I'm on my 2nd of this iron. I don't know about carbon monoxide because I don't have one of those sensors either. Maybe those sensors are available from Home Depot. I'm not worrying and I'm not going to stop using mine, but I do know they go bad. Always unplug this iron when you leave it. I thought I turned my first one off with the heat control, only to find it still warm two weeks later after not using it. I have it attached to a power strip that also has a small Ott light attached. When the light is on, the iron is on, so I have a big reminder.
My 1st one just quit heating after several years. Oh well, they're a helluva lot cheaper that other leaky irons, the brand of which we shant mention.
I really like using this iron.
For steam, I have a very inexpensive T-Fal with a Teflon sole plate that works just fine. I use a press cloth if I need more steam.