Powder explosion in a aluminium processing plant

The fire broke out on a worm ("vis sans fin") supplying a conveyor of aluminium.
The ignition of the powder on the ground was caused by the flame cutting operation on the worm shell which generated scales. The incandescent aluminium dust has been then swept by the wind spread to the atomisation tunnels, the sewers and a lost well.
The dust and hydrogen formed upon contact with water caused four violent explosions.

The fire spread to a stock of auminium powder stored in bags and drums.

INITIATING cause was (maintenance?) work at the transportation system.
ROOT CAUSE is unknown. An absence of proper risk assessment before allowing mechanical work could have plaid a role. The description of the plant is however not enough detailed to perform a proper risk assessment analysis of this incident,

Aluminium production, aluminium powder conveyor

This event does not belong to the hydrogen value chain.
Accidental production of hydrogen was caused by the ignition of Al [powder and its subsequent coming in contact with water. The oxidation reaction of Al + H2O has caused the production and consequent ignition of H2.

Release of Al powder to the environment