An explosion at the Ghadir Steel Smelter in Yazd has left at least 19 workers dead or wounded.

Iranian media report that Yazd Governor Azizollah Seifi said seven people had died so far and 12 others have been hospitalized for medical treatment.

The explosion reportedly occurred yesterday evening. The plant’s director and other officials are under arrest during the investigation into what caused the blast.

The Ghadir Steel Smelter, which employs more than 150 people, was launched last May with Mahmoud Ahmadinejad in attendance.