Firefighters work to put out giant blaze after railroad ties catch fire in southern Colorado

Fire officials in southern Colorado sent out a warning to residents on Saturday after a large fire started in an industrial area in the city of Pueblo. Firefighters were working to try to put out a huge amount of burning railroad ties.

No structures were threatened by the fire, according to the Pueblo Fire Department. A post on the agency's Facebook page in the early afternoon showed towering flames and dark black smoke, and firefighters spraying water on the fire.

The blaze was burning in the Midtown area of the city, which is close the railyard and not far from the Pueblo Riverwalk.

There have been no reports of injuries and so far it's not clear how much damage the fire has done. It's not clear how it started.

The fire department posted the following warning: "Due to the nature of the fuel we advise that anyone with respiratory issues or is downwind of the fire take the necessary precautions to avoid the plume. Turn off all outside air handling units, close windows and doors and leave the area if the smoke settles in your area."