Leviticus 5:2-3, 6-7, 18-19

‘Or if a person touches any unclean thing, whether it is the carcass of an unclean beast, or the carcass of unclean livestock, or the carcass of unclean creeping things, and he is unaware of it, he also shall be unclean and guilty. Or if he touches human uncleanness—whatever uncleanness with which a man may be defiled, and he is unaware of it—when he realizes it, then he shall be guilty.

and he shall bring his trespass offering to the LORD for his sin which he has committed, a female from the flock, a lamb or a kid of the goats as a sin offering. So the priest shall make atonement for him concerning his sin. ‘If he is not able to bring a lamb, then he shall bring to the LORD, for his trespass which he has committed, two turtledoves or two young pigeons: one as a sin offering and the other as a burnt offering.

And he shall bring to the priest a ram without blemish from the flock, with your valuation, as a trespass offering. So the priest shall make atonement for him regarding his ignorance in which he erred and did not know it, and it shall be forgiven him. It is a trespass offering; he has certainly trespassed against the LORD.”