28/11/2014 Uncategorised “Toxic alarm in the control room” presents an accident that occured in a French chemical plant in 2012, that led to the emission of a small amount of toxic gaz to the atmosphere. However, this accident could have had much more dramatic consequences. The mecanisms of this accident show that safety takes place in a technical but also a human context : the display of a false information parameter led the control room operators to a dangerous decision that worsened the accident and required the intervention of the last barriers of the “defense in depth” safety system.