At least four workers were killed in an explosion at a hydroelectric power plant on a reservoir in northern Italy on Tuesday. The authorities feared in the evening that the number of fatalities at the plant on the Suviana reservoir between the cities of Bologna and Florence could rise: Several hours after the accident, which occurred at around 3 pm (1300 GMT), three workers were still missing. At least five workers suffered burn injuries. According to initial findings, fire broke out in the plant during work on a turbine at a depth of around 30 metres for an initially unexplained reason, which…