Gas water heater in basement vents into chimney. See pic. #1.
In the fireplace above, no damper is provided and flue is 95% sealed with what appeared to be asbestos containing material.
In the fireplace above, vented gas logs are installed and are regularly used per the owner (also my client).
One to two feet below the gas logs, you can see the exhaust flue for the water heater.
Amazing. She had nothing nice to say about her ex-husband when I informed her of these issues (he did all this). She said, “we always got sleepy in this room when we ran the gas logs”. :shock: