Devecser is a town in Veszprém county, Hungary. It is situated approximately 35 km north of Tapolca and 15 km southwest of Pápa, at the foot of the Bakony Mountains.
Devecser is primarily known for the Ajka alumina plant sludge spill of October 4, 2010. The spill, also known as the Kolontár disaster, involved the rupture of a reservoir dam at the Ajkai Timföldgyár alumina plant near Ajka, releasing a torrent of toxic red sludge (a byproduct of aluminum production) that flooded several nearby towns, including Devecser. The disaster caused significant environmental damage, fatalities, injuries, and property destruction. Recovery efforts in Devecser and the surrounding areas were extensive and ongoing for many years following the event.
Prior to the disaster, Devecser was a relatively quiet agricultural town. The local economy was centered around agriculture and small businesses. The town has a history dating back to the medieval period and features a castle, the Esterházy Castle, although it sustained damage in the 2010 spill.
Since the disaster, Devecser has been significantly affected by the clean-up and rebuilding efforts, and the long-term environmental and economic consequences of the red sludge spill continue to be a concern for residents and the Hungarian government.