This paper develops a theoretical basis for using process algebra and associated model checking tools to verify asynchronous circuits. We extend existing verification theory for asynchronous circuits, and integrate it into the framework of standard process algebra theory. Our theory permits analysis of safeness (i.e. choke) and progress (i.e. illegal stop, divergence and relative starvation) conditions. We show how the model can be translated into CSP, and how the satisfaction of safeness and progress requirements can be reduced to refinement checks in CSP.