More than half of the water cooling towers in a section of New York City's Upper East Side currently under investigation for a Legionnaires' disease outbreak have been cited for violations in recent months, according to records obtained by The Post. Approximately 59% of the cooling towers in the three zip codes under the city's probe received violations between March 2025 and March 2026.
These violations include failures to perform regular monitoring and cleaning, as well as not submitting required Legionella test results to the health department. The city Health Department stated that fines for such infractions can range from $500 to $2,000 for repeat offenses.
Eight cooling towers in the affected area were found to not be collecting, recording, analyzing, or submitting Legionella samples to the city as mandated by law since March 2025. These sites include buildings at 445 East 86th St., 247 E 87th St., 188 E 78th St., 1520 York Ave., 1150 Madison Ave., 1101 Lexington Ave., 1025 Madison Ave., and 1010 Park Ave. The buildings at 1520 York Ave. and 1101 Lexington Ave. accumulated the highest number of violations, with nine and seven respectively, for infractions related to cleaning, monitoring, chemical use, and Legionella sampling in February.
Across the city, more than 200 water cooling towers were flagged for violations during the same period, with 70 of those being Legionella-related monitoring violations.
As of Wednesday, the Legionnaires' outbreak had sickened 36 people in zip codes 10028, 10128, and 10075. City investigators are continuing to probe the source, and cases are expected to rise as additional testing is conducted. This outbreak follows a deadly cluster in Harlem last summer that resulted in seven deaths and 114 illnesses.
A new law that took effect in May now requires cooling towers to be tested for Legionella bacteria monthly, an increase from the previous three-month testing requirement. However, reports indicate that only about half of the active cooling towers in the affected Upper East Side zip codes had Legionella test results on file for the current year.
The health department has tested nearly all cooling towers in the affected area, with results being released on a rolling basis. The mayor's office has committed to releasing the addresses of buildings that test positive for Legionella. One cooling tower at 1511 Third Avenue, which has accumulated numerous violations since 2017, has already tested positive for the bacteria. Cooling towers that test positive for Legionella are ordered to be drained and disinfected.
New York City Council Speaker Julie Menin expressed concern that the source of the spread has not yet been identified, particularly in a densely populated neighborhood with a significant senior population. Menin has urged the health commissioner to proactively order disinfection for buildings that have not yet been inspected or have not yet tested negative for the bacteria.