It’s not like your average dungeon or lich cave has OSHA approved vents, fans or electric lighting. Your average party, without specific magical aid, is burning torches and lanterns in unventilated spaces.
ETA: if you’re going to run carbon monoxide, etc rules, your supply shops should stock and recommend caged canaries to anyone buying large quantities of torches and lamp oil, dungeoneering/mining gear, etc. People would know about it and have figured out a primitive solution that merchants would be happy to capitalize on if this is an in-world issue.
People don’t realize how dangerous the air in confined underground spaces can be
How would you deal with this in 5e? From spells I’m seeing you’ve really only got water breathing and air bubble from spell jammer. It’s a pretty classic dnd trope so I’m surprised there’s no solution.
The Necklace of Adaptation is probably the best option. It’s an uncommon magical item from the DMG that requires attunement.
While wearing this necklace, you can breathe normally in any environment, and you have advantage on saving throws made against harmful gases and vapors (such as cloudkill and stinking cloud effects, inhaled poisons, and the breath weapons of some dragons).
Poison immunity (monk), not breathing (various races), blasting open the entrances to increase ventilation
Tortle Monk - immune to poison, ac17 at first level, and can hold breath over an hour.
Poison immunity wouldn’t help, at best it would prevent the panic feeling and hallucinations caused by breathing in CO, but the lack of oxygen would still kill you.
In Pathfinder, Air Bubble and Life Bubble would be the best choices.
Gust of Wind would probably work well too, at least for a good chunk of the dungeon. 60ft long 10ft wide for 1m. That’s going to be a lot of airflow. It depends on if there’s a constant source of carbon monoxide or if it’s a limited amount that can be cleared eventually.
Science, lich!
Life bubble not a spell in DnD?
Not in 5e; it dumbs down a lot of it’s spells/casting.
If a DM pulled this and was really hard nosed, I would be pulling out my 3.5e books. All the really good planar/space stuff belongs to this gen.
Ah yeah. Too used to pathfinder/3.5, so this would be an annoyance but as long as prep life bubble or have an oracle you’re fine lol. Not a spell that comes up a TON unless you’re going underground pretty deep.
“It’s okay, I brought a Bag of Holding full of air with me. Now I’ll just put it on my head, and…”
Blind, works for ten minutes.
