Seveso III Directive (2012/18/EU): Lower and Upper Tier Thresholds, Safety Reports and Emergency Planning
What are the qualifying thresholds and obligations under the Seveso III Directive (2012/18/EU)? The Seveso III Directive (2012/18/EU) regulates industrial establishments holding dangerous substances above threshold quantities listed in Annex I. Establishments are classified into Lower-Tier or Upper-Tier. Lower-Tier establishments must notify authorities, implement a Major Accident Prevention Policy (MAPP), and maintain a Safety Management System (SMS). Upper-Tier establishments are subject to significantly more stringent duties: they must produce an extensive Safety Report containing quantitative risk assessments (QRA), establish an Internal Emergency Plan (IEP), supply data for External Emergency Plans (EEP), and undergo mandatory on-site inspections at least once every 12 months.
Regulatory guide to Directive 2012/18/EU: qualifying chemical inventory thresholds, MAPP policy, Upper-Tier Safety Reports, and domino effect audits.
Technical Specifications & Regulatory Comparison Matrix
| Hazardous Substance / Category | Seveso III Annex I Column | Lower-Tier Threshold (Tonnes) | Upper-Tier Threshold (Tonnes) |
|---|---|---|---|
| Chlorine (Toxic gas) | Named Substance (P20) | 10 tonnes | 25 tonnes |
| Flammable Gases, Category 1 or 2 (P2) | Hazard Category Section P | 10 tonnes | 50 tonnes |
| Liquefied Petroleum Gas (LPG, propane, butane) | Named Substance (P18) | 50 tonnes | 200 tonnes |
| Petroleum Products (Gasoline, diesel, gas oil) | Named Substance (P34) | 2,500 tonnes | 25,000 tonnes |
| Ammonium Nitrate (Fertilizer grade with hazard potential) | Named Substance (P1) | 1,250 tonnes | 5,000 tonnes |
| Substances Hazardous to Aquatic Environment (E1 Acute/Chronic) | Hazard Category Section E | 100 tonnes | 200 tonnes |
1. The Seveso Summation Rule (Aggregation Rule)
Even if no single substance reaches threshold limits, establishments holding multiple chemicals must apply the Summation Rule: q1/Q1 + q2/Q2 + ... >= 1, where q is quantity present and Q is threshold quantity. The summation must be calculated separately for: health hazards (toxic/very toxic), physical hazards (flammables/explosives), and environmental hazards.