Major accidents involving hazardous substances (Seveso)

Scope and levels

Royal Decree 840/2015 applies to establishments, defined as the entire area under the control of an industrial operator where hazardous substances are present in one or more facilities, or where such substances are present or may be generated in quantities equal to or greater than the thresholds in Annex I, which lists both hazard categories according to Regulation (EC) 1272/2008 (CLP) and designated substances. Excluded, among others, are military establishments, radiological hazards, transport outside establishments, and mining extraction activities, except for the exceptions provided for in the regulation.

Lower-level establishments are those where the quantities present equal or exceed the thresholds in column 2 of Annex I without reaching those in column 3; higher-level establishments are those where the thresholds in column 3 are reached or exceeded. The classification determines the scope of obligations: higher-level establishments must prepare a safety report, have an external emergency plan approved by the authority and provide information to the public on a regular basis, in addition to being subject to inspections more frequently.

Obligations of the industrialist

• Notification. Communication to the competent authority of the autonomous community of the data of the establishment, the hazardous substances, their quantities and the environment, within the established deadlines and in the event of any significant change.
• Major accident prevention policy. A written document that guarantees a high level of protection, with objectives and principles of action and its application through a safety management system proportionate to the risks.
• Safety management system. Organization and personnel, identification and assessment of major accident risks, operational control, management of modifications, emergency planning, monitoring of objectives, and auditing and review.
• Safety report. For higher-level establishments, a document that demonstrates the application of the policy and management system, identifies serious accident scenarios and prevention and mitigation measures, and provides the information necessary for territorial and emergency planning; it is reviewed at least every five years.
• Internal emergency plan. Self-protection plan with the measures to be taken inside the establishment, prepared in consultation with the staff, including subcontractors, and which serves as the basis for the external emergency plan prepared by the authority.
• Public information and domino effect. Ongoing information on safety measures and procedures in case of an accident, and cooperation with neighboring establishments when there is a possibility of a domino effect.
• Accident reporting. Immediate notification to the authorities of serious accidents, including their circumstances, substances involved, consequences, and measures taken.

Relationship with occupational risk prevention

• Risk assessment. Serious accident scenarios are integrated into the occupational risk assessment required by Law 31/1995, along with the assessment of chemical agents and explosive atmospheres .
• Emergency measures. The internal emergency plan develops article 20 of Law 31/1995 and is coordinated with the Basic Self-Protection Standard (Royal Decree 393/2007) and with civil protection planning (Law 17/2015 and Royal Decree 1196/2003).
• Consultation and participation. The internal emergency plan is consulted with staff and their representatives, and the prevention policy is communicated to the workforce and contracting companies.
• Coordination of activities. Contracting companies involved in the establishment receive information and instructions on the risks of serious accidents and emergency measures, in accordance with Article 24 of Law 31/1995.
• Training. Staff receive specific training on the scenarios, safety barriers and their actions in emergencies.
• Inspections. The authority inspects establishments according to a plan, annually for those of a higher level and every three years for those of a lower level, except for criteria of systematic risk assessment.

Organizational application: how to manage a Seveso establishment

1. Inventory the hazardous substances present or that may be generated, classify them according to the CLP Regulation and compare them with the thresholds in Annex I to determine if the establishment is affected and at what level.
2. Submit the notification to the competent authority and keep it updated in the event of changes in substances, quantities, processes or environment.
3. Define the policy for the prevention of major accidents and implement the safety management system with responsibilities, operating procedures, change management, maintenance of critical barriers and incident investigation.
4. Identify and assess serious accident scenarios using appropriate techniques ( HAZOP , fault and event trees, bow-tie, quantitative analysis where appropriate) and document prevention and mitigation barriers.
5. Prepare the safety report for higher-level establishments and the internal emergency plan for all, in consultation with staff and coordination with the authority for the external emergency plan.
6. Inform and train staff and contracting companies, inform the public where appropriate, and cooperate with neighboring establishments to prevent a domino effect.
7. Conduct drills, audits and periodic system reviews, attend inspections by the authority and immediately report any serious accident.

Preventive management software allows you to maintain the inventory of substances and their classification, link serious accident scenarios with risk assessment and barriers, manage maintenance and inspection tasks of critical barriers, plan drills and training, and maintain the documentary traceability required for inspections.

Limits and common mistakes

1. Failure to review the inventory and classification of substances after process changes, which alters the establishment’s level without notification.
2. Treat the safety report and emergency plan as administrative documents, with no connection to daily operations or barrier maintenance.
3. Do not integrate serious accident scenarios into the occupational risk assessment or the coordination with contractors.
4. Conducting drills without evaluating the results or updating the internal emergency plan.
5. Ignoring the domino effect with neighboring establishments and the required public information.
6. Failing to investigate incidents and near misses that demonstrate the degradation of barriers.

The specific application depends on the substances, quantities, and regional regulations for implementation; this information sheet is for informational purposes only.

Regulatory and reference framework

• Royal Decree 840/2015, of September 21. Measures for the control of risks inherent in major accidents involving hazardous substances; transposes Directive 2012/18/EU.
• Directive 2012/18/EU (Seveso III) . Control of major-accident hazards involving dangerous substances.
• Royal Decree 1196/2003, of September 19. Basic guideline for civil protection for the control and planning in the face of the risk of major accidents with hazardous substances.
• Law 17/2015, of July 9. National Civil Protection System; planning and response to emergencies.
• Regulation (EC) 1272/2008 (CLP) . Classification, labelling and packaging of substances and mixtures; basis of the categories in Annex I.
• Law 31/1995, of November 8. Law on the Prevention of Occupational Risks; risk assessment, emergency measures and coordination of activities.
• Royal Decree 393/2007, of March 23. Basic Self-Protection Standard; self-protection plans.

The autonomous communities are the competent authorities for notification, evaluation of the safety report, the external emergency plan and inspections, and may establish implementing regulations.