Risk identification involves the systematic use of data to identify hazards that could affect CPPs, CQAs, or critical aspects of a process gas system. Risk identification should consider likely, rather than rare events such as earthquakes. A pre-defined scale can be used to rank the severity of impact of identified hazards on a process gas system.Potential risks to typical product CQAs from a compressed air system include:• hydrocarbon (oil vapor and particulate) content• increased moisture levels• viable particulates• non-viable particulates (other than hydrocarbon)• gaseous impurities• process gas mix-up (e.g., connection of oxygen container to nitrogen distribution system)• reverse flow