A powerful explosion occurred at the Tupraş Oil Refinery in Izmit, northwest Turkey, on Tuesday, injuring 12 people. This refinery is one of Turkey’s largest industrial facilities in the province, located 95 kilometers east of Istanbul.

According to initial reports, Mayor of Kocaeli Metropolitan Municipality, where Izmit is situated, Tahir Büyükakın, reassured the public that the blast was caused by an issue that arose during a scheduled emergency preparedness drill.

Following the blast, the company released a statement saying that twelve workers sustained minor injuries and were then transported to the hospital for evaluation.

The company also affirmed that the fire has been brought under control, and the unit has been safely shut down. Operations at the rest of the refinery are reportedly continuing as usual.