Q. My son’s class is planning to spend Shabbos in Northern Israel (in the Golan) in the town of Nov. It is a nice place, where most of the best Hadassim in Israel are grown.

I was once there and due to the enormous cow farms they have there (a great deal of Israel’s milk is produced there as well) there is an ever-present odour of cow manure. The odour is so strong that it permeates everywhere. The only place that is free of the smell is in the town schul (they must have a terrific air filtration system).

When I asked how people make Brachos elsewhere in town, I was told that a Heter exists somewhere for someone who is used to the smell. Does the Rav know a source for this Heter?

If such a Heter exists, how much time qualifies for getting used to the smell, because my son’s class will arrive on Friday, and unless they will be spending every waking moment in schul, I cannot imagine how they will be able to bentch or hear Kiddush.

A. Mishna Berura (79: 28) and Biur Halacha (ibid.) quoting Chaye Adam, rule that you are not allowed to recite brochos in a refes bokor or animal barn that has a bad smell due to animal excretions.
Mishna Berura (85: 7) prohibits even for a person that can’t smell. See similar in Vehaya  Machanecha Kadosh (2:2:2); that even if the bad smell does not particularly bother someone, since he is used to it, it is prohibited. (Piskei Teshuvos (79:1).
However, Shvilei Dovid (76: end) is lenient for one that cannot smell or has become used to it, as long as the waste material is not human.
It stands to reason that every individual has his own particular adaptation time period for different smells.
Horav Shlomo Miller suggested that in your case, the visitors should bring with them a can of spray air-freshener or odor eliminating product, and spray the area before reciting a brocho. (See similar in Maharsham 2: 38, Minchas Yitzchoh 8: 9, Shevet Halevi 3: 17, Piskei Teshuvos 79:2). Those spray cans could be used also on Shabbos (Igrois Moshe quoted in 39 Melochos 2: p. 377).

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a