminated feed had been fed to livestock for months before the dioxin was discovered.