Initial investigation into a fire at PetroChina's refinery and petrochemical complex at  Lanzhou City in the northwestern province of  China's Gansu province shows the blaze was triggered by a leak of propylene at a 300,000 t/y air separation unit, the government of Gansu said on its website

No casualties were reported.

The PetroChina facility is one of China's oil refining hubs, with crude refining capacity of just over 200,000 barrels per day.

It was not immediately clear if other main production facilities at the complex were affected by the fire, the news agency Reuters said.