A major explosion and fire have struck a large oil refinery in Port Arthur, Texas, sending thick plumes of black smoke into the sky and prompting emergency warnings for nearby residents. The incident has raised immediate concerns about energy infrastructure safety amid already heightened global tensions.

The blast occurred at a facility operated by Valero, one of the largest refineries in the United States. Officials say the explosion originated in a diesel processing unit, triggering a fire that forced a temporary shutdown of the entire plant.

Local authorities quickly issued a shelter-in-place order due to air quality concerns, advising residents to remain indoors while emergency crews worked to contain the blaze. The order was later lifted after the fire was brought under control.

Preliminary investigations indicate the explosion was likely caused by an industrial accident—specifically a sudden release of process fluid—rather than any deliberate attack. However, officials emphasize that a full investigation is still ongoing to determine the exact cause.

Despite the scale of the explosion, no injuries have been reported, and all workers have been accounted for.