Frequently asked questions

MHFs are facilities that store and process very large quantities of hazardous substances. These facilities have the potential to generate catastrophic events which could cause harm to people, the environment and the wider economy.

A facility becomes a MHF if WorkSafe designates it as such. If the quantity of a specified hazardous substance at a facility meets the threshold for a MHF then the operator must notify WorkSafe and be assessed for designation as a MHF. 

All workplaces with hazardous substances must comply with applicable requirements in the Health and Safety at Work Act 2015 and associated regulations, particularly the Health and Safety at Work (Hazardous Substances) Regulations 2017. 

Workplaces that store and use large quantities of specified hazardous substances must comply with the Health and Safety at Work (Major Hazard Facilities) Regulations 2016 (MHF Regulations). The MHF Regulations are implemented by WorkSafe and specify types of hazardous substances and thresholds.

If a workplace meets the threshold for a MHF then the person operating the facility must seek designation as an MHF and fulfil the duties, as set out in the MHF Regulations.

It is important that territorial authorities are aware of MHFs in their area. Significant failure to control risks associated with these large quantities of hazardous materials doesn’t happen often, but when it does the consequences can be catastrophic. Because of this, territorial authorities should consider the presence and location of any MHF in their planning decisions. A list of MHFs is available on our website.

Under the Health and Safety at Work (Major Hazard Facilities) Regulations 2016, MHF operators must:

  • carry out a safety assessment to identify potential major incidents and major incident hazards
  • have and test an emergency plan
  • put in controls to manage risks
  • consult with the territorial authority on their emergency plan (Regulation 31)
  • notify the territorial authority in the event of a major incident (Regulation 67).
  • If the MHF is an Upper Tier MHF it must also -
    • have a safety case (Regulation 45), which is a written demonstration the operator has the ability and means to control major incident hazards effectively. The safety case must include demographic information about the local community, including surrounding land uses, within a 2 km radius of any point on the perimeter of the facility, that are permitted by the territorial authority (Schedule 7)
    • provide general information to the local community about their operation (Regulation 66)
  • If the MHF is a Lower Tier MHF it must have a Major Accident Prevention Policy in place (Regulation 36).

The Health and Safety at Work (Major Hazard Facilities) Regulations 2016 require MHF operators to consult territorial authorities and provide information to the local community. While the Regulations do not require or impose any additional responsibility on territorial authorities, they do have duties as Person Conducting a Business or Undertaking to consider the presence and location of a MHF in their planning decisions.

There are two types of MHFs – Upper Tier and Lower Tier. The difference between them is the aggregated quantity of specified hazardous substances on site.

 Many of the duties of Upper and Lower Tier MHFs are the same, except that:

  • An Upper Tier MHF must have a safety case that has been formally accepted by WorkSafe and provide general information to the local community about their operation (Regulation 66)
  • A Lower Tier MHF must have a Major Accident Prevention Policy in place (Regulation 36).

A safety case is a written demonstration that the MHF operator has the ability and means to control major incident hazards effectively. It must be formally accepted by WorkSafe.

The MHF regulations(external link) do not have a direct relationship with the RMA(external link), as they specifically apply to a facility or proposed facility where specified hazardous substances are present or likely to be present in significant quantities. The regulations specify how MHF operators will manage the risks of the specified hazardous substances. The regulations do not deal with planning matters.

A The operator of a Lower Tier MHF must have a Major Accident Prevention Policy (MAPP) in place. The purpose of a MAPP is to prevent the occurrence of major incidents and to limit their consequences to persons at or near the facility by appropriate means, structures and management systems. A MAPP must:

  • Include measures that are proportionate to any major incident hazards that could occur at the facility
  • Describe how the operator will control a major incident hazard
  • Be in writing.