Heavy smoke billowed over Mobile, Alabama, on Wednesday afternoon after a "multi-story, oil rig-like structure" caught fire, according to Mobile Fire-Rescue.
Several fire trucks and boats responded to the rig, which contains diesel, hydraulic fluid, oil, and other potentially hazardous materials.
Mobile Fire-Rescue Chief Jeremy Lami told reporters at the scene that the fire was hundreds of feet in the air, complicating first responders' efforts.
There were no initial reports of injuries. The fire appeared to break out in a shipyard on the east side of the Mobile River across from the city's business district.
More on this developing story at FoxNews.