As New York City battles another deadly outbreak of Legionnaires' disease, facilities with cooling towers across the city are ramping up cleaning and maintenance.
Clarity Water is among the companies being hired by to clean cooling towers at thousands of towers all over New York. On Friday, one crew was going out calls on Manhattan's West Side, and Clarity managing partner Greg Frazier showed NBC 4 New York how crews spray the inside and outside of towers with a mix of water and bleach.
Frazier says cooling towers are a breeding ground for Legionella, the bacteria that causes the potentially severe pneumonia-like disease in people who are exposed to it, because "it's the perfect environment: it's the right temperature, it's the right pH, it has the right amount of food -- it has organisms."
That bacteria lives in a biofilm, or slime, inside the tower.
1 Dead in New NYC Legionnaires' Cluster as Outbreak Expands
But even a cleaning apparently isn't a guarantee that Legionella is gone. The most recent cluster of Legionnaires' cases that's affected 13 people and left one person dead is centered in Morris Park in the Bronx. When 35 cooling towers in the area were tested for Legionella, 15 came back positive -- even though officials said they had recently been in cleaned with new regulations put in place after the other Bronx outbreak over the summer.
Frazier said there are a few reasons Legionella can stay in cooling towers after a cleaning: the cleaning crew can miss some spots, and maintenance is crucial in the weeks following a cleaning.
"It's a difficult battle, it's something that has to be waged every day, and if you don't have the proper program in place maintaining the proper bioside levels, it's very likely you're going to have Legionella come back," said Frazier.
There can also be underlying mechanical issues specific to each facility.
Clarity Water Technologies says the warmer weather is a breeding ground for Legionella bacteria, so with the recent cooler weather, Legionella should taper off. Still, they expect to see a boom in business with all the new regulations of cooling towers across New York.
Under the new legislation, cooling towers across the city must be tested regularly for Legionella bacteria; any found to be contaminated must be disinfected immediately. The regulations specify penalties for violations, and the legislation makes New York City the first major city in the United States to regulate cooling towers.
Prior to the recent outbreak, no city records were kept as to which buildings had cooling towers.
Legionnaires' disease usually sets in two to 10 days after exposure to the bacteria and has symptoms similar to pneumonia, including shortness of breath, high fever, chills and chest pains. People with Legionnaires' also experience appetite loss, confusion, fatigue and muscle aches.
It cannot be spread person-to-person and those at highest risk for contracting the illness include the elderly, cigarette smokers, people with chronic lung or immune system disease and those receiving immunosuppressive drugs. Most cases can be treated successfully with antibiotics.