Numbers 19:14-16

14‘This is the law when a person dies in a tent: everyone who comes into the tent and everyone who is in the tent will be unclean for seven days.

15And every open container, which has no cover tied down on it, will be unclean.

161Also, anyone who in the open field touches one who has been killed with a sword or one who has died naturally, or touches a human bone or a grave, will be unclean for seven days.