MARSEILLE (FRANCE): A furnace exploded at the Marcoule nuclear waste treatment site in southern France on Monday, killing one person, but there was no leak of radioactive material outside the furnace, France’s ASN nuclear safety watchdog said.

Four other people were injured, one seriously, in the blast at the Centraco site, owned by French power utility EDF and adjacent to the Marcoule nuclear research centre. The site does not house any nuclear reactors.

The furnace that exploded is used to melt waste with levels of radioactivity ranging from low to very high, ASN said.

It did not immediately give a reason for the blast but said it was completely contained within the furnace.