New York City tightens cooling tower inspections after legionnaires' outbreaks
Following two deadly legionnaires' disease outbreaks in the past two summers, New York City is toughening cooling tower regulations and facing new lawsuits, while experts warn rising temperatures could increase future risk.
New York lawmakers are pushing for stricter rules and more frequent inspections of building cooling towers to curb the spread of legionnaires' disease, after two major outbreaks over the past two summers and a wave of new lawsuits.
Legionnaires' disease is a severe form of pneumonia caused by the legionella bacterium. It typically originates in large air-conditioning systems used in hotels, hospitals and high-rise buildings, where water in cooling towers, if not properly maintained, becomes a breeding ground for the bacteria, which can then be dispersed into the air through fans.
Outbreaks and consequences
In August 2025, seven people died and more than 100 fell ill during an outbreak in Harlem. This summer, Manhattan's Upper East Side recorded 92 cases, 79 hospitalizations and seven deaths. The city's health department collected samples from more than 180 cooling towers, of which 59 tested positive for the bacterium — including at the Guggenheim Museum, apartment buildings, a Whole Foods store and a private school.
Victims of the 2025 Harlem outbreak and their families have filed four lawsuits against the city, its public hospital system, and the contractors responsible for maintaining the towers.
New regulations
Experts say deaths are preventable through regular cleaning, water testing and rigorous government inspections. However, reporting shows the city's legionella inspections dropped sharply in recent years — from 3,190 towers inspected in the first half of 2017 to 1,167 in the same period of 2025, which a health department spokesperson attributed to staffing shortages.
In May, the city announced an additional $13m for inspections in fiscal year 2027, including funding for 23 new water ecologists, and introduced a requirement for building owners to test for the bacterium every 31 days of operation. Governor Kathy Hochul has signed legislation requiring biannual cooling tower certification and raising penalties to $12,500 for violations resulting in serious illness or death.
Experts caution that as global temperatures rise and air conditioning use increases, cooling systems work harder and the water inside them grows warmer, creating more favorable conditions for the bacteria. At the same time, funding additional inspections could prove difficult for a city facing a projected $8.8bn budget gap in fiscal year 2028.
