It was not immediately clear what caused the blast, which set ablaze the silo located on the banks of the river Rhine, on the border with Germany.
The site is owned by agricultural cooperative Comptoir agricole. Local grain brokers said it had a storage capacity of 40,000 tonnes.
Comptoir agricole declined to comment.
France is the European Union’s largest grains producer and exporter. The Rhine serves an important route for transporting grain from eastern France to northern European countries like Germany and the Netherlands.
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