249. Foul Odors
Kriyas Shema 3:11
If there is excrement in a hole in the ground, one may stand with his shoe over the hole and recite Shema provided that his shoe doesn’t touch the excrement. If there is some very small excrement, the size of a drop, one may spit thick saliva to cover it and then recite Shema. Let’s say that one has the residue of excrement on his skin or his hands are dirty from using the restroom. If there is no foul smell, either because of the tiny quantity or because it has dried, then one may recite Shema. If it is still in its place, he may not recite Shema until he cleans himself thoroughly. This is because it is moist, has a foul odor, and is visible when he sits. Many Geonim ruled that a person may not recite Shema with dirty hands; it is appropriate to follow their ruling.
Kriyas Shema 3:12
If a foul odor is coming from some object, one may distance himself four cubits (about six feet) from that object and recite Shema, so long as he can no longer smell it. If he can still smell it, he must continue moving away until that is no longer the case. If a foul smell is not coming from an actual object, such as if someone broke wind, then one should distance himself until he can no longer smell it, then he may recite Shema. One may not recite Shema next to a cesspool or chamber pot even if it is empty and has no foul odor. This is because it is the same as a restroom.