New York City’s largest outbreak of Legionnaires’ disease in years has sickened at least 108 people and killed at least five, and has officials scrambling to contain the outbreak. But public health experts say the conditions that made parts of the city fertile ground for the disease this summer have been spreading widely, and all Americans need to understand the risk factors involved.
“This is not just a New York City problem,” said Hannah Greenwald Healy, a professor of environmental health at the Harvard School of Public Health. “I think of it as a problem in industrialized countries. We’ve been seeing increases in Legionnaires’ disease for decades now across the United States, across Canada, and across a lot of European countries.”
New York City’s Legionnaires’ outbreak linked to cooling towers
As USA TODAY’S Eduardo Cuevas has previously reported, Legionnaires’ is a severe form of pneumonia caused by a bacteria called Legionella. The bacteria − found naturally in freshwater − grows in warm or hot water, according to the Centers for Disease Control and Prevention. The disease spreads through mist containing bacteria that people inhale.
In New York, officials have tracked the summer outbreak to the cooling towers – the external structures that regulate the temperature in large buildings. Those towers rely on water to “lift that heat away,” Healy explained. When that water in turn heats up, it provides the ideal breeding ground for Legionella.
On Aug. 20, attorney Ben Crump, the Weitz & Luxenberg law firm, and Reverend Al Sharpton announced a lawsuit against a construction company filed on behalf of construction workers who contracted Legionnaires’ after working in Central Harlem. Local health officials trace the disease to a dozen cooling towers serving ten buildings, including Harlem Hospital.
“It is believed that the cooling towers at Harlem Hospital were filled with rainwater after several large July storms,” a statement issued by the law firms said. “The water was left untreated, which permitted bacteria to spread causing workers at the site to become sick.”
“This outbreak was not a natural disaster. It was the direct result of negligence. When corporations cut corners and put profits over people’s lives, tragedies like this happen, and that is why we are here: to hold them accountable,” Crump said in remarks emailed to USA TODAY. “Harlem has already endured so many injustices. This community deserves safety, dignity, and respect. Instead, it has been made the epicenter of yet another health crisis.”
Jared Scotto, an attorney with Weitz & Luxenberg, told USA TODAY, “We believe this was preventable. (Legionnaires’ disease) is something that should not be happening in 2025. We’re looking to hold accountable everyone who’s responsible and we’re going to follow the facts.”
“We’re very concerned about the role the city played,” Scotto added, and says the firm intends to pursue legal action against the city.
Sharpton’s representatives did not respond to a USA TODAY request for comment before the publication deadline.
Climate change increases the risk of Legionnaires’ disease
As the planet heats up, we’re experiencing not just hotter temperatures, but more humid conditions as well. Climate change also means that more and more regions that never needed cooling infrastructure in the past now do. Think of the recent heat waves in places like the Pacific Northwest, where a lack of air conditioning probably contributed to the deaths of dozens of people in 2021, according to research conducted a few years later.
And while some news reports about the outbreak in New York have focused on older infrastructure, which may be more conducive to harboring the bacteria, Healy explains that newer construction, and “green” buildings in particular, may have low-flow plumbing systems that allow water to sit longer in the pipes, increasing the risk that Legionella spreads.
Compromised health also raises risk of Legionnaires’ disease
Many experts suspect that some residents of the areas where Legionnaires’ has been found in New York may be more susceptible to various diseases. Central Harlem, site of the recent outbreak, is a poorer area, and residents may lack access to preventive health care. As Cuevas also previously reported, these communities tend to have higher rates of chronic health conditions, such as asthma or chronic obstructive pulmonary disease, which are greater risk factors.
A resident of a New York City public housing authority building in Brooklyn died of Legionnaires’ as recently as 2023.
Still, as the broader population across the United States ages, experts say this is as good a time as any to take note of important preventative measures for overall health.
“You should be talking to your doctor, making sure you’re getting your appropriate vaccines like the flu, pneumonia, and RSV,” said Dr. Michael Phillips, the chief epidemiologist for New York’s NYU Langone Health System.
If you feel sick – particularly with some sort of respiratory condition, get checked out quickly, Phillips added.
Finally, know that building-wide drinking water filters that attempt to remove all, or most, of the chlorine in water may be counter-productive, Healy told USA TODAY: having some chlorine in the water actually helps prevent Legionella from growing.
The Jacob Riis Houses, a New York City Housing Authority complex.
Governments need to be trusted to manage public health emergencies
As a public health crisis, any outbreak of Legionnaires’ flourishes in a perfect storm of stretched government budgets, an erosion of public trust, and a fear of litigation, said Iziah Thompson, senior housing analyst for New York’s Community Service Society.
“This is a national problem where we’re having governments not really doing a great job at explaining and being forthcoming about what they’re doing when it comes to water quality, what the reality is,” Thompson told USA TODAY.
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One of the biggest challenges in New York City has been different agencies communicating different messages to the public, Thompson pointed out. That confuses residents and makes them less likely to trust government officials.
On the other hand, Thompson said, taxpayers have to accept that it takes money and a minimum level of staff to make upgrades to aging infrastructure and for testing and mitigation efforts. It’s fair to ask questions and hold public agencies accountable, but also recognize that there are professionals in the agencies working hard and learning as they encounter each outbreak.
That’s important, said Langone’s Phillips. “I think (people) should just be cognizant of the fact that infectious diseases are going to change as our climate changes. We live in a changing world.”
Contributing: Eduardo Cuevas
This article originally appeared on USA TODAY: Legionnaires’ disease is spreading thanks to these factors