What are hazards in digital circuits and how do you eliminate them?

Hazards are unwanted transient output glitches caused by unequal propagation delays through different paths. Static hazards occur when output should remain constant but briefly glitches; dynamic hazards cause multiple transitions during a single expected transition. Static-1 hazard prevention: include consensus term covering adjacent 1s in K-map that aren't in same group. Static-0 hazard: similar for POS implementation. Hazard-free design adds redundant terms or uses hazard-free coding styles. Synchronous design inherently tolerates hazards by sampling stable signals at clock edges.