On 10 July last year a chemical factory blew up near Seveso just north of Milan. It released a cloud of poison which covered a wide area of houses, factories and farms. Nearly a thousand people had to leave their homes. It was the worst accident of its kind to hit a populated area. One year after, Robert Fox has been talking to the people of Seveso and the authorities responsible. Experts from different countries hit by similar disasters discuss the implications of Seveso, and the safety standards that must be adopted urgently to avoid any repetition. Producer TOM READ