71. An underground tank may be abandoned on its site where removal would be impracticable for one of the following reasons:
(1) removal of the tank would compromise the soundness of the structure of the building or of an element which is indispensable in terms of the building’s intended use; or
(2) the necessary machinery for the removal of the tank cannot materially access the location of the tank.
Every abandoned tank shall be decontaminated, then filled with an inert material.