Legionella Found in 10 Bronx Cooling Towers, Including Yankee Stadium

New York City health officials have detected Legionella bacteria in ten cooling towers across the Bronx, including one at Yankee Stadium, as they investigate a likely community cluster of Legionnaires' disease in the South Bronx.

The Health Department said ten people have tested positive for the illness, one of whom has died, while three remain hospitalised. Further testing is under way to establish whether the bacteria found in the towers were alive, since only live bacteria can cause the disease. Initial checks on the ten towers last week turned up traces of both living and dead bacteria.

Owners of the affected towers have been ordered to clean and disinfect them by Monday. The Yankees said the stadium's cooling tower that tested positive was drained and cleaned on Sunday morning.

The team said new cooling towers were installed at the stadium in 2024 and have been tested weekly for water quality and bacteria since then, with results reported to the city each month. Testing on August 20 came back negative for Legionella, the Yankees said, noting that their method differs from the one the city used last week. The club added that no current cases have been linked to Yankee Stadium and that the Health Department has not asked it to postpone any games this month.

City officials are now running culture tests on samples from the ten towers, a process that can take up to two weeks to confirm whether the bacteria were live.

Legionnaires' disease is a treatable form of pneumonia but kills about 10% of patients, according to the U.S. Centers for Disease Control and Prevention. It is caused by Legionella bacteria, which thrive in warm water and can spread through sources such as hot tubs and building cooling equipment. People may fall ill by inhaling contaminated water droplets, and the disease does not pass from person to person.

Residents and workers in the Melrose and Morrisania sections of the Bronx, or anyone who has visited those areas since late August and is experiencing flu-like symptoms, have been urged to contact a healthcare provider immediately.

The city has recorded other Legionnaires' outbreaks in recent months. One on Manhattan's Upper East Side earlier this summer killed 11 people among more than 90 who tested positive, with 59 cooling towers at 58 buildings found to harbour live bacteria; all were cleaned and disinfected. A separate outbreak in Harlem last year killed seven people and sickened dozens.