A fire broke out at around 6.30pm on Thursday in a 2000m2 warehouse at the Metalutex factory. An industrial equipment storage company. The 45 firefighters who were on site were able to contain the fire. However, they will spend the night on surveillance. Staff have been evacuated. There are no casualties. Forensics and insurers arrived on the scene quickly to understand the reasons for the accident. You are a trainee investigator and responsible for assisting them in their investigation. Here are the first testimonies collected. Statement from the neighbors of the factory who arrived first on the scene We heard a loud explosion, then we saw an employee stagger out of Warehouse C. This man asked us to warn the fire department that a fire had started. When firefighters arrived the entire warehouse was on fire. Statement from Mr. Férieux, the night watchman I was doing my rounds to check that there was nothing wrong. When I arrived at Warehouse C, I smelled a pungent smell and saw, with my flashlight, a viscous liquid on the floor. As I was turning on the switch to turn on the light to see what was going on, I saw a spark and there was an explosion that violently threw me outwards. Fortunately I had nothing serious, just a good headache and some cracked ribs. Last week I had already reported that vials of hydrochloric acid stored in the nearby B warehouse were poorly secured and could overturn and break. Statement by Mr. Chlorex, Warehouse Manager I can't explain this accident. In Warehouse C, there are only stocks of iron chip that we keep before shipping them to the steelworks. Warehouse B contains only hydrochloric acid, which is not an explosive liquid. Therefore, there is no reason for an explosion and a fire. Statement by Mr. Lancier, Fire Chief After extinguishing the fire we found the presence of a seecy liquid with a pungent smell at the boundary between Warehouse B and Warehouse C. Traces of unknown greenish liquid have also been found that would be good to identify. We have no known where it might come from. We leave you this table of data on some commonly encountered gases. Gas formula Oxygen Recognition Test O2 It revives a flame. H2 hydrogen It creates a detonation a presence of a flame. CO2 carbon dioxide It disturbs the lime water. H2O water vapour Upon contact, the white anhydrous copper sulphate turns blue.