Major accident hazard and COMAH interfaces for construction
Major accident hazards in construction refer to events that can cause significant harm to people, property, or the environment, such as explosions or toxic releases. The Control of Major Accident Hazards (COMAH) regulations set legal and statutory requirements to manage these risks. Construction projects on COMAH sites must interface closely with site operators to ensure compliance, including risk assessments, safety management, and coordination to prevent and mitigate major accidents during construction activities.
Major accident hazard and COMAH interfaces for construction
Major accident hazards in construction refer to events that can cause significant harm to people, property, or the environment, such as explosions or toxic releases. The Control of Major Accident Hazards (COMAH) regulations set legal and statutory requirements to manage these risks. Construction projects on COMAH sites must interface closely with site operators to ensure compliance, including risk assessments, safety management, and coordination to prevent and mitigate major accidents during construction activities.
💡 Key Takeaways
- Understand what COMAH is and why its interfaces matter on construction sites with other major-accident hazards.
- Identify typical major accident hazards on construction projects (flammable liquids, pressurised gases, large energy releases) and the basic controls to mitigate them.
- Describe how to manage interfaces with neighbouring MAH installations and emergency services, including information sharing and joint response planning.
- Know the key COMAH duties on construction activities (duty holders, risk assessment, safe design/changes, permit to work, training and supervision).
- Recognize how to integrate MAH risk reduction early in the project life cycle, including design decisions and coordination with CDM requirements.
❓ Frequently Asked Questions
What is COMAH and what is its purpose?
COMAH stands for Control of Major Accident Hazards. Its purpose is to prevent major accidents involving dangerous substances and to limit their consequences for people and the environment, by requiring safety management and emergency planning at sites that store or use MAH substances above threshold quantities.
What counts as a Major Accident Hazard (MAH) substance?
MAH substances are dangerous chemicals or materials that could cause a major accident if released. They include flammable liquids/gases, toxic substances, oxidizers, and explosives, above quantities defined by COMAH. On construction sites, this can include fuels, solvents, acids, and other hazardous chemicals stored or used in significant amounts.
How do COMAH requirements affect construction projects and interfaces?
If a site stores or uses MAH substances above thresholds, duty holders (clients, designers, principal contractors, etc.) must coordinate safety measures across the project. This includes information sharing, safe design and storage decisions, emergency planning, and cooperation with the relevant authority (e.g., HSE in the UK). Effective interface management is essential.
What are the main COMAH duties for those working on MAH-related sites?
Top-tier duty holders must ensure a major accident prevention policy, safety management systems, and emergency arrangements. Lower-tier duty holders must cooperate, implement safety measures, provide information, ensure contractors are aware of MAH hazards, and maintain risk assessments and change management.