Eleven people in New York City perished this past summer as a result of breathing air that had come into contact with tainted water. They weren’t traveling to a far-off place or in a hospital where there was a known risk of infection. The majority of them lived in Manhattan, specifically on the Upper East Side, and went about their daily lives close to structures with cooling towers that were in danger of becoming fatal. That’s what usually sticks with you.
By late August 2026, the outbreak, which started earlier this summer, had resulted in at least 79 hospital admissions and 94 confirmed cases of Legionnaires’ disease. In a public update, New York City Health Commissioner Dr. Alister Martin confirmed the final death count of 11, pointing out that no patients were still hospitalized as part of the cluster and that the last new case had been diagnosed more than six weeks earlier.
Health officials think the source has been removed. Even after officials said the worst was over, the numbers continued to rise covertly for weeks, which begs the question of how these tallies are compiled and when the public is made aware of them.
A serious type of pneumonia brought on by the Legionella pneumophila bacteria is known as legionnaires’ disease. It doesn’t spread from person to person. Rather, it moves through water—more precisely, microscopic water droplets released from large building plumbing systems, hot tubs, cooling towers, and ornamental fountains.
The bacteria may settle in the lungs after those droplets are inhaled. The symptoms appear two to fourteen days after exposure and initially resemble a severe case of the flu, including a high fever, aches in the muscles, and a deepening cough. The illness has advanced considerably by the time confusion sets in and breathing becomes challenging.
This summer’s outbreak in New York is especially annoying to read about because the circumstances that made it possible were mostly predictable. 59 of the more than 180 cooling towers tested by the city health department in Manhattan tested positive for Legionella bacteria.
The Guggenheim Museum, apartment complexes, a Whole Foods, and a private school were among the locations impacted. These are not remote places. And it wasn’t the first time. A different outbreak in Harlem during the summer of 2025 resulted in seven fatalities and over 100 illnesses. Two summers. There were two outbreaks. There’s a pattern emerging that’s hard to write off as bad luck.
Maintenance, or rather the absence of it, is the explanation that frequently comes up in public health conversations. Regular cleaning, water testing, and disinfection are necessary for cooling towers. Legionella bacteria flourish if the water within them warms without being treated. Those bacteria are released into the air when the fans turn on. You don’t even need to be inside the building, according to a Virginia Tech civil engineering professor.
It can be sufficient exposure to stand close by on the sidewalk and pause for a conversation. This information conflicts with the Gothamist’s report that cooling tower inspections in New York City have drastically decreased recently, from over 3,000 towers inspected in the first half of 2017 to about 1,167 during the same period in 2025, which is attributed to a staffing shortage.
Now, New York is taking action to address that. Governor Kathy Hochul approved legislation requiring biannual cooling tower certifications, the city has committed $13 million in additional funding for cooling tower inspections, and the penalties for infractions connected to serious illness or death have been increased. Operating towers are now subject to the most stringent monthly testing requirements in the nation. The real question is whether enforcement will be in line with the law, particularly since the city anticipates a budget deficit of almost nine billion dollars in 2028.
New York was not the only place where the outbreak occurred. After looking into a different cluster of six confirmed cases close to Bathurst and Dupont streets, Toronto Public Health was able to identify a cooling tower at a Toronto Transit Commission facility as the source. A Legionnaires’ outbreak in Basel, Switzerland, resulted in 26 cases and one fatality.
There were also cases in Central Ohio. The timing suggests something about where we are with aging building infrastructure and rising summer temperatures, both of which create conditions that Legionella bacteria find hospitable, even though it’s not a coordinated crisis because these are geographically distinct events. The illness can be avoided. The experts keep saying the same thing. They’re not incorrect either.
