South Bronx Legionnaires’ Cluster Prompts Cleanup of 10 Towers

New York City ordered 10 cooling towers in the South Bronx to be drained, cleaned and disinfected by September 14 as officials investigate a likely community cluster of Legionnaires’ disease.

The city reported nine diagnosed cases connected to the cluster as of September 12, including one death. Three people were hospitalized, four had been discharged and one did not require hospitalization. The city’s public health page later listed 10 positive cases, so the September 12 figures should be understood as a dated snapshot while the investigation continues.

Preliminary PCR testing detected Legionella DNA in samples from all 10 towers. That result does not show whether the bacteria were alive and does not establish that any particular tower caused the illnesses.

Why the city ordered cleanup before final results

The Health Department began the investigation September 10 after identifying a likely cluster in parts of Melrose and Morrisania, within ZIP codes 10451 and 10456. The September 13 order requires all 10 listed towers to be drained, cleaned and disinfected by September 14.

The city is proceeding with remediation while it awaits culture testing because cleanup can reduce any possible ongoing exposure. Culture results may take up to two weeks and can help determine whether live Legionella bacteria were present when the samples were collected.

The Centers for Disease Control and Prevention says environmental PCR can be used to screen and prioritize samples for culture. If live bacteria are recovered, molecular comparisons between environmental and patient isolates, combined with exposure information, may help investigators assess whether they are related and identify a possible source.

The city has not identified any cooling tower as the confirmed source of the illnesses. A positive PCR result is not the same as a culture-confirmed finding, and it does not by itself show that a building’s indoor air, drinking water or plumbing is unsafe.

What residents should know

Under current city guidance, people in the affected ZIP codes do not need to avoid tap water, showers, air conditioners or the interiors of the listed buildings. Legionella exposure in a community cluster is generally associated with breathing mist from contaminated outdoor water sources such as cooling towers, not with drinking tap water or cooled air from an air conditioner.

Legionnaires’ disease is a serious form of pneumonia caused by inhaling mist containing live Legionella bacteria. It is not typically spread from person to person. Symptoms usually develop two to 14 days after exposure and can include fever, chills, cough, shortness of breath, muscle aches, headache, fatigue, confusion or diarrhea.

People age 50 and older, those who smoke or vape, and people with chronic heart, lung, kidney or liver disease, diabetes or weakened immune systems face a higher risk of severe illness. Anyone who lives, works or recently visited the affected area and develops flu-like symptoms should seek medical care promptly and mention the possible Legionella exposure.

What happens next

Officials are expected to review culture results, inspect towers that tested positive by PCR, track additional cases and determine whether environmental and patient samples can be compared. The city also scheduled an in-person town hall for September 15 at Metropolitan College in the Bronx.

The remediation order is a precautionary public-health action intended to reduce possible ongoing exposure while testing continues. It is not a final finding about the source of the South Bronx illnesses.

Sources

• CDC methods for Legionella testing and specimen collection
• NYC Health Legionnaires’ disease guidance