Numbers 19:14-16

14“This is the law when a person dies in a tent: everyone who enters the tent and everyone who is already in the tent will be unclean for seven days,

15and any open container without a lid tied on it is unclean.

16Anyone in the open field who touches a person who has been killed by the sword or has died, or who even touches a human bone, or a grave, will be unclean for seven days.