Legionella is a bacteria often found in lakes, rivers and reservoirs but in numbers low enough not to be any cause for concern. However, once the bacteria infiltrate man-made water systems such as hot tubs, humidifiers, indoor fountains, commercial water systems, evaporative condensers and cooling towers, they can thrive and multiply to the point where they become hazardous to health.

An overgrowth of the Legionella bacteria can cause a number of diseases in humans, collectively known as Legionellosis, which includes Pontiac fever and Lochgoilhead fever. The most well-known variant is known as Legionnaire’s disease, named after the first documented outbreak which occurred at an American Legion conference in the 1970s. Often fatal, the disease attacks the lungs and is of particular concern to those with a compromised immune system, older people and anyone suffering from a respiratory disease.

How do People Catch Legionellosis?

The disease cannot be passed from person to person but is contracted through inhalation of bacteria contained in airborne droplets of water. One of the major influences that increase the chances of bacteria growing to dangerous levels includes a water temperature of between 20 to 45 degrees Celcius. Cooling towers are of particular concern since they create the perfect environment for contaminated droplets of water, but anywhere that recirculates or stores water can be considered a high-risk area. Some deposits such as organic matter, sludge, scale and rust can also provide a nutrient source that encourage growth of bacteria.

Symptoms and Treatment

The symptoms of Legionellosis are very similar to flu, including raised temperature and fever, muscular pain, headache and cough. Blood and urine tests can confirm the diagnosis, at which point medical practitioners will attempt to identify the source of the disease as other people are also likely to be infected.

If not treated promptly, the disease can quickly develop into pneumonia. Urgent antibiotic treatment is required in order to limit the impact of the disease.

Legal Implications

Employers who discover a case of Legionnaire’s disease that may have been acquired on work premises have a legal obligation to report this fact to their local Health and Safety Executive. The employer will need to prove that risk assessments had been carried out and the company adhered to COSHH guidelines in order to avoid prosecution. This is why legionella awareness training is so important for any company which could potentially be affected.

Training

Legionella awareness training needs to be appropriate for the needs of the company, as risk assessments, control measures and monitoring regimes vary according to the type of business and potential risks involved. Building engineers and facilities managers need to undertake training appropriate to their working practices, whilst people working in and around cooling towers require specialised knowledge of risk management.

It is of great importance that training is relevant, effective and timely, hence the need to continually monitor and update working practices to ensure that control measures to safeguard against Legionellosis remain effective at all times.