Legionnaires’ disease can be fatal. Yet in the United States, cases have been increasing. According to the National Institutes of Health, reported cases of Legionnaires’ disease have risen significantly since 2000. A separate study estimates that 8,000 to 18,000 people in the U.S. are hospitalized for the disease each year, with a fatality rate of 10%. Last August, New York City faced one of its largest outbreaks ever, linked to contaminated water in 12 cooling towers across 10 buildings.