What is Legionella?
Legionnaires' disease is a lung infection (pneumonia) caused by a bacterium named Legionella pneumophila. The name Legionella pneumophila was derived from the original outbreak at the 1976 American Legion Convention in Philadelphia. Pneumophila means lung-loving in Greek.

What organism causes Legionnaires' disease?
Legionnaires' disease is caused by bacteria that belong to the family Legionellaceae. This family now includes 48 species and over 70 serogroups. Approximately half of these species have been implicated in human disease. Legionella pneumophila is responsible for approximately 90% of infections. Most cases are caused by L. pneumophila, serogroup 1. Legionella species are small (0.3 to 0.9 ¼m in width and approximately 2 ¼m in length).

Is Legionnaires' disease contagious?
Legionnaires' disease is not contagious. The disease is transmitted by breathing contaminated water droplets or aerosols, not by infected persons.

Legionella Risk Assesment

Do all work places need a legionella risk assessment?
The HSC approved code of practice for legionella (L8) applies to ' any undertaking involving a work activity and to premises controlled in connection with a trade, business or other undertaking where water is used or stored and where there is a means of creating and transmitting water droplets which may be inhaled, thereby causing a reasonably foreseeable risk of exposure to Legionella Bacteria legionella bacteria '. So if have water on-site you need a Legioneall Risk assessment.

What do I need to do after the legionella risk assessment?
The Legionella Risk Assessment will either find the site to be either low or negligible risk, in which case a simple review of the assessment should be made every 2 years, or it may be that a reasonably foreseeable risk is identified. In this instance, remedial work may be recommended together with a programme for continual monitoring and control.

Legionella Control

What site monitoring will I need to do?
The required level of monitoring will depend on the plant and water services at the site. Typically, a standard office with simple domestic welfare facilities would require monthly monitoring of water temperatures, annual inspections of cold water storage tanks and an annual review of the management programme. In addition, water services that are used infrequently would need to be flushed weekly. In situations where water is used in a process or a cooling tower or evaporative condenser is in operation more frequent and in-depth Legionella monitoring would be required.