NYC mayor pledges to publish addresses of buildings with Legionella-positive cooling towers

Mayor Zohran Mamdani said the city will disclose the addresses of all buildings whose water-cooling towers test positive for Legionella, the bacteria that cause Legionnaires’ disease, as officials investigate a recent outbreak on Manhattan’s Upper East Side. The announcement was made ahead of a town hall meeting attended by about a hundred residents.

The health department has confirmed 28 cases of Legionnaires’ disease, with 21 hospitalizations and no deaths reported. Cases are concentrated in ZIP codes 10028, 10128 and 10075, an area that spans from the East River to Central Park. City health officials suspect a cooling tower emitting contaminated mist is the source.

Water ecologists are sampling all 160 cooling towers in the affected ZIP codes. To date, 139 towers have been tested, and the city will publish the addresses of any that return positive results, health commissioner Dr. Alister Martin told attendees. Building owners whose towers test positive are being ordered to clean and disinfect the systems, and officials said they will follow up to ensure compliance.

"When there’s a public health threat, New Yorkers deserve urgency and transparency from their government," Mamdani said. "This is a matter of life and death," Martin added.

Deputy commissioner for environmental health Corinne Schiff said non-compliance has not been an issue in past incidents. Martin noted that initial PCR tests can detect bacterial DNA even when the organisms are no longer viable, and that culture analysis and whole-genome sequencing will be needed to confirm live bacteria and match strains to patient cases.

Residents in the affected ZIP codes are advised to monitor for symptoms such as fever, cough, body aches and gastrointestinal issues, and to seek medical attention promptly. Officials said masks are unlikely to provide protection and that mist can travel beyond the building that houses a cooling tower.

Some community members expressed concern about testing access and the lack of concrete preventive measures, while others indicated they might temporarily leave the city until the situation is resolved.