⚡고압 주의High voltage. Means electricity, lightning and sudden energy. Use it for storms, shocks and "electric" moments.
⚠️주의A warning. Means caution, danger and "heads up". Use it for warnings and important notices. Alternative: ⚠️ — same.
☢️방사능Radioactive. Means radiation, hazard and glowing danger. Use it for hazard warnings and "toxic" jokes.