Legionnaires’ Disease Tears Through Upper East Side

An outbreak of Legionnaires’ disease raging through the Upper East Side had resulted in 36 cases and 22 hospitalizations as of Wednesday, July 8. Fortuantely, nobody has died.

The NYC Health Department has tested over 150 cooling towers so far, between East 74th Street and East 96th Street, to trace the source of the spread.

Officials have also told local residents living in the Carnegie Hill and Yorkville neighborhoods—or the ZIP codes 10028, 10128, and 10075—to monitor for symptoms; these can include a cough, a fever, or difficulty breathing.

Legionnaires’ disease, a severe form of pneumonia, spreads via water vapor infected with the Legionella bacteria. The warm basins of cooling towers, which sit on the top of city buildings and release waste heat, can serve as fertile breeding grounds for Legionella if left untreated.

While not contagious and hard to contract, Legionnaires’ poses a serious risk to people with certain underlying health conditions such as lung disease or a history of smoking. There is no vaccine for Legionnaires’, although it can be treated effectively with antibiotics if caught early.

The Health Dept. hosted a virtual town hall about the outbreak on July 6, which was notably attended by City Council Speaker Julie Menin, who represents the area. She also attended an in-person town hall held at the Church of St. Ignatius Loyola, located on Park Place, the next day.

“This is obviously an evolving situation, and so this update is very, very important. We want to make sure that people have the necessary information,” Menin said at the virtual July 6 meeting.

Menin specifically wanted answers from officials concerning compliance with a City Council law that went into effect on May 8, which mandates regular Legionnaire’s testing for building owners.

“How many buildings tested for Legionnaires’ and provided that information to the Health Department? How many buildings did not? Is the Health Department focusing on those buildings that were not compliant? Obviously we are deeply concerned that the source of this outbreak has not yet been identified,” Menin said.

NYC Health Commissioner Alister Martin, who spoke after Menin, acknowledged that the source of the outbreak would take a bit of time to narrow down to a specific cooling tower or two.

“While we are absolutely looking forward to trying to identify the one smoking gun, as they say...we are going to make sure that we treat anything and everything that could potentially be associated with a positive test,” he said.

The determination of the “smoking gun” outbreak source would come from a lengthy and time-consuming genome sequencing process, Martin elaborated.

According to the CDC, some smaller outbreaks never result in the identification of a definitive source. In the meantime, officials are prioritizing informing local residents about which building owners have bee instructed to clean their cooling towers.

The testing law Menin has referred to was technically passed not long after a deadly Legionnaires’ outbreak tore through Harlem last July and August, sickening 114 people and killing seven.

Health inspectors are required to pursue a probe at any address where two people test positive for the disease within a year, with the new law strengthening fines for noncompliance.

Later reporting in Gothamist found that seven out of ten of the buildings tied to the outbreak had not been tested in over a year, with inspection staffing stuck at low levels.

According to a new report in that same outlet, it appears that the rate of city Legionnaires’ inspections have only risen modestly this year, although inspection hiring has picked up and could result in increased testing. A total of 20 percent of building owners did not submit Legionnaires’ test results for the first five months of 2026.

Other outbreaks of Legionnaires’ have been detected by Health Dept. probes earlier this year, including two in January—one at a co-op complex between E. 78th Street and E. 78th Street, and the other at a large residential complex located in Harlem at 3333 Broadway.

An outbreak in Harlem last year killed seven and sickened over 110 people.

A third probe by the Health Dept. this year, turned up Legionnaires’ Disease in the East Village last month at a housing complex on Avenue C known as Haven Plaza. However, the bacteria was detected in internal-facing water systems in all of these probes, limiting wider community risk. Residents were told to take precautions such as avoiding showers.