Was asked in last session about the situation where the player who is an alchemist/Eldritch poisoner is using a Toxic Censure. His question/potition was does Poison Use mean he is unaffected by the poisonous fumes from the censure. My inclination is no, while the poison use will protect him from being poisoned by putting the poison in the censure, the fumes are still poisonous and he is equally effected by them as is anyone within range.
Thoughts?
The poison use class feature doesn't protect you from a toxic censure while it's lit, regardless if you or someone else is carrying it.
The only thing poison use does is prevent the 5% chance that exists to poison yourself when attempting to apply poison to something.
Applying poison to a weapon or single piece of ammunition is a standard action. Whenever you apply or ready a poison for use, there is a 5% chance that you expose yourself to the poison and must save against the poison as normal. This does not consume the dose of poison. Whenever you attack with a poisoned weapon, if the attack roll results in a natural 1, you expose yourself to the poison. This poison is consumed when the weapon strikes a creature or is touched by the wielder. If you have the poison use class feature (such as from the assassin prestige class or the alchemist base class), you do not risk accidentally poisoning yourself when applying poison.
Note that having the Poison Use class feature technically doesn't even stop you from poisoning yourself if you roll a 1 on an attack roll (though I imagine many DMs run it this way).