Combustion was detected around 8:30 am in four of the twelve 500-tonne cells of a 30-m high concrete cereal silo, subsequent to sealing work completed by a subcontractor adjacent to the dust extractors installed on the container tops. These 4 cells contained wheat (a 450-tonne cell) and barley (3 cells of 300, 350 and 500 tonnes, respectively). 4 other cells were filled with smoke, as were the four 100-tonne spaces between cells. Fire-fighters sprinkled the smouldering dust and then unclogged the dust accumulating beneath the cell roofs; all the containers were drained. At 9 pm, first responders no longer detected any hot spot in the silo, yet 2 monitoring rounds were still conducted at 1 am and 7 am using a thermal camera. The use of hot spot tooling (blowtorch to heat the bituminous substance) during the sealing works and failure to clean the extractors resulted in this accident. The fire had no impact on either public safety or the environment. Following the accident, the silo operator updated the site’s prevention plan and hot work permit while revising the safety and operating instructions (cleaning, thermometric tracking). Site personnel were also reminded of all works-related risks.