What king of piping?

[Eli Smith]

Duplex 1954, can you help me by telling me what kind of pipe is this?
Crazy to think it could be an underground oil tank in the basement even though they usually are located outside?
Thank you.

[John Dirks Jr]

It might be an abandoned galvanized water supply line. They tend to corrode from the inside cutting the supply volume. Many times, they get abandoned when an new supply line is installed.

[Erby Crofutt]

From the pictures, I'd guess a galvanized water supply line that's been abandoned, like this one.

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[Garry Blankenship]

Definitely threaded, it's rigid steel and most likely galvanized. I've seen what I knew to be called "black iron" pipe used for indoor systems like sprinklers or gas, but never in the ground. So I'm all in w/ my predessors on galvanized steel - - - final answer.

[Eli Smith]

Thanks to everyone.