Report provides road map to improve Legionnaires’ disease response and conserve water


A new policy report, “Electronic Registration Systems for Cooling Towers – Improving Public Health and Sustainability Outcomes”, published by the Urban Sustainability Directors Network (USDN) proposes a standardized yet flexible template for cooling tower registries that are designed to improve health outcomes, address disparity in affected populations, and increase water and energy efficiency.

Poorly maintained cooling towers can disperse Legionella through contaminated water droplets that are created as part of the cooling process. Once inhaled, the bacteria can cause Legionnaires’ disease, an acute form of pneumonia, and the less severe Pontiac fever. According to a study published in April 2018 in Current Environmental Health Reports, cooling towers were implicated or suspected in the majority of Legionnaires’ disease outbreak-associated deaths examined during the study period between 2006-2017.

The report argues that cities, states and water utilities should create electronic cooling tower registration systems to improve surveillance and response to cases, as well as to prevent exposure to Legionella bacteria by encouraging proper maintenance of cooling towers.

Additionally, since poor energy conservation practices increase water demand on buildings, registries are an important sustainability tool that can help evaluate the effectiveness of maintenance plans and identify areas for improved efficiency, the report highlights.


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The U.S. Centers for Disease Control and Prevention (CDC) reported a record number of 9,933 Legionnaires’ cases in 2018, a more than eightfold increase since 2000. According to NSF International (NSF), Response time is critical in an outbreak and proactively knowing the locations of cooling towers can help public health investigators pinpoint the source for remediation.

According to Health Canada, “the average number of reported cases of Legionnaires’ disease is generally less than 100 per year. However, the actual number of cases is thought to be much higher, as many people with pneumonia may not be tested for infection with Legionella.”

Most North American cities do not track the location of cooling towers and are “forced to rely on imprecise methodologies during public health emergencies,” the report says, adding that there is a “continued tolerance of widely divergent maintenance practices by building owners.”

“Cooling tower registries are a demonstrably effective and proactive tool for improving public health and fulfilling water efficiency goals,” said Patrick Ryan, Chief Building Official from Vancouver, a key participant city in the new report.

According to the report, registries provide municipalities with a management tool for maintenance record-keeping and support to building owners to meet regulations.

New York City was the first U.S. city to create an electronic cooling tower registry system after a large outbreak in 2015 that sickened 138 people and led to 16 deaths. According to NSF there are only a handful of Canadian cities and provinces that require cooling towers to be registered, including: Hamilton, Ontario; Vancouver, British Columbia; and Quebec.

Registries can also be a crucial tool to measure key sustainability performance indicators, aiding jurisdictions in evaluating the effectiveness of a building’s water conservation plans and identifying areas for improved energy efficiency.

Cooling towers can be a significant source of water demand for a building, representing 20-50% of total water usage, according to the report, which added that poor management practices result in millions of wasted gallons of water per year in a single cooling tower. In Los Angeles alone, for example, it is estimated that more than two billion gallons of water per year are wasted, according to the report.

NSF Health Sciences LLC, an NSF International company, and GroveWare Technologies developed the report for USDN with workshop input from more than 20 federal, state, provincial, city health, environmental, sustainability, water and/or building agencies.

Click here to download the full report (PDF).


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