Storage stable quickly acting tablets for combatting vertebrates preponderantly in underground structures

A process for combatting vertebrate animals living in an underground structure having an opening therein comprising providing a packaged storage stable, quickly acting tablet for combatting said vertebrates, said package consisting essentially of a tablet which consists essentially of a mixture of commercial magnesium phosphide and a mold assistant located in a cavity in a first film which is water vapor and air impermeable, tear and break resistant, said cavity having an open top, and covering the cavity across the open surface thereof a second film which is water vapor and air impermeable, non-tear resistant and non-break resistant, the two films being sealed together at their edges tightly against water vapor and airs so that water vapor and air cannot reach the tablet in the cavity, breaking the tablet and the non-tear resistant, non-break resistant second film without touching the magnesium phosphide and introducing the package with the broken film and tablet into the opening of the underground structure in order to gas the underground structure.