This trefoil is the hazard symbol for radioactive material. Don't go near it, there will be bad after-effects.




This is the hazard symbol for toxic substances. Don't touch it or drink it!




This symbol accompanies explosive materials. Beware of it...




This is the symbol for a biohazard, or a material which represents a threat to cellular materials or living organisms. Trust me, you DO NOT want to touch it in.