Radioactive materials are present throughout Earth’s crust. Many useful industries may incidentally cause radiological contamination through their normal operations (e.g., oil & gas exploration and production, mining, and petrochemical plants) since they work with materials pulled from within the Earth that may contain some of those radioactive elements. Radiological contamination may result from the use of contaminated fill dirt, an improperly or incompletely decommissioned industrial site, the movement of improperly decontaminated industrial equipment, or simply being in a region in which there are radioactive elements closer to the surface of the ground.