Abstract: A vial adapter is described comprising a housing, the housing comprising an expandable chamber to contain a volume, an internal passage in communication with the expandable chamber, at least one opening in communication with the internal passage, and an access member integral with the housing. A hollow spike comprising a proximal end is integral with the housing and a distal end. The spike comprises a vent lumen open at the distal end and a fluid lumen open at the distal end, the vent lumen is in communication with the internal passage and the fluid lumen is in communication with the access member. A first check valve restricts communication from the expandable chamber to the internal passage, and a second check valve restricts communication from the internal passage to the opening. Methods of reconstituting and/or withdrawing hazardous material using the vial adapter are described.