Pollution
Humain
Environnement
Economique

In a plastic and rubber manufacturing company, vinyl chloride monomer (VCM) was released from an autoclave (pressure vessel) at 11:40 p.m., after a voltage drop on the high voltage feeding line. The emergency electric power generators failed, causing the blockage of the mixer. The internal pressure of the vessel increased up to the burst of the rupture disk and consequent release of VCM gas. The vessel was provided with a system for feeding a reaction inhibitor which did not work.

The on-site emergency plan was activated and the gas cloud was abated with water curtains. The neighbourhood was alerted.

No personal or material damage was recorded, except for the 12 h-shut-down of the affected installation.

The operator improved its emergency electric power supply system and the feeding system of the reaction inhibitor. He installed a fixed water curtain system at the outlet of the waste gas collecting system to reduce the response time. The capacity of the waste gas collecting system was increased to convey possible gas releases from the pressure vessels through it. Finally, the operator improved staff training on emergency response measures as well as of the content of the on-site emergency plan.