Trespass offering: To be offered for Involuntarily Touching Unclean Things
Source: TTT
Leviticus 5:2, 3
Or if a person touches anything unclean—whether the carcass of any unclean wild animal or livestock or crawling creature—even if he is unaware of it, he is unclean and guilty. / Or if he touches human uncleanness—anything by which one becomes unclean—even if he is unaware of it, when he realizes it, he is guilty.