An explosion occurred around 6:40 pm at a port petrochemical facility, located on the Algerian coast and composed of 6 gas and hydrocarbon treatment units; a total of 12,000 workers were employed on this site at the time, which was in part fuelled by gas and oil from the Sahara region.
The accident occurred inside the natural gas (LNG) treatment facility, subsequent to the explosion of a high-pressure boiler responsible for producing the vapour. Given the violence of the explosion, nearby tanks containing inflammable substances were also damaged: the resulting leaks then caused the fire to spread, with different outbreaks in turn triggering new explosions (the “domino effect”). The blast from the explosion, heard over a 10-km radius, broke building and shop windows in the vicinity. A crisis unit was set up by the operator and the Interior Minister; the prefect (“Wali” in the local administration) activated the equivalent of an external emergency plan. It took local fire-fighters around 8 hours to bring the blaze under control.
The ultimate human toll was very serious: 27 killed among the staff, including 9 security agents manning neighbouring stations, and 74 injured (43 of whom left hospital the next day after undergoing medical exams). The majority of deaths were caused by the effects of a pressure surge or the projections and collapse of structures.
The estimate of property damage rose to 800 million dollars. Three of the six liquefaction units were destroyed. Debris was ejected up to 250 m from the epicentre of the explosion, yet actual damage at the site remained limited.
According to witnesses, strange noises corresponding to vibrations or leaks from valves were heard prior to the powerful explosion. The unit (“Train 40”) where the explosion occurred seemed to display frequent operating anomalies. After a major leak notified by a maintenance agent, who would die in this explosion, a mix of air and gaseous hydrocarbons was suctioned by the air inlet of the Train 40 boiler, causing an initial explosion inside this boiler, followed by a second deflagration outside and then a fire destroying adjacent “Trains 20 and 30” separated just 60 m from one another.
