Officials Cite Hydrogen in French Factory Explosion, Four Injured
Saint-Fons, France – 23 December 2025
An explosion at a chemical factory in eastern France, potentially linked to hydrogen, has injured four people, three of them seriously.
The blast occurred at 14:30 local time on Monday at the Saint-Fons site of Norwegian chemical company Elkem, according to the regional government, Préfecture Auvergne-Rhône-Alpes. The explosion triggered a fire that burned for several hours before being brought under control. At its peak, approximately 100 firefighters and 30 fire engines were deployed.
Local reports, citing officials speaking to Agence France-Presse (AFP), stated that the explosion took place in a laboratory at the site and was “caused by hydrogen.” All four injured individuals were employees of Elkem.
However, a company spokesperson told Hydrogen Insight that it has not yet been confirmed whether hydrogen molecules directly caused the blast:
“The product being handled by the researchers contains hydrogen molecules; however, we do not know the cause of the incident at this stage. A thorough investigation will be conducted promptly to examine what happened.”
Elkem manufactures silicones and silicone oils, for which hydrogen is an essential input, at the Saint-Fons plant, which also hosts some of the company’s research and development (R&D) facilities.
Immediately after the explosion, authorities established a 1 km security perimeter, and nearby A27 motorway, rail, and river routes were temporarily closed. Residents were advised to avoid the area, although officials confirmed there is no toxic risk. The lockdown was lifted at 18:30 local time.
Elkem’s Saint-Fons site is classified as “high threshold” under the EU’s Seveso Directive, reserved for facilities handling large quantities of dangerous substances, requiring strict compliance with safety and reporting rules.
According to Hydrogen Insight, hydrogen has been implicated in six other major industrial explosions worldwide over the past 12 months, all of which caused worker injuries or fatalities.
