Sharps and hygiene — scissors, razors, needles (where in scope)
Cuts during service, handling used blades, bloodborne exposure on a nick. The cut itself is rarely the problem — it's what the blade carries. A used blade or unsterilised clipper can pass hepatitis B or C on a nick you barely feel, in either direction — you to a client or a client to you. Disinfecting between clients and sterilising after use are different bars; the second is what breaks the chain.
This is one hazard. Your register is the set that applies to you — under 20 questions, about five minutes, free.