Abstract: On November 10, 2008, Employee #1, who had been working in a health center, was diagnosed Legionnaires Disease. It was determined that she was exposed to the disease through a mist produced from contaminated water coming from leaking pipes. The pipes had been leaking from the ceiling into a bucket for a four-month period. Employee #1 became ill in early November, 2008, but was not diagnosed until she was hospitalized on the tenth day of the month. The accident investigation identified that the building that houses the health center has its air treated by a cooling tower. A water sample taken from the cooling tower revealed that the water from the cooling tower was contaminated with Legionella bacteria. Although Employee #1's doctor reported that such bacteria could cause the type of Legionella pneumophila that Employee #1 contracted, he did not indicate that the water from the cooling tower was the cause.