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Major hazard facilities

Major hazard facilities

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Major hazard facilities (MHFs) are workplaces that have significant inherent hazards due to the storage and use of large quantities of specified hazardous substances.  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. The Health and Safety at Work (Major Hazard Facilities) Regulations 2016 (the regulations) mandate specific duties relating to process safety that apply to designated MHFs and outline requirements for potential MHFs. Transitional provisions are included for existing major hazard facilities (see below).

MHFs are designated as Lower Tier (LT) or Upper Tier (UT) depending on the aggregated quantities of specified hazardous materials listed in Schedule 2 of the regulations. The main difference in the regulatory requirements of the two categories is that UT MHFs must submit a safety case to WorkSafe which must be accepted to allow continued operation as an MHF. A safety case is a document that summarises and describes process safety related systems and controls in sufficient detail to demonstrate their adequacy. For example demonstrate the adequacy of the selection, implementation and functionality of such systems and controls at the facility.

An LT MHF is not required to prepare a safety case but have additional process safety related duties that are proportionate to potential major incident hazards at the facility. This includes a requirement to prepare a major accident prevention policy (MAPP) that sets out the policy and principles by which the MHF operator prevents and limits the consequence of a potential major incident.

Five good practice guidelines now published

WorkSafe has developed a suite of five good practice guidelines for operators of facilities or proposed facilities on how to fulfil their duties under the Health and Safety at Work (Major Hazard Facilities) Regulations 2016.

Visit the guidance page.

The Health and Safety at Work (Major Hazard Facilities) Regulations 2016, deal with the health and safety of people involved in operating major hazard facilities that produce, use or store certain hazardous substances


On Monday 4 April 2016, the New Health and Safety at Work Act 2015 (HSWA) came into effect.


HSWA repeals the Health and Safety in Employment Act 1992, with immediate effect.

All references to the 1992 Act on this website will be progressively removed.


Amendments to the Health and Safety at Work (Major Hazard Facilities) Regulations 2016

The Health and Safety at Work (Major Hazard Facilities) Regulations 2016 have been amended with these amendments coming into force on 1 September 2016.

The amended MHF regulations include changes to:

  • introduce fees for the assessment of safety cases for upper tier major hazard facilities and annual levies for all designated major hazard facilities
  • clarify that the designation is an authorisation to operate as an MHF


Major Hazard Facilities inspectorate

WorkSafe’s High Hazards Unit (HHU) Major Hazard Facilities inspectorate has the inspection and enforcement role for the regulations. The team of Specialist MHF Inspectors has a predominant focus on the process safety systems supporting workplace practices aimed at reducing the potential for a major incident to occur at the facility.

WorkSafe’s MHF Team is committed to working collaboratively on engagement and education with industry on the development and implementation of improved systems and processes relating to risks from potential major incidents.

To receive updates about Major Hazard Facilities – please sign up for major hazard facilities updates here.


Key dates and transitional provisions

The regulations include transitional provisions for existing major hazard facilities (schedule 1). Proposed facilities have specific requirements that relate to timing of notifications, design notices and safety cases (for proposed UT).



4 April 2016

Health and Safety at Work Act 2015 and Health and Safety at Work (Major Hazard Facilities) Regulations 2016 enter into force

Operators of all existing facilities that may exceed the lower tier threshold quantity of specified hazardous substances must notify WorkSafe within 3 months (i.e. by 4 July 2016), unless WorkSafe has granted an extension. Notification of Major Hazard Facility form [403 KB PDF]

Proposed facilities that plan to operate above the threshold quantities after 4 April 2016 must notify WorkSafe in accordance with the regulations and if they plan to operate above the upper tier threshold quantity must submit a design notice, and safety case as required by regulations. The transitional provisions do not apply to such facilities.

4 July 2016

All existing operators must have notified WorkSafe of the quantities of specified hazardous substances

From the date that WorkSafe notifies a facility that it is a Major Hazard Facility

All Major Hazard Facilities must comply with regulation 34 (notifiable incident)

1 September 2016 Amendment regulations come into force

From 4 December 2016 and no later than 4 April 2018

An operator of an existing upper tier major hazard facility must give Work Safe a completed safety case within the indicated time period.

4 April 2018

An operator of an existing facility that contains hazardous substances that exceed the lower threshold quantities is not required to comply with the requirements of Part 4 of the regulations until 4 April 2018, other than regulation 34 (notifiable incident).

Major Hazard Facility operators are not required to comply with Part 4 until 4 April 2018, including:

  • Control measures
  • Emergency plans
  • Ongoing review
  • Lower tier MHFs preparation of a major accident prevention policy by establishing safety management system
  • Upper tier major hazard facilities conduct a safety assessment and establish and implement a safety management system

Further information is included in guidance on some of these topics

4 April 2021

WorkSafe must accept or finally reject the safety case no later than 4 April 2021