Abstract: The subject matter is the assembly of a containment means with an aseptic working chamber and associated decontamination arrangement. The working chamber is delimited at the bottom by a base, and above the working chamber is a circulating air zone, in which a circulating air filter with a circulating air fan is arranged. The circulating air zone and the working chamber are delimited towards the outside by a housing. At least a first returning air channel leads from the working chamber into the circulating air zone. A returning air filter is fluidically connected to the returning air channel, specifically is arranged facing the circulating air zone. The returning air filter can be arranged at the opening of the returning air channel into the circulating air zone or arranged in the circulating air channel, set back from the opening. The returning air filter and the circulating air filter are in the form of a plate filter or an exchangeable filter cartridge or a replaceable filter insert.