New York City investigates Legionnaires' disease cluster linked to cooling towers on Upper East Side
Health officials have confirmed 46 cases of Legionnaires' disease tied to contaminated water-cooling towers in Manhattan, prompting aggressive testing and disinfection orders.
New York City health officials have identified 46 cases of Legionnaires' disease in residents of the Upper East Side, attributing the outbreak to bacteria in water-cooling towers of nearby buildings. As of Wednesday, 22 patients were hospitalized, some in intensive care, according to the health department.
The city announced an "aggressive" response, ordering testing of all cooling towers in the area and requiring immediate cleaning and disinfection after a single positive result. Officials said the effort covers roughly 160 towers and is proceeding without waiting for additional confirmatory tests.
At a town-hall meeting, Health Commissioner Alister Martin said early identification of the cases was a positive development. Council Speaker Julie Menin expressed concern that the Department of Health and Mental Hygiene had not yet mandated proactive disinfection of all towers under investigation.
Dr. Wafaa El-Sadr, an epidemiology professor at Columbia University, explained that Legionella bacteria thrive in warm water and can cause severe pneumonia when inhaled in aerosolized mist. She suggested that wearing a well-fitted mask and keeping windows closed could reduce exposure for residents in the affected zone.
The department has advised residents to monitor for symptoms and seek medical care if they develop signs of illness. No comment was received on whether officials have formally recommended mask use for the public.
Legionnaires' disease has previously affected major cities, including a 2025 outbreak in London, Ontario, and a 2023 cluster in Harlem, Manhattan, both linked to cooling-tower sources.