Control of Major Accidents 

Key Legislation:

For more detail on the Legislation relevant to this page, please use the following links:

Supporting Legislation:
  • A guide to the Control of Major Accident Hazards Regulations 1999 (as amended) (ISBN 071766175X). This revised guidance on the COMAH Regulations gives detailed advice on the scope of the Regulations and the duties imposed by them. The guidance is aimed at operators of establishments that are covered by the Regulations.
  • Guidance on the interpretation of Major Accident to the Environment for the Purposes of COMAH Regulation, DTI 1999 (ISBN 011753501X) available from the Stationery Office or available for download on the Defra website (PDF document). This guidance is a 1999 update on major accidents to the environment, reviewed to ensure its scope is adequate for the purposes of COMAH.
  • Guidance on the Environmental Risk Assessment Aspects of COMAH Safety Reports, COMAH Competent Authority 1999 Preparing Safety Reports: Control of Major Accident Hazard Regulations 1999, HSE 1999 (ISBN 0717616878) A guide to the reporting of injuries, diseases and dangerous occurrences regulations 1995, HSE 1999 (ISBN 0717610128) Emergency Planning for Major Accidents, Control of Major Accident Hazard Regulation 1999, HSE 1999 (ISBN 0717616959) COMAH Safety Report Assessment Manual, HSE 2015available here (PDF document). The HSE has released a guidance document detailing the CHIP Regulations 2009, providing a basic introduction to CHIP and an introduction as to how the regulations work and covering the changes to the law that will be coming into effect soon. The change will involve the replacement of the CHIP regulations with the new European Regulation on classification, labelling and packaging.

Further details are available on the HSE website (PDF document).

Link to HSE Books Website.

  • Dangerous Substances and Explosive Atmospheres Regulations 2002 (Approved Code of Practice and guidance) (PDF document). This Approved Code of Practice (ACOP) and guidance provide practical advice on how to comply with the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR). These Regulations require the elimination or reduction of risk of fire and explosion from substances connected with work activities.
  • The Offshore Installations (Offshore Safety Directive) (Safety Case etc) Regulations 2015 – Guidance on Regulations (L154). HSE has published the final version of its guidance on the Offshore Installations (Offshore Safety Directive) (Safety Case etc) Regulations 2015 (SCR 2015), which came into force on 19 July 2015. The Regulations apply to oil and gas operations in external waters, that is, the territorial sea adjacent to Great Britain and any designated area within the UK continental shelf. They replace the Offshore Installations (Safety Case) Regulations 2005 (SCR 2005) in these waters, subject to certain transitional arrangements.
  • Offshore Major Accident Regulator (OMAR) (previously known as the Offshore Safety Directive Regulator) Framework Diagrams and Guidance. OMAR has issued framework diagrams and guidance. These documents outline the legal requirements and administrative arrangements and describe the processes employed by OMAR.
  • SCR2015 and SCR2005 – the dual regime, differences in terminology and interpretation, and impact on guidance material. This Operations Notice identified the differences in terminology and interpretation applied in each regime and highlights how guidance material will be managed to support both regimes. The dual regime arises from parallel safety case regulations: the Offshore Installations (Offshore Safety Directive) (Safety Case etc.) Regulations 2015 (SCR2015) and the Offshore Installations (Safety Case) Regulations 2005 (SCR2005). SCR2015 replaces SCR2005 for oil and gas operations in external waters.  The new regulations now cover the majority of offshore regulations and will be regulated by the Offshore Major Accident Regulator (OMAR).
Consent Needed:

No consent is required but operators must produce and maintain a Major Accident Prevention Policy (MAPP) as outlined below.

The Safety Report should also include sufficient particulars to demonstrate that the operator has established a Safety Management System (SMS) including organisational structure, responsibilities, practices, procedures, processes and resources for determining and implementing the Safety Report.

Top-tier establishments are not required to produce a documented version of the Safety Report and SMS separately as under Regulation 7 can both be incorporated in the Safety Report.

Lower-tier establishments must produce a stand alone MAPP as they are not required to produce a Safety Report. Within this document lower-tier site operators must demonstrate that an SMS has been established.

All operators are also required under Regulation 9 to produce Emergency Plans.

