His electoral fortunes were otherwise mixed, but he retained his mayoral position till 1914, at which point he was succeeded in the post by his son (also called Léopold Maissin).
The munitions firm hit the headlines in connection with the explosions and sinkings, in 1907 and 1911, of the Iéna and the Liberté, two battleships anchored at the vast Toulon naval base.
[10] In a decree issued by the Ministry for War dated 6 June 1876, Léopold Maissin was one of six students nominated "élève ingénieur" (literally, "pupil engineer").
[11] In 1890, by now a qualified "ingénieur des poudres" (literally, [explosives] engineer")", Maissin was sent by Ministry for War Charles de Freycinet as a government delegate to Russia as part of the preparation for a Franco-Russian Alliance which would lay the ground work for the important diplomatic and military developments during the first half of the twentieth century.
Tests were conducted by the explosives engineer and factory director Albert Louppe at the "Moulin-Blanc" munitions plant, located in the Costour Valley which, administratively, came under the control of the municipality of Le Relecq-Kerhuon near Brest after a reconfiguration of local authority boundaries in 1895.
[17] Léopold Maissin, meanwhile, having previously opposed the development, became a backer of the Grande-Palud powder factory a rival enterprise also located in Landerneau, but financed by German investors.
[20] Léopold Maissin, who had taken over from Albert Louppe as plant director of the powder mill at Pont-de-Buis-lès-Quimerch, insisted that the catastrophic explosions at Toulon had resulted from failures in the manufacturing process at Pont-de-Buis.
[21] However, the explosions at the Toulon naval base in 1907 and 1911 had resulted from the condition of "Powder B" that had been sold and delivered to the navy when Albert Louppe was responsible for the manufacturing plant.
"[21] Subjected to questioning by members of parliament and by the departmental council ("conseil général") for Finistère, Léopold Maissin expressed himself on the matter in detail and at length.
[21] Général Gaudin, a soldier-politician who at this time was serving as the national director responsible for "powders and saltpetres", was mandated by the minister for war to review Maissin's accusations.
Gaudin's investigations were summarized in a report dated 5 November 1911: his work had included a meticulous audit of the various letters that Maissin had submitted to a succession of ministers for war,[c]and others in positions of national authority, over the previous four and a half years.
In 1911 The government responded to the increasingly public nature of the dispute by ordering the dismissal of both men a couple of days after receiving Gaudin's report.
Camille Chautemps reported on behalf of the commission which noted that the revelations of Léopold Maissin had confirmed the presence of "indiscipline that was rife in certain powder mills because their directors flattered their unionised work forces in order to obtain their electoral support".
[e] The political ambitions of the two directors caught up in the matter, Albert Louppe and Léopold Maissin, were in that sense a direct cause of the explosions at Toulon harbour.