NYC Legionnaires' disease outbreak July 2026
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Legionella positive tests more than double in Upper East Side buildings
The initial testing of cooling towers in the affected ZIP codes is complete.
City health officials released a list of 45 new buildings whose cooling towers tested positive for Legionella on Tuesday evening.
As of Tuesday, 57 building owners had completed the remediation process for their cooling towers.
A Sensible New Yorker's Guide to Legionella Season
The Ardsley's hot-water system tested positive for Legionella.
Dr. Wafaa El-Sadr is an epidemiologist at Columbia University's Mailman School of Public Health.
Legionnaires' disease has a 10 percent fatality rate.
NYC Legionnaires' outbreak: cooling towers test positive for Legionella
New York City Mayor Zohran Mamdani said officials had tested all of the cooling towers in the area.
New York City Council Speaker Julie Menin wrote a letter to Health Commissioner Martin expressing concern that the health department had failed to require building owners to proactively disinfect all cooling towers in the area under investigation.
In the 2025 Harlem outbreak, 114 people were infected and seven people died.
“Our facilities are regularly tested, and like hundreds of other cooling towers at buildings and facilities across the affected area, have been examined again in recent days, with one showing a positive result. In an abundance of caution, we have sanitized all three NYC Transit cooling towers on Second Avenue and will be subsequently retesting,”
Legionnaires' disease outbreak on Upper East Side near Central Park
New York City health officials reported 18 cases of Legionnaire's disease on the Upper East Side as of Monday.
City health officials advised visitors to the East Side of Central Park between 76th Street and 97th Street to monitor for symptoms.
No fatalities had been reported in the outbreak.