Power cut at a refinery causes a oil and hydrogen fire

The utility production facilities (electricity, water, air, and steam) at a refinery were isolated from the power grid and switched to two turbine generators in anticipation of a storm. However, at 9:50 p.m., both turbine generators shut down at the same time. Deprived of the necessary water and air, the boilers and all the production units entered a safe state.
1. The effluents drained from the stopped units were sent to detention ponds.
2. The gases were directed to the flare stack.

A leak with burning hydrogen and petrol occurred in one of the units.
The facility was restarted over the course of several days, but efforts were plagued by incidents due in particular to thermal fluctuations (pump breakage, water leak, steam leak, clogs, boiler with a punctured heating source).
The burning leak, which was quickly brought under control, may have been caused by differential thermal stresses applied to the tightening bolts of the two companion flanges and significant pressure fluctuations that occurred when the units transitioned to a safe state. The temperature difference caused by the cooling inertia of the connected facilities and the thickness of the ring joint facilitated the loss of hydrogen.
The cascade shutdown of the turbine generators was due to the control system, which failed because of an improperly connected electronic circuit board and a lack of pressure in the hydraulic circuit.

The INITIATING cause of the hydrogen leak was probably the failure of ha flanges join, subjected to thermal and pressure fluctuations occurred during the shutdown of the production units.
The unplanned shutdown was caused by the failure of the emergency auxiliary systems was caused by an improperly connected electronic circuit board and a lack of pressure in the hydraulic circuit.

unspecified production unit of a refinery

In preparation to a storm, the site electricity supply had been switched from the power grid to two turbine generators.