2,909. Not Rot

Hilchos Nezirus 7:4

Let’s say that two corpses were buried together, the hair and nails of one deceased person were cut off and buried together with another, or a pregnant woman was buried with the fetus still inside her. In all of these cases, rot doesn’t transmit ritual impurity. The same is true if someone ground a corpse into mulch; a corpse must decompose naturally for the laws of rot to apply. If someone ground a corpse and then left it until it decomposed naturally, or if a part of a body decomposed while the person was still alive, after which he died and the rest of his body decomposed, there is a doubt as to whether rot transmits impurity. Therefore, a nazir who is exposed to such rot is in a state of doubt regarding his ritual purity. Likewise, there’s a doubt if a nazir is rendered unclean by a quarter-kav of bone from the spine or the skull when he’s under the same canopy with them.

Hilchos Nezirus 7:5

If a nazir touches one of the 12 types of impurity listed in halacha 7:2, or if he carries it, hovers over it, or it hovers over him, or if he and it were both under the same canopy, the nazir is rendered unclean. He must shave in impurity and bring the impurity offerings. All of his nezirus days are voided. This rule excludes rot, which doesn’t transmit impurity through touch because, not being a single entity, it’s impossible to touch it all at once. However, if he carried it or was under the same canopy with it, then he’s unclean and must shave.