a secondary containment apparatus for use in combination with primary containers for hazardous wastes such as drums or large barrels , comprising a generally rectangular base member and two generally rectangular lid members of a size sufficient to enclose one or more primary containers . the lid members are moveable only laterally in relation to the base member , the lateral movement allowing access to the drums contained within . the lid members have interlocking means to form a releasable closure , and have engagement means for attachment to the base member . the base member is impermeable to liquids , and is preferably composed of translucent plastic for visual inspection .