Legionellosis

Legionellosis is an infection caused by the bacterium Legionella pneumophila. The disease has two distinct forms:

• legionnaires' disease, the more severe form of infection, which includes pneumonia
• pontiac fever, a milder illness.

Legionella bacteria can be found in both water and soil in the New Zealand environment and can breed in built environments, such as cooling towers. To prevent the growth of the bacteria, cooling towers must be designed appropriately, treated and tested regularly.

There are a number of formal mechanisms to ensure testing for legionella bacteria takes place on a regular basis. Some are governed by the Building Act, others by the Health Act. (This information provides background on testing for legionella bacteria under the Building Act and the roles of a number of agencies.)

Building owners’ responsibilities

The Building Act 2004 requires that all buildings that contain a mechanical ventilation system have a compliance schedule. A compliance schedule requires specific inspection, maintenance and reporting procedures for a variety of systems including mechanical ventilation systems, which can incorporate air-conditioning cooling towers.

The New Zealand Building Code Handbook contains a model compliance schedule for mechanical ventilation systems. This requires monthly testing for the presence of bacteria and legionella bacteria. Legionella tests with results greater than or equal to 1000 cfu/ml should be notified within 48 hours to the local medical officer of health at the public health service of the district health board.

If building owners do not comply with the requirements of a compliance schedule, a notice to fix can be issued by the territorial authority. This notice would require the owner to comply with the inspection, maintenance and reporting procedures stated in their compliance schedule. If this notice was not complied with the owner could be fined up to $200,000. In the case of a continuing offence, a further fine not exceeding $20,000 can be given for each day or part day during which the offence is continued.

Building owners are responsible for ensuring their buildings are properly maintained, and comply with the compliance schedule. This requirement is fulfilled by way of a building warrant of fitness, which is a statement supplied by the building owner to the territorial authority confirming that specified systems listed on the compliance schedule have been inspected, maintained and reported on in accordance with the compliance schedule.

In providing the building warrant of fitness, the building owner will be confirming that the mechanical ventilation systems (if present) have been inspected, maintained and reported on in accordance with the compliance schedule.

As in the case of a compliance schedule, the territorial authority can issue a notice to fix if the requirements of the building warrant of fitness are not met. The building owner could be fined up to $200,000 and, in the case of a continuing offence, a further fine not exceeding $20,000 for each day or part day during which the offence is continued.

Territorial authorities (councils)

Territorial authorities are required to comply with the Building Act 2004 and associated regulations to ensure buildings are safe and healthy. They administer and enforce the building warrant of fitness/compliance schedule regime, which identifies safety systems and features present in a building (such as sprinkler systems, lifts or cooling towers), the performance standards for those systems, and how they will be inspected and maintained to ensure they continue to function safely.

Department of Building and Housing

The Department of Building and Housing administers the Building Act 2004 and associated regulations. While fulfilling this role it ensures that buildings are safe and healthy under the Building Act 2004. The Building Act 2004 sets the framework to achieve this.

For buildings with cooling towers, provisions include:

• the building warrant of fitness/compliance schedule regime
• offence provisions
• territorial authorities setting policies on dangerous and insanitary buildings.

Department of Labour

The role of the Department of Labour is to assess a workplace’s ability to understand and manage hazards which may arise in their day-to-day work. The Department of Labour works with businesses to promote compliance with health and safety legislation, establish health and safety controls around work processes, and educate on managing hazards. In the event of an outbreak of Legionnaires’ disease, the lead agency in charge of the investigation is Public Health.

If a workplace is identified as being a possible source of legionella bacteria, the Department of Labour will work with Public Health and other agencies such as territorial authorities to investigate specific risks in the workplace that may have contributed to the growth of the bacteria.

In serious cases, action may be taken under the Health and Safety in Employment Act to improve the health and safety of the workplace, prohibit dangerous activities or to prosecute.

Cooling towers outside of the building warrant of fitness, such as those associated with a manufacturing process, are covered under the Health and Safety in Employment Act 1992 administered by the Department of Labour and are expected to comply with AS/NZS 3666 Parts 1, 2 and 3.

Ministry of Health and public health services

In New Zealand, legionellosis is a notifiable disease. A doctor is required to notify the medical officer of health at the public health service if they suspect a patient suffers from, or is diagnosed with legionellosis.

The public health service will investigate by interviewing the patient and/or their relatives to find out any risk features or exposures the patient has had. For a single case, such exposures may include exposure to soil or potting mix, or the hot water system in the person's home. When there is more than one case in an area, the public health service will look for their exposures in common, such as visiting a building with cooling towers or visiting areas where there have been earth works.

The public health service will take samples to test for legionella bacteria in these sources and may make recommendations if there are any health risks identified. The Ministry of Health will assist the public health service by providing technical advice, if necessary.

Standards New Zealand

In April 2004, a more rigorous testing regime for cooling towers was introduced (NZS 3666.3). It increased the frequency of testing for legionella bacteria from 6-monthly to monthly tests. This assists building owners to demonstrate their building’s compliance to the New Zealand Building Code and to demonstrate their ongoing compliance to territorial authorities.