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Legionnaires' Disease


In July 2015, New York City experienced an outbreak of Legionnaires’ disease in the Bronx. An investigation was launched and on August 20, 2015, a cooling tower at a local hotel was confirmed as a source of the outbreak. Legionnaires’ disease (or Legionellosis) is a type of pneumonia. It is caused by bacteria (Legionella) that grow in warm water. Most people exposed to the bacteria do not become ill but to some, Legionnaires’ disease can be deadly.

The 2015 outbreak prompted Governor Cuomo and New York State Health Commissioner Dr. Howard Zucker to issue preventive regulations to keep the public safe from Legionnaires’ disease, a potentially deadly disease. More information about the regulations, Legionnaires’ disease and cooling towers can be found on these links.

Legionnaires' Disease FAQs

 What is Legionnaires' disease? Legionnaires' disease (or Legionellosis) is a type of pneumonia. It is caused by bacteria (Legionella) that are found naturally in the environment, usually in water. The bacteria grow best in warm water, in areas such as hot tubs, cooling towers, hot water tanks, large plumbing systems and decorative fountains. They do not seem to grow in car or window air-conditioners.

 Is Legionnaires' disease new? No. The disease was named in 1976 when American Legion members who attended a Philadelphia convention suffered from an unusual pneumonia (lung infection).

 Is Legionnaires' disease contagious? Legionnaires' disease is not spread from person to person. People get sick by breathing in water vapor containing the bacteria. The bacteria are not spread from one person to another person.

 Who is at risk? Groups at high risk include people who are middle-aged or older -especially cigarette smokers- people with chronic lung disease or weakened immune systems and people who take medicines that weaken their immune systems (immunosuppressive drugs).

 What should I do if I think I have been exposed to Legionnaires' disease? Most people exposed to the bacteria do not become ill. If you have reason to believe you were exposed to the bacteria, talk to your healthcare professional or call your local health department.* Be sure to mention if you have traveled in the last two weeks. If you have flu-like symptoms, seek medical attention, especially if you have a medical condition that affects your breathing, like emphysema, or if you are a smoker.

 What are the symptoms of Legionnaires disease? Symptoms are like the flu and can include fever, chills, muscle aches and cough. Some people may also have headaches, fatigue, loss of appetite, confusion or diarrhea.

 What is the treatment for Legionnaires' disease? The disease is treated with antibiotics. Most people get better with early treatment, although they may need to be hospitalized. Some people may get very sick or even die from complications of the disease. That's why it is important to seek medical help if you develop symptoms.

*To speak with a Suffolk County healthcare professional about possible exposure to Legionella bacteria, call (631) 854-0333.

Cooling Towers and Air Conditioner FAQs

Frequently Asked Questions about Cooling Towers and Air Conditioners


 What is a cooling tower? A cooling tower is designed to remove heat from a building or facility by spraying water down through the tower to exchange heat into the inside of the building. Air comes in from the sides of the tower and passes through the falling water. As the air passes through the water, heat is exchanged and some of the water evaporates. This heat and evaporated water flow out the top of the tower in the form of a fine cloud-like mist. The cooled water is collected at the bottom of the tower and pumped back into the plant or building for reuse. Cooling towers provide large scale air-conditioning where land and (or) water are expensive, or regulations prohibit the return of once-through cooling waters (USGS).

 What are cooling towers used for? Cooling towers are primarily used for heating, ventilation, and air conditioning (HVAC) and industrial purposes. Cooling towers provide a cost-effective and energy efficient operation of systems in need of cooling. More than 1,500 industrial facilities use large quantities of water to cool their plants (EPA). HVAC systems are used typically in large office buildings, schools, and hospitals. Industrial cooling towers are larger than HVAC systems and are used to remove heat absorbed in the circulating cooling water systems used in power plants, petroleum refineries, petrochemical plants, natural gas processing plants, food processing plants, and other industrial facilities.

 How do cooling towers cause Legionnaires’ disease? Cooling towers contain large amounts of water and are potential breeding grounds for Legionella bacteria if they are not properly disinfected and maintained. Water within cooling towers is heated via heat exchange, which is an ideal environment for Legionella heat-loving bacteria to grow. Legionnaires’ disease can be acquired when an individual breathes in water droplets containing Legionella bacteria. (CDC)

 What is the difference between a cooling tower and a water tank? A cooling tower is used by some buildings as part of their air conditioning, ventilation and/or heating systems. A cooling tower contains water, but the water never enters the inside of the building.

 Is it safe to drink and wash with water if a building’s water tower has tested positive for Legionella? The cooling tower system for a building is separate from the tap water system. Public water in Suffolk County is routinely tested and monitored for its safety.

 Are air conditioning units safe to use? Legionella do not seem to grow in car or window air-conditioners.


Additional Information on Legionnaires' disease can be found here:

Cooling Tower Regulations

In August 2015, Governor Cuomo issued an emergency health regulation requiring all owners of cooling towers to register with the New York State Department of Health, to inspect the cooling towers and to obtain bacteriological samples from the towers for culture testing. Depending on test results, appropriate action must be taken.

All cooling tower owners must use a statewide electronic system to register and report actions required by the new regulations, through the following website:

Additionally, any owner of a cooling tower must develop and implement maintenance and sampling plan by March 1, 2016. Owners must maintain a copy of the plan and all maintenance records on the premises where the cooling tower is located. These documents must be reported annually to the New York State Department of Health.

The Emergency Legionella Regulations can be found here:
protection against

Building owners who need assistance with registration of cooling towers may call : New York
State at
(581) 402-7650

Suffolk County Government

H. Lee Dennison Bldg

100 Veterans Memorial Hwy
P.O. Box 6100
Hauppauge, NY 11788

Riverhead County Center

County Road 51
Riverhead, NY 11901