Abstract: A vent assembly useful for venting bags containing radioactive waste material includes a base plate with a chamber projecting therefrom and a cap plate which has a center portion that snap fits over the chamber. The base plate and cap plate have flange portions which overlie the inner and outer surfaces of the bag to secure the vent to the bag by clamping against the wall of the bag. A ring is snap fitted into the chamber prior to snap fitting the cap plate to the base plate and a compressible mass of fibrous filter material is contained within the ring. The filter material may be selected from a number of filter materials such as spun polyester, activated carbon felt, fibrous cellulose or sintered stainless steel fibers. Preferably, the filter material is electrically charged, fibrous polymer material.