An outbreak of Legionnaires\' disease in Edinburgh, Scotland, has sickened more than 20 people -- mostly men --and killed one, health officials said. Some health officials pointed to industrial cooling towers as the potential source of the infection and the cooling systems at four facilities in southwest Edinburgh have been inspected and treated, but other sites are also being tested, the Daily Telegraph reported. Legionnaires\' disease is caused by the bacteria Legionella contaminating water supply systems such as air conditioning systems, hot water supplies and cooling towers, health officials said. People become infected after breathing in droplets of contaminated water.