Taichung prosecutors have indicted four companies and 15 executives in one of Taiwan's biggest food safety scandals. Prosecutors say the executives knew a shipment of Brazilian soybeans had high rates of heat damage, raising the risk of the formation of benzopyrene, which can cause cancer. Managers at Fwusow Industry Co., Formosa Oilseed Processing Co. Ltd. and Taisun Enterprise Co. also knew of the problem but failed to immediately stop sales. Those indicted could face prison sentences and large financial penalties. Food safety officials say they are tightening market checks, while local authorities say the companies cannot resume operations until they pass safety reviews.