31 Upper East Side Buildings Have Cooling Towers Testing Positive for Legionella Bacteria
The New York City Health Department identified 31 Upper East Side buildings with cooling towers that preliminarily tested positive for Legionella, prompting immediate cleaning orders as an outbreak has sickened 46 people.
The city health department announced that cooling towers at 31 Upper East Side buildings have preliminarily tested positive for Legionella bacteria, the pathogen that causes Legionnaires’ disease. The outbreak, centered in the Carnegie Hill and Yorkville neighborhoods, has resulted in 46 confirmed cases, with 22 patients still hospitalized and no deaths reported.
Nineteen of the towers have already been cleaned and disinfected, including those at the Guggenheim Museum, Asphalt Green’s Upper East Side campus and a Whole Foods Market. The remaining twelve, such as the cooling tower at Trevor Day School, have been ordered to complete remediation by Saturday.
Officials emphasized that the PCR screening detects bacterial genetic material but does not confirm the presence of live, infectious bacteria. Culture testing is underway and may take up to two weeks, after which any live bacteria will be compared to patient samples using whole-genome sequencing.
"It’s important for us to not wait two weeks," Health Commissioner Dr. Alister Martin said at a briefing.
"We want to be transparent with New Yorkers about this," Mayor Zohran Mamdani added.
The department reassured residents that there is no additional risk from being inside the listed buildings, as the cooling towers release mist outdoors, not through indoor plumbing or air-conditioning systems. Tap water, showers, and indoor air-conditioners can be used as usual.
The investigation, launched after two confirmed cases were identified on July 2, has expanded to include additional ZIP codes. Health officials warned that new cases may continue to appear for up to two weeks after exposure, given the disease’s incubation period.
The city is also reviewing compliance with cooling-tower testing and maintenance regulations, though no penalties have been announced.
Legionnaires’ disease is a serious form of pneumonia transmitted by inhaling aerosolized water containing live Legionella. It is not contagious. Residents who develop flu-like symptoms and have been in the affected area since late June are advised to seek medical care.