Need more information on where the gas line is located. Does it just pass through the masonry part going to a different part of the house or is it actually inside the firebox/flue area? And I am assuming it is a masonry chimney and not a prefab metal unit. The only reason I could think of a gas line being inside a wood burning fireplace is if there was a gas log conversion sometime in the past.

Pictures would be helpful if you have access to the house.

The fireplace was originally a wood burning fireplace. There are now gas logs inside. I would like to convert it back to a wood burning, however. So I don't know what this gas line is for. It's an estate sale. The children say that it's for lighting the fire.
I guess we will have to ask the inspector. He did not write anything about this in his report, but he's the "deal breaker" inspector and cost us 1500, so he caught everything else. This leads me to believe that it really is supposed to be there??

THe inspector recommended we get the AC inspected and the AC guy is the one that noticed it in the attic running through the chimney.

A photo would make a lot of this much more clear to us.

It's not strange to have a gas liine in the fireplace in order to light wood logs.

but what you're saying and I'm imagining is a gas line that runs up the fireplace into the chimney and out the top and running over the roof. that would be strange.