Legionella

High-risk facilities and factors that promote proliferation

• Cooling towers and evaporative condensers. Installations with a higher risk due to the dispersion of aerosols to the outside; they must be notified to the health authority within one month of their installation.
• Domestic hot water and drinking cold water. Storage tanks, networks with unused branches, showers and taps that are rarely used in hotels, hospitals, residences, sports facilities, workplaces and changing rooms.
• Spas, hot tubs, and mist pools. Warm temperatures and water agitation.
• Other facilities. Sprinkler irrigation, ornamental fountains, humidifiers, fire water systems with regular testing, vehicle washing, respiratory therapy equipment, and nebulizers.
• Proliferation factors: Temperatures between 25 and 45 degrees, stagnation, dirt, scale, corrosion, biofilm, unsuitable materials, and absence of residual disinfectant.
• Routes of exposure: Inhalation of aerosols and, less frequently, aspiration of contaminated water; it is not transmitted from person to person.

Obligations of Royal Decree 487/2022

The facility owner is responsible for ensuring compliance with health requirements and must implement a Legionella Prevention and Control Plan, based on the initial facility assessment and action programs (maintenance, inspection, cleaning and disinfection, water treatment, sampling and analysis, staff training, and record-keeping), or a Legionella Health Plan based on Hazard Analysis and Critical Control Points (HACCP), adapted to the facility’s characteristics and validated by qualified technical personnel. The plan includes procedures for responding to unfavorable analytical results and outbreaks, notification to the health authority, and corrective measures.

Personnel performing operations must have the appropriate training for their roles: technical personnel require specific qualifications, and those applying treatments must demonstrate training in the hygienic and sanitary maintenance of facilities at risk of Legionella. Records of operations, analyses, incidents, and corrective measures are kept for at least five years, preferably in electronic format, and made available to the health authority. Cooling towers and evaporative condensers are reported to the competent authority, along with their technical specifications and any modifications.

Relationship with occupational risk prevention

• Group 2 biological agent. Legionella pneumophila is listed in Annex II of Royal Decree 664/1997, which requires assessing exposure, reducing it, informing and training, applying hygiene and protection measures and ensuring health surveillance.
• People exposed. Maintenance, cleaning and disinfection personnel of facilities, air conditioning technicians, cooling tower operators, laboratory personnel who take samples and workers near aerosol sources.
• Protective measures. Work procedures that minimize the generation of aerosols, equipment shutdown during operations, appropriate respiratory protection (particle filtering masks), eye protection and gloves, and training on the risks.
• Coordination of activities. Information and instructions to maintenance and treatment companies, and to companies working in the vicinity of the facilities.
• Health surveillance. Specific protocols for exposed personnel and care for particularly vulnerable individuals.
• Occupational disease. Infectious diseases caused by the work of people who are involved in the prevention, assistance and care of the sick, and those associated with biological agents in certain jobs, are included in the list of occupational diseases.

Organizational application: how to manage the risk of legionella

1. Inventory the risk facilities of each workplace (towers, accumulators, hot and cold water networks, showers, spas, irrigation, fountains, humidifiers) and classify them according to their probability of proliferation and dispersion.
2. Carry out the initial diagnosis and implement the Legionella Prevention and Control Plan or the Legionella Health Plan, with maintenance, cleaning and disinfection programs, water treatment, sampling and training.
3. Notify the health authority about cooling towers and evaporative condensers and, where appropriate, hire treatment companies with qualified personnel.
4. Evaluate the occupational exposure of internal and external personnel involved in the facilities in accordance with Royal Decree 664/1997 and define the work procedures, respiratory protection and health surveillance.
5. Train the staff involved and coordinate with maintenance companies and those working near aerosol sources.
6. Record all operations, analyses, incidents and corrective measures, and keep them for at least five years.
7. Review the plan in the event of unfavorable results, cases or outbreaks, facility modifications, and regulatory changes.

Preventive management software allows you to maintain an inventory of risk facilities by center, schedule and record maintenance, cleaning, disinfection and sampling operations with expiration notices, keep certificates and analyses for the required period, manage training and protection of exposed personnel and coordinate actions with external companies.

Limits and common mistakes

1. Limit management to cooling towers and forget about domestic hot water networks, changing room showers and underutilized water points.
2. Delegating to the treatment company without the owner assuming responsibility or supervising the plan and records.
3. Do not maintain safe temperatures or purge dead branches and low-use points.
4. Perform cleaning and disinfection without protecting staff from inhaling aerosols and chemicals.
5. Do not keep records or update the plan after facility modifications.
6. Ignoring the occupational exposure of maintenance personnel and contracting companies.

Specific requirements depend on the type of installation and the regional regulations for its development; this sheet is for informational purposes only.

Regulatory and reference framework

• Royal Decree 487/2022, of June 21. Health requirements for the prevention and control of legionellosis.
• Royal Decree 664/1997, of May 12. Protection of workers against risks related to exposure to biological agents during work; Legionella pneumophila, group 2.
• Law 31/1995, of November 8. Law on the Prevention of Occupational Risks.
• Royal Decree 773/1997, of May 30. Use of personal protective equipment; respiratory protection.
• Royal Decree 1299/2006, of November 10. Table of occupational diseases; diseases caused by biological agents.
• Royal Decree 614/2024, of July 2. Amends Royal Decree 487/2022.

Royal Decree 487/2022 came into force on January 2, 2023 and repealed Royal Decree 865/2003; the autonomous communities exercise the powers of health control and may establish additional requirements.