Legionella prevention in the workplace
Learn about Legionella contamination and how to prevent exposure in the workplace.
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Legionella bacteria and Legionnaires’ disease
Employers must take every precaution reasonable in the circumstances for the protection of workers. This includes protecting workers from infectious hazards, such as Legionella. Legionella bacteria can cause:
- Legionnaires’ disease, a severe form of pneumonia
- Pontiac fever, a milder influenza-like illness
In workplaces, likely sources of contamination may include:
- cooling towers
- fountains and water features
- hot water tanks
- plumbing systems
- shower heads
Legionnaires' disease is most often contracted by breathing in mist from aerosolization of contaminated warm water sources. Legionnaires' disease has an incubation period (the time from exposure to the onset of symptoms) of 2 to 10 days.
Symptoms of Legionnaires' disease can include:
- muscle aches
If a worker has concerns that they are unwell because of exposure to Legionella bacteria, they should:
- talk to a health care provider
- consider contacting the local public health unit for more information about Legionella risks
- let their supervisor know about their concerns, and consider informing their joint health and safety committee (JHSC)
Workplace parties, such as employers, supervisors and workers share the responsibility for occupational health and safety under the internal responsibility system. Where the internal responsibility system fails to adequately address the health and safety issues in a workplace, a Ministry of Labour, Training and Skills Development (MLTSD) health and safety inspector may investigate concerns further. If the Occupational Health and Safety Act (OHSA) and its regulations are not being followed, MLTSD inspectors have the authority to enforce the law.
Learn more about how workplace health and safety issues are addressed under the Occupational Health and Safety Act.
This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. Health and safety inspectors apply and enforce these laws based on the facts they find in the workplace.
The following are key legal requirements under the Occupational Health and Safety Act that apply to Legionella. Other laws may also apply to prevent the spread of Legionella bacteria. As Legionella is a public health issue, employers are reminded that they must cooperate with local public health authorities who may independently investigate cases of infection caused by Legionella.
An employer must take every precaution reasonable in the circumstances for the protection of a worker. As part of this duty an employer should:
- be knowledgeable of the hazards caused by Legionella bacteria
- assess and evaluate the hazards caused by Legionella bacteria in their workplace
- protect workers from exposure to Legionella bacteria, particularly when doing work or performing maintenance on systems where it is likely that Legionella bacteria would be encountered, in particular when work involves Legionella prevention and remediation.
As a best practice, employers should ensure that appropriate maintenance programs are in place to prevent workplace health hazards arising from Legionella bacteria. This includes maintaining water systems and ventilation systems in buildings to protect workers from the hazard of exposure to Legionella bacteria.
To control hazards posed to workers when they are engaged in Legionella prevention employers must:
- ensure workers who participate in any sort of preventive maintenance and control program for equipment that may harbour Legionella bacteria (along with other potential risks) are provided with information, instruction and supervision to protect the health and safety of the worker
- acquaint the worker or a person in authority over that worker with the hazards of working in potential exposure to Legionella
- ensure equipment, materials and protective devices provided by the employer are maintained in good condition and used as prescribed
As a best practice, employers should also implement measures and procedures to control the Legionella hazards posed to workers engaged in this work.
If Legionella is found in the workplace
In addition to the measures taken for prevention, employers may be required to take further measures if they identify:
- Legionella bacteria in the workplace
- one or more cases of infection caused by Legionella occurring in workers at the workplace
If contamination with Legionella bacteria is present and anticipated to cause a hazard to workers, employers must implement remediation strategies and worker protection measures to prevent workers from being exposed to equipment or environments where Legionella contamination could pose a risk to their health.
Employers also have an obligation to report to the Ministry of Labour, Training and Skills Development (MLTSD) any cases of occupational illness in workers associated with workplace exposure to Legionella. This includes investigating for potential sources or processes that led to the exposure and the steps taken to prevent a recurrence or further illness, which may include plans to control any further hazard posed to other workers.
The OHSA requires that a supervisor take all precautions reasonable in the circumstances for the protection of a worker. A supervisor must also ensure a worker uses and wears the equipment, protective devices or clothing the employer requires to be used or worn. Where a supervisor is aware that Legionella bacteria are or potentially exist where the worker is doing work, the supervisor must advise workers of any potential or actual danger to the health and safety to the worker posed by the Legionella bacteria.
The OHSA requires workers to use or wear the equipment, protective devices or clothing that a worker’s employer requires to be used or worn. This may include situations when workers must use the equipment, protective devices or clothing the employer has required them to use or wear to be protected from the hazard of exposure to Legionella bacteria.
Health care and residential facilities
Workplaces that are regulated by the Health Care and Residential Facilities Regulation must also meet the following requirements.
Written measures and procedures
The employer must develop, establish and put into effect written measures and procedures for worker health and safety in consultation with the joint health and safety committee or health and safety representative, and in consideration of their recommendations, if any.
These written measures and procedures may include:
- safe work practices and safe working conditions
- proper hygiene practices and the use of hygiene facilities
- the proper use, maintenance and operation of equipment
- the control of infections
- the use of appropriate antiseptics, disinfectants and decontaminants
- the use, wearing and care of personal protective equipment and its limitations
Sections 8-9 of the regulation deal with written measures and procedures.
Employers must also:
- in consultation with and in consideration of the recommendations of the JHSC and health and safety representative (HSR), develop, establish and provide training and educational programs in health and safety measures and procedures that are relevant to the workers’ work
- ensure that the measures and procedures are reviewed and revised at least once a year in accordance with the regulation
Employers must ensure that indoor ventilation is adequate to protect the health and safety of workers and must ensure that a mechanical ventilation system is inspected by a qualified person every six months to ensure it is in good condition.
An employer must also ensure that the ventilation system is serviced and maintained as frequently as recommended by the manufacturer.
Sections 19-20 of the regulation deal with ventilation.
The Regulation for Industrial Establishments requires that industrial establishments be adequately ventilated so the atmosphere does not endanger the health and safety of workers.
- Infrastructure Health and Safety Association, Legionellosis Cause and Controls
- Public Health Ontario, Legionella: questions and answers, 2nd edition
- Canadian Centre for Occupational Health and Safety (CCOHS), Legionnaires’ Disease
- U.S. Department of Labor--Occupational Safety and Health Administration, Legionella (Legionnaires’ Disease and Pontiac Fever)
- Centers for Disease Control and Prevention (CDC), Legionella (Legionnaires’ Disease and Pontiac Fever), Toolkit for Controlling Legionella in Common Sources of Exposure
- Health and Safety Executive, United Kingdom, Legionella and Legionnaires’ Disease
We have included links to other websites, but this does not mean that we endorse their information as compliant with the OHSA or the regulations.