08/05/2026
Training: The Neglected Factor in Reducing Legionella
Matt Freije, a well-known expert in building water management and Legionnaires' disease prevention, recently asked an important question:
"What do you think are the key factors for reducing Legionella in the years ahead?"
My answer is simple:
Training.
Matt first highlighted several major milestones in the fight against Legionnaires' disease.
Fifty years ago, approximately 4,000 members of the American Legion gathered at the Bellevue-Stratford Hotel in Philadelphia for their 58th annual convention. A few days later, 221 people became ill and 34 died (Fraser, 1976).
One of the largest epidemiological investigations of its time followed. About six months later, investigators from the CDC identified the previously unknown bacterium that became known as Legionella.
During the 1990s, more than one hundred scientific papers were published, along with practical guidance such as OSHA (1996) and Freije (1996), translating scientific knowledge into actions building operators could implement to reduce risk.
In 2000, ASHRAE published Guideline 12. Fifteen years later, the release of ASHRAE Standard 188 marked a turning point by establishing broad consensus among government agencies and industry organizations on both the need for Legionella prevention and the best approach to managing building water systems.
The Future of Legionnaires' Disease Prevention
A 2021 study evaluating more than 900 water management programs demonstrated that fully implementing a comprehensive Water Management Program significantly reduces Legionella in building water systems. The CDC also reported that 70% of the deficiencies associated with Legionnaires' disease outbreaks between 2015 and 2019 were related to failures in Water Management Program implementation.
Matt concluded that the future depends on two essential elements:
smart regulations;
effective inspections of Water Management Programs.
I agree—but I believe there is a third pillar.
Quebec adopted regulations for cooling towers in 2013. Since then, I have dedicated my work to Legionnaires' disease prevention. My experience has taught me that regulations are necessary, but they are not sufficient.
After fifty years of investigations, scientific research, guidelines, standards, and regulations, one critical element still does not receive the attention it deserves:
Training.
That is why I developed the Risk–System–Program framework. It became the foundation of TOP GUN Training, a program designed to transform professionals from technical task performers into guardians of public health.
This is the future of Legionnaires' disease prevention: technology, regulations— and training.
What do you think?
Can you imagine the future of Legionnaires' disease prevention without training?