Nearly 20 people have now been sickened by Legionnaires’ disease in the ongoing outbreak on the Upper East Side — including some currently hospitalized, according to city health officials.
The Department of Health said 18 people tested positive for the pneumonia-like illness, after previously reporting 14 cases on Sunday — a nearly sevenfold increase from when the first two diagnoses were announced July 2.
“We’re tracking 18 patients so far, and what I can say right now is that many of them are hospitalized at this moment,” Health Commissioner Dr. Alister Martin told Eyewitness News on Monday.
Some of the patients are in critical condition and in the intensive care unit, Martin told the outlet.
“Luckily, we’ve had our first discharge — meaning someone who’s made it through the cycle. But I will say we’re early, right? We’re still early in this process,” the commissioner said.
The city’s public dashboard currently notes the 18 confirmed cases as of 9:30 p.m. Sunday — meaning the count could still grow by later Monday.
“As of now, we have 18 confirmed cases related to this investigation,” a city DOH spokesperson said in a statement.
“Testing of cooling towers is ongoing as we move quickly to identify and stop the bacteria from growing,” the spokesperson said.
Officials are urging New Yorkers who have lived or worked in ZIP codes 10028, 10128 and 10075 — the neighborhoods of Yorkville and Carnegie Hill, from East 74th to East 96th Streets — to contact a healthcare provider if they develop any flu-like symptoms.
The health department believes a cooling tower in that area to be the source of the bacteria.
The disease, which spreads through contaminated water vapor, is not contagious and can be treated using antibiotics.
But it can be fatal if not treated in a timely manner and people over 50, smokers and those with chronic lung disease or weakened immune systems are at higher risk.
City officials passed laws requiring quarterly inspections for the roughly 5,000 cooling-towers across the Big Apple — where Legionella bacteria can thrive — after a 2014 outbreak in The Bronx killed 16 people.
Another outbreak killed seven people and left more than 90 hospitalized in Harlem last year, prompting officials to strengthen regulations, with building owners now required to test for Legionella bacteria every 31 days when a cooling tower is in active use.
An additional $13 million was added to DOH coffers to grow its ranks of cooling tower inspectors to 54, with community engagement initiatives also being launched under Mayor Zohran Mamdani, following a recommendation from his predecessor Eric Adams’ administration.
State level legislation that has remained dormant since September 2025 would require the Department of Environmental Conservation and public water operators to maintain minimum levels of disinfectants in the water tanks, rather than relying on the monitoring inspections.
