The new symbol does not replace the old one, but it amends it. It was designed to show the danger of radiation to people who do not know about radiation, or who do not know the symbol for it. The symbol was developed because of nuclear accidents that happened because people opened containers with radioactive materials, such as the Goiânia accident in 1987, or the Samut Prakan disaster near Bangkok in 2000. The new symbol will not be placed on the containers. Rather, it will directly placed on the substances emitting radiation, of the highest categories, 1 to 3. Containers will continue to bear only the old symbol, as they do not pose a direct risk. This also applies to rooms with radiation sources or x-ray equipment in them.