As offices and facilities reopen and employees start returning to work in the course of the COVID-19 pandemic, it’s important to assess the potential risks posed by buildings that have been shut down or have had limited use for an extended period. One of these risks is the development of hazardous mold and bacteria, including Legionella, which causes Legionnaires’ disease. Before reopening a building, it’s a good idea to take steps to protect employees and visitors from potentially harmful microbes.
Health Risks Associated with Microbial Growth
Mold, Legionella, and other microbes can grow in buildings with excess moisture and stagnant water. These microscopic agents can cause a range of illnesses, from mild allergies to acute respiratory illness.
Legionella grows primarily in stagnant or standing water found in unused plumbing and other inadequately maintained building water systems.
Legionella health risks. Inhaling Legionella bacteria from aerosolized water can cause Legionnaires’ disease. Legionnaires’ disease is a severe form of pneumonia. Its symptoms include cough, shortness of breath, fever, muscle aches, and headache. Legionnaires’ disease has a case-fatality rate of about 10%.1
Moisture intrusion from the exterior building envelope, internal moisture sources, and elevated relative humidity can all give rise to mold growth within buildings on materials such as carpet, wallboard and other furnishings.
Mold health risks. Elevated indoor mold concentrations most commonly result in allergy health symptoms, such as sneezing, coughing, and itchy eyes. People with asthma or comprised immune systems can develop more serious illnesses, including respiratory infections and sinusitis. Some molds also produce mycotoxins, which are associated with a range of adverse health effects when found in high concentrations.
Tips for Reducing Legionella Risk
You can minimize the risks of Legionella by implementing a water management program in accordance with ASHRAE Standard 188, minimizing stagnation of water systems during periods of minimal occupancy, and performing regular maintenance on the following three areas:
Tips to Reduce Mold Health Risks
For more information on Legionella risk, see: Reducing the Risk of Legionnaire’s Disease.
For more information about protecting your business, visit our Risk Engineering Services.
1 Centers for Disease Control and Prevention: Legionella Fast Facts.
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