Chemical process synthesis typically accounts for model uncertainty b flexibility. However, process flexibility does not guarantee the existence of a plantwide control system to maintain the process at a desired steady state in the presence of uncertainty (i.e., steady-state robust feasibility). We show, through examples, that the distinction between process flexibility and. steady-state robust, feasibility can be observed at, three levels of severity. A definition for plantwide controllability that guarantees steady-state robust feasibility is proposed.