The Seveso III Directive is the EU framework for controlling major-accident hazards involving dangerous substances, the regime behind COMAH in the UK and equivalent national laws across Europe. It applies to sites holding hazardous substances above threshold quantities, and it demands a safety management system that turns hazard studies into maintained, evidenced controls. Named after the 1976 Seveso disaster, it exists because major accidents are low-frequency, catastrophic, and almost always preceded by degraded barriers. Educational overview, not legal advice.
A Seveso safety report is built on hazard studies, HAZOP and LOPA, and on the barriers those studies credit, often visualized as bowties. Every one of those barriers, safety instrumented functions, relief systems, containment, detection, is a maintenance obligation: proof-tested, inspected, kept effective. The directive’s demand to "demonstrate control" is, in practice, a demand to show that credited barriers are maintained. A safety report that describes barriers the maintenance system cannot prove are working is describing intentions, not control.
A competent-authority inspection of an upper-tier site picks a scenario from the safety report, loss of containment from a reactor with a runaway pathway, and follows its barriers into the plant. The high-integrity trip: show me its proof-test records. The relief system: show me its examination. The independent high-level alarm: show me it was tested. On a well-run site, each barrier resolves to a schedule, a completed test, and a result, the safety report is alive. Where a barrier’s maintenance record is missing or overdue, the inspector has found the gap that matters most: a credited major-accident barrier that may not be there when needed. Seveso enforcement increasingly probes exactly this seam between the paper safety case and the maintained reality, and the seam is held together by management of change and a maintenance record.
Seveso safety management systems require monitoring of safety performance, including the health of major-accident barriers over time. Overdue safety-critical maintenance, barriers found defective, and repeated bypasses are not housekeeping metrics; they are leading indicators of eroding control, the data a mature site reviews precisely because the accident it prevents is the one that never appears in ordinary statistics.
Fabrico is not a safety-report or process-safety tool and plays no part in the hazard studies or the safety case, process safety specialists own those. What Fabrico provides is the demonstrable-control layer the directive effectively requires: every credited barrier as an asset with proof-test, inspection, and maintenance schedules; test results and defects recorded against it; overdue safety-critical work made conspicuous; and barrier-health trends visible for the safety management system’s performance monitoring. When the competent authority follows a scenario into the plant, the evidence is an export, not an excavation, and it stays under EU governance. EU-built, with EU data residency.
Seveso III is the EU directive; COMAH (Control of Major Accident Hazards) is the UK regulation that implemented it, and other member states have their own transposing laws. The substantive duties, tiering, safety management, demonstration of control, are common; the names and enforcing authorities differ by country.
It depends on the dangerous substances held and their quantities against the directive’s thresholds, which determine whether a site is out of scope, lower-tier, or upper-tier. The inventory assessment is a specialist judgment; sites near thresholds should assess carefully, as small inventory changes can change status.
The safety report claims that major-accident risks are controlled by specific barriers; maintenance evidence is how a site demonstrates those barriers remain effective. Increasingly, inspections test that link directly, tracing a report’s credited barriers to their actual test and maintenance records.
Want every major-accident barrier’s maintenance provable on demand? Book a Fabrico demo to see safety-barrier evidence run through a field-ready CMMS.
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