Pollution
Humain
Environnement
Economique

A tap ruptured at around 8 am inside a rubber factory; 6 m³ of hot cement (75% hexane, 25% polymer) spread on the ground and a hexane cloud formed, but did not ignite. The plant’s IOP was activated and its internal rescue team intervened without notifying the fire department; four affected employees had to be hospitalised. A press release from the operator indicated that the situation was rapidly brought under control and that discharges had not resulted in any impacts beyond the site boundary. The incident occurred on a polymerisation chain.

A tap welded onto the discharge line of a pump and connected to a sampler and pressure switch had deviated; a break was created, through which cement escaped. Under the influence of the heat and depressurisation, the hexane contained in the cement vaporised to form a flammable cloud. The gas detectors were activated, resulting in closure of the reactor valve and an alarm sounded inside the control room. The production line was isolated by closing the upstream and downstream manual valves on the pump. Foam diffusers were activated to cover the cement, while effluent was channelled towards the containment basins.

The operator stated that the bypass with a pressure switch had been added in 2004 to the tap installed in 2003, without reinforcing the weld on the pump discharge line. The Classified Facilities Inspectorate noted that this change had not been recorded or formalised and moreover did not undergo an adequate risk assessment. The operator declared that reinforcing the bypass created an imbalance compounded by vibrations due to pump operations. This situation eventually led to fatigue failure, most likely at the tap weld on the main line.

After this incident, the operator disassembled the discharge line of the faulty pump and the tap for repair purposes. All polymerisation lines were shut down. The operator then checked for the absence of similar taps on the other lines. Restarting the polymerisation lines was conditional upon submitting evidence that: no other faulty taps of a similar configurations existed; the inspections necessary to prove the proper working order of equipment had been conducted; and preventive measures to reduce the risk of repeating such an incident had been implemented. Moreover, the operator was required to provide a chronological account of the facts, along with a description of the equipment involved, an analysis of incident causes and the effects on individuals and the environment. Compliance with the order imposing these emergency measures meant that the line could be restarted 3 months following the incident. Operating losses were estimated at €900,000.