an expandable liquid barrier having an expandable layer attached to an adhesive layer is disclosed . the barrier provides constant containment without restricting access or creating a hazard in an area . the barrier is generally low profile like a length of tape until contacted by a liquid . once in contact with a liquid the barrier expands and provides containment of the liquid . one means for expanding the barrier in the presence of liquid is to provide an expandable fill , such as super absorbent polymer , between the layers . other means for releasing expanding the barrier include using a water - soluble adhesive to hold a resilient expanding layer and providing contracting section which increases the profile of the barrier . the barrier may be used in combination with a switch to enable reaction to the spill .