At around 2 p.m., following the final run by the material loading vehicle, the operations manager at a biogas plant noticed an outbreak of fire in a pile of chopped straw on the methanisation facility’s plant input storage platform. The operator called emergency services and unsuccessfully fought the fire using extinguishers. Rail traffic was disrupted. Firefighters contained the fire at around 8 p.m. Two fires broke out again, 2 and 3 days later at around 5 p.m., requiring firefighters to intervene for 3h. Following these 2 fires, firefighters scheduled a visit every 6 hours including spraying the smouldering pile once daily in the early afternoon for a week. Subsequently, site staff spread the materials and systematically sprayed them to cool them faster. Two weeks after the first fire, the fire was declared extinguished. The water used on the fire was collected in a dedicated basin.

100t of plant matter were unsuitable for methanisation and transferred to a composting centre.

The incident was probably due to:

• either emission of incandescent matter from the loader’s exhaust;
• or a spark due to the blade of the bucket striking a flint in the straw.

To eliminate the risk of sparks from the bucket, the steel scraper blade was replaced with a composite blade. To reduce the risk of emission of incandescent particles from the loader’s exhaust, a flame arrestor will be installed to make the loader compliant with the ATEX dust standard. Material storage on the platform was reviewed to reduce the domino effect. A technical solution to reduce the volume of chopped straw stored on the site was studied. The hazard analysis was updated to take account of feedback from this accident.