Methods to managing effect of hazardous substances in RMA Plans

One of the key circumstances where councils may want to consider addressing hazardous substances in their RMA plans is where the risk to the receiving environment is of such significance that the risk of a hazardous facility in a specific location may not be acceptable without additional mitigation, taking into account controls under HSNO Act and the HSW Act. In order to understand this risk, a risk analysis needs to be undertaken.

There are no standard risk criteria for hazardous substances in New Zealand but there are international criteria which are widely referenced.  In particular, the New South Wales Hazardous Industry Planning Advisory Papers no. 3 (Risk Assessment) and 4 (Risk Criteria for Land Use Safety Planning) has widely been used in the New Zealand context, and can be reflected in risk any management area overlays.  These papers (and more) can be found here.

As a first step, councils should focus on the following when they are reviewing their RMA hazardous substances plan provisions:

  1. Identifying specific hazardous substance related activities that are occurring within their area that might pose a risk off site (such as Major Hazard Facilities
  2. Identifying the probability of a particular risk event (such as a fire or explosion)
  3. Identifying specific sensitive land uses that may require additional protection (e.g. sites of ecological significance and areas prone to natural hazards).  

Councils need to then determine whether there is appropriate environmental protection through the HSNO Act and/or HSW Act or any other relevant legislation. Consideration should then be given to whether adequate controls are provided through zoning/overlay controls and, if not, work out if it is necessary to provide additional protection for any of these areas or activities. This analysis should be undertaken in consultation with key stakeholders (i.e. operators of hazardous facilities that understand their HSW Act and the HSNO Act compliance requirements).  

In most circumstances, this analysis is likely to show that the HSNO Act, the HSW Act and/or existing zoning controls and/or overlays in plans provide adequate protection to manage the risks of hazardous substances and it is unnecessary to place additional control on hazardous substances.  For example, hazardous substances in non-domestic quantities are usually associated with industrial activities, which are generally undertaken in industrial zones. Industrial activities are less likely to experience reverse sensitivity effects from neighbouring land uses who would typically be undertaking similar activities. Conversely, activities that use hazardous substances in large quantities in more sensitive zones (i.e. within residential areas) have greater potential for adverse effects on surrounding land uses. In these areas, additional controls on the establishment of hazardous facilities may be necessary to ensure that the effects/risks of these activities are addressed.  Councils will also need to be satisfied that any controls around hazardous facilities (existing or anticipated) are sufficient to ensure sensitive activities cannot establish without appropriate consideration of risk, including reverse sensitivity effects. 

Use of Risk Overlays and/or Separation Distances

Councils may include controls on hazardous substances to address effects not appropriately addressed by compliance with the HSNO Act and HSW Act through the use of location specific risk overlays or separation distances (using risk contours based on a risk analysis). For example, a risk overlay or a separation distance rule could be used to as a method to manage the risk around major hazard facilities to prevent the encroachment of sensitive activities within a certain contour/distance. 

Overlays or separation distances could also be used in relation to a particularly sensitive receiving environment (e.g. unconfined aquifers used for drinking water purposes and/or particular natural hazard areas) to manage hazardous facilities near or within these areas.  

These methods may be justifiable to enable the risk to be managed to an acceptable level, provide for the establishment of hazardous facilities in suitable locations, and protect people, property and the environment from unacceptable risks.