The recent outbreak of Legionnaires’ disease bacteria (LDB) in New York City speaks to a common truth about biological hazards – they are usually ignored until someone gets sick.
“Biological hazards are a serious concern for both construction laborers and the public, and they need to be treated that way,” says LHSFNA Management Co-Chairman Noel C. Borck. “We know how these diseases are spread and where they occur. Now it’s time to give them the attention they deserve.”
The New York outbreak of LDB killed 12 people in the South Bronx and sickened at least 100 more. New York typically sees about 200-300 cases of LDB a year, while estimates put the total number of annual cases across the U.S. at between 10,000 and 50,000.
Causes and Symptoms of LDB
The disease is caused by the water-borne Legionella bacteria, which causes symptoms similar to pneumonia. These symptoms normally begin with a high fever or cough, but also include nausea, muscle aches, headaches, diarrhea and chest pain. Because the symptoms of LDB are so close to pneumonia, diagnostic tests at a doctor’s office are usually required to tell the two apart.
The disease isn’t spread from person to person, but gets into the body when people breathe in mist or water vapor that contains the bacteria. LDB, also known as Legionellosis, is most often traced back to stagnant water in water transport systems. Fortunately, most people are resistant to the disease at low levels. However, chances of contracting Legionellosis rise when concentrations reach high levels in water systems or when people have compromised immune systems. In the recent New York case, the disease originated in the cooling towers of large rooftop air-conditioning units.
“Legionella love water systems, particularly old, clunky and corroded ones that are not well maintained and have a little sludge,” said Dr. Glenn Morris, the director of the Emerging Pathogens Institute at the University of Florida and a specialist in infectious disease.
Protecting Workers from LDB
The best way to protect workers from LDB is to keep it from occurring in the first place. Specific preventive steps include:
- Regularly maintaining and cleaning cooling towers and evaporative condensers at least twice per year and periodically with chlorine or another biocide.
- Maintaining domestic water heaters at 60°C (140°F). Water temperature should be 50°C (122°F) or higher at the faucet.
- Avoiding conditions that allow water to stagnate (e.g., by frequently flushing unused water lines).
The LHSFNA maintains Health Alerts on many different biological hazards:
- Bird and Bat Droppings
- Handling Medical Waste
- Hazardous Waste in Construction
- Lyme Disease in Construction
- Mold and Fungi
- Protecting Sewage Treatment Workers from Infection
- Seasonal Influenza
- Valley Fever
- West Nile Virus
These materials can be ordered through the Fund’s Publications Catalogue or by calling 202-628-5465. For more information, the Canadian Public Health Agency has developed Pathogen Safety Data Sheets on many different biological hazards.
Proper personal protective equipment (PPE) is essential to prevent the spread of biological hazards. The LHSFNA recommends workers do the following:
- Wear at least N95 respirators when cleaning, repairing or maintaining open cooling, HVAC or ventilation systems.
- Wear a half or full-face respirator when working on systems or in buildings that have a known or suspected LDB risk.
If a worker does contract Legionellosis, early treatment reduces the severity and improves chances for recovery.
Biological hazards, including bacteria, viruses and fungi occur in places construction laborers work every day. Knowing how to identify and protect against these unseen hazards before they are found on your jobsite is the key to keeping workers and the public safe.
To find out more about LDB, visit the Centers for Disease Control and Prevention’s page on the bacteria at www.cdc.gov/legionella/index.html.