Four people were killed from an explosion at a storage tank in Turkey's Tupras, sole oil refining company, in the western province of Izmir, according to Aliaga district governor Bayram Yilmaz on Wednesday.
Yilmaz told Anadolu Agency that the accident killed four people and injured two.
"This is a work accident, and not an attack," he confirmed.
However, the Tupras company announced that the explosion, which occurred at 09.25 local time, seriously injured four who were taken to the local hospital in Izmir.
Further details were not immediately available, but the company is expected to make an announcement later.
By Murat Temizer