Other contributors have said "What are the 3 hazards volcanic eruptions?" is the same question as "What are the 3 hazards of volcanic eruptions?" If you believe that these are not asking the same thing and should be answered differently, click here
The three major products of volcanic eruptions are ash, gas, and lava. Ash can cause asphyxiation, building collapses, and lahars (mudflows). Lava bombs burn buildings and forests, and flows can burn...