Abstract: A containment system for samples of dangerous goods stored at cryogenic temperatures includes a bag made of a cryogenically compatible polymer film and a porous structural cartridge made of a polypropylene polymer compound for holding a plurality of sample receptacles separate from one another to comply with the standards of UN Class 6.2 certification. The porous structural cartridge has a cartridge base with a plurality of sample receptacle apertures for holding the plurality of sample receptacles. A cartridge cover mates with the cartridge base to enclose the plurality of sample receptacle apertures. Additional cartridge bases can be included as part of the porous structural cartridge. Each cartridge has sufficient absorbing capacity to absorb the entire contents of all of the sample receptacles held within its sample receptacle apertures.