Operations Notice 30: Arrangements for Reporting of Offshore Incidents

Duty Holders of offshore installations that transition to SCR2015 Regulations before 31 December 2016 are to report against the new arrangements (as well as well operators associated with these installations). All other duty holders will be notified when to begin using the new arrangements.

A single tool has been made available for reporting under the various relevant pieces of legislation. The updated version of Operations Notice 30 details the changes to arrangements for reporting of incidents in relation offshore workplaces, wells, offshore pipelines or pipeline works and diving operations.

Who does COMAH Apply to:

Any establishment is subject to the COMAH 1999 Regulations (as Amended), if it has on site any substance specified in Schedule 1 of the COMAH regulations above the qualifying quantity.

Substances listed include liquefied extremely flammable gases (including LPG) and natural gas (whether liquefied or not). Substances classified as toxic, oxidising, explosive, flammable and dangerous for the environment are also included.

There are two threshold quantities:

  • Establishments with quantities equal to or greater than the upper threshold are known as top-tier establishments.
  • Establishments with lower quantities, but which are equal to or greater than the lower threshold, are known as lower-tier establishments.

Operators of existing installations that come under COMAH are required to notify the Competent Authority (HSE and SEPA/EA) of the details of their activities as detailed within Schedule 3 of the COMAH regulations, unless the information has already been supplied in a CIMAH or COMAH Safety Report.

Operators of new establishments should send notification within a reasonable time before the start of construction, normally 3 to 6 months. Additional notification is only required prior to the commencement of operations if any of the details in the pre-construction notification were missing or have changed.

Who is subject to a Safety Report:

Regulation 3 of COMAH states that all operators of establishments subject to COMAH must have a Safety Report. This document must be proportionate to the major accident hazards presented by the establishment and should include their overall aims and principals of action with respect to the control of major accident hazards.

What is included in a MAPP:

Schedule 2 of the COMAH regulations lists principals to be taken into account when preparing a MAPP, including:

  1. Organisation and Personnel
  2. Identification and evaluation of major hazards
  3. Operations control
  4. Management of change
  5. Planning for emergencies
What is included in a COMAH Safety Report:

Regulation 7 requires operators of top-tier establishments to submit a Safety Report, the purpose and contents of which are described in Schedule 3.

The Safety Report must include:

  1. Information on the management system of the organisation and the establishment with a view to major accident prevention.
  2. A description of the environment of the site including its geographical location, meteorological, geological and hydrographic conditions and if necessary its history. This section must also include the human environment of the plant including other establishments, local communities and their sensitivities.
  3. Description of installation including main activities, processes and operation methods. This section must also include information on the chemical characteristics of substances contained on site.
  4. Identification and accidental risks analysis and prevention methods, including potential triggers and consequences both internal and external and a description of the technical parameters and equipment used for the safety of installations.
  5. Measures of protection and intervention to limit the consequences of an accident including equipment both on and off site, organisation of alert and intervention procedure and a summary of the elements necessary for drawing up the on-site Emergency Plan.
Who is subject to an Emergency Plan:

Regulation 9 stipulates that all establishments subject to COMAH must produce an Emergency Plan, however the procedure varies depending on the classification of the site:

  • Top-tier establishments must produce two emergency plans in writing:
  1. On-site emergency plan, which is prepared by the operator, to specify the response of those who work on site.
  2. Off-site emergency plan, which is prepared by the local authority, to specify the coordinated response of agencies to an emergency which has off-site effects.
  • Lower-tier sites do not have to produce a specific emergency plan, however the MAPP required by Regulation 5 should include information on the management system and procedures for identifying foreseeable emergencies. The level of planning for these emergencies should be proportional to the probability of the accident occurring.
What is included in an Emergency Plan:

Schedule 5, Part 1 of COMAH describes the objectives of Emergency Plans which are referred to in Regulations 9(1) and 10(1) as follows:

  1. To contain and control incidents so as to minimise their effects, and to limit damage to persons, the environment and property
  2. To implement the measures necessary to protect persons and the environment from the effects of major accidents
  3. To communicate the necessary information to the public and to the emergency services and authorities concerned in the area
  4. To provide for the restoration and clean-up of the environment following a major accident.
On-Site Emergency Plans:

