Meet your COMAH Duties with Confidence
You have a legal and moral responsibility to prevent major accidents and protect your people.
A robust, well-evidenced COMAH management framework ensures you meet your responsibilities while reinforcing governance, operational resilience, and leadership credibility.
Build Operational Discipline with Consistent Execution and Control
Our experts translate COMAH requirements into structured, repeatable operational practices, helping your teams consistently plan, execute, and verify safety-critical activities.
- Establish clear operational accountability: convert COMAH duties into defined roles, responsibilities, and decision-making authority, ensuring everyone understands who owns critical tasks and controls across the organisation.
- Shift from reactive response to disciplined execution: Strengthen management of change, learning, and feedback systems to control variability, manage non-routine work, and maintain discipline where critical risk is highest.
- Apply proven, practical expertise: our experienced COMAH specialists deliver pragmatic solutions that integrate seamlessly into how your site plans, executes, and verifies critical work.
Sigma-HSE offers disciplined execution of mission critical safety activities, reduced operational drift, and reliable control of major accident risk during normal operations and change.
Strengthen Risk Control and Prevent Major Loss
Our COMAH support is focused on establishing and maintaining effective control of major accident hazards, reducing both the likelihood and consequences of fires, explosions, and toxic releases.
- Demonstrable control of risk: translate high-consequence incident scenarios into resilient, proportionate prevention and mitigation measures, supported by effective safety barriers that you define, maintain, and assure.
- Prevent high-consequence failures: identify weaknesses in barriers, systems, and technical safeguards early — before degradation, change, or human factors lead to loss of control.
- Protect people, assets, and business value: strengthen prevention and mitigation measures to safeguard your workforce, critical infrastructure, and the long-term viability of high-hazard operations.
Sigma-HSE will help you prevent high-impact events, reduce exposure to catastrophic loss, and maintain a COMAH framework that demonstrably controls major accident risk.
Ensure Inspection, Audit & Enforcement Readiness
Our COMAH support guarantees you are always inspection-ready, with verified evidence that severe hazards are understood, controlled, and effectively managed in line with regulatory expectations.
- Clear, defensible evidence of control: accurately document, justify, and support major accident hazards, safety barriers, and management arrangements with evidence that can be readily demonstrated during inspection.
- Prepared for audit and regulatory scrutiny: align Safety Reports, management systems, and site practices so they remain consistent, current, and reflective of how you actually contain critical accident risk on site.
- Confident, consistent regulatory engagement: equip leaders, managers, and frontline teams to understand their role in controlling major risk and can respond clearly and consistently to inspection and audit questioning.
Sigma-HSE will ensure you have smoother inspections, fewer regulatory findings or enforcement actions, and sustained confidence that your COMAH arrangements will stand up to scrutiny.
Structured COMAH Assessments That Deliver Control
Sigma-HSE’s four-stage COMAH assessment framework helps EHS managers gain defensible insight into major accident risk without unnecessary disruption or resource strain. Our approach cuts through complexity to identify what matters most, prioritise action, and provide regulator-ready evidence, allowing you to focus time and budget where it delivers the greatest risk reduction.
Targeted COMAH Baseline Review
Risk & Control Assessment
Prioritised Findings & Practical Actions
Regulator-Ready Evidence & Support
Our core COMAH assessment & compliance services can include the following:
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COMAH Expertise Across Every High-Hazard Industry
Our team has planned and executed COMAH assessments across a wide range of industries, including:
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Inspection
Documentation
Post-project support
Prevent Major Accidents.
Protect Your People.
Safeguard Your Licence.
Unlock COMAH compliance clarity and process safety peace of mind with Sigma-HSE.
Frequently asked questions
How can Sigma-HSE help determine our COMAH status?
Determining if you are “Lower Tier” or “Upper Tier” is a critical first step. Sigma-HSE provides site-specific gap analyses and chemical inventory reviews. We use precise aggregation calculations to assess your hazardous substance levels against Schedule 1 thresholds.
What makes Sigma-HSE's approach to COMAH different?
Our team includes process engineers with hands-on operational experience in high-hazard facilities. We deliver practical, implementable recommendations that reflect how sites actually work, not just theoretical compliance.
Additionally, our in-house hazardous materials testing capability (IEH & CRH) means we can directly verify the technical data underpinning your Safety Reports, ensuring consistency and eliminating reliance on third-party labs or outdated information.
How quickly can Sigma-HSE respond to my COMAH needs?
We understand that COMAH compliance often operates on tight regulatory deadlines. Our team typically responds to enquiries within 24 hours and can provide a detailed, fixed-price quote within 3-5 working days of an initial site discussion.
For urgent compliance needs—such as imminent inspections or submission deadlines, we can mobilize assessment teams within days, not weeks.
Can Sigma-HSE assist with MAPP and Safety Report preparation?
Yes. For Lower Tier sites, we draft concise Major Accident Prevention Policies (MAPP) that align with your management systems.
For Upper Tier sites, our specialists help build the comprehensive COMAH Safety Report, providing the technical “demonstrations” required by the Competent Authority. This includes:
- Identifying Major Accident Hazards (MAH).
- Conducting detailed risk assessments (e.g., HAZID, HAZOP, or LOPA).
- Undertaking evidence-based modelling to predict the consequences of potential accidents.
What ongoing support does Sigma-HSE offer for COMAH maintenance?
Compliance isn’t a “one-and-done” task. Sigma-HSE supports your long-term resilience through:
- Management of Change (MOC): Prevent new equipment or process changes from creating hidden risks or triggering re-classification. We can verify that new equipment or processes don’t compromise your safety status.
- Training Programs: Closing knowledge gaps within your workforce to confirm that everyone understands their role in preventing catastrophic events.
- Audit & Review: Periodically reviewing your MAPP or Safety Report (legally required every 5 years) to reflect operational changes and new regulatory guidance.
What are the COMAH Regulations and do they apply to my business?
The COMAH Regulations (2015) are designed to prevent major accidents involving dangerous substances and limit the consequences to people and the environment should an accident occur.
Your business is likely to fall under COMAH if you store, handle, or produce hazardous substances (such as chemicals, LPG, explosives, or petroleum products) in quantities that meet or exceed specific thresholds. These thresholds are defined in Schedule 1 of the regulations. Even if you don’t exceed the limit for a single substance, “aggregation rules” may apply if the combined total of similar hazardous materials reaches the limit.
What is the difference between "Lower Tier" and "Upper Tier" sites?
COMAH classifies sites into two categories based on the volume of hazardous materials present. The higher the volume, the more stringent the safety requirements:
- Lower Tier: Sites that exceed the minimum threshold but stay below the upper limit. Operators must notify the Competent Authority (HSE/Environment Agency) and maintain a Major Accident Prevention Policy (MAPP).
- Upper Tier: Sites holding significantly larger quantities. In addition to a MAPP, these operators must produce a detailed Safety Report, create an Internal Emergency Plan, and provide information for the Local Authority to develop an External Emergency Plan.
What are my primary legal duties as a COMAH operator?
All operators have a “general duty” to take all measures necessary to prevent high-consequence incidents. Specifically, you must:
- Notify: Inform the Competent Authority (HSE/EA) about the hazardous substances on your site.
- Prevent: Develop a Major Accident Prevention Policy (MAPP) to identify and manage risks.
- Plan: Create robust emergency procedures and train staff to execute them.
- Inform: Provide safety information to the local community and authorities regarding potential risks.