Upper East Side buildings swept up in the city’s investigation into a deadly Legionnaires’ outbreak are now largely in compliance with a new local law aimed at preventing the disease through increased testing for harmful Legionella bacteria in water cooling towers, the city health department said.
But for some building operators, it took being publicly outed as potential sources of the outbreak in order for them to fall in line, according to health officials, who are still working to boost compliance with the testing requirements citywide. And even after being targeted in the investigation, a handful of Upper East Side buildings remain noncompliant with the new testing law, city health officials said.
Among the 183 Upper East Side cooling towers that were tested for disease-causing Legionella bacteria as part of the city’s investigation into the outbreak, 74% were in compliance with the new reporting requirements as of July 11, according to the city health department. As of July 24, that figure had increased to 92%, the health department said.
Among the cooling towers that actually tested positive for Legionella bacteria in the city’s initial round of testing, 97% are now in compliance with the new law, according to the health department. City officials said releasing the results of the tests starting on July 10 helped boost compliance.
“From the start of this investigation, we made a commitment to not just rapidly respond to cut off the source of exposure, but to make sure New Yorkers had more insight into this process than ever before,” Health Commissioner Dr. Alister Martin said. “Transparency works.”
But even with news of the outbreak — and the city publicizing a list of buildings that might have caused it — there has been no significant increase in compliance with the new law citywide.
About 80% of all cooling towers across the city are now in compliance, up from about 77% at the time the first list was released, according to the city health department.
Legionella can grow in the stagnant water that sits in cooling towers and get released with water vapor into the air, which can get passersby sick when inhaled.
The new law, which took effect May 8, requires the operators of building water cooling towers to test them for Legionella and submit the test results to a city database every 31 days.
The City Council changed the requirement from every 90 days in response to a deadly outbreak of Legionnaires’ disease in Harlem last year. Boosting compliance with the law has taken on new urgency since the outbreak was identified on the Upper East Side in early July. So far, 90 people have been sickened and six have died.
William Fowler, a spokesperson for the city health department, said buildings tested for Legionella as part of the investigation into the Upper East Side outbreak were not automatically in compliance with the new law; they still had to submit their own testing results to the city’s database.
City Council Speaker Julie Menin and Council Health Committee Chair Lynn Schulman have said they want the city health department to take more aggressive action as soon as test results are found to be missing from city records, and to provide more transparency around which buildings have been fined for not complying with the new law.
“We have to make sure that the fines are being assessed,” Schulman said at a press conference earlier this month.
But the city health department said violations are issued based on in-person inspections of cooling towers by city employees and that fines cannot be announced right away because building owners are entitled to an administrative hearing.
In 2025, the city issued more than $600,000 in fines for violations of cooling tower maintenance and testing laws, Martin said last week.
Fowler said the health department is still figuring out how to increase compliance with the latest Legionella testing requirements. He said efforts to do so have so far included educating cooling tower operators and sending out email reminders, in addition to issuing summonses.
Meanwhile, the city health department is still addressing a staffing shortage that has hampered the pace of cooling tower inspections in recent years.
The city has conducted more than 630 cooling tower inspections since the new testing law took effect on May 8 and issued more than 700 violations for lack of compliance with the law and other issues, the health department said.
City councilmembers said they were still figuring out what additional reforms are needed to prevent future Legionnaires’ outbreaks. The City Council is planning to hold an oversight hearing on the health department’s handling of this outbreak in September.
