New York Committee for Occupational Safety and Health.
A Fact Sheet for Workers and Unions.
Legionaires” Disease is an infection of the lungs that is a form of pneumonia. There are over 25,000 cases of Legionaires’ Disease Bacteria ( LDB), each year in the U.S., with more then 4000 deaths. This has been brought to light by the 12 deaths in the last week, in NYC. The fatality rate is 15%. However, fewer then 5% of people exposed to LDB, develop the disease. LDB is primarily transmitted by inhaling water mist that is contaminated with elevated levels of LDB. Certain conditions promote amplification of high concentrations. Such as, man-made water transport, distribution, and heating and cooling systems. Equipment that can amplify LDB include: cooling towers, evaporative condensers, humidifiers, holding tanks, potable water plumbing systems and heaters, and pipes that contain stagnant warm water. Legionaires’ Disease is not contagious.
Symptoms usually appear in 2 to 10 days. Early symptoms can include low fever, headache, aching joints and muscles, fatigue and lack of energy, and loss of appetite. Later symptoms include high fever (102*-105*), cough, difficulty breathing, chills, chest pain, and gastrointestinal symptoms.
Legionaires” Disease usually attacks individuals with weakened immune systems. Certain groups of workers who maintain, clean, decontaminate, or work in close proximity to water systems and system components, as previously mentioned, are at an increased risk to exposure.
Legionaires’ Disease is difficult to diagnose. It is quite similar to other forms of pneumonia. Chest x-rays and lab work are needed to confirm the diagnosis.
Treatment requires the use of antibiotics. Early treatment can reduce the severity of the symptoms and improve the chances of recovery.
The best method of prevention is to eliminate water conditions that allow the bacteria to grow to high levels. Regular maintenance and the cleaning of cooling towers and evaporative condensers, twice yearly, and the use of chlorine or another effective biocide, is required. Also, prevent the discharge air from towers or condensers, not be drawn-in to the outside air intakes of air handlers and make-up supply air units. Ensure drift eliminators on towers and condensers are maintained. Speed drives that reduce the fan rates of towers and evaporative condensers, on low load conditions, decrease the discharge air plumes, that you normally see rise high into the atmosphere. Keep air filters for outside air dry. Also, when maintaining equipment, use the proper personal equipment (PPE). The proper respirator protection, although not mandated, is recommended.
Preventative Maintenance should not be an after-thought. Lack of… does have its consequences, that affect us all. LJ