A bomb?
Come on… When, on January 14, a Second World War machine was discovered on a construction site in Mantes-la-Jolie (Yvelines), elected officials and authorities barely jumped.
This is the fourth in a few months at this location.
And it will probably not be the last.
The worksite linked to the extension of the RER E to Mantes-la-Jolie regularly brings to light numerous machines dropped by the Allies.
Impossible to know how much remains in the basements of the city.
"Let's say that if you dig 4 or 5 meters, there is a chance to find it", summarizes a civil servant passionate about this period in history.
Railway axes, industrial sites, strategic infrastructures ...
A map of the time allows us to get an idea: dozens of points, which are as many bombs dropped, dot the Mantaise agglomeration, a region which, despite itself, concentrated part of the fighting.
One anecdote alone sums up this local specificity: the Normal School of Deminers was based, just after the war, in Septeuil, a village near Mantes ...
In order to liberate France from Nazi Germany, the British and American Allies systematically bombed the major rail axes, industrial sites and strategic infrastructures in this key sector of the western Paris region.
Mantes-la-Jolie was particularly targeted: at the Liberation, the Germans transited there to send their reinforcements to Normandy.
The presence of the marshalling yard and a locomotive repair shop encouraged the bombardment of the Mantois.
The offensive was intense from the spring of 1944 and 500 inhabitants of Mantes-la-Jolie lost their lives there.
“The order was to destroy all the bridges between Paris and Le Havre to prevent the Germans from responding and attacking major infrastructures,” recalls Bruno Renoult, local historian and author of several books on the subject.
Bombing of the Mantes bridge, May 30, 1944. DR
Trappes marshalling yard, Saint-Cyr-l'Ecole and Vélizy-Villacoublay aerodrome, Boulogne-Billancourt (Hauts-de-Seine), Villiers-le-Bel (Val-d'Oise) factories … All these areas were shelled for several months, drowned under hundreds of Allied bombs.
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So many buried relics, buried several meters deep and which are now resurfacing thanks to major projects, such as the extension of the RER E in Yvelines.
A historical diagnosis before "passing the sector on the radar"
The presence of an underground explosive carpet prompted the State services to create, in 1953, a specially dedicated team.
Its operation is well established and the fluidity of its interventions impresses.
Each demining operation is a meticulously calibrated exercise in which elected officials, firefighters, deminers and police officers work in bluffing serenity.
In the Yvelines, eight people make up this cell placed under the authority of Olivier Fliecx, head of the interministerial defense and civil protection service at the Yvelines prefecture.
The team identified a number of hot spots that could potentially hide a bomb.
Before each site, spotting is carried out by specialized teams in order to detect any explosive devices.
LP / MG
"In the event of a construction site on one of these areas, the project manager calls on a pyrotechnic research firm which will first conduct a historical study," explains the manager.
This cabinet will have access to military archives, period photos… Once this diagnosis has been established, we pass the area on radar.
In the event of an explosive presence, the deminers intervene upstream.
"
This procedure allows the site to be started in complete safety.
Or almost.
Because there are still devices buried, as in Mantes-la-Jolie or Saint-Cyr-l'Ecole a few years ago.
The workers who work on these sites are made aware of the risk and operate with precaution.
In January 2019, a bomb was discovered on the T13 tramway construction site in Saint-Cyr-l'Ecole (Yvelines).
LP / Margaux Bourgasser
The risk of "typing" exists, but it is very low according to this specialist who forecasts a next batch of discoveries: the burying site of the Nationale 10 in Trappes which will start in the coming months ...
The deminers have "still six to seven centuries of work"
Established near Versailles, the Ile-de-France demining service covers eleven departments in the greater suburbs and provinces.
It employs 15 specialists who, on a daily basis, intervene for “classic” bomb threats in public transport, the securing of official trips, police operations and counter-terrorism missions which explain the anonymity required for its members.
Collecting and defusing war machines is also part of their daily life: last year, deminers in Versailles received 750 requests for intervention in their area.
They deactivated 25 tons of ammunition.
This is explained to us by Jean-Yves, the head of the interdepartmental demining service at Versailles.
Which sectors were the most targeted by these bombings?
Jean Yves.
Historians will answer more precisely, but railways and large industrial sites have been particularly affected.
It is therefore logical to find them today in these places, whether in Mantes-la-Jolie, Trappes or Dreux (Eure-et-Loir).
They are also found in places where major works are taking place.
Those of Greater Paris, for example, logically uncover buried machines.
How many bombs are still to be discovered?
Vast question… It is very difficult to answer but we usually say, knowing approximately the number of bombs dropped during the war, that we still have six to seven centuries of work!
How deep are they?
It all depends on the bombs used, but generally they are between two and five meters deep.
85% of the devices found are those of the Allies, Americans or British.
The rest come from the Germans.
Are there any devices more dangerous than others?
Yes.
There are one or two types that we do not know how to defuse.
This is why we have opted, in France, for a strict protocol: if a device is discovered, the authorities must evacuate the areas and us, come as quickly as possible.
Because the risk is obviously to be in contact with these bombs.
Machine operators are also exposed ...
Yes.
They are, however, made aware of the risk when they work on sites in sensitive areas.
They are quite cautious and work with caution.
What relationship do you have with a bomb that you have just discovered?
Everyone reacts differently to a bomb.
Some will give it a nickname, others will break away from it.
In any case, it is never trivial.
A bomb is important.
It is always a risk.
Sometimes, it allows us to meet colleagues, to work together, to create a dynamic.