Thermoplastic dot labels, with the red internationally recognized trefoil symbol on a yellow background, for the identification of vials, tubes as well as other containers and surfaces that contain or may have been in contact with radiation-emitting materials. These round radioactivity warning labels are suitable for prolonged storage in deep-freeze conditions, as well as transportation of radioactive material, such as radioisotopes, in dry ice containers, and portable freezers. The waterproof, tearproof, warning labels will resist exposure to harsh chemical and solvents, as well as mechanical friction, rubbing, and physical damage.