Pollution
Humain
Environnement
Economique

At 11.30 am., a fire developed in a furnace section of a steam cracker. Naphtha, which had been released into the environment near a distribution station, caught fire after contact with an operating cracker furnace. The on-site emergency team fought the fire and took measures to reduce the temperature of adjoining parts of the installation. It was then decided to let the naphtha burn under control. Four persons were injured, among 2 seriously that were treated in hospital. Material damage amounted to 0.5 M euros.

Maintenance works on a cracking furnace were the cause of the accident. A cleaning of the coke deposited inside the cracking tubes as a consequence of the reaction mechanisms was taking place. To do this, besides shutting off the valves, blanking plates are placed in the inlets of the furnace. A blanking plate plan in the control room documents the extraction and the placing of blanking plates .

In the beginning, the team correctly followed the sequence of procedures required by the operating instructions and the plan. However, at some time, the blanking plate from a nearby pressurised naphtha pipe was extracted instead of a blanking plate from the pipe leading to the furnace which had to be decoked.

Spectacle blanking plates will be mounted instead of the fast-exchange blanking plates used in the context of the incident. Moreover, manometers are going to be installed in evidence close to the blanking plates, providing a supplementary possibility for the personnel to check that the system is not under pressure. Finally, organisational measures will be integrated to the blanking plate plan.