Hello all,
I am considering exploring some abandoned steam tunnels that I suspect run underneath my town. My town was heated by a central steam tower that was abandoned around the 20s or 30s maybe. I have explored this steam tower, and it's amazing. Near the tower, in the woods, there is a manhole cover that says "Steam" on it and it is clear to see the path of where the pipes used to go. I cannot find any access to the steam tunnels from the tower and I have really searched that place. It looks like the steam pipes ran above ground for maybe 200 feet before disappearing into a hill. It is possible that it was inside a covered area, but I cannot find remains of such a covering. I would like to pop the manhole cover off and go down there. I cannot be sure of anything that I will find. My questions are:
Would I need to be worried about hydrogen sulfide or other bad air?
Would I need to be worried about animals inhabiting the tunnels and if so should I bring a weapon?
Any other dangers?

Thanks a lot,
ryan5685

This is really interesting! I hope you do find them.

The sorts of hazards you'll encounter depend on how well holed up the tunnels have been. Animals could be a concern if there is an easy way for them to burrow in and out - but they will likely be only near the exits, and not if it's only ladders and manholes to get in.

Animals are only a risk when you are threatening their babies - make noise when you're going in, so that they'll either a) retreat, and you have no problem; or b) get up in your face to warn you not to touch their babies, which warns you before you get cornered. Bringing a weapon is usually not necessary.

The risk of bad air depends on how much air circulation it gets, and how wet it is. Active tunnels tend to be very dry - abandoned ones vary depending on depth and geology of the area. I recommend going in with a respirator regardless - and definitely don't go alone.

What city?

Cincinnati, OH

Oh my. Hope you have a bag of kryptonite.

Posted by blackhawk Oh my. Hope you have a bag of kryptonite.

Why?

Posted by The Viscount Andrew Dalton This is really interesting! I hope you do find them. The sorts of hazards you'll encounter depend on how well holed up the tunnels have been. Animals could be a concern if there is an easy way for them to burrow in and out - but they will likely be only near the exits, and not if it's only ladders and manholes to get in. Animals are only a risk when you are threatening their babies - make noise when you're going in, so that they'll either a) retreat, and you have no problem; or b) get up in your face to warn you not to touch their babies, which warns you before you get cornered. Bringing a weapon is usually not necessary. The risk of bad air depends on how much air circulation it gets, and how wet it is. Active tunnels tend to be very dry - abandoned ones vary depending on depth and geology of the area. I recommend going in with a respirator regardless - and definitely don't go alone.

I'd recommend a respirator regardless in an old tunnel like that, especially one with pipes. They used to wrap steam pipes in asbestos.

That said, first sign I came across any I'd either bail completely, or go back to a safe point and throw on a tyvek suit.

+1 on the bad air comment.

You might also run across homeless folks. Depending on the city, some of them have huge populations living in tunnels under them. Really common in the older cities.

Pop the manhole cover and do it! Don't spend the rest of your life regretting that you pussied out. Man-up, beeyotch.

Use exsteam caution.

Posted by DarkAngel I'd recommend a respirator regardless in an old tunnel like that, especially one with pipes. They used to wrap steam pipes in asbestos.

Don't get a false sense of security though; a respirator will not save you from toxic gasses or a simple lack of oxygen. The thing that scares me has always been low oxygen levels; elevated Co2 from our own respiration, not lack of oxygen, is what actually makes us feel short of breath and realize we need air, so if there is no elevated Co2 & simply not enough oxygen in a tunnel, you can just suddenly pass out without ever knowing what happened. And if you're alone you die.

Just something to keep in mind.

But in all honesty, I would love to see pics if you find anything down there, even if it's not that interesting! Just be careful, abandoned tunnels are not something to always take lightly

Posted by LuminousAphid Don't get a false sense of security though; a respirator will not save you from toxic gasses or a simple lack of oxygen. The thing that scares me has always been low oxygen levels; elevated Co2 from our own respiration, not lack of oxygen, is what actually makes us feel short of breath and realize we need air, so if there is no elevated Co2 & simply not enough oxygen in a tunnel, you can just suddenly pass out without ever knowing what happened. And if you're alone you die. Just something to keep in mind. But in all honesty, I would love to see pics if you find anything down there, even if it's not that interesting! Just be careful, abandoned tunnels are not something to always take lightly

This. If there isn't fresh air, the best filter in the world won't save you. If a tunnel/cave has been sealed up for years, I'd definitely bring a gas detector and see about getting it aired out first.

That said, if I were in ANY way thinking there was the possibility of heavy gasses or anything off gassing, I'd be skipping the explore. A lot of the stuff that can kill you insanely fast, you can't smell once it hits that ppm. But after hazmat classes, I'm paranoid as fuck around anything that could have hydrogen sulfide, ammonia, etc.

I'll stick to stuff where I don't have to worry about that lol