Residents in the areas hit by this summer’s Legionnaires’ disease outbreak, which has resulted in three fatalities, have been on edge. The city’s Department of Health and Mental Hygiene reported locating 11 buildings with active Legionella bacteria, yet they’ve withheld their specific locations. Instead, officials only revealed five ZIP codes where risks are elevated.
Health Commissioner Michelle Morse expressed concerns about giving New Yorkers a false sense of safety by sharing details about the infected buildings. It’s important to understand that Legionella bacteria, which can thrive in cooling towers on rooftops, might affect individuals even if they don’t reside in those specific buildings.
However, many residents feel left in the dark and are yearning for more detailed information. An analysis by Gothamist examined nearly ten years of public inspection data from the specified ZIP codes, highlighting that inspections have significantly decreased since Mayor Eric Adams took office, particularly in the areas most affected by the outbreak.
Despite inquiries, the health department did not comment on whether more frequent testing could have possibly averted the current situation.
How many cooling towers are in the affected ZIP codes?
New York City boasts thousands of buildings equipped with rooftop cooling towers, which circulate water for air conditioning. Unfortunately, these warm water tanks can host Legionella bacteria, escalating to hazardous levels if unmonitored for just a couple of weeks, as public health experts warn.
When the bacteria is aerosolized, inhalation can lead to Legionnaires’ disease, a severe form of pneumonia. Since the outbreak began in Harlem in late July, over 20 individuals have been hospitalized.
As of mid-August, there were 97 cooling towers in the ZIP codes 10027, 10030, 10035, 10037, and 10039. The 10027 area, which includes Morningside Heights, Manhattanville, and Central Harlem, hosts more than half of those, totaling 50 cooling towers.
This number pales in comparison to the overall 4,929 towers across the city, with Manhattan containing the highest count at approximately 3,635, or about 75% of the total.
How much have inspection numbers declined in those ZIP codes?
To provide some context, a city law enacted in 2015 after a severe outbreak that claimed 16 lives allows for inspections of cooling towers. These inspections initially ramped up in 2017, reaching 5,095, but saw a dramatic decline during the pandemic.
By 2022, inspections rebounded to 4,443, but have since dropped again to nearly pandemic lows since Adams took office. This year, the city is on track to inspect less than half of the towers compared to early in his administration.
This decline has been even more stark in the ZIP codes where the outbreak is most concentrated. A record 100 towers were inspected in 2021; however, the city’s pace in the first four months of 2025 was projected to be only about a quarter of that number, notwithstanding some uptick in inspections prompted by the current outbreak. Updated figures, however, aren’t available yet.
Chantal Gomez, a spokesperson for the health department, noted that the agency strives for annual inspections of all towers, but about 40% haven’t been inspected since 2023, citing staffing shortages as a significant factor.
“We prioritize inspections based on a risk-based approach, considering compliance history,” Gomez stated in an email.
Juan Genao, who assists with water testing at LaGuardia Community College, emphasized the necessity of city inspections for ensuring cooling tower safety. “We’re talking about people’s health and safety here,” he commented. “Without oversight, it’s easy for corners to be cut, leading to outbreaks.”
William Fowler, a spokesperson for the Adams administration, claimed that the health department has sufficient staff to manage the ongoing outbreak.
What have building owners been doing to comply with the law and ensure safety?
City inspections are just one facet of the regulatory framework. Building owners are required to conduct regular testing, which acts as the frontline defense. According to the 2015 law, owners must test their cooling towers weekly for bacteria and report results to the city every three months.
Gothamist’s analysis revealed that a slightly higher percentage of building owners in the affected ZIP codes maintained compliance compared to the city’s overall average. Approximately 75% of towers in these areas had up-to-date Legionella testing reports, while the citywide figure sat at 73%.
However, just over half of the towers in these affected ZIP codes had not undergone city inspections since 2023.
What about the towers that were behind on testing? Were they inspected?
It’s uncertain whether buildings that fail to report Legionella test results receive prioritized inspections from the health department. The agency did not respond to questions about whether this is incorporated into its risk-based approach.
While 75% of towers in the outbreak-affected ZIP codes were current with their testing, 17 had no test results on record. The health department indicated that some of these towers might be inactive, thus exempt from testing, but did not clarify which towers were no longer operational.
To work around this ambiguity, Gothamist identified cooling towers that had tested at some point in the past year but were not reported in the last three months.
By this definition, 5% of the towers in the affected ZIP codes that fell behind on test results had also not been inspected since 2023, totaling five towers. This figure is somewhat higher than the citywide average of 3%.
