A massive explosion struck the Valero refinery in Port Arthur, Texas, on Monday, sending a large plume of black smoke into the sky and prompting emergency officials to issue shelter-in-place orders for surrounding communities. The blast occurred shortly after midday at the Gulf Coast facility, one of the largest refining sites in the United States.

Local authorities said the cause of the explosion remains under investigation. The Port Arthur Fire Department confirmed that emergency crews and hazardous materials teams responded to the scene to contain the fire and assess potential risks.

Jefferson County Sheriff Zena Stephens said there were no reported injuries and no evacuations had been ordered. Officials also confirmed that all refinery employees have been accounted for following the incident.

Residents in multiple areas, including Sabine Pass, Pleasure Island, and neighborhoods south of Highway 73, were advised to remain indoors as a precaution. City officials cited ongoing air quality monitoring and fire suppression efforts as the situation developed.

The refinery, operated by Valero, produces approximately 435,000 barrels per day of gasoline, diesel, and jet fuel, making it a critical part of the nation’s energy infrastructure. The explosion and resulting smoke plume were visible for miles across Southeast Texas, drawing heightened attention as investigators work to determine the cause and any potential environmental impact.