Photo: Centers for Disease Control and Prevention

Atlanta — Workplace water systems in facilities that had reduced occupancy or were unoccupied during the COVID-19 pandemic are at increased risk for bacterial growth such as Legionella, the Centers for Disease Control and Prevention and a Canadian safety and health training center are warning employers and building managers.

The Workers Health and Safety Center – designated by the Canadian government as Ontario’s health and safety training center – in August warned of Legionella bacteria in government buildings or “any building that goes more than one week with low or no occupancy.” The center specifically mentions workplaces in which processes using water or water-based fluids (e.g., metalworking fluids) have been left to stagnate.

According to CDC, stagnant or standing water in a plumbing system can increase the risk for growth and spread of Legionella. This could leave workers, especially those with weakened immune systems, at increased risk of contracting the potentially deadly Legionnaires’ disease from the water system when buildings reopen and employees return to the workplace.

The government agency Public Services and Procurement Canada in June published an updated safety alert that provides minimum requirements for building water systems. They include:

  • Periodic flushing
  • Maintaining trap seals
  • Annual potable water sampling and Legionella testing
  • Completion of the water system’s return-to-occupancy checklist

CDC provides eight steps to minimize Legionella risk in its guidance on reopening buildings after a prolonged shutdown or reduced operation. The steps include developing a comprehensive water management program, ensuring proper maintenance and settings for water heaters, and cleaning decorative water features.