Legionella found in Suffolk Supreme Court cooling tower in Riverhead

A cooling tower on the roof of the Riverhead Supreme Court at 235 Griffing Avenue tested positive for Legionella on July 27, putting courthouse workers, jurors, attorneys, witnesses and visitors under immediate public-health scrutiny. Suffolk County said its testing consultant flagged the result during routine required New York State testing, and the tower went into online disinfection on July 28.

Officials said there was no threat to the public, but the finding matters because the Suffolk Supreme Court building is one of Riverhead’s busiest government sites. Judges, county employees and members of the public move through the courthouse daily, and a problem in the mechanical system can quickly become a concern for everyone who uses the building.

Legionnaires’ disease is caused by Legionella bacteria and is not spread person to person. The risk comes when people breathe in contaminated mist or vapor, which is why cooling towers are watched so closely. If a tower is not properly treated, it can spread water droplets over a wide area, turning a routine HVAC component into a public-health problem.

The Centers for Disease Control and Prevention says Legionella grows best in warm water and is found in cooling towers, hot water tanks, large plumbing systems and decorative fountains when those systems are not properly maintained. People who have been in or near a building with a positive test and later develop fever, cough, shortness of breath or other pneumonia-like symptoms should seek medical care promptly.

Suffolk County said the Riverhead tower would be retested within 3 to 7 days after disinfection. That timeline suggests the county was treating the positive result as a maintenance and water-treatment issue first, with the goal of clearing the system before it could pose a broader risk.

The Riverhead finding also fits a wider public-health pattern across New York, where cooling towers have drawn close scrutiny after earlier outbreaks. New York City later moved to testing cooling towers every 31 days, a sign of how seriously public agencies now treat these systems after the 2015 city outbreak, which the National Library of Medicine described as history-making, and a 2026 Upper East Side cluster that led to orders to clean and disinfect affected towers.