Complex sentence: The depot was used until 1966 when the site was closed however in late 1966 when France withdrew from NATO's integrated military structure the site was briefly used between 1967 and 1973.
Split into simpler sentences: The depot was used until 1966 when the site was closed. However in late 1966 when France withdrew from NATO's integrated military structure the site was briefly used between 1967 and 1973.