Regulation 9(3) and Schedule 5 provide for the production of an on-site emergency plan. The on-site plan must include:

  • Names and positions of persons authorised to set emergency procedures in motion
  • Person in charge of and coordinating the on-site response
  • Name or position of the person with responsibility for liaising with the local authority (off-site emergency plan)
  • For foreseeable scenarios, a description of the action which should be taken, including a description of the safety equipment and the resources available
  • Arrangements for limiting the risks to persons on site including, warning, and alert procedure
  • Arrangements for providing early warnings of the incident to the local authority, to set the off-site emergency plan in motion, the type of information which should be contained in the initial warning and the arrangements for the provision of more detailed information as it becomes available
  • Arrangements for training staff in the duties they will be expected to perform, and where necessary coordinating this with the emergency services
  • Arrangements for providing assistance with off-site mitigatory actions
Off-site Emergency Plans:

Local authorities for the area where a top-tier site is located must prepare in writing an adequate emergency plan for dealing with the off-site consequences of possible major accidents. This document must include the following:

  • Names of positions of persons authorised to set emergency procedures in motion and take charge of and coordinate off-site action
  • Procedure for the early warning of incidents, alert and call out procedure
  • Coordinating resources to implement the off-site emergency plan
  • Arrangements for providing assistance with on-site mitigatory action
  • Arrangements for all off-site mitigatory action
  • Arrangements for providing the public with specific information relating to the accident and the behaviour which they should adopt

Local authorities must also consult with the public when preparing an off-site emergency plan.

When to Apply:

Top-tier establishments:

New establishments must have a MAPP available from the day that the regulations apply (1st April 1999):

Other establishments have to prepare a MAPP as quickly as possible after coming into scope and should discuss the timescale with the Competent Authority (HSE/EA/SEPA)

Lower-tier establishments:

New establishments must submit a COMAH report “within a reasonable period of time prior to the start of operations”. Start of operation is taken as the first time that dangerous substances are introduced into the plant including commissioning. This is normally taken to mean up to six months before operation.

Existing establishments must submit a COMAH report when a review or update is due, or when changes in the establishments require an update. The minimum period for review is five years.

Approval of a MAPP:

It is not necessary to submit a MAPP document to the Competent Authority (HSE/EA/SEPA), unless requested to do so. It will usually be requested before a visit and should be kept available for inspection. Inspectors will use it along with other data and information to plan and structure inspections.

Enforcement Authority: The Health and Safety Executive will be the enforcing authority unless a transfer of responsibility is made. The responsibility for enforcement may be transferred from the HSE to a local authority, relevant to the sale of goods, or the storage of goods for retail or wholesale distribution, except at container depots where goods are mainly stored prior to transit from docks; or at sites where wholesale distribution takes place. Such a transfer of responsibility may be made only by agreement between the Executive and the local authority.

The regulations provide for the Competent Authority (HSE and SEPA/EA) to undertake regular inspections and investigations where necessary.

Operators must implement procedures for the ongoing assessment of compliance with the objectives set by both the MAPP and the SMS.

This must include mechanisms for investigation and corrective action in cases of non-compliance. Following a major accident the Competent Authority will make a full analysis of the technical, organisational and managerial aspects of the major accident and collect by inspections, investigation or other appropriate means, the information necessary for that purpose. Appropriate action will them be taken to ensure that the operator takes any necessary remedial measures.

Reporting of Accidents:

All occurrences which qualify as major accidents must be reported. A major accident is defined under Regulations 2(1) of COMAH as:

  • “An occurrence (including in particular, a major emission, fire or explosion) resulting from uncontrolled developments in the course of the operation of any establishment and leading to serious danger to human health or the environment, immediate or delayed, inside or outside the establishment, and involving one or more dangerous substances”.
What to Report:

The following information must be provided when a major accident is reported:

