At least eight people were reported injured after a blast hit Eurenco's military explosives site in Bergerac in southwest France on Wednesday.
The firm produces military explosives, propellants and fuels. It also makes explosives for civil use.
The Dordogne prefecture said that emergency services were at the site, where the fire was burning after the explosion.
Of the victims, one was seriously hurt while others suffered slight injuries.
The press release said the situation was under control and there was no risk of the fire spreading.
Interior Minister Gerald Darmanin said significant resources were deployed and a crisis center was activated at the site.
Eurenco is a major player in the defense sector and develops and manufactures explosive materials for military ammunition. It is a Seveso classified site owing to the use of hazardous materials.
