I think the more likely reason is in case you start to drown in the bath.

There's a danger of carbon monoxide poisoning in the bathroom???

If you have a gas fired bath water heater in there, yes.

Not as common today as they once were but there are still plenty of them.

In the US? Perhaps in other countries, but in the US, I've never seen a water heater in a bathroom.

right - I live in the US nowadays and nobody has them - but back in the UK they're all over the place - stay at someone's house and there's a good chance they have one

I've never heard of such a thing, let alone actually seen one in a bathroom. I've lived in the UK for all (bar a couple of years) of my life.

[edit] I found an academic paper that discusses the safety of these heaters - dated 1973. I'd guess that they've gradually disappeared thanks to better heating systems and improved safety regulations. The paper: http://hej.sagepub.com/content/32/4/120.abstract

They are still alive and well in slum housing. I know several people who have gas heaters in the shared bathroom of their block of bedsits.

I have one and I live in the UK, so the definitely do exist. Of course, I may be unique.

You presumably have central heating in your house, and hot water? If so, you probably have a boiler. And this boiler probably runs on gas!

The comment was referring to "gas fired bath water heaters", which appears to be a specific type of heater fitted in bathrooms for heating the bath water…hence the potential for increased CO risk in the bathroom.

My hot-water + heating system is gas-fired, but the boiler is in a utility closet vented to the outside.

We have central heating but the boiler runs with a heat pump driven by electricity.

You are of course right in pointing out that central heating often goes along with central water heating and that heating is often based on fossil fuels such as gas.

All the people who had them died of CO poisoning.

In Poland quite common 'till very recently; I still have one (just reminded me to buy a CO detctor). My two friends actually got poisoned by CO - one when taking a bath, the other when trying to rescue her - because the landlord didn't bother to maintain ventilation properly.

I've had one blow up in Poland. Ul. Winklera, Poznan. I'll never forget that. My s.o. was about to use the (common for three apartments) bath and the thing blasted its outer cover clear across the room. She ran into the hallway totally forgetting her state of dress or lack thereof. The neighbours, alerted by the explosion that something was up, all piled into the hallway and sure appreciated the view.

Fortunately she was only scared but otherwise ok. Quite the bang, I've had a healthy respect for old Junckers products that have gas lines fed into them since.

Good that nothing happened to her except getting a bit scared.

Jacques, if you happen to come to Poland again, shoot me an e-mail, I'll buy you a beer :).

Deal :)

That might be quite soon actually. I'll be travelling to Krakow and on another trip I'll be going to Bialestok.

Great, I actually live in Kraków :).

Oh cool. You're Jacek right? I'll be there the 30th and the 31st of August (wedding).

My cell is + 31 6 30 366 241, I won't have email during those days. Send me a text please so I'll be able to reach you when I'm there.

Jacek, right :).

Let me continue this conversation via e-mail then.

Absolutely. Certainly not common, but I've seen a few in the desert.

Thanks for your explanation, I have never lived in a home with water heaters directly in the bathroom.

That is a very specific design for bathrooms. Modern houses tend to have a bathroom with strong ventilation that pushes air out from the house. As such, most bathrooms door tend to leave rather larger space at the bottom for air flow into the bathroom.

Every modern bathroom lock I've seen in the last decade or so can be opened from the outside with a coin. A quick Google suggests this is a legal requirement in public buildings, and simply a good idea in private homes.

I use Firefox, but it seems from the screenshots that Chrome has that minor barrier of clicking before they reveal the password.