Pollution
Humain
Environnement
Economique

In an insecticide production plant, between 50 litres (according to the operator) and 250 to 500 litres (according to the rescue team) of chlorpyriphos-ethyl (Xn) solubilised into hydrocarbon flow from a 34-m³ storage reservoir used as buffer capacity prior to packing the insecticide in 200-liter barrels. Located just a few meters from the production building, the reservoir was connected via a permanently open buffer at its apex to the aboveground stainless steel pipe. The installation was devoid of any level measurement sensors, with an operator being assigned to monitor the filling and transfer steps involving the toxic solution. At the time of the accident, this acid overflowed by the buffer and spilled into the retention basin, which was in a poor state of repair: punctured retention (2-cm hole), deteriorated concrete lining. The substance released from the retention structure seeped through an equally structurally-deficient wall, separating the plant from a neighbouring business, then flowed until reaching a stormwater collection ditch and an underground gutter near the retention basin. The basin outflow had been emptying into a stream running 50 m away. Fish were found dead in the channel and at the mouth of the fishing port; moreover, bird populations were being threatened. Sampling carried out using 3 piezometers installed onsite confirmed the trace presence of iridescence. A floating dam was set up at the mouth of the port and a membrane blocked the pipe. Activated carbon was to be spilled at the level of the dams on the following day and a plug placed on the pipe 4 days later. Production was halted and the problem tank emptied into barrels. Absorbent products were spread within the polluted zone. The head of operations officially recognised having neutralised with soda 50 litres of insecticide that had overflowed the same morning. The director and an inspector working with the Regional Environmental Agency (DRIRE) initially examined together the extent of pollution around 7:00 pm. The lens formed above the clayey loam for protecting the water table underneath the retention basin would leach the substance for another several days. The Inspectorate established a record of the facts. A Prefecture order to initiate emergency measures was issued on December 11, while a second order indicated the protocol to be followed in order to restart the plant, along with the corresponding prevention and environmental monitoring measures. Several external companies were commissioned to perform pollution cleanup, i.e.: pumping, borehole sampling, dismantling of both the tank and its retention basin, excavation of polluted soil.