A mail box configured to contain and reduce exposure to hazardous particulates, which includes a container having a deposit port at an upper end and a collection chamber at a lower end. There is at least one door at the upper end for mail to be placed into the deposit port. A normally open sealable bag is located in the collection chamber for receiving mail and for being sealed when the mail is to be removed from the container. There is a bag holder constructed and arranged to hold a bag in place and normally open so that in a first position, mail placed into the deposit port falls downwardly through the bag holder and into a bag in the collection chamber and which bag may be preliminarily sealed while in this position, and in a second position, the bag may be more securely sealed and removed from the bag holder. The bag holder is movable from its first position in which the bag is within the collection chamber to the second position in which the bag is outside of the collection chamber and includes two open frames hinged together for removably holding the top of a bag. The bag holder has an upper frame and a lower frame which are arranged so that the top of an open bag may be clamped between the upper and lower frames to hold an open bag in place in the collection chamber.