In a methane terminal, at the time of resuming operations following maintenance work, an incident occurred near the flare tower. Two valves connecting the low-pressure gas circuit to the evaporation gas circuit stayed open, causing intake of liquefied gas at the flare tower and producing a flame 50 m high. The POI emergency plan was activated and the situation brought under control 30 min after decompression of these two gas circuits. Procedures for the shutdown and startup phases or for the case of operations under degraded conditions had to be devised or updated.