The HAZOP technique is used to identify potential hazards and plant operating deviations. The principles and practice of the HAZOP technique, as adopted within the process industries, are demonstrated by case study material selected to illustrate a wide range of applications. This module is essentially participative and gives experience of study team involvement. Guidance is given on the management of HAZOP and case studies include consideration of both continuous and batch processes. Use of the technique Layers of Protection Analysis (LOPA) is also described. This may be used to examine in more detail, some of the scenarios which have been identified in the HAZOP. The module is aimed at improving plant safety at the design stage.