Explanation:
The Ionizing radiation symbol is used to alert people of the presence of a dangerous level of ionizing radiation emitting from a high-level sealed radioactive source. Such a radiation can cause serious injury or death if not handled with caution. The symbol was introduced by the United Nations in 2007 to minimize accidental exposure to large radioactive sources. This supplementary symbol to the existing trefoil symbol was developed after conducting a 5 year project in 11 countries around the world.