[Avodah] Hevel and bor

[Moshe Y. Gluck]

R' MB (B'sheim his father):
> According to the gemara, eg BK 50b-51a, a bor that is 10 tefachim deep
> or more contains hevel which is dangerous to breathe. And even if it's
> less than 10 tefachim, the air is still injurious.
> 
> My father was surprised that he couldn't find any rishonim or acharonim
> who compare this to the experimental data. Not whether to dismiss it or
> explain how it works -- no one seems to think it's intriguing and worth
> discussion?!


I'm afraid I don't have a Mareh Makom, but one of my High School Rebbeim
told us that (IIRC) R' Elchanan Wasserman said, "I'm learning Bava Kama for
_____ years, and I still don't understand what Havla is!"

KT,
MYG