Halakhah for Numbers 19:16

4. Rabbis Munk and Lombard, Yeshurun, X, 563, note 33, suggest that, although presence of the requisite empty space may negate defilement engendered by the corpse, nevertheless, the bricks or cinder blocks are themselves a source of defilement and, as is quite evident, there is no empty space above the bricks or concrete blocks to prevent such defilement from affecting an object or person above the grave. Both the verse "And whosoever in the open field touches one that is slain by a sword or a bone of a man or a grave shall be unclean seven days" (Numbers 19:16) and the verse "and a clean person … shall sprinkle it upon the tent … and upon him that touched the bone or the slain or the dead or the grave" (Numbers 19:18) posit defilement for contact with a grave no less so than for contact with a corpse. In their recently published monograph dealing with the laws of priestly defilement, Tohorat ha-Kohanim (Jerusalem, 5762), pp. 91f., Rabbis Munk and Lombard, citing the comments of Sifri, show that the "grave" specified in Numbers 19:16 and 19:18 is not the earth in which the corpse is buried but a man-made tomb or structure in which the body is placed within the ground. Accordingly, the cinder blocks or bricks themselves constitute a tomb or "grave" which, in turn, causes defilement independently from the corpse.