Radioactive material! Stay away! Sometimes when atoms in earth are unbalanced, they create radioactive waste. Large amounts of radiation isn’t great for you and it could be deadly. This emoji shows a warning sign with the radioactive symbol in the middle. Use this emoji when referring to something that is not safe, dangerous or harmful. This is also used a lot when talking about nuclear energy or harmful material left over from a nuclear bomb. Example: Shannon you should take heed to the ☢ warning. That area isn't safe.