Pollution
Humain
Environnement
Economique

In a tyre manufacturing plant, following an intervention the previous week to replace a leaking connection on the hydraulic system controlling the operations of a tyre vulcanising press, the replacement connection ruptured during system pressurisation. The vulcanising press activated the technical alarm after detecting a defect in oil pressure; oil flowed into the gutter along the hydraulic units, and the amount lost was estimated at 200 litres. This hydraulic oil then entered a collection chamber equipped with an automatic pump, sending the oil into the internal wastewater system. The oil was partially stopped at the site’s removal tank. The analysis, conducted the same day as discharge to a ditch leading to the COURAUD, indicated a hydrocarbon concentration of 7.8 mg/litre. The leak occurred during the weekend of 2nd and 3rd June, and was not discovered and treated until Monday, 4th June.

Repair of the connection and the intervention to limit the oil release by installing an absorbent sausage close to where the leak had taken place was carried out on the same day. Oil was also recovered in the outlet oil separator. Production was interrupted during repairs to the connection. An analysis performed on 5th June at the point of discharge into the natural environment showed a hydrocarbon concentration of 7.8 mg/l: it appeared that the final oil separator was not able to purify the discharge below this value.

No measures outside the establishment were apparently taken. No water pollution was found, but the presence of pollution was indeed likely. Following this incident, a change in pump use would be adopted to stop pumping if the oil circuit level were to drop. The Classified Facilities Inspectorate only became aware of the incident upon examining the discharge monitoring results received on 13th July, 2007.