After 17 months of investigation, the Italy Prosecutor's Office in Prato has formally moved nine individuals toward trial for their roles in the December 2024 explosion at an Eni fuel depot in Calenzano, near Florence. The blast killed five workers and injured 27 others, but prosecutors concluded that the corporate parent, Eni S.p.A., cannot face administrative charges despite individual negligence charges naming seven company executives and supervisors alongside two employees from contractor Sergen srl.
Why This Matters
• Criminal proceedings now advance: Nine defendants receive formal notification of charges including negligent homicide, negligent disaster, and bodily injury—moving the case toward a preliminary indictment hearing within months.
• Individual accountability tested: The prosecution strategy isolates personal criminal responsibility from corporate liability, potentially leaving systemic safety gaps unaddressed.
• Environmental damage still under investigation: A parallel probe examines hydrocarbon spillage into adjacent drainage channels, with potential penalties exceeding millions of euros if waterway contamination is confirmed.
How the Tragedy Unfolded
The explosion occurred in the truck-loading bay during afternoon operations. Workers from Sergen, contracted for routine maintenance, began dismantling equipment on what they believed to be a decommissioned, empty fuel line. The pipeline remained active and pressurized—a critical miscommunication that released a massive plume of gasoline vapor into the loading area.
At the same moment, an uncertified diesel-powered forklift motor operated nearby. Under ATEX regulations governing explosion hazards, the zone should have been classified as Zona 1—the highest-risk category where only explosion-proof equipment is permitted. Instead, site management had labeled it Zona 2, allowing non-certified combustion engines to operate. The forklift's heat ignited the gasoline cloud.
The resulting deflagration destroyed the loading bay structure and killed the five workers present.
The Safety Cascade That Broke Down
The Prato investigation, which ran from March 2025 through April 2026, identified "grave and inexcusable errors" across multiple layers of operation. These were not isolated mistakes but overlapping failures that prosecutors argue were foreseeable and preventable.
Incompatible operations ran simultaneously. Eni scheduled fuel-loading operations while Sergen conducted maintenance work—a combination explicitly forbidden under standard industrial safety protocols. Coordination between the two firms appears never to have occurred at the operational level, despite the shared risk.
Work permits ignored equipment realities. Despite a combustion engine being present at the maintenance location, site supervisors issued a "cold work" permit rather than the more restrictive "hot work" authorization required when ignition sources are active. This procedural shortcut appears to have stemmed from administrative routine rather than genuine site assessment.
Critical bolts were missing. Post-blast analysis revealed two safety bolts absent from a pipeline flange undergoing maintenance. Whether they were never installed, removed without replacement, or lost during work remains unclear—but their absence weakened containment at the precise failure point.
The safety coordination document was purely formal. Italy requires facilities to maintain a Unified Risk Assessment Document (DUVRI) specifying how contractors and regular operations coordinate hazards. Calenzano's document existed but, according to investigators, lacked operational substance—it was a checkbox exercise rather than a functional safety tool.
A new fuel line created hidden interference risks. Installation of a new HVO (hydrotreated vegetable oil) system involved valves not specified in the original engineering blueprints. This gap in technical planning meant nobody formally assessed where new equipment interfaced with existing maintenance schedules, creating blind spots for both Eni and Sergen teams.
The Corporate Shield Survives
Under Legislative Decree 231/2001, Italy holds corporations administratively liable for crimes by employees when those crimes reflect systemic organizational failures. Eni S.p.A. avoided this liability because prosecutors determined the company's organizational model was "formally correct" and found no causal link between the compliance framework and the actual events.
This conclusion has triggered debate among labor safety advocates. The company maintains written safety procedures, designates responsibility structures, and conducts documented risk assessments. On paper, its system appears compliant with Italian law. Yet workers died because those procedures were not followed operationally—the DUVRI was hollow, operations ran in parallel despite prohibition, and ATEX zones were misclassified.
Prosecutors did not dispute this reality. They simply concluded that the law as written does not hold corporations liable when formal compliance exists, even if actual implementation fails. This leaves Eni exposed to civil damages from victims' families but shielded from criminal prosecution as an entity.
The Human and Environmental Cost
Five men died: truck drivers and maintenance workers whose presence in the loading bay that afternoon meant they were near the ignition point when the vapor cloud formed. Twenty-seven others sustained injuries ranging from severe burns to respiratory trauma from toxic fumes and smoke inhalation. Several remain hospitalized as of May 2026.
The explosion also ruptured fuel storage infrastructure, releasing hydrocarbons into a drainage channel adjacent to the facility. The separate environmental investigation focuses on whether the spill violated Italy's water protection statutes and whether emergency containment was adequate. Soil and groundwater sampling is underway, with results not yet disclosed publicly. If contamination reached protected waterways, penalties could reach several million euros.
What Happens Next
With the preliminary investigation closed, the Prato Prosecutor's Office will request a preliminary indictment hearing (udienza preliminare) in coming months. At this stage, Italian law permits defendants to negotiate plea agreements—reduced charges or sentences in exchange for avoiding full trial.
The trial itself, if it proceeds, will focus on chain-of-command responsibility: which specific individuals authorized simultaneous operations, who approved the cold-work permit despite active combustion equipment, and whether senior executives knew of the ATEX misclassification. Eni defense attorneys are expected to argue that operational decisions were made by mid-level site managers without boardroom involvement—a strategy that could fragment culpability across multiple defendants rather than establishing unified corporate knowledge.
Criminal convictions could result in prison sentences ranging from 1 to 10 years depending on negligence severity and individual role. Individual fines are also likely. Since Eni S.p.A. was excluded from administrative liability, financial penalties will be limited to personal judgments and civil damages—not corporate-level prosecution.
An Industry Under Scrutiny
The Calenzano facility held status as a Seveso III site, subject to the strictest European safety directives for major-accident hazards. Prosecutors' findings that a zone requiring explosion-proof equipment was mislabeled point to failures in both internal audits and external regulatory oversight.
The Italy Ministry of Labor and Social Policies has not announced systemic reforms following the investigation. However, regional labor inspectorates across Tuscany and Emilia-Romagna have reportedly intensified unannounced inspections at fuel depots and chemical plants. Union representatives have publicly called for mandatory third-party certification of ATEX classifications and tighter restrictions on simultaneous operations at high-hazard facilities.
Whether these calls translate into regulatory change remains uncertain. The trial will offer one measure of accountability. Whether it produces structural change in how fuel depots coordinate safety, manage concurrent operations, and apply risk assessment tools remains an open question—one that matters for workers at similar facilities across Italy.
