Fire on the methanation unit of a refinery

In a petrochemical plant, a fire occurred on the methanation unit (95% H2 + 5% CO -> CH4 + H2 + H2O) of a steam cracker. A seal break on a flange of the circuit caused of the accident. No casualties were reported. The internal operational plan was started.

INITIATING CAUSE: a seal break on a flange of the circuit.

The description of the plant and the unit affected is somehow contradictory.
A steam cracker is a petrochemical process which breaks down saturated hydrocarbons into smaller, often unsaturated, hydrocarbons. It is the principal industrial method for producing the lighter alkenes (commonly called olefins), including ethene (or ethylene) and propene (or propylene). Its feedstock can be naphtha, liquefied petroleum gas (LPG), ethane, propane or butane.
The main unit of a steam cracker is a furnace which make the steam reacting with the feedstock up to  very high temperature of 850C. At the end of the process, de-methanizer towers separate hydrogen and methane in in the cracked gas stream. Cryogenically (−250 °F (−157 °C)) treating this overhead stream separates hydrogen from methane. Methane recovery is critical to the economical operation of an ethylene plant.
[Wikipedia: https://en.wikipedia.org/wiki/Steam_cracking#]

Therefore, in a steam cracking plant, there is no methanisation reaction, as mentioned in the ARIA report, but  a demethanisation step, basically a gas treatment tower. 

No casualties were reported.

The internal operational plan was initiated.