A large explosion during maintenance operations damaged one of the production units of Syria's Baniyas oil refinery, Syria's Oil Minister said on Thursday. A worker was killed and an engineer injured at the refinery on Syria’s Mediterranean coast, Ali Ghanem said. It was not clear how extensive the damage was and if it affected the refinery, which has the capacity to process more than 130,000 barrels of crude a day. A report on state-owned Ikhbariyah television station said the explosion occurred when a tank at the refinery was being welded. Baniyas, along with Syria’s only other refinery at Homs, covers a significant part of the country’s demand for diesel, fuel for heating, petrol and other petroleum products, industry experts SAY. Some oil and products have been imported from Iran and Russia during the Syrian war but US and EU sanctions have made it difficult to get reliable supplies of Iranian crude and certain products to cover shortfalls. Oil production in government-controlled areas in Syria collapsed after Damascus lost control of most of its oil producing fields, located between Deir Ezzor and Hassakeh. These oilfields have been in the hands of Kurdish-led Syrian Democratic Forces since they seized them from ISIS militants. US President Donald Trump has authorised a wider mission to secure Syria’s oil and stop it coming under ISIS control. A significant part of the oil processed at Baniyas comes from these areas. Lorries transport crude from Kurdish-controlled fields in Hassakeh and Deir Ezzor into government-held territory. Washington allows this trade to help secure a source of revenue for the Kurdish-led authorities to finance their administration, diplomats and industry experts say.