iPad Air battery leaking?

The glass on my daughters Ipad Air was broken, so I took it off, and discovered that one of the two batteries had a couple of bulges, and one of them even had a little hole in the middle, with some oxidized zink or the like showing through.

Would it be unsafe to keep using this iPad (with a new glass installed ;-)?

I would have liked to ask Apple directly since it is a safety issue, but that doesn't seem possible...

It is 3 years old, but runs fine, and shows no problems otherwise with battery life etc.