Pollution
Humain
Environnement
Economique

In a fertiliser plant, an ammonia synthesis unit stopped following the malfunction of an alternator (due to a thunderstorm). The safety features were operating normally, yet the synthesis gas (N2 / H2) emitted into the atmosphere ignited in the chimney (sparked by lightning?). Alerted by the noise and after noticing the flames raging for 15 min, neighbours contacted the fire department. During this time, the facility operator cut the natural gas intake that supplied the unit and secured the installations. Fire-fighter presence was not required at the site. An investigation was undertaken to identify the causes of alternator malfunction.