Authorities in Port Arthur have issued an emergency shelter-in-place order following an explosion at a major oil facility operated by Valero Energy Corporation.

Emergency officials warned people living close to the refinery to remain indoors as a precaution, citing safety concerns after the incident. The directive covered a wide area surrounding the facility as responders worked to contain the situation.

The company confirmed that a fire broke out within one of the processing units at its Port Arthur refinery. It also stated that all workers on site had been accounted for, stressing that employee safety remains its top priority.

Witness accounts and local media reports described large flames and thick black smoke rising into the sky shortly after the explosion. Residents in nearby neighborhoods also reported hearing a loud blast that shook buildings and rattled windows.

The refinery, located roughly 90 miles east of Houston, is one of the largest in the region. It processes hundreds of thousands of barrels of crude oil daily, producing key fuels such as gasoline, diesel, and jet fuel.

Emergency crews continue to monitor the situation as investigations into the cause of the explosion get underway. No casualties have been reported so far, but authorities remain on alert until the fire is fully under control.