Event
- Event ID
- 209
- Quality
- Description
The accident occurred during the maintenance of a sulphuric acid storage tank in an industry for the fertilizers production. The maintenance works consisted in cutting operations (to remove some plates fastened with bolts) by using oxyacetilenic flame on the storage tank.
The flame ignited hydrogen formed inside the storage tank.
The explosion hurled the tank over a hangar, demolishing two other tanks (also containing sulphuric acid) and causing the escape of the product which invaded the basin of containment. The two men who were performing the cutting operation died. The released sulphuric acid evaporated from the basin originating a toxic cloud which dispersed without consequences for the population. The basin invaded by the sulphuric acid was emptied and neutralized with sodium carbonate in order to avoid that sulphuric acid could corrode the ammonia piping inside the basin itself.- Event Initiating system
- Classification of the physical effects
- Hydrogen Release and Ignition
- Nature of the consequences
- Macro-region
- Europe
- Country
- Unknown
- Date
- Component involved
- chemical storage tank (H2SO4)
- Failure mode
- internal explosion
- Initiating cause
- accidental hydrogen formation
- Root CAUSE analysis
On the internal surface of a tank containing sulphuric acid a corrosion phenomenon associated with the accumulation of hydrogen occurred owing to poor maintenance. The hydrogen was then ignited by the oxyacetylene flame. The hydrogen was then ignited by the oxyacetylene flame used by two workers for cutting operations.
- Root causes
- Date entry in HIAD
- 01/01/2021
Facility
- Application
- Chemical industry
- Sub-application
- Fertilisers production
- Hydrogen supply chain stage
- All components affected
sulphuric acid storage tank, cutting tool, oxyacetilenic flame
- Process temperature range [C]
- ambient temperature (-50°C to +50°C)
- Location type
- Unknown
- Location
- industrial area
- Operational condition
- Pre-event occurrences
The accident occurred during the maintenance of a sulphuric acid storage tank in an industry for the fertilizers production. The maintenance works consisted in cutting operations (to remove some plates fastened with bolts) by using oxyacetilenic flame on the storage tank.
Emergency & Consequences
- Number of fatalities
- 2
- Number of injured persons
- 0
- Post-event summary
The basin invaded by the sulphuric acid was emptied and neutralized with sodium carbonate in order to avoid that sulphuric acid could corrode the ammonia piping inside the basin itself.
Lesson Learnt
- Lesson Learnt
Too few details are known to be able to draw a specific lesson learnt from this event. However, this page reports general lessons learnt and the evolution of this type of hazard prevention:
http://www.sulphuric-acid.com/sulphuric-acid-on-the-web/Hydrogen-Safety.htm.
This report goes well in details of single cases:
http://www.sulphuric-acid.com/sulphuric-acid-on-the-web/Acid%20Engineering%20&%20Consulting%20Inc.%20-%20Leonard%20J.%20Friedman.pdf
In-depth data
- Release type
- Gas-liquid mixture
- Involved substances (% vol)
- H2,
H2SO4 - Release temperature [°C]
- 25
- Probable IGNITION SOURCE
- Explosion type
References
- Sources categories
- eMARS
- Reference & weblink
From public part of MARS database
Event no 22249 of the French database ARIA
https://www.aria.developpement-durable.gouv.fr/accident/22249/
(accessed May 2026)
