An outbreak of legionnaires’ disease on Manhattan’s Upper East Side has led to the deaths of four individuals and left 76 others ill, according to health officials. The source of the outbreak has been traced to several cooling towers in the area.
Efforts to control the outbreak have involved the cleaning and disinfection of cooling systems at affected buildings. This response aims to eliminate the legionella bacteria responsible for the illness, which typically proliferates in water systems such as cooling towers.
Legionnaires’ disease, a serious form of pneumonia, is treatable but kills about 10% of patients, according to the US Centers for Disease Control and Prevention (CDC). The Legionella bacterium that causes the sickness grows in warm water and can proliferate in cooling towers, hot tubs and showerheads.
Health officials believe the source of the “community cluster” causing the outbreak in New York City was buildings in the Upper East Side neighborhoods of Carnegie Hill and Yorkville. In all, 76 buildings tested positive for either living or dead Legionella bacteria in cooling towers, including museums, private schools and apartment houses. Their owners were ordered to drain and sanitize cooling systems.
A previous outbreak in Harlem in August 2025 killed seven people and sickened more than 100. That outbreak followed a similar pattern, with new cases declining rapidly after the source was identified and remediated. Health officials declared the outbreak over approximately three weeks later.
Frequently Asked Questions
What caused the legionnaires’ disease outbreak on the Upper East Side?
The outbreak was traced to cooling towers in the area, where legionella bacteria can grow.
How many people were affected by the outbreak on the Upper East Side?
The outbreak resulted in four fatalities and 76 illnesses.
What measures were taken to control the legionnaires’ outbreak?
Buildings were ordered to clean and disinfect their cooling systems to combat the spread of legionella bacteria.
Where did the legionnaires’ disease outbreak occur?
The outbreak occurred on the Upper East Side of Manhattan.
Incident Details
- Location: Upper East Side, NYC, Manhattan
- Date: Jul 20, 2026 at 3:00 PM
- Type: News Report
- Injuries: 76 | Fatalities: 4
