The NYC Department of Health and Mental Hygiene (DOHMH) will tighten cooling tower regulations with more frequent legionella inspections and stiffer fines beginning on May 8. The new rules stem from last summer’s Legionnaires’ disease outbreak in Harlem which killed at least seven people. The spread was attributed to contaminated cooling towers, which can spread bacteria outdoors. On April 7, a notice of adoption was published on the City Record database.
“The NYC Health Department and our partners across local government continue to learn from the deadly Legionnaires’ cluster in Harlem last summer, and have implemented many new policies, procedures, and rules to improve all aspects of how we monitor and respond to Legionnaires clusters in cooling towers,” said a DOHMH spokesperson. “This includes a new rule requiring building owners citywide to test their cooling towers for legionella bacteria every 31 days, set to take effect on May 8.”
These amendments largely update a section in the Rules of the City of New York to reflect Local Law 159 of 2025, which the City Council passed in October in response to the outbreak. Legionella bacteria cause Legionnaires’ disease, a severe pneumonia, and cultivates in warm water. Unchecked cooling towers can proliferate infected droplets during the hotter months when they are in use. Breathing in those vapors can lead to contracting Legionnaires’ disease.
Previously, the city mandated sampling every 90 days when cooling towers were operational. Local Law 159 of 2025 also requires a “qualified” state-licensed professional to perform the testing. Building owners will also face four-digit fines for ignoring or violating cooling tower regulations.
To be clear, Legionnaires’ disease does not infect everyone exposed to legionella and is most dangerous to the elderly and/or people with weakened immune systems. It is also not contagious and only spreads from inhaling or aspirating the infected mist. Given there are no vaccines for Legionnaires’, prevention usually falls onto building owners.
“Every Harlem resident has the right to know that the buildings around them are safe,” said councilmember Yusef Salaam, a Local Law 159 co-sponsor. “These new rules give our community real tools to hold building owners accountable. Public health is not a privilege. It is a guarantee.”
Last month, a DOHMH public hearing opened the floor to feedback on the rule changes. Roughly 170 of the 200 written comments came from Harlemites in support of the amendments and several proponents took the floor during a virtual meeting, including Kim Smith, a local journalist who founded the Harlem Legionnaires’ Task Force.
“Thankfully we’ve been able to, you know, accomplish a couple of things in such a short amount of time because of the urgency of our neighbors dying [from] a disease that’s preventable,” Smith told the AmNews. “We can’t just sit back in the cut and [say] we can’t do that … I’m hopeful that we — the community [and] the stakeholders — continue to build on the notion of how [can] we improve.”
The notice credits the Harlem Legionnaires’ Task Force for collecting many of the letters supporting the reforms. Smith says she leveraged relationships in the community as a lifelong resident to bring in those knowledgeable in housing and health last August to help with these efforts.
Back when the taskforce started, the neighborhood scrambled for more information. Initially, the city did not publicly identify the infected buildings and Smith later learned she lived between two such clusters. More than 110 known infections were ultimately recorded, and one of the contaminated cooling towers was later revealed to be located at Harlem Hospital.
Frustration has also mounted because the city’s Legionnaires’ outbreaks largely occur in communities of color, most notably in the South Bronx in 2015, which left at least 16 people dead and fueled many of the original cooling tower regulations.
The remaining 30 or so written comments largely raised concerns about how this would impact property owners and managers as well as questioned the effectiveness of increasing the frequency of monitoring and testing.