At a chemical facility, an explosion and fire occurred around 5 pm inside a laboratory on the first floor of a 4-storey, 400-m² building. The personnel were evacuated and the internal emergency plan activated. Air samples extracted from the premises were negative; only carbon monoxide (CO) could be detected on the top floor. The building was ventilated before employees were allowed back in to collect their belongings.
The fire extinction water underwent treatment. Property damage was extensive: the laboratory room totally devastated, shattered panes on several R&D building windows located on the 1st and 3rd floors.
The accident involved some highly flammable solvents (tetrahydrofuran and hexane) contained in an open 15-litre flask and in 2 jars, with all 3 of these containers being placed in a hood that was running while the laboratory technician left the room for 3 to 4 minutes. The electronic controller on the hot air bath (inside the hood) triggered ignition of the solvent / air mix that had formed in the hood. A technical defect in the controller, which had not been designed for use in explosive atmospheres, actually caused this accident.
The conclusions of investigations conducted following the accident indicated that the cause could not merely be ascribed to faulty equipment, but also pointed to operator error and a lack of certification and supervision of personnel assigned to the laboratory. Also cited were: insufficient delimitation of zones with a risk of explosive atmosphere; appropriate safety measures not fully implemented by technicians; and inadequate onsite fire-fighting resources.