For operators of chemical processing facilities and industrial sites handling hazardous materials, the terminology around safety regulations can get a bit confusing. You might hear colleagues discussing Process Safety Management in one meeting, then COMAH requirements in another. Whilst these frameworks share common goals, they operate quite differently and apply in distinct contexts. Understanding these differences matters because it affects how you approach compliance, allocate resources, and structure your safety programmes.
Process Safety Management refers to a systematic approach to preventing major accidents in facilities that handle hazardous chemicals. The concept originated in the United States following the Bhopal disaster in 1984 and other serious industrial incidents. The US Occupational Safety and Health Administration (OSHA) formalised PSM through regulations requiring facilities to implement 14 specific elements.
These elements cover everything from process hazard analysis and operating procedures to mechanical integrity and emergency planning. The framework aims to identify potential hazards before they cause harm, establish controls to manage those risks, and create a culture where safety becomes part of daily operations.
PSM principles have spread globally because they work. Many international organisations have adopted similar frameworks, adapting them to local contexts and regulatory environments. The fundamental approach remains consistent: understand your hazards, control your risks, and maintain rigorous oversight of critical safety systems.
Not sure which framework applies to your site? Our team at C3 Technical has extensive experience with both PSM and COMAH compliance. Give us a call and a qualified consultant will help you understand your obligations and the best approach for your operations.
The Control of Major Accident Hazards Regulations, known as COMAH, represents the UK's approach to preventing major accidents involving dangerous substances. These regulations implement the European Seveso III Directive, though the UK has maintained and updated its own version following Brexit.
COMAH applies to establishments where dangerous substances are present in quantities that meet or exceed specified thresholds. The regulations create two tiers of sites. Lower Tier sites face certain notification and emergency planning requirements. Upper Tier sites must meet more extensive obligations, including preparing a safety report and implementing a Safety Management System.
The competent authority for COMAH comprises the Health and Safety Executive, the Environment Agency, and the Office for Nuclear Regulation where relevant. These bodies work together to regulate sites, conduct inspections, and ensure operators maintain appropriate safety standards.
Whilst both frameworks aim to prevent major accidents, they differ in scope, structure, and application. PSM originated as an American standard and remains primarily used in the United States and countries following similar approaches. COMAH is specifically a UK and European framework, designed to address the particular regulatory environment and industrial landscape of these regions.
The threshold for application differs between the two systems. PSM typically applies based on the presence of specific chemicals above certain quantities, with a focus on process safety in chemical manufacturing and petroleum refining. COMAH uses a broader approach, applying to any site where dangerous substances exceed threshold quantities, including storage facilities, logistics sites, and various industrial operations.
Here's where it gets interesting. PSM prescribes 14 specific elements that operators must implement. These elements provide a detailed roadmap for compliance, from conducting process hazard analyses to investigating incidents. COMAH takes a more goal setting approach, requiring operators to demonstrate they have suitable Safety Management Systems without prescribing exact methods. This gives you flexibility in how you achieve safety objectives but also requires you to justify your approaches.
Documentation requirements also vary. PSM requires specific documents for each element, such as process safety information, operating procedures, and mechanical integrity programmes. COMAH focuses on the Safety Report for Upper Tier sites, which must demonstrate that major accident hazards have been identified and appropriate measures taken to prevent them and limit their consequences.
The regulatory oversight structure differs too. In the PSM system, OSHA conducts inspections and enforces compliance through its standard processes. Under COMAH, the competent authority takes a more collaborative approach, working with operators to improve safety whilst maintaining the ability to take enforcement action when necessary.
Struggling to navigate the complexity of COMAH compliance? Email us at C3 Technical and we'll connect you with a consultant who can provide clear, practical guidance tailored to your specific site requirements.
For UK operators, COMAH represents the legal requirement you must meet. If your site handles dangerous substances above threshold quantities, you need to comply with COMAH regardless of any other frameworks you might use. This isn't optional or a matter of choosing between systems.
However, many UK sites find value in adopting PSM principles alongside their COMAH obligations. The 14 PSM elements provide a structured approach to building a Safety Management System. They offer practical guidance on areas like management of change, contractor safety, and pre-startup safety reviews. These elements can form the backbone of your COMAH Safety Management System whilst ensuring you meet UK legal requirements.
Some organisations operate in both the US and UK or work with American parent companies familiar with PSM. In these cases, adopting PSM elements makes sense for consistency across international operations. You can implement PSM whilst ensuring your UK sites meet all COMAH requirements.
The key is recognising that COMAH sets the legal bar in the UK. Any additional frameworks you adopt should complement and strengthen your COMAH compliance, not replace it or create conflicting requirements. Your Safety Report must address COMAH requirements, your emergency plans must meet UK standards, and your engagement with the competent authority must follow COMAH processes.
Need help building a Safety Management System that meets COMAH requirements? Fill out our online enquiry form and a qualified C3 Technical consultant will be back in touch with you very shortly to discuss how we can support your compliance journey.
Understanding these differences affects how you structure your safety programmes. If you're working purely within the UK context, focus your compliance efforts on COMAH requirements first. Build your Safety Management System around COMAH expectations, prepare your Safety Report to address competent authority concerns, and engage with HSE and Environment Agency guidance.
When developing specific elements of your system, you can draw on PSM principles for practical implementation. The PSM approach to process hazard analysis, for example, provides detailed methods for identifying hazards. The PSM focus on mechanical integrity offers useful frameworks for maintaining critical equipment. These tools help you build robust systems that meet COMAH requirements whilst following proven methodologies.
For sites with international connections, consider how to harmonise requirements. If your parent company uses PSM, map PSM elements to COMAH requirements. Show how implementing PSM elements satisfies COMAH obligations. This approach satisfies corporate expectations whilst ensuring UK legal compliance.
Training represents another area where understanding both frameworks helps. Your team needs to understand COMAH requirements because that's what UK inspectors will assess. However, training materials based on PSM elements can provide clear, structured content that builds competence. The key is ensuring any PSM based training explicitly addresses how it relates to COMAH requirements.
Looking to harmonise international safety standards across your operations? Contact C3 Technical today. Our consultants have practical experience working with sites that need to balance PSM and COMAH requirements, and we'll work with you to find the right solution.
Both PSM and COMAH aim for the same outcome: preventing major accidents that could harm workers, the public, and the environment. Neither framework should be viewed as a bureaucratic burden but rather as a structured approach to managing real risks.
The best safety programmes go beyond minimum compliance with either framework. They create environments where people understand hazards, feel empowered to raise concerns, and take responsibility for safe operations. Whether you call it PSM or COMAH, the goal remains the same: getting everyone home safely at the end of each day whilst protecting your surrounding community.
For UK operators, COMAH provides the legal framework and regulatory structure you must work within. PSM offers proven tools and methodologies that can strengthen your approach. By understanding both, you can build safety programmes that meet legal requirements whilst drawing on international best practice.
The complexity of modern industrial operations demands rigorous safety management. Understanding the landscape of safety frameworks, knowing which apply to your operations, and implementing them effectively protects your people, your business, and your community. That makes the effort to understand these differences worthwhile.
Ready to strengthen your process safety management? Get in touch with C3 Technical through our online enquiry form, drop us an email, or give us a ring. A qualified consultant will be back in touch very shortly to discuss how we can help you achieve compliance with confidence.
