A widely used hazard identification technique within the process industry is hazard and operability study (HAZOP). To overcome the repetitive and time-consuming nature of the technique, automated hazard identification systems that emulate HAZOPs are being developed. This work considers batch processes, in which material undergoes processing in distinct stages within the plant equipment items according to a set of operating procedures, rather than each equipment item remaining in a "steady state", as is normal for continuous plants. In batch plants deviations which can lead to hazards can arise both from deviations from operating procedures and process variable deviations. Therefore, the effect of operator actions needs to be considered. CHECKOP is an automated batch HAZOP identification system being developed as a joint project between HAZID Technologies Ltd. and Loughborough University. CHECKOP uses a state-based approach to HAZOP analysis. CHECKOP takes a plant description and a set of operating instructions as input and produces a HAZOP report automatically. The overall system architecture and the details of the major components of the systems will be described. The advantages and limitations of CHECKOP will be discussed. (C) 2008 Elsevier Ltd. All rights reserved.