Image: Roni Rekomaa / Lehtikuva

An as of yet unidentified substance in a waste container unit at the Forcit Vihtavuori explosives plant at Laukaa is believed to have caused a chemical reaction, posing a potential hazard at a facility that manufactures explosives used in mining and blasting.

Containers and warehouses at the site contain explosive equivalent to 150 tons of TNT.

The danger zone was emptied of residents by early Wednesday afternoon. Of the 2,100 people residing in the area, over 400 were evacuated by the authorities, while the rest had left the area on their own accord or were away during this holiday season.

Both police and soldiers from the nearby Keuruu garrison aided in the evacuation. Officials cleared a zone 1.5 kilometres around site, which possibly could be further expanded if experts judge it necessary.

Traffic is being restricted and several roads have been closed.

A military bomb disposal robot has been brought in to investigate the smoking waste container unit, which authorities are attempting to cool and stabilize.