In a metalwork plant, a leak of hydrochloric acid at 30% occurred at around 10 am on a sub-contractor’s road tanker connector, during the transfer of acid from a fixed tank to the vehicle’s tanker. The 2 technicians who monitor the transfer alerted a manager who immediately called the public emergency services. A truck driver wearing anti-acid clothes closed the vehicle’s valve and depressurised the tanker. Between 200 to 300 l of HCl were spread over the ground. The plant’s staff installed closure plates on the sewer openings but a proportion of the acid flowed into the VESLE river bordering the establishment.

An employee affected by acid vapours and the truck driver were taken to hospital for tests. Arriving at the scene at around midday, officers from the Water Police and the Federation of Fisheries noted no pollution of the river.

The melting of the connector of the truck’s valve caused the accident. According to the operator, this alteration of the untreated section of the connector could be caused by a combination of factors : concentration of acid, pressurisation at 0.5 bar during pumping and insufficient sealing of the connector following an impact. The unloading procedure was completed : presence of the driver in appropriate clothes near the vehicle’s valves, installation of a retention tank below the truck’s connectors and delimitation of a safety area during the intervention.