A technician detected a leak when opening a transfer valve during the unloading of 2.58 t of chloroprene from a road tanker in a waste treatment centre. He reduced the pressure of the tank truck to shut the valve on the mobile tank. 1,200 l of chloroprene spilt onto the drains and the retention area. After having stopped the leak and switching over the installation to safety mode, the operating team informed the gatehouse and the establishment’s on-call team.

The use of absorbent products helped to limit evaporation of the liquid. The gatehouse did not record any complaints from the neighbourhood regarding odour problems. However, firefighters and a team from the gas utilities went on site to find the gas leak. The proximity of the 2 events led the staff to set up a crisis unit in accordance with the procedures.

The chloroprene transfer was carried out nitrogen pressurised with a dip tube due to the regulatory obligation of transporting this chemical in a tank that is filled and unloaded from the top; 7 tanks (i.e. 117.8 t of chloroprene) had already been emptied seamlessly according to the same procedure, specifically established for this campaign. After analysing the incident, the leak was located on the connector between the tanker and the transfer line. The leaktightness of all of the pipes, tanker and transfer components concerned was tested the next day at around 10 am; conclusive results authorised the drainage which ended at around 3.20 pm.

Due to the problems encountered for obtaining a perfect seal with the connectors used and the space available in the tanker’s compartment, the tankers were modified and the ‘firefighter’ type (quick-fitting) connectors were replaced with flat flange connectors used for pressurised unloading operations.