At 16:30 hrs in a chemical company, 85 m³ of hydrogen peroxide (H2O2) under decomposition overfilled the storage tank, thereby sounding the overflow alarm ; 30 l of phosphoric acid are added for stabilisation, but without effect. A valve between the first tank and an adjacent tank was closed and the tank’s contents was drained into a secondary containment basin. At the same time, the drained hydrogen peroxide was diluted with water, and the vapours were abated. In addition, the tank was externally cooled with water.

Around 17:30, a fountain-like jet of hydrogen peroxide erupted from an open manhole. The tank burst and the remaining hydrogen peroxide was dispersed over 30 m. 10 members of the fire brigade suffered skin burns. A minor quantity of hydrogen peroxide came down beyond the perimeter of the plant as a droplet cloud, in the neighbourhood of the plant. As a preventive measure, the population was alerted. The material damage amounted to 0.5 M euros.

The cause of the hydrogen peroxide decomposition relied in its contaminated by alkaline process solution coming from a ventilation pipe of a ring line leading to a decanter, used for drainage in case of release of H2O2. The ventilation pipe of the closed circuit line was modified to avoid the suction of process solution. Local temperature indicators are replaced by remote indicators, releasing the alarm automatically when a fixed temperature gradient is exceeded. New tanks to be installed, will be equipped with a pressure relief system (folding roof).