The Gemara (Baba Basra 58a) states that Rav Binuh set markings of graves so that people wouldn’t become tamei. The Gemara says he went to Me’aras HaMachpela to mark where the graves were. Some wish to use this passage in the Gemara as a source that tzaddikim convey tumah. Otherwise, why would Rav Binuh need to mark the graves at Me’aras HaMachpela?
However, the Minchas Elazar (3:64) says we cannot deduce anything from this passage because the Gemara elsewhere (Sotah 13) says that Chushim, the son of Dan, decapitated Eisav, whose head rolled into Me’aras HaMachpela. Since Eisav was a Jew (Kiddushin 18a), he conveys tumah and it was perhaps due to the presence of Eisav’s head in Me’aras HaMachpela that necessitated Rav Binuh marking Me’aras HaMachpela.