7 Bible Verses about Contamination

"When a person has touched a ceremonially unclean thing inadvertently, such as the carcass of an unclean animal, or some unclean creeping thing, he will be unclean and guilty nevertheless.

"Anyone whom the one with the discharge touches without rinsing his hands with water is to wash his clothes and bathe with water, and he will remain unclean until evening.

Anyone who comes in contact with a dead person (that is, with the corpse of a human being who has died), but who does not purify himself, defiles the LORD's tent. That person is to be eliminated from Israel, because the water of impurity wasn't sprinkled on him. He remains unclean and his uncleanness will remain with him.

"Depart! Depart! Go out from there; touch no unclean thing; go out from the midst of her; purify yourselves, you who carry the vessels of the LORD.

The LORD spoke to Moses and Aaron: "When you enter the land of Canaan that I'm about to give you as your own possession, and if I put a contagion in a house in the land that you possess, then the owner of the house is to approach the priest and tell him, "There appears to be a contagion in the house.'read more.
"The priest is to command that the house be cleared before he comes to examine the contagion so that not everything in the house becomes unclean. After this, the priest is to enter the house and examine it. He is to determine if the contagion is indeed on the walls of the house, with greenish or reddish streaks, and to determine if it appears to be deeper than the surface of the wall. The priest is to leave through the entrance to the house and seal the house for seven days. He is to return after seven days to examine it. If the contagion has spread to the walls of the house, then the priest is to command that they take out the contaminated stones and discard them in an unclean place outside the city. "Now as for the house, they are to scrape off inside and outside the house and then discard the torn out plaster in an unclean place outside the city. They are then to take other stones and bring them to replace those stones. Lastly, they are to replaster the house." "If the contagion returns and spreads throughout the house after the stones have been removed, after the house has been scraped out, and after it has been re-coated, and the priest comes, undertakes an examination, and determines that the contagion has spread in the house, it's a chronic fungal infection in the house. It's unclean. He is to pull down the house, its stones, its lumber, and all the plaster on the house, and discard them in an unclean place outside the city. Moreover, whoever enters the house during the time it was isolated is to be considered unclean until the evening. Whoever has slept in the house is to wash his clothes, along with whoever has eaten in the house.

The LORD told Moses, "Command the Israelis to send outside the encampment every leper, everyone who has a discharge, and whoever is ritually defiled by contact with a corpse. Whether male or female, send them outside the camp so that they won't defile their camp, because I live among them." read more.
So the Israelis sent them outside the camp. The Israelis did just what the LORD had told Moses.

Instead, we should write to them to keep away from things polluted by idols, from sexual immorality, from anything strangled, and from blood.