Abstract: A substantially tubular bag for containing materials and protecting same against moisture and fine particle contamination, and having improved resistance to breakdown of structural integrity during loading and handling. At least one outer layer forms an outer tube member, while at least one inner layer forms an inner tube member. The at least one inner layer is formed from a substantially moisture and fine particle-impermeable material. An inner seal closes an end of the inner tube member. Outer closure means are arranged across the end of the outer tube member substantially adjacent to the inner seal. The end of the bag is folded to isolate the inner seal, and the outer closure means is affixed in place against one side of the bag, so as to prevent shock and disruption of the inner seal during loading and/or handling of the bag.