Firefighters on Monday were unable to put out an ongoing fire on a military training ground in eastern France, because the area is littered with unexploded leftover World War I shells. Several shells have exploded since the fire started on June 26.
The training camp is located in Suippes, roughly 50 kilometres outside of Reims where officers practice shooting and artillery.
The heat of the fire can cause leftover shells to reheat and subsequently explode.
"The fire is preventing the intervention operation to go further," the Suippes mayor Jean-Raymond Egon told Euronews. "Shells have exploded since the fire started five days ago."
He added that the firefighting operation was limiting the fire from spreading, but could not put it out due to their inability to enter the "red zone", where bombs could keep exploding.
Egon confirmed several shells have exploded but said there is no precise way of knowing how many have done so as the camp is littered with bombs dating back from WWI. The Suippes forest was a battlefield for the four years of the war (1914 - 1918).
"In 1926, the area was turned into a military camp, precisely because the volume of buried WWI bombs was so important that it was impossible to clean it", Egon told Euronews.
WWII bombs might also be found on site, Egon said, which makes it hard to know which ones have been exploding recently: "Explosions can be heard, but we don't know how many there are, as they could go off simultaneously, or even whether the bombs date back to 1914 or 1945."
Since then, the camp has been used as a military training ground where various weapons have been tested, Egon added.
Every year in July, the camp is combed for unexploded devices during its annual cleaning operation. "Every year, between 5,000 and 6,000 unexploded shells turn up, and usually 3/4 of them date back to WWI", Egon told Euronews. "In this camp remain munitions aplenty."
It's not the first time a grenade from either WWI or WWII has exploded in France.
In February, authorities exploded a shell from World War II in Paris after it was found in the north of the city. At least 1,800 people were evacuated from the surrounding area, according to French media reports.
"A quarter of the one billion shells fired during the First World War and a tenth of the shells fired during the Second World War did not explode during the conflict," a 2001 French Senate report on demining states.
The same report states that between 1945 and the start of the 21st century, at least 660,000 bombs had been dismantled, 13.5 million mines and 24 million shells or other explosives were dismantled in France.