Hungarian authorities have evacuated 800 villagers, saying a second flood of toxic sludge from an aluminium processing plant is likely after new cracks appeared in a reservoir.The villagers were evacuated at dawn from the western village of Kolontar, closest to the reservoir that burst on Monday, killing seven people and injuring scores, and poisoning the surrounding countryside.Authorities meanwhile warned thousands of residents in the nearby village of Devecser to be ready to be moved if necessary. The first flood on October 4 released 1.1 million cubic metres of foul-smelling red toxic sludge into villages and rivers.