Bromates (carcinogenic) were detected in the River Durance at levels higher than the acceptable limit. Samples taken at the city’s (pop. of 5000) extraction points upstream and downstream of the water treatment system confirmed the presence of bromates. On 22 March, the city implemented water restrictions and distributed bottled water to its citizens. Analyses conducted at a chemical manufacturing site confirmed high chlorate levels along with high bromate levels.

The pollution came from treated effluent discharged from the chlorinated waste incinerator. This waste also contained bromine. Discharges from the electrolysis’ workshop were diverted to the emergency containment basins

On 31 March, the prefecture issued an emergency order prohibiting discharges from incineration plants and requiring daily monitoring of water collection points and the environment. On 3 April, all the levels measured at the company’s discharge points were below the detection limit.

The operator has installed an ultrafiltration drinking water system pending a permanent solution to the situation. It also has installed a mobile reverse osmosis system to treat the 10,000 m³ of contaminated water stored in the containment basins.

When the incident occurred, chlorinated waste from Spain was being burnt in the incinerator. Investigations found that the waste’s bromine content was up to four times higher than what is usually in the incinerator. The gases from the incinerator were sent through a wet scrubber.