The following is a partial list of poskim who Asur smoking,
[sources were posted already at http://www.theyeshivaworld.com/coffeeroom/topic/smoking-why-should-it-be-muttar
R’ Ahron Kotler,
R’ Yaakov Kaminetsky,
R’ Elyashiv,
R’ Chaim Kanievsky,
R’ Dovid Feinstein,
the Be’er Moshe,
the Tzitz Eliezer,
R’ Moshe Shternbuch,
R’ Osher Veis,
the Rivvos Ephraim,
R’ Nissim Karelitz,
R’ Ovadia Yosef,
R’ Bentzion Aba Shaul,
R’ Shlomo Zalman Aurbach
and Rav Shmuel Aurbach
among many others.
You cannot do any act that allows or encourages a Sakana, even if the other person thinks it’s Mutar. In fact, one is obligated to be Mechalel Shabbos to save someone from danger, even if it’s against that persons will, and even if the risk is only small, and even if it’s only a long term risk!
In reality what this Baal Hamachsir is (unintentionally) doing is helping cause families of Almanos and Yesomim. And he’d never even know who.