UIL and CGIL trade unions march in Bologna on Thursday to demand action on health and safety. Explosion at Enel Green Power's Bargi hydroelectric plant on Lake Suviana killed three people, with four others missing, feared dead.

Police said at least 1,500 people took part in the demonstration, marching behind a banner that read "Enough Now" Unions' members are also striking for eight hours in EmiliaRomagna on Thursday, doubling the length of an already-planned nationwide general strike that is especially affecting public transport.Investigators have opened a probe into alleged culpable homicide and culpable disaster, firefighters said on Wednesday that there is little hope of finding the missing people alive. The disaster, in which five other people were injured, is the latest in a long series of deadly workplace accidents in Italy. the unions have expressed anger that the workers were employed by external contractors. "These are sub-contract deaths," said BologNA CGIL Secretary Michele Bulgarelli.