August 18, 2025 Rethinking Legionella Control in Manufacturing

Manufacturing: A hotbed for legionella risk. Cases of Legionnaires’ disease in the U.S. have surged, posing risks for manufacturers.

By Greg Rankin, Hydrosense

It is widely understood that manufacturing environments pose a series of unique and often elevated risks for Legionella growth and transmission, for a number of reasons.

Fundamentally, these facilities tend to feature large-scale infrastructure that uses water intensively for cooling, cleaning, or processing. In addition to standard domestic plumbing, in  any one site there may be any number of specialized water systems such as cooling towers, process water networks, large storage tanks, and machinery-specific cooling or humidification units. The diversity and scale of these systems increase the opportunities for Legionella bacteria to proliferate if not managed correctly.

Complex pipework, irregular usage patterns, and areas of stagnation further increase the risk, especially when systems are difficult to fully drain or disinfect. Additionally, the widespread use of aerosolizing equipment – such as water jet cutters, floor scrubbers, spray booths, humidifiers, and misting systems – can create fine water droplets that, if contaminated, allow Legionella bacteria to become airborne and potentially inhaled. A striking example of this occurred during the 2022 Legionellosis outbreak at a manufacturing plant in South Carolina.¹ In this tragic incident, 34 employees fell ill, with 15 hospitalizations and two fatalities. Investigations identified unexpected sources as the root cause – specifically water jet cutters and floor scrubbers that aerosolized contaminated water, enabling the rapid spread of Legionella bacteria throughout the facility.

Of course, though, none of this is a new concern. For decades, Legionella bacterium – responsible for the potentially fatal Legionnaires’ disease – has been present in various man-made water systems and manufacturing sites will be well versed in the standards and procedures necessary to minimise risks.

However, what is new is the expanding scope of the risk. In the USA, the incidence of Legionellosis has surged by approximately 1000% over the past two decades.² Though the reasons for this dramatic global rise have been declared a ‘scientific mystery’ it’s clear that factors such as climate change, warming temperatures and increasingly complex water systems have all contributed to the rapidly increasing count. Combined, these factors are creating conditions that not only increase the likelihood of Legionella growth but also make it more difficult to detect and control.

Given these challenges, it’s becoming vital that manufacturers adopt a multi-layered, risk-based approach to Legionella control – one that extends far beyond traditional periodic testing and reactive responses. But to fully appreciate the need for this shift, it’s important to first understand why the traditional approach is no longer fit for purpose.

Real-World Response: Why Traditional Testing Fails

Imagine the scene: a large car manufacturing plant relies on a single, substantial cooling tower to regulate the temperature of 20 plastic molding machines, each equipped with its own dedicated cooling loop and sampling point branching off the main pipework. For the past two months, one of these machines has consistently tested positive for Legionella bacteria. Despite initially low counts and multiple attempts at control, laboratory analyses show that Legionella levels are steadily rising.

An immediate and efficient on-site solution for accurate Legionella testing is needed to take control of the situation. However, most lab culture tests – the standard approach of Legionella testing – take 7-10 days to return results. Yet Legionella can double in a day. This large time lag means increased exposure and risk for employees, while allowing the bacteria to spread further. It also means that a shutdown of the cooling tower is needed, thus halting all 20 plastic mould machines, resulting in extensive production downtime and disruption.

Adding to the challenge, lab culture testing is not infallible. Water samples transported to off-site labs can be compromised in transit, potentially killing Legionella bacteria and leading to false negative results. Even more concerning is the inability of traditional culture methods to detect Viable but Non-Culturable (VBNC) Legionella – dormant bacteria capable of “waking up” and causing infection. Consequently, the plant may be lulled into a false sense of security when lab results return negative, only to discover persistent contamination in further tests.

The upshot is clear –  the traditional approach to Legionella testing could leave the plant exposed to financial, operational, and reputational harm. Fortunately, there is a better way.

Proactive Protection: How Rapid Testing Transforms Risk Management

Developed to address these limitations, the latest rapid Legionella testing technology delivers results in just 25 minutes. It not only offers exceptional accuracy in identifying Legionella pneumophila – the most common and potentially fatal species of the bacterium but can also find VBNC Legionella too.

This level of speed and precision enables manufacturers and duty holders to respond to contamination in real time, taking immediate corrective action to reduce the risk of exposure and infection. When integrated into existing protocols – such as cooling system management plans – this approach allows for regular, proactive monitoring with minimal disruption to operations. It also helps to prevent minor issues from escalating into full-scale incidents, ensuring both business continuity and occupant safety.

Furthermore, rapid testing generates valuable, actionable data that can be used to inform and enhance ongoing risk assessments. By providing a clearer, more immediate picture of overall and individual system health, it supports smarter decision-making, more effective control measures, and stronger evidence of regulatory compliance.

The Manufacturing Mandate: Lead, Don’t Lag

Legionella represents a serious and, by all accounts, a rising risk in industrial settings, with manufacturing environments now responsible for approximately 62% of all workplace-associated Legionellosis cases.³ This makes the manufacturing sector the largest single contributor to occupational Legionella outbreaks.

Against this backdrop, it is critical that manufacturers take every possible step to optimize safety for their workforce and surrounding communities. History has shown that early adopters of best practices and emerging technologies enjoy distinct advantages: better regulatory standing, improved public trust, and fewer costly incidents. In this way, it will be those manufacturers who act now to implement robust, risk-based Legionella control programs with rapid testing technology who will not only reduce their exposure to health, legal, and operational risks – but will be recognized as industry leaders driving safer and more resilient operations.

About the Author:
Greg Rankin is a seasoned technology product veteran with a deep passion for protecting public health from Legionella bacteria. Since joining Hydrosense as CEO in 2017, he has led the company’s rapid growth, tripling revenue and spearheading innovation in Legionella rapid testing solutions. Under his leadership, Hydrosense has revolutionised water safety by providing the world’s fastest on-site test, enabling businesses to detect Legionella bacteria in just 25 minutes – significantly reducing risks and allowing for immediate action to keep people safe.

With a decades of experience in technology, marketing, and business development, Greg’s expertise spans end-to-end marketing and product management, with a strong focus on meeting customer’s needs. His career has seen him hold key roles at leading companies such as Oracle, Ingenico, and Metaforic, as well as a number of startups, where he honed his skills in delivering innovative solutions to global markets.

Greg fosters a culture of trust, values diversity, and encourages a ‘test and learn’ approach within his team. He is dedicated to raising awareness about the broader risks of Legionella outbreaks, advocating for greater vigilance and early detection in all sectors. His unwavering commitment to public health and respect for his team, industry, and customers continue to drive the Hydrosense mission to make water safer for everyone.

About Hydrosense: 
Hydrosense is on a mission to make Legionella detection easier, faster, and more effective than ever before with its innovative, world-leading rapid Legionella testing solutions.

Ideal for industries that require more stringent action levels, Hydrosense overcomes the limitations of traditional lab-culture testing with its innovative Hydrosense Legionella testing kits. This includes the Hydrosense PRO range, which can detect the presence of Legionella pneumophila serogroups 1-15, and the Hydrosense ONE range, which can detect the presence of Legionella pneumophila serogroups 1 only. Easy to use, accurate, and with results delivered in just 25 minutes, the result is the early detection of problems, speedy remedial action, and a reduction in potential exposure and the associated risks.

For further information please visit: https://hydrosense-legionella.com/

¹ https://pubmed.ncbi.nlm.nih.gov/39714278/
² https://pmc.ncbi.nlm.nih.gov/articles/PMC10540183/
³ https://pubmed.ncbi.nlm.nih.gov/27717486/

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