In a pharmaceutical plant producing active substances for medicines, a flash occurred at 9 am when technicians introduced sodium hydride into a reactor. The site’s internal emergency plan was triggered. First responders transported 2 burn victims from among the personnel (one of whom sustained serious injuries to the neck, torso and shoulders) to the hospital.

The temperature rose to 79°C inside the reactor and plastic objects in the immediate vicinity were consumed, especially bags containing the hydride. Plant technicians and internal fire-fighters quenched these objects using powder extinguishers and then covered the affected 20-m² zone, where hydride residue was still present. The reactor was subjected to forced nitrogen inerting, and its temperature had dropped back to 49°C by 11:30 am. The zone was cleaned and the reactor, which had been hermetically closed, was sealed while awaiting expert appraisal upon the prosecutor’s request. The residue was stored in inerted barrels. The internal emergency plan was lifted at 12:40 pm.

As indicated on the operations report, the 1,600-litre reactor had been washed with methanol, then dried and inerted with nitrogen; the lack of water streaks had been verified. The flash occurred while technicians were pouring the second 5-kg bag of sodium hydride at 60% concentration (powder coated by paraffin oil).

According to the classified facilities inspectors, who had arrived on the scene at 10:30 am, several hypotheses could be forwarded: presence of water due to technician perspiration, sodium hydride releasing hydrogen due to a strong reaction with this compound, or perhaps the presence of solvent and oxygen; static electricity was also cited as a possible cause.