Icologiq Knowledge · Regulation
Seveso III
European legislation aimed at preventing major accidents involving dangerous substances and limiting their consequences for people and the environment.
Also known as:
Seveso Directive, Directive 2012/18/EU, Seveso 3
At a glance
Type
Regulation
Topic
Process Safety
Applies to
Tank Terminals & Chemicals
Current version
Directive 2012/18/EU
Status
In force EU major-accident-hazards directive
Last reviewed
October 9, 2026
Definition
The Seveso III Directive establishes EU requirements for establishments where dangerous substances are present above defined thresholds. Depending on the establishment tier, obligations can include major-accident prevention policies, safety management systems, safety reports, emergency planning, information and inspections.
Why it matters
Seveso III matters because establishments handling significant quantities of dangerous substances may need to demonstrate that major-accident hazards are understood, controlled and supported by appropriate prevention, emergency and safety-management measures.
Operators determine whether the establishment falls within the directive based on listed dangerous substances, quantities and aggregation rules.
Applicability and dangerous-substance thresholds
•
Covered establishments provide required information about the operator, site, substances and activities to the relevant national authority.
Notification to the competent authority
•
Operators establish a policy proportionate to major-accident hazards and implement it through appropriate management arrangements.
Major-accident prevention policy
•
Upper-tier establishments have more extensive demonstration requirements, including a safety report and structured safety-management arrangements.
Safety management and safety report for upper-tier sites
•
Required emergency-planning arrangements support preparation for and response to major accidents, with external coordination where applicable.
Emergency planning
•
The directive includes provisions on information to the public and consideration of major-accident hazards in relevant land-use planning.
Public information and land-use considerations
•
Authorities inspect covered establishments, while serious incidents trigger reporting and learning obligations under the national implementation framework.
Inspection, reporting and learning
•
Regulation explained
Core control areas under Seveso III
Seveso III is the EU directive for controlling major-accident hazards involving dangerous substances. Duties depend on the substances and quantities present and whether an establishment is lower- or upper-tier, so operators need to determine applicability before assigning specific obligations.
A systematic approach to preventing major incidents by managing hazards associated with hazardous processes, substances, equipment, procedures and organizational change.
Process Safety Management
Framework
· Process Safety
A structured assessment used to identify hazards or uncertainties, estimate their risk and determine whether controls or further action are required.
Risk Assessment
Process
· Risk
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