The assessment of operating failures and catastrophic risks of high temperature and high pressure circulating fluidized bed transport gasifier (CFB-TG) is presented. The safety analysis is based on the guide words set of a typical HAZOP study. CFB-TG pilot plant consisted of coal feeding arrangement, gasification column (riser), a dis-engager, a cyclone and gas handling system (scrubber). Safety analysis supported by the guide word technique starts with the detail study of the process, breaking down the process flow diagram into three nodes (coal feeding system, gasification loop, gas cleaning & cooling). For each node, deviations by using guide words highlighted by the team members with subsequent causes, consequences and corresponding safeguards were tabulated in HAZOP work sheets. The operational failures and catastrophic risks include explosion, noise pollution, gas emissions, ignition of coal in the feed line, back flow of gases, and feed line blockage, syngas failure at the outlet of gasifier, L-valve blockage, air supply cut off, and high moisture content of the feed. Hence, this step by step examination of process by guide word technique led to the modification in P & ID like installation of low and high pressure alarms and switches, level and temperature indicators, alarm systems, non-return valves as preventive measures to avoid operational and catastrophic failure.