Chinese authorities have seized 64 tonnes of milk powder and products laced with the same deadly toxic additive that sparked an uproar in 2008. <br/><br/>The official Xinhua news agency said, samples of milk powder found in north-west provinces Gansu and Qinghai had levels of the chemical melamine up to 500 times the permitted limit. <br/><br/>Melamine can cause kidney stones and is used to make plastics, fertilisers and concrete. Two years ago, at least least six children died and nearly Three lakh children fell ill from drinking powdered milk laced with melamine. <br/><br/>China executed two people last November for their role in the scandal. The latest report did not mention any deaths or illnesses blamed on the latest batches of toxic dairy products.