Pollution
Humain
Environnement
Economique

A sub-contractor working at a refinery’s alkylation unit complained of chemical burns on the arm at around 3.10 a.m. A routine check carried out in the unit revealed a leak on a tapping (3/4”) of a pressure sensor at the top of a column, at a height of 55 m. The leak of 4 to 5 kg/s for around 4 hours comprised butane (95%-99% by mass) and hydrofluoric acid (1%-5% by mass).

The operator launched the internal emergency plan at 3.40 a.m. Rail traffic was suspended in the vicinity of the plant. The unit was in a safe status at 7.40 a.m. Rail traffic resumed at 8.00 a.m. The internal emergency plan was lifted at 11.00 a.m. following checks in the vicinity of the unit. The town hall, the classified installations inspectorate and the prefecture were informed. The operator issued several press releases.

The suspected cause of the leak is corrosion of the tapping.