Transuranic waste consists of waste that has been contaminated with man-made radioactive elements, heavier than uranium, like neptunium, plutonium, and americium. They might be produced from uranium and plutonium during reactor operations. The methods of disposal might be hiding it away in isolation plants, such as the Waste Isolation Pilot Plant, or diluting it so that the radionuclides returning to the atmosphere are harmless, or even burying them in the ground.