Pollution
Humain
Environnement
Economique

At 07:45 am., the rupture of a ball valve shaft installed on the liquid outlet pipe of a tank caused a LPG leak on a storage site consisting of 4 insulated tanks of 150 m3 each. The valve, constructed in 1966 and installed in 1967, had never been serviced. When a technician was opening the valve, the control shaft of the ball valve was suddenly ejected, releasing 8 t of LPG in liquid phase at approx. 5 kg/cm2 hrough the cylindrical opening formed by the control shaft housing of the valve. The worker who was opening the valve was thrown to the ground and suffered bruising without serious consequences. A gas cloud formed, which luckily did not ignite despite the presence of a refinery and a beach nearby.

The on-site emergency plan was activated involving the refinery and the monitoring of the gas cloud. The gas cloud was confined and diluted with water sprays and water curtains fed by the refinery water network. The off-site emergency plan was activated involving the fire brigade, the prefecture, the municipality and the police forces ; the personnel not needed for the emergency response operations were evacuated. The first fire brigade team arrived at 8:05 hrs and substituted the personnel of the installation in the response operations. Water was then pumped through the pipe coming from the refinery, usually used for transferring LPG from the refinery into the storage tanks. The water was pumped at a higher pressure than the pressure inside the tank (approximately 5 kg/cm2), so as to displace the LPG in the bottom of the tank and substitute it in the leakage.

This measure allowed the surrounding area to secured by 9:30 hrs and to approach the ruptured valve and seal it by 10:00 hrs. The LPG remaining in the tank was then transferred to another adjacent tank.

The loss of product was evaluated at 7,000 euros. The failure of the valve was caused by ageing (35 years) and the wear of the bush thread. The operator substituted the similar valves on the other tanks with valves with an inherently safer design (better technology).