Seveso : what are we talking about ?
The term comes from the accident that occurred in Seveso, Italy, in 1976. The resulting European directive has been revised twice. The version currently in force is Directive 2012/18/EU, known as Seveso 3, as noted in the dossier from Officiel Prévention.
In France, it was transposed by Decrees No. 2014-284 and No. 2014-285 of March 3, 2014, supplemented by the Order of May 26, 2014, regarding the prevention of major accidents, according to the INERIS (AIDA database). This order was subsequently amended by the Order of September 24, 2020, issued with the Decree No. 2020-1168 of the same date.
Lower tier and upper tier : two levels of requirements
The directive distinguishes between two types of establishments based on the total quantity of hazardous materials present on-site, as specified by INERIS. Classification therefore depends on what you store and handle, not on the size of the company. The higher the quantity, the stricter the requirements.
This table summarizes the presentation by INERIS. The exact classification of your facility and its requirements are listed in your prefectural order: that is the document that prevails.
The operator's obligations, in practice
The major accident prevention policy
All Seveso establishments must define, document, and implement a major accident prevention policy. It sets out management's commitments and serves as the starting point for the rest of the system.
Hazard assessment
The hazard assessment identifies potential accident scenarios, evaluates their impacts, and justifies risk control measures. According to INERIS, it must be updated at least every five years for upper-tier sites. It then serves as the foundation for emergency plans, public communication, and land-use planning.
The safety management system
For upper-tier sites, the SMS complements the prevention policy. It organizes long-term risk management, including roles, procedures, change management, feedback, and audits. Its requirements are set by the amended decree of May 26, 2014. It is a management system in the sense of the standards familiar to QHSE teams, requiring the same focus on evidence and continuous improvement. Our article on ISO 45001 in an industrial environment details this approach regarding health and safety.
Emergency plans: POI and PPI
The internal emergency plan (POI) organizes the operator's response to an accident within the site. The specific intervention plan (PPI) organizes the public authorities' response outside the site. According to INERIS, these plans must be tested and reviewed every three years. Several professional sources suggest more frequent drills for certain sites; check the frequency applicable in your prefectural decree.
Public information and land-use planning
The operator must inform the public. Data is available on Géorisques. For upper-tier sites, a site monitoring committee ensures dialogue with stakeholders, and a technological risk prevention plan may regulate urban development around the facility.
The directive also provides for cooperation between neighboring facilities to limit the domino effect, including the exchange of information such as safety reports and emergency plans.
Reporting and learning from events
Every operator of a classified installation must report accidents and incidents related to the operation of their facility to the classified installations inspectorate, in accordance with Article R.512-69 of the Environmental Code, as noted by Previlink. These reports feed into the BARPI's ARIA database, which serves as a source of feedback for the entire sector.
The current context calls for vigilance : 1,534 incidents and accidents were recorded in ICPE facilities in 2025, an increase of 23.3% compared to 2024, according to the DGPR report relayed by CITEPA. For an overview of risks and obligations in an industrial environment, see our article on industrial safety.
Managing compliance for a high-risk site on a daily basis
On a Seveso site, the challenge is not knowing the requirements, but tracking them : hazard study update dates, emergency plan (POI) drills to schedule, contractor safety plans, work permits, and actions resulting from audits and inspections. A few practices can help :
- Maintain a single regulatory calendar : revisions, drills, periodic inspections, and deadlines set by the prefectural decree.
- Link every non-conformity to a tracked action, with an assigned owner and a deadline.
- Centralize safety plans for contractors. See our guide on the safety plan.
- Track certifications for staff and contractors. See industrial certifications.
- Organize your monitoring of ICPE and Seveso regulations, detailed in our article on ICPE regulatory monitoring.
Operators of high-risk sites can find QHSE management solutions tailored to these constraints on our page for infrastructure and high-risk sites.
