On September 29th, 2011, 4 hours after the start-up of the ammonia plant at GPN Grand-Quevilly, a hydrogen leak followed by a fire occurred on a 1 inch synthesis gas line on the discharge side of the synthesis gas compressor. The plant was tripped immediately, the plant personnel were evacuated to a safe location, and the fire was finally extinguished about 90 minutes later, after depressurization and nitrogen purging of the synthesis loop. The damages to the compressor room were considerable, but no one was injured and there was no release of toxic chemicals or pollutants outside the plant. The fire could be seen several miles away, and there was a large media impact locally. The root cause of the leakage was the failure of the yoke bushing on a 1 inch forged steel manual valve. The cost of the reconstruction was more than 16 million € ($20 million USD) including implementation of additional safety measures. The total length of the shutdown was 11 months. The mother company of GPN, TOTAL, has performed a complete safety review of the plant.