Four workers have been hurt in today’s oil refinery explosion in Big Spring–as the blaze continues to burn. Officials said they are unsure on caused the explosion at the West Texas unit operated by Dallas-based Alon USA.

Authorities said one company worker suffered burns and has been transported to a hospital. His condition wasn’t immediately available, the Associated Press reported. Company spokesman Blake Lewis says three injured contractors were treated at the scene.

There was also no word on yet available on how the fire would affect fuel supply in the region, though Blake said the company would be able to meet its supply contract.

Alon primarily markets gasoline and diesel under the FINA brand name, through a network of approximately 1,200 locations, of which about 300 are company owned. The company is also the largest 7-Eleven licensee in the U.S. The 70,000-barrels-per-day Big Spring refinery delivers products to marketers from Ft. Smith, Ark. to Phoenix via company-owned and third-party pipelines. The plant employs approximately 170 people.

Alon acquired ownership of the Big Spring plant in August 2000, when ALON Israel Oil Company Ltd. purchased the U.S. fuels marketing and refining assets of Atofina Petrochemicals Inc. (FINA). The refinery has been in service for more than 75 years.