  • The circumstances of the accident
  • The dangerous substances involved
  • Any data available for assessing the effects of the accident on persons and the environment
  • The emergency measures taken
  • Steps proposed to prevent the recurrence of such an incident
  • Such other information in the operators possession as will enable the Competent Authority (HSE and SEPA/EA) to notify the European Commission.
Who to report to: All incidents should be reported to the HSE through the RIDDOR website is introducing a form named Report of an Oil and Gas Incident (ROGI), which replaces three existing reporting forms (OIR8, OIR9b & OIR12) and relates to the reporting of incidents in relation to offshore workplaces, wells, offshore pipelines or pipeline works and diving operations. The change is being made in response to European Commission Directive 2013/30/EU on the Safety of Offshore Oil and Gas Operations, which is implemented in Great Britain by the Offshore Installations (Offshore Safety Directive) (Safety Case etc.) Regulations 2015. More information can be found here.
When to Report: All major accidents as described above must be reported immediately as described in the Emergency Plan (and Safety Report) for all top-tier establishments and as outlined in the MAPP for all lower tier establishments.
Reporting major industrial accidents: A European Council Directive Decision, 96/82/EC, on the control of major-accident hazards involving dangerous substances, has produced a form (PDF document) to be used in reporting major industrial accidents.

In respect of enforcement the COMAH regulations fall under the Health and Safety at Work Act 1974. The duty placed in the Competent Authority (HSE and SEPA/EA) by these regulations shall not be an offence, and Section 33(1)(c) of the 1974 Act shall have effect accordingly.

COMAH Report Review: COMAH safety reports must be reviewed and where necessary updated at least every five years. This review must include not only changes that have occurred but also must assess their significance, including any environmental changes which may have an influence on the prevention control and mitigation of major accidents.
SCR2015 and SCR2005 – the dual regime, differences in terminology and interpretation, and impact on guidance material This Operations Notice identified the differences in terminology and interpretation applied in each regime and highlights how guidance material will be managed to support both regimes (link here).The dual regime arises from parallel safety case regulations: the Offshore Installations (Offshore Safety Directive) (Safety Case etc.) Regulations 2015 (SCR2015) and the Offshore Installations (Safety Case) Regulations 2005 (SCR2005). SCR2015 replaces SCR2005 for oil and gas operations in external waters.  The new regulations now cover the majority of offshore regulations and will be regulated by the Offshore Safety Directive Regulator (OSDR) (previously regulated by HSE).
Consultation: The role of planning in preventing major-accident hazards involving hazardous substances: The Department for Communities and Local Government seeks views on their proposals to transpose the requirements of the Seveso III directive, which affect the way hazardous substances consents operate, and the way in which the planning system reduces the likelihood/impact of major accidents.Further details can be accessed through the UK Government website.
Consultation on Proposals for the Consolidation of Petroleum Legislation:

HSE is consulting on proposals to consolidate and modernise the petroleum legislative framework in Great Britain. The consolidation is intended to update current legislative provisions and make them simpler to understand.

Consultation commenced in December 2013 and ended in February 2014.

Further details can be accessed through the HSE website.

Buncefield Oil Storage Depot:

Since the December 2005 explosions and major fire at the Buncefield, Herts, Oil Storage Depot, worldwide perception about such sites has changed. The Health and Safety Commission established an independent investigation. Finding of the investigation are accessible via the Buncefield Report (PDF document).

The HSE have established a Task Group to report on the incident.

Bulk storage:

To improve protection of people and the environment, the EA/SEPA/HSE has consulted on the future policy of the storage of bulk hazardous chemicals, specifically petrol. This review is in response to many recommendations of the Buncefield investigation. The potential change in policy would apply immediately to any new sites. It is estimated that existing storage sites may take 10-20 years to comply with best practice.

Environmental Liability Directive 2004/35/EC: The Environmental Liability Directive was adopted in 2004 and was required to be implemented by 30 April 2007. The Directive enforces strict liability for prevention and remediation of environmental damage to ‘biodiversity’, water and land from specified activities and remediation of environmental damage for all other activities through fault or negligence.The Environmental Liability Directive is now implemented in England and Wales. In Scotland The Environmental Liability (Scotland) Regulations 2009 came into force on 24 June 2009.Following the Deepwater Horizon incident in the Gulf of Mexico in 2010 and the European Commission’s communication “Facing the challenge of the safety of offshore oil and gas activities”(published in October 2010); the EU Directive on the “Safety of Offshore Oil and Gas Operations” was published on 28 June 2013 (Directive 2013/30/EU (PDF